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Walking one hour or more per day prevented mortality among older persons: Results from ilSIRENTE study
Preventive Medicine 47 (2008) 422–426
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Preventive Medicine j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / y p m e d
Walking one hour or more per day prevented mortality among older persons: Results from ilSIRENTE study Francesco Landi a,⁎, Andrea Russo a, Matteo Cesari b, Marco Pahor b,c, Rosa Liperoti a, Paola Danese a, Roberto Bernabei a, Graziano Onder a a b c
Department of Gerontology, Geriatrics and Physiatry, Catholic University of Sacred Heart, Roma, Italy Department of Aging and Geriatric Research, University of Florida – College of Medicine, Gainesville, FL, USA Geriatric Research, Education and Clinical Center (GRECC), Malcom Randall Veteran's Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
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Article history: Available online 11 July 2008 Keywords: Walking activity Mortality Frail elderly
a b s t r a c t Objective. Maintaining or increasing physical activity in late-middle age has been shown to be associated with a reduction in mortality. The aim of the present study was to explore the relationship between regular walking and the risk of all-cause death in a large population of frail and very old people living in community. Methods. We analyzed data from the Aging and Longevity Study in the Sirente Geographic Area (ilSIRENTE study), a prospective cohort study that collected data on all subjects aged 80 year and older living in a mountain community. Baseline assessments of participants started in December 2003 and were completed in September 2004. All subjects were followed-up for 24 months. To the purpose of this study we selected all subjects without impairment in the activities of daily living (n = 248). The main outcome measure was the relative hazard ratio of death over two years of follow-up for different levels of walking activity. Results. During a mean follow-up time of 24 months from baseline assessment, 30 subjects (12%) died. There was an uneven distribution of the risk. After adjusting for age, gender and other possible risk factors of death (functional and cognitive disability, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and reactive C protein) subjects walking 1 h or more per day were less likely to die compared to participants walking less than 1 h per day (RR, 0.36; 95% CI 0.12–0.98). Conclusions. Our results obtained from a representative sample of very old and frail elderly subjects expand the knowledge that high levels of walking activity are associated with better survival. © 2008 Published by Elsevier Inc.
Introduction Locomotion is a key feature of human functioning (Cress et al., 1999). Exercise capacity and physical activity are associated with low all-cause mortality and with low morbidity and mortality for cardiovascular diseases (Cohen-Mansfield et al., 2004; Landi et al., 2007; Wannamethee et al., 2000). Exercise may be beneficial to many morbid conditions that underlie disability, including falls (Gardner et al 2000; Tinetti et al., 1994), hip fracture (Feskanich et al., 2002), respiratory diseases (Mador et al., 2004), cancer (Holmes et al., 2005), diabetes (Manson et al., 1991), osteoporosis (Abell et al., 2005) and obesity (Littman et al., 2005). However, the contribution of moderateintensity physical activity, such as regular brisk walking, to reducing coronary events and mortality is still unclear. In fact, although some authors have demonstrated that only participation in vigorous physical activity and/or high-intensity exercise programs are asso-
⁎ Corresponding author. Centro Medicina dell'Invecchiamento (CEMI) Istituto di Medicina Interna e Geriatria Universita' Cattolica del Sacro Cuore Largo Agostino Gemelli, 800168 Rome, Italy. Fax: +39 06 3051911. E-mail address: [email protected] (F. Landi). 0091-7435/$ – see front matter © 2008 Published by Elsevier Inc. doi:10.1016/j.ypmed.2008.06.020
ciated with reductions in mortality (Lee et al., 1995), others have extended these benefits to moderate activities (Slattery et al., 1989). Maintaining or increasing physical activity in late-middle age has been shown to be associated with a reduction in mortality (Landi et al., 2007; Talbot et al., 2007). However, few studies explored the effects of regular walking across a broad spectrum of ages. In fact, most of the physical activity intervention studies focused on young-adult population (Lan et al., 2006). To date, the best level of physical activity associated with health benefits among older people has not been identified. The aim of the present study is to explore the relationship between regular walking and the risk of all-cause death in a large population of very old people living in community. Methods The ilSIRENTE study is a prospective cohort study performed in the mountain community living in the Sirente geographic area (L'Aquila, Abruzzo) in the Central Italy. This study was designed by the Department of Gerontology, Geriatrics, and Physiatric Medicine of the Catholic University of Sacred Heart (Rome, Italy) and developed by the teaching nursing home, Opera Santa Maria della Pace (Fontecchio,
F. Landi et al. / Preventive Medicine 47 (2008) 422–426
L'Aquila, Italy) in partnership with local administrators and primary care physicians of Sirente Mountain Community Municipalities. The Catholic University of Sacred Heart ethical committee ratified the entire study protocol. All the participants signed an informed consent at the baseline visit. Details of the ilSIRENTE study protocol are described in details elsewhere (Landi et al., 2005). Study population A preliminary list of all persons living in this well defined area was obtained at the end of October 2003 from the Registry Offices of the 13 municipalities involved in the study. From this preliminary list, potential study participants were identified by selecting all persons born in the Sirente area before 1st January 1924 and actually living in such area. As a result, the overall sample population enrolled in the ilSIRENTE study consisted of 364 subjects. For the purpose of this study we selected all subjects without impairment in the activities of daily living (MDS-ADL = 0). The score “0” in the MDS-ADL scale means that the subject was completely independent in the following daily activities: dressing, eating, toilet use, bathing, mobility in bed, locomotion, and transfer. This was done to select subjects able to walk outside their homes. Consequently, we excluded 116 subjects with an MDS-ADL score at the baseline assessment equal or more than 1. Therefore, the final sample for present study consisted of 248 subjects. Data collection Baseline assessments of participants started in December 2003 and were completed in September 2004. Assessors were trained on how to perform each component of the ilSIRENTE study protocol (Landi et al., 1996). The Minimum Data Set for Home Care (MDS-HC) form was administered to all study participants following the guidelines published in the MDS-HC manual (Morris et al., 1996). The MDS-HC contains over 350 data elements including socio-demographics, physical and cognitive status variables, as well as major clinical diagnoses (Morris et al., 1997). Moreover, the MDS-HC also includes information about an extensive array of signs, symptoms, syndromes, and treatments (Morris et al., 1997). The MDS items have shown an excellent inter-rater and test–retest reliability when completed by nurses performing usual assessment duties (average weighted Kappa = 0.8) (Landi et al., 2000). Additional information about family history, lifestyle, physical activity and behavioral factors were collected using specific questionnaires from the “Invecchiare in Chianti Study” (Ferrucci et al., 2000). Functional and cognitive status measures Basic activities of daily living were assessed using the MDS-HC instrument (Landi et al., 2000). The ADL scale is based on seven levels of self-performance including dressing, eating, toilet use, bathing, mobility in bed, locomotion, transfer. Similarly, the IADL scale is based on seven levels of self-performance, including meal preparation, housework, managing finance, phone use, shopping, transport and managing medications. Cognitive performance was assessed using a six-item, seven-category scale (Cognitive Performance Scale-CPS) (Morris et al., 1994). The CPS was scored on a 7-point ordinal scale in which higher scores were associated with worse cognitive performance. The CPS includes two cognitive items (short-term memory, skills for daily decision making), one item describing communication ability (understood by others), one ADL measure (self-performance in eating), and one item indicating the presence of comatose status. Walking assessment Walking intensity information was obtained using a single and “easy” question: “How many minutes do you walk each day?”. The
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possible answers were: 1—never or less than 30 min; 2—30 min; 3—1 h; 4—more than 1 h. This item was the same as that used in the inCHIANTI study form (Ferrucci et al., 2000). For analytic purpose, participants were categorized into non walkers or very light walkers (those walking less than 1 h each day; score 1 or 2) and moderate or intense walkers (those walking 1 h or more each day; score 3 or 4). The reliability and validity of this walking activity assessment has not been established. Blood measurements Venus blood samples were drawn in the morning after an overnight fast. The samples were immediately centrifuged and stored at −80 °C until final analysis. Standard determinations of serum albumin, cholesterol (HDL and LDL), and triglycerides were performed by commercially available kits (Olympus, Italy) suitable on Olympus 2700 instrumentation. Covariates Medical diagnoses and drugs were directly collected by general practitioners. Medical diagnoses were defined as those conditions that have an impact on the patients' functional, cognitive, and behavioral status, medical treatment and risk of death. The diagnoses were listed on the MDS-HC form in a check-box section containing 27 specific diagnostic categories. General practitioner collected information on up to 18 different drugs received by each patient in the 7 days preceding the assessment. Drugs were coded using the Anatomical Therapeutic and Chemical (ATC) codes. Body weight was measured with light clothes using a calibrated bathroom scale. Body height was measured using a standard stadiometer. Body mass index (BMI) was defined as weight (kilograms) divided by the square of height (meters). Alcohol consumption was assessed asking participants about the number of glasses of wine they used to drink during a standard day. Alcohol abuse was defined as a consumption of more than half of liter of wine per day. Smoking status was assessed asking participants about the number of cigarettes they currently smoked or they had smoked in the past. Survival status Vital status was obtained from general practitioners and confirmed by the National Death Registry. Time to death was calculated from the date of baseline assessment to the date of death. All subjects were followed-up for 24 months. Statistical analysis Data were analyzed to obtain descriptive statistics. Continuous variables are presented as mean values ± standard deviation. We evaluated trends of sociodemographic variables and indicators of disease severity using the Fisher exact test. Differences between continuous variables were assessed by ANOVA comparisons for normally distributed parameters; otherwise, the Kruskal–Wallis test was adopted. A level of p b 0.05 was chosen for statistical significance. Time to death was calculated from the date of baseline assessment to the date of death. We examined all events occurred during a followup of 24 months. Cox proportional hazard models, adjusted for age, gender, baseline comorbidities (congestive heart failure, hypertension, osteoarthritis, depression, number of medications), body mass index, cholesterol, reactive C protein level, functional capacity (as measured by MDS-IADL score) and cognitive impairment (as measured by MDSCPS score) were used to estimate the relative risk of death. Hazard rate ratios (RRs) and corresponding 95% confidence intervals (95% CIs) were derived from the final models. The impact of walking 1 h or more per day on survival was also tested comparing the survival curves
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obtained with the Kaplan–Meier method. Differences between curves were evaluated using the log-rank test. Statistical analysis was performed using the SPSS 10.0 package (Chicago, Illinois).
Table 2 Characteristics of study population according to death (2-year follow-up), in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 Characteristics
Dead (n = 30)
Alive (n = 218)
p
Results
Age, years Gender Women Men Living alone Marital status Married Widowed Never married Education, years Cognitive performance scale score IADL scale score Sensory impairment Hearing Vision Body mass index, kg/m2 Alcohol abuse Smoking habit Diseases Ischemic heart disease Congestive heart failure Hypertension Stroke Peripheral vascular disease Diabetes Chronic obstructive pulmonary disease Parkinson's disease Cancer Osteoarthritis Depression Number of medications Hematological parameters Albumin, g/dl Cholesterol, mg/dl Triglycerides, mg/dl C reactive protein, mg/dl
87.3 ± 5.6
84.4 ± 3.9
b0.001
21 (66) 9 (34) 11 (36)
145 (70) 73 (30) 83 (38)
0.43
5 (17) 22 (73) 3 (10) 5.1 ± 0.5 0.6 ± 1.0 2.7 ± 2.0
69 (31) 126 (58) 23 (11) 5.2 ± 1.9 0.3 ± 0.7 1.3 ± 1.6
0.21
0.71 0.06 0.001
9 (30) 4 (13) 24.6 ± 4.6 3 (10) 2 (6)
33 (15) 41 (18) 26.3 ± 4.1 28 (13) 6 (3)
0.04 0.32 0.03 0.65 0.25
5 (16) 4 (13) 23 (76) 1 (3) 2 (7) 9 (30) 4 (13) 1 (0) 2 (7) 6 (20) 7 (23) 3.8 ± 2.7
24 (11) 6 (3) 167 (76) 3 (1) 8 (4) 50 (23) 24 (11) 2 (1) 7 (3) 43 (20) 46 (21) 2.9 ± 1.9
0.36 b0.001 0.99 0.42 0.43 0.39 0.70 0.59 0.34 0.97 0.78 0.02
4.1 ± 0.3 180.1 ± 42.2 135.1 ± 68.2 4.9 ± 3.1
4.2 ± 0.2 205.7 ± 44.9 148.2 ± 62.1 3.2 ± 2.7
Mean age of 248 subjects participating in the study was 85.9 (standard deviation 4.9) years, and 166 (67.0%) were women. Characteristics of the study population according to the different levels of walking are summarized in Table 1. Compared to participants walking less than 1 h per day, those walking 1 h or more per day were younger (85.4 ± 4.5 year versus 84.4 ± 4.3, p = 0.09), less likely to be depressed and had a lower prevalence of cognitive impairment, congestive heart failure, hypertension and osteoarthritis. The mean number of drugs was higher among subjects less active compared with subjects walking 1 h or more per day (3.6 ± 2.3 versus 2.7 ± 1.8, respectively). In particular, more participants among the non walkers or very light walkers received digoxin (23/83, 27% versus 17/165, 10%, p = 0.001) and furosemide (22/83, 26% versus 11/165, 7%, p b 0.001), compared to moderate or intense walkers. The proportion of walkers for 1 h or more was significantly higher for males than females (78% and 60%, respectively; p = 0.05). We also evaluated the baseline
Table 1 Characteristics of study population according to the number of hours walked per day, in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 Characteristics
Age, years Gender Women Men Living alone Marital status Married Widowed Never married Education, years Cognitive performance scale score IADL scale score Sensory impairment Hearing Vision Body mass index, kg/m2 Alcohol abuse Smoking habit Diseases Ischemic heart disease Congestive heart failure Hypertension Stroke Peripheral vascular disease Diabetes Chronic obstructive pulmonary disease Parkinson's disease Cancer Osteoarthritis Depression Number of medications Hematological parameters Albumin, g/dl Cholesterol, mg/dl Triglycerides, mg/dl C reactive protein, mg/dl
Walking level, h/day
p
b1 h/day (n = 83)
N 1 h/day (n = 165)
85.4 ± 4.5
84.4 ± 4.3
0.09
65 (78) 18 (22) 27 (33)
101 (61) 64 (39) 67 (42)
0.05
26 (32) 46 (55) 12 (13) 4.9 ± 1.3 0.5 ± 1.0 2.6 ± 2.1
48 (30) 102 (61) 15 (9) 5.3 ± 2.0 0.2 ± 0.6 1.5 ± 1.4
0.08 0.04 0.01
18 (21) 19 (23) 26.0 ± 4.8 12 (14) 2 (2)
24 (14) 26 (16) 26.2 ± 3.9 19 (12) 6 (4)
0.10 0.11 0.77 0.8 0.4
11 (13) 9 (11) 69 (83) 3 (4) 4 (5) 16 (19) 11 (19) 1 (1) 3 (4) 24 (29) 30 (36) 3.6 ± 2.3
18 (11) 1 (1) 121 (73) 1 (1) 6 (5) 43 (26) 17 (10) 2 (1) 6 (4) 25 (15) 25 (14) 2.7 ± 1.8
0.36 b0.001 0.05 0.11 0.61 0.15 0.31 0.55 0.64 b0.01 b0.001 b0.01
4.2 ± 0.3 208.3 ± 51.3 153.9 ± 68.6 3.5 ± 3.4
4.2 ± 0.3 190.6 ± 41.8 142.9 ± 59.6 3.3 ± 2.5
0.11 0.50
0.72 0.16 0.19 0.51
Data are given as number (percent) for the following variables: gender, living alone, marital status, sensory impairment, alcohol abuse, smoking habit, diseases; for all the other variables means ± SD are reported. Cognitive performance scale score: range 0–6, a higher number indicates higher impairment. IADL (Instrumental Activity of Daily Living) score: range 0–7, a higher number indicates higher impairment.
0.46
0.13 0.004 0.28 0.002
Data are given as number (percent) for the following variables: gender, living alone, marital status, sensory impairment, alcohol abuse, smoking habit, diseases; for all the other variables means ± SD are reported. Cognitive performance scale score: range 0–6, a higher number indicates higher impairment. IADL (Instrumental Activity of Daily Living) score: range 0–7, a higher number indicates higher impairment.
characteristics of the sample according to the vital status to identify potential risk factors for death (Table 2). During a mean follow-up of 24 months, 30 subjects (12%) died. There was an uneven distribution of the risk (Table 2). Twelve subjects died among the physically active group compared to 18 subjects among the sedentary group (RR, 0.28; 95% CI 0.12–0.62). After adjusting for age, gender and other potential confounders (functional and cognitive disability as expressed by IADL and CPS scores, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and reactive C protein), physically active subjects (walking 1 h or more per day) were less likely to die compared to participants walking less than 1 h per day (RR, 0.36; 95% CI 0.12–0.98) (Table 3, model 1). The addition to the model of variables for digoxin and furosemide use in place of a variable indicating the overall number of medications taken did not change the estimate of risk (RR, 0.37; 95% CI 0.11–1.01). Additional analyses using different categorization for walking were performed to further investigate the protective effect of regular walking on mortality. As shown in Table 3 (model 2), the lowest risk of death was observed among participants involved in walking activity for 1 h or more per day. Considering the small number of death observed, the significant difference in the prevalence of congestive heart failure between the two groups could have influenced study results. For this reason we repeated the analysis after excluding those subjects with congestive
F. Landi et al. / Preventive Medicine 47 (2008) 422–426 Table 3 Crude and adjusted relative risks (RRs) of mortality in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 and after 24 months Dead (n = 30)
Alive (n = 218)
Crude Model RR (95% CI)
Adjusted Modela RR (95% CI)
Model 1 Sedentary Active
18 12
65 153
1.0 (Referent) 0.28 (0.12–0.62)
1.0 (Referent) 0.36 (0.12–0.98)
Model 2 No walkers Walkers for 30 min Walkers for 1 h Walkers for more than 1 h
5 13 10 2
10 55 104 49
1.0 0.47 0.19 0.08
1.0 (Referent) 0.33 (0.07–1.57) 0.16 (0.04–0.79) 0.11 (0.02–0.95)
(Referent) (0.13–1.62) (0.05–0.67) (0.01–0.48)
Sedentary: subjects walking less than 1 h per day; Active: subjects walking 1 h or more per day. a Adjusted for age, gender and for other possible risk factors for death (functional and cognitive disability, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and C reactive protein).
heart failure. Again, physically active subjects from this restricted sample (walking 1 h or more per day) were less likely to die compared to participants walking less than 1 h per day (RR, 0.31; 95% CI 0.10– 0.92). Similarly, the inclusion in the analyses of those deaths occurred in the first 6–12 months after the baseline assessment could have biased results. However, after excluding all those subjects who died during the first year of follow-up (14 subjects), subjects walking 1 h or more per day resulted less likely to die compared to sedentary participants (RR, 0.23; 95% CI 0.06–0.85). Finally, the impact of walking activity levels on 2-year survival was also tested comparing the survival curves obtained with the Kaplan– Meier method. Survival curves for different levels of walking activity are shown in Fig. 1. Discussion The present study shows that walking 1 h or more per day exerts an important influence on mortality in older adults living in the community, independently of age and other clinical and functional variables. After adjusting for several potential confounders, such as comorbidities and cognitive impairment, mortality was more frequently reported in the lowest level of physical activity group (no walkers or walkers less than 1 h per day). Even though longevity has a genetic contribution, physical activity practice is the primary determinant of health in adults and changes in physical activity result in changes in health and subsequent mortality (Church et al., 2007). Evidence for a beneficial effect of physical exercise on health outcomes mainly comes from observational longitudinal research. Various large epidemiological studies show that a high level of physical exercise has been associated with a low risk of cardiovascular mortality and morbidity for both older men and women (Ellekjaer et al., 2000; Haapanen et al 1997; Patel et al., 2006; Kushi et al., 1997). Furthermore, randomized trials in post-myocardial infarction patients suggest that physical exercise programs may prevent the recurrence of cardiovascular events and mortality (Hedback et al., 1993; Dorn et al., 1999). Two meta-analyses showed that physical exercise has beneficial effects on cardiovascular mortality and recurrent myocardial infarction among patients recovering from myocardial infarction (O'Connor et al., 1989; Oldridge et al., 1988). However, relatively few studies have evaluated the contribution of moderate-intensity physical activity, such as regular walking, on coronary events and mortality. The octogenarians and nonagenarians enrolled in this study represent an interesting and new model to investigate the biological and non-biological determinants of aging and longevity, as well as their interactions. Furthermore, studies performed in a specific and well defined geographic region – such as the Sirente Mountain
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Community – can be particularly useful in interpreting and disentangling all the complex interactions involved in the development of disability status and longevity (Landi et al., 2005). The benefits of aerobic exercise, strength training and/or vigorous physical activity have already been described and well established (Fiatarone et al., 1995; Keysor et al., 2001). However, this kind of heavy training usually is not a reasonable goal for older people, especially for those who have a high prevalence of comorbidities. Our analysis focused on walking because it is the most commonly performed and one of the safest form of physical activities. In fact, this kind of moderate physical activity is highly attractive for older persons, even those with functional limitations and/or health problems. Furthermore, walking brings a substantial benefit in terms of longevity (Aijo et al., 2002), is easily undertaken by the oldest age-group and does not present substantial contraindications (Morey et al., 2002; Fiatarone et al., 2002). Some limitations of the present study need to be cited. Physical inactivity makes a major contribution to chronic diseases such as coronary artery diseases (i.e. myocardial infarction), cerebrovascular accidents, obesity, diabetes mellitus, and arthritis. On the other hand, severe and chronic diseases may be associated with low physical activity. In this respect, we cannot completely exclude that this reverse causation may play an important role in the relationship between low walking activity level and elevated mortality risk observed in our sample. Reverse causation is particularly likely with diseases with a long natural history preceding death, such as chronic obstructive pulmonary disease, dementia, and arthritis. However, because of the use of an extensive multidimensional assessment instrument, the present study could comprehensively investigate the different domains of elderly status influencing walking activity and survival. For this reason and to rule out the effect of large number of potential confounders, we incorporated in our model a large number of variables, including comorbidities and measures of cognitive status. In addition, as in all cohort studies, selective survival before entry the cohort has to be taken into account. In this longitudinal observational study, results may be confounded by unmeasured factors. In the absence of randomization, it is likely that there are significant, not considered differences between the evaluation groups that may have biased the study results and conclusions. For example, we were not able to identify the specific site of arthritis (spine, hip, or knee). Furthermore, it can be hypothesized that subjects with a higher level of walking activity had an easier access to medical care service compared to sedentary subjects. Another limitation of the present study is determined by the lack of any documentation concerning the cause of death. However, we were interested in characterizing the impact of walking activity itself on all-cause mortality. In this respect, it is important to underline that we can only hypothesize that the elders enrolled in our study walked for an hour each day for years and
Fig. 1. Survival curves for patients stratified across levels of walking time per day at baseline assessment. Sedentary: subjects walking less than 1 h per day; Active: subjects walking 1 h or more per day.
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that this was not a new activity. Similarly, the classification of walking activity used in the present study (i.e. of those walking 30 min–1 h/ day) could affect the results observed. Finally, the ilSIRENTE sample population was composed by persons aged 80 years or older, so our results may not be applicable to other age groups. In conclusion, our results expand the knowledge that moderate physical activity carried out as part of everyday activities can be of substantial benefit even to frail and older persons. Vigorous exercise is not always required, while regular leisure activities – such as walking, gardening, or housekeeping – seem to be enough to reach considerable benefits. Older people are repeatedly told about the benefits of physical exercise. Encouragement of older men and women to maintain or increase their walking activity can help lose weight, lower blood pressure, improve cholesterol levels, lower blood sugar and slow down osteoporosis. All these positive effects help maintain mobility, prolong independence, and reduce the risk of all-cause mortality. In this respect, health educational authorities and health care organizations together with primary care physicians should encourage all the older people to be physically active even during the extreme ages of life (Brown et al., 2003; Malmberg et al., 2005; Schutzer et al., 2004). Conflict of interest statement None.
Acknowledgments First of all, we thank all the participants for their enthusiasm in participating to the project and their patience during the assessments. We are grateful to all the persons working as volunteers in the “Protezione Civile” and in the Italian Red Cross of Abruzzo Region for their support. We sincerely thank the “Comunità Montana Sirentina” and in particular its President, who promoted and strongly supported the development of the project. The ilSIRENTE Study Group is composed as follows: Steering Committee: R. Bernabei, F. Landi Coordination: A. Russo, M. Valeri, G. Venta Writing Panel: C. Barillaro, M. Cesari, L. Ferrucci, G. Onder, M. Pahor, V. Zamboni, E. Capoluongo Participants: Comune di Fontecchio: P. Melonio, G. Bernabei, A. Benedetti; Comune di Fagnano: N. Scarsella, A. Fattore, M. Fattore; Comune di Tione: M. Gizzi; Comune di Ovindoli: S. Angelosante, E. Chiuchiarelli; Comune di Rocca di Mezzo: S. Pescatore; Comune di Rocca di Cambio: G. Scoccia; Comune di Secinaro: G. Pizzocchia; Comune di Molina Aterno: P. Di Fiore; Comune di Castelvecchio: A. Leone; Comune di Gagliano Aterno: A. Petriglia; Comune di Acciano: A. Di Benedetto; Comune di Goriano Sicoli: N. Colella; Comune di Castel di Ieri: S. Battista; RSA Opera Santa Maria della Pace: A. De Santis, G. Filieri, C. Gobbi, G. Gorga, F. Cocco, P. Graziani. References Abell, J.E., Hootman, J.M., Zack, M.M., Moriarty, D., Helmick, C.G., 2005. Physical activity and health related quality of life among people with arthritis. J. Epidemiol. Community Health 59, 380–385. Aijo, M., Heikkinen, E., Schroll, M., Steen, B., 2002. Physical activity and mortality of 75year-old people in three Nordic localities: a five-year follow-up. Aging Clin. Exp. Res. 14, S83–S89. Brown, D.W., Balluz, L.S., Heath, G.W., et al., 2003. Associations between recommended levels of physical activity and health-related quality of life Findings from the 2001 Behavioral Risk Factor Surveillance System (BRFSS) survey. Prev. Med. 37, 520–528. Church, T.S., Earnest, C.P., Skinner, J.S., Blair, S.N., 2007. Effects of different doses of physical activity on cardiorespiratory fitness among sedentary, overweight or obese postmenopausal women with elevated blood pressure: a randomized controlled trial. JAMA 297, 2081–2091. Cohen-Mansfield, J., Marx, M.S., Biddison, J.R., Guralnik, J.M., 2004. Socio-environmental exercise preferences among older adults. Prev. Med. 38, 804–811. Cress, M.E., Buchner, D.M., Questad, K.A., Esselman, P.C., deLateur, B.J., Schwartz, R.S., 1999. Exercise: effects on physical functional performance in independent older adults. J. Gerontol. A. Biol. Sci. Med. Sci. 54, M242–M248.
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Preventive Medicine j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / y p m e d
Walking one hour or more per day prevented mortality among older persons: Results from ilSIRENTE study Francesco Landi a,⁎, Andrea Russo a, Matteo Cesari b, Marco Pahor b,c, Rosa Liperoti a, Paola Danese a, Roberto Bernabei a, Graziano Onder a a b c
Department of Gerontology, Geriatrics and Physiatry, Catholic University of Sacred Heart, Roma, Italy Department of Aging and Geriatric Research, University of Florida – College of Medicine, Gainesville, FL, USA Geriatric Research, Education and Clinical Center (GRECC), Malcom Randall Veteran's Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
a r t i c l e
i n f o
Article history: Available online 11 July 2008 Keywords: Walking activity Mortality Frail elderly
a b s t r a c t Objective. Maintaining or increasing physical activity in late-middle age has been shown to be associated with a reduction in mortality. The aim of the present study was to explore the relationship between regular walking and the risk of all-cause death in a large population of frail and very old people living in community. Methods. We analyzed data from the Aging and Longevity Study in the Sirente Geographic Area (ilSIRENTE study), a prospective cohort study that collected data on all subjects aged 80 year and older living in a mountain community. Baseline assessments of participants started in December 2003 and were completed in September 2004. All subjects were followed-up for 24 months. To the purpose of this study we selected all subjects without impairment in the activities of daily living (n = 248). The main outcome measure was the relative hazard ratio of death over two years of follow-up for different levels of walking activity. Results. During a mean follow-up time of 24 months from baseline assessment, 30 subjects (12%) died. There was an uneven distribution of the risk. After adjusting for age, gender and other possible risk factors of death (functional and cognitive disability, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and reactive C protein) subjects walking 1 h or more per day were less likely to die compared to participants walking less than 1 h per day (RR, 0.36; 95% CI 0.12–0.98). Conclusions. Our results obtained from a representative sample of very old and frail elderly subjects expand the knowledge that high levels of walking activity are associated with better survival. © 2008 Published by Elsevier Inc.
Introduction Locomotion is a key feature of human functioning (Cress et al., 1999). Exercise capacity and physical activity are associated with low all-cause mortality and with low morbidity and mortality for cardiovascular diseases (Cohen-Mansfield et al., 2004; Landi et al., 2007; Wannamethee et al., 2000). Exercise may be beneficial to many morbid conditions that underlie disability, including falls (Gardner et al 2000; Tinetti et al., 1994), hip fracture (Feskanich et al., 2002), respiratory diseases (Mador et al., 2004), cancer (Holmes et al., 2005), diabetes (Manson et al., 1991), osteoporosis (Abell et al., 2005) and obesity (Littman et al., 2005). However, the contribution of moderateintensity physical activity, such as regular brisk walking, to reducing coronary events and mortality is still unclear. In fact, although some authors have demonstrated that only participation in vigorous physical activity and/or high-intensity exercise programs are asso-
⁎ Corresponding author. Centro Medicina dell'Invecchiamento (CEMI) Istituto di Medicina Interna e Geriatria Universita' Cattolica del Sacro Cuore Largo Agostino Gemelli, 800168 Rome, Italy. Fax: +39 06 3051911. E-mail address: [email protected] (F. Landi). 0091-7435/$ – see front matter © 2008 Published by Elsevier Inc. doi:10.1016/j.ypmed.2008.06.020
ciated with reductions in mortality (Lee et al., 1995), others have extended these benefits to moderate activities (Slattery et al., 1989). Maintaining or increasing physical activity in late-middle age has been shown to be associated with a reduction in mortality (Landi et al., 2007; Talbot et al., 2007). However, few studies explored the effects of regular walking across a broad spectrum of ages. In fact, most of the physical activity intervention studies focused on young-adult population (Lan et al., 2006). To date, the best level of physical activity associated with health benefits among older people has not been identified. The aim of the present study is to explore the relationship between regular walking and the risk of all-cause death in a large population of very old people living in community. Methods The ilSIRENTE study is a prospective cohort study performed in the mountain community living in the Sirente geographic area (L'Aquila, Abruzzo) in the Central Italy. This study was designed by the Department of Gerontology, Geriatrics, and Physiatric Medicine of the Catholic University of Sacred Heart (Rome, Italy) and developed by the teaching nursing home, Opera Santa Maria della Pace (Fontecchio,
F. Landi et al. / Preventive Medicine 47 (2008) 422–426
L'Aquila, Italy) in partnership with local administrators and primary care physicians of Sirente Mountain Community Municipalities. The Catholic University of Sacred Heart ethical committee ratified the entire study protocol. All the participants signed an informed consent at the baseline visit. Details of the ilSIRENTE study protocol are described in details elsewhere (Landi et al., 2005). Study population A preliminary list of all persons living in this well defined area was obtained at the end of October 2003 from the Registry Offices of the 13 municipalities involved in the study. From this preliminary list, potential study participants were identified by selecting all persons born in the Sirente area before 1st January 1924 and actually living in such area. As a result, the overall sample population enrolled in the ilSIRENTE study consisted of 364 subjects. For the purpose of this study we selected all subjects without impairment in the activities of daily living (MDS-ADL = 0). The score “0” in the MDS-ADL scale means that the subject was completely independent in the following daily activities: dressing, eating, toilet use, bathing, mobility in bed, locomotion, and transfer. This was done to select subjects able to walk outside their homes. Consequently, we excluded 116 subjects with an MDS-ADL score at the baseline assessment equal or more than 1. Therefore, the final sample for present study consisted of 248 subjects. Data collection Baseline assessments of participants started in December 2003 and were completed in September 2004. Assessors were trained on how to perform each component of the ilSIRENTE study protocol (Landi et al., 1996). The Minimum Data Set for Home Care (MDS-HC) form was administered to all study participants following the guidelines published in the MDS-HC manual (Morris et al., 1996). The MDS-HC contains over 350 data elements including socio-demographics, physical and cognitive status variables, as well as major clinical diagnoses (Morris et al., 1997). Moreover, the MDS-HC also includes information about an extensive array of signs, symptoms, syndromes, and treatments (Morris et al., 1997). The MDS items have shown an excellent inter-rater and test–retest reliability when completed by nurses performing usual assessment duties (average weighted Kappa = 0.8) (Landi et al., 2000). Additional information about family history, lifestyle, physical activity and behavioral factors were collected using specific questionnaires from the “Invecchiare in Chianti Study” (Ferrucci et al., 2000). Functional and cognitive status measures Basic activities of daily living were assessed using the MDS-HC instrument (Landi et al., 2000). The ADL scale is based on seven levels of self-performance including dressing, eating, toilet use, bathing, mobility in bed, locomotion, transfer. Similarly, the IADL scale is based on seven levels of self-performance, including meal preparation, housework, managing finance, phone use, shopping, transport and managing medications. Cognitive performance was assessed using a six-item, seven-category scale (Cognitive Performance Scale-CPS) (Morris et al., 1994). The CPS was scored on a 7-point ordinal scale in which higher scores were associated with worse cognitive performance. The CPS includes two cognitive items (short-term memory, skills for daily decision making), one item describing communication ability (understood by others), one ADL measure (self-performance in eating), and one item indicating the presence of comatose status. Walking assessment Walking intensity information was obtained using a single and “easy” question: “How many minutes do you walk each day?”. The
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possible answers were: 1—never or less than 30 min; 2—30 min; 3—1 h; 4—more than 1 h. This item was the same as that used in the inCHIANTI study form (Ferrucci et al., 2000). For analytic purpose, participants were categorized into non walkers or very light walkers (those walking less than 1 h each day; score 1 or 2) and moderate or intense walkers (those walking 1 h or more each day; score 3 or 4). The reliability and validity of this walking activity assessment has not been established. Blood measurements Venus blood samples were drawn in the morning after an overnight fast. The samples were immediately centrifuged and stored at −80 °C until final analysis. Standard determinations of serum albumin, cholesterol (HDL and LDL), and triglycerides were performed by commercially available kits (Olympus, Italy) suitable on Olympus 2700 instrumentation. Covariates Medical diagnoses and drugs were directly collected by general practitioners. Medical diagnoses were defined as those conditions that have an impact on the patients' functional, cognitive, and behavioral status, medical treatment and risk of death. The diagnoses were listed on the MDS-HC form in a check-box section containing 27 specific diagnostic categories. General practitioner collected information on up to 18 different drugs received by each patient in the 7 days preceding the assessment. Drugs were coded using the Anatomical Therapeutic and Chemical (ATC) codes. Body weight was measured with light clothes using a calibrated bathroom scale. Body height was measured using a standard stadiometer. Body mass index (BMI) was defined as weight (kilograms) divided by the square of height (meters). Alcohol consumption was assessed asking participants about the number of glasses of wine they used to drink during a standard day. Alcohol abuse was defined as a consumption of more than half of liter of wine per day. Smoking status was assessed asking participants about the number of cigarettes they currently smoked or they had smoked in the past. Survival status Vital status was obtained from general practitioners and confirmed by the National Death Registry. Time to death was calculated from the date of baseline assessment to the date of death. All subjects were followed-up for 24 months. Statistical analysis Data were analyzed to obtain descriptive statistics. Continuous variables are presented as mean values ± standard deviation. We evaluated trends of sociodemographic variables and indicators of disease severity using the Fisher exact test. Differences between continuous variables were assessed by ANOVA comparisons for normally distributed parameters; otherwise, the Kruskal–Wallis test was adopted. A level of p b 0.05 was chosen for statistical significance. Time to death was calculated from the date of baseline assessment to the date of death. We examined all events occurred during a followup of 24 months. Cox proportional hazard models, adjusted for age, gender, baseline comorbidities (congestive heart failure, hypertension, osteoarthritis, depression, number of medications), body mass index, cholesterol, reactive C protein level, functional capacity (as measured by MDS-IADL score) and cognitive impairment (as measured by MDSCPS score) were used to estimate the relative risk of death. Hazard rate ratios (RRs) and corresponding 95% confidence intervals (95% CIs) were derived from the final models. The impact of walking 1 h or more per day on survival was also tested comparing the survival curves
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obtained with the Kaplan–Meier method. Differences between curves were evaluated using the log-rank test. Statistical analysis was performed using the SPSS 10.0 package (Chicago, Illinois).
Table 2 Characteristics of study population according to death (2-year follow-up), in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 Characteristics
Dead (n = 30)
Alive (n = 218)
p
Results
Age, years Gender Women Men Living alone Marital status Married Widowed Never married Education, years Cognitive performance scale score IADL scale score Sensory impairment Hearing Vision Body mass index, kg/m2 Alcohol abuse Smoking habit Diseases Ischemic heart disease Congestive heart failure Hypertension Stroke Peripheral vascular disease Diabetes Chronic obstructive pulmonary disease Parkinson's disease Cancer Osteoarthritis Depression Number of medications Hematological parameters Albumin, g/dl Cholesterol, mg/dl Triglycerides, mg/dl C reactive protein, mg/dl
87.3 ± 5.6
84.4 ± 3.9
b0.001
21 (66) 9 (34) 11 (36)
145 (70) 73 (30) 83 (38)
0.43
5 (17) 22 (73) 3 (10) 5.1 ± 0.5 0.6 ± 1.0 2.7 ± 2.0
69 (31) 126 (58) 23 (11) 5.2 ± 1.9 0.3 ± 0.7 1.3 ± 1.6
0.21
0.71 0.06 0.001
9 (30) 4 (13) 24.6 ± 4.6 3 (10) 2 (6)
33 (15) 41 (18) 26.3 ± 4.1 28 (13) 6 (3)
0.04 0.32 0.03 0.65 0.25
5 (16) 4 (13) 23 (76) 1 (3) 2 (7) 9 (30) 4 (13) 1 (0) 2 (7) 6 (20) 7 (23) 3.8 ± 2.7
24 (11) 6 (3) 167 (76) 3 (1) 8 (4) 50 (23) 24 (11) 2 (1) 7 (3) 43 (20) 46 (21) 2.9 ± 1.9
0.36 b0.001 0.99 0.42 0.43 0.39 0.70 0.59 0.34 0.97 0.78 0.02
4.1 ± 0.3 180.1 ± 42.2 135.1 ± 68.2 4.9 ± 3.1
4.2 ± 0.2 205.7 ± 44.9 148.2 ± 62.1 3.2 ± 2.7
Mean age of 248 subjects participating in the study was 85.9 (standard deviation 4.9) years, and 166 (67.0%) were women. Characteristics of the study population according to the different levels of walking are summarized in Table 1. Compared to participants walking less than 1 h per day, those walking 1 h or more per day were younger (85.4 ± 4.5 year versus 84.4 ± 4.3, p = 0.09), less likely to be depressed and had a lower prevalence of cognitive impairment, congestive heart failure, hypertension and osteoarthritis. The mean number of drugs was higher among subjects less active compared with subjects walking 1 h or more per day (3.6 ± 2.3 versus 2.7 ± 1.8, respectively). In particular, more participants among the non walkers or very light walkers received digoxin (23/83, 27% versus 17/165, 10%, p = 0.001) and furosemide (22/83, 26% versus 11/165, 7%, p b 0.001), compared to moderate or intense walkers. The proportion of walkers for 1 h or more was significantly higher for males than females (78% and 60%, respectively; p = 0.05). We also evaluated the baseline
Table 1 Characteristics of study population according to the number of hours walked per day, in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 Characteristics
Age, years Gender Women Men Living alone Marital status Married Widowed Never married Education, years Cognitive performance scale score IADL scale score Sensory impairment Hearing Vision Body mass index, kg/m2 Alcohol abuse Smoking habit Diseases Ischemic heart disease Congestive heart failure Hypertension Stroke Peripheral vascular disease Diabetes Chronic obstructive pulmonary disease Parkinson's disease Cancer Osteoarthritis Depression Number of medications Hematological parameters Albumin, g/dl Cholesterol, mg/dl Triglycerides, mg/dl C reactive protein, mg/dl
Walking level, h/day
p
b1 h/day (n = 83)
N 1 h/day (n = 165)
85.4 ± 4.5
84.4 ± 4.3
0.09
65 (78) 18 (22) 27 (33)
101 (61) 64 (39) 67 (42)
0.05
26 (32) 46 (55) 12 (13) 4.9 ± 1.3 0.5 ± 1.0 2.6 ± 2.1
48 (30) 102 (61) 15 (9) 5.3 ± 2.0 0.2 ± 0.6 1.5 ± 1.4
0.08 0.04 0.01
18 (21) 19 (23) 26.0 ± 4.8 12 (14) 2 (2)
24 (14) 26 (16) 26.2 ± 3.9 19 (12) 6 (4)
0.10 0.11 0.77 0.8 0.4
11 (13) 9 (11) 69 (83) 3 (4) 4 (5) 16 (19) 11 (19) 1 (1) 3 (4) 24 (29) 30 (36) 3.6 ± 2.3
18 (11) 1 (1) 121 (73) 1 (1) 6 (5) 43 (26) 17 (10) 2 (1) 6 (4) 25 (15) 25 (14) 2.7 ± 1.8
0.36 b0.001 0.05 0.11 0.61 0.15 0.31 0.55 0.64 b0.01 b0.001 b0.01
4.2 ± 0.3 208.3 ± 51.3 153.9 ± 68.6 3.5 ± 3.4
4.2 ± 0.3 190.6 ± 41.8 142.9 ± 59.6 3.3 ± 2.5
0.11 0.50
0.72 0.16 0.19 0.51
Data are given as number (percent) for the following variables: gender, living alone, marital status, sensory impairment, alcohol abuse, smoking habit, diseases; for all the other variables means ± SD are reported. Cognitive performance scale score: range 0–6, a higher number indicates higher impairment. IADL (Instrumental Activity of Daily Living) score: range 0–7, a higher number indicates higher impairment.
0.46
0.13 0.004 0.28 0.002
Data are given as number (percent) for the following variables: gender, living alone, marital status, sensory impairment, alcohol abuse, smoking habit, diseases; for all the other variables means ± SD are reported. Cognitive performance scale score: range 0–6, a higher number indicates higher impairment. IADL (Instrumental Activity of Daily Living) score: range 0–7, a higher number indicates higher impairment.
characteristics of the sample according to the vital status to identify potential risk factors for death (Table 2). During a mean follow-up of 24 months, 30 subjects (12%) died. There was an uneven distribution of the risk (Table 2). Twelve subjects died among the physically active group compared to 18 subjects among the sedentary group (RR, 0.28; 95% CI 0.12–0.62). After adjusting for age, gender and other potential confounders (functional and cognitive disability as expressed by IADL and CPS scores, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and reactive C protein), physically active subjects (walking 1 h or more per day) were less likely to die compared to participants walking less than 1 h per day (RR, 0.36; 95% CI 0.12–0.98) (Table 3, model 1). The addition to the model of variables for digoxin and furosemide use in place of a variable indicating the overall number of medications taken did not change the estimate of risk (RR, 0.37; 95% CI 0.11–1.01). Additional analyses using different categorization for walking were performed to further investigate the protective effect of regular walking on mortality. As shown in Table 3 (model 2), the lowest risk of death was observed among participants involved in walking activity for 1 h or more per day. Considering the small number of death observed, the significant difference in the prevalence of congestive heart failure between the two groups could have influenced study results. For this reason we repeated the analysis after excluding those subjects with congestive
F. Landi et al. / Preventive Medicine 47 (2008) 422–426 Table 3 Crude and adjusted relative risks (RRs) of mortality in the Italian cohorts of the ilSIRENTE study, examined at baseline between 2003 and 2004 and after 24 months Dead (n = 30)
Alive (n = 218)
Crude Model RR (95% CI)
Adjusted Modela RR (95% CI)
Model 1 Sedentary Active
18 12
65 153
1.0 (Referent) 0.28 (0.12–0.62)
1.0 (Referent) 0.36 (0.12–0.98)
Model 2 No walkers Walkers for 30 min Walkers for 1 h Walkers for more than 1 h
5 13 10 2
10 55 104 49
1.0 0.47 0.19 0.08
1.0 (Referent) 0.33 (0.07–1.57) 0.16 (0.04–0.79) 0.11 (0.02–0.95)
(Referent) (0.13–1.62) (0.05–0.67) (0.01–0.48)
Sedentary: subjects walking less than 1 h per day; Active: subjects walking 1 h or more per day. a Adjusted for age, gender and for other possible risk factors for death (functional and cognitive disability, congestive heart failure, hypertension, osteoarthritis, depression, number of medications, body mass index, cholesterol and C reactive protein).
heart failure. Again, physically active subjects from this restricted sample (walking 1 h or more per day) were less likely to die compared to participants walking less than 1 h per day (RR, 0.31; 95% CI 0.10– 0.92). Similarly, the inclusion in the analyses of those deaths occurred in the first 6–12 months after the baseline assessment could have biased results. However, after excluding all those subjects who died during the first year of follow-up (14 subjects), subjects walking 1 h or more per day resulted less likely to die compared to sedentary participants (RR, 0.23; 95% CI 0.06–0.85). Finally, the impact of walking activity levels on 2-year survival was also tested comparing the survival curves obtained with the Kaplan– Meier method. Survival curves for different levels of walking activity are shown in Fig. 1. Discussion The present study shows that walking 1 h or more per day exerts an important influence on mortality in older adults living in the community, independently of age and other clinical and functional variables. After adjusting for several potential confounders, such as comorbidities and cognitive impairment, mortality was more frequently reported in the lowest level of physical activity group (no walkers or walkers less than 1 h per day). Even though longevity has a genetic contribution, physical activity practice is the primary determinant of health in adults and changes in physical activity result in changes in health and subsequent mortality (Church et al., 2007). Evidence for a beneficial effect of physical exercise on health outcomes mainly comes from observational longitudinal research. Various large epidemiological studies show that a high level of physical exercise has been associated with a low risk of cardiovascular mortality and morbidity for both older men and women (Ellekjaer et al., 2000; Haapanen et al 1997; Patel et al., 2006; Kushi et al., 1997). Furthermore, randomized trials in post-myocardial infarction patients suggest that physical exercise programs may prevent the recurrence of cardiovascular events and mortality (Hedback et al., 1993; Dorn et al., 1999). Two meta-analyses showed that physical exercise has beneficial effects on cardiovascular mortality and recurrent myocardial infarction among patients recovering from myocardial infarction (O'Connor et al., 1989; Oldridge et al., 1988). However, relatively few studies have evaluated the contribution of moderate-intensity physical activity, such as regular walking, on coronary events and mortality. The octogenarians and nonagenarians enrolled in this study represent an interesting and new model to investigate the biological and non-biological determinants of aging and longevity, as well as their interactions. Furthermore, studies performed in a specific and well defined geographic region – such as the Sirente Mountain
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Community – can be particularly useful in interpreting and disentangling all the complex interactions involved in the development of disability status and longevity (Landi et al., 2005). The benefits of aerobic exercise, strength training and/or vigorous physical activity have already been described and well established (Fiatarone et al., 1995; Keysor et al., 2001). However, this kind of heavy training usually is not a reasonable goal for older people, especially for those who have a high prevalence of comorbidities. Our analysis focused on walking because it is the most commonly performed and one of the safest form of physical activities. In fact, this kind of moderate physical activity is highly attractive for older persons, even those with functional limitations and/or health problems. Furthermore, walking brings a substantial benefit in terms of longevity (Aijo et al., 2002), is easily undertaken by the oldest age-group and does not present substantial contraindications (Morey et al., 2002; Fiatarone et al., 2002). Some limitations of the present study need to be cited. Physical inactivity makes a major contribution to chronic diseases such as coronary artery diseases (i.e. myocardial infarction), cerebrovascular accidents, obesity, diabetes mellitus, and arthritis. On the other hand, severe and chronic diseases may be associated with low physical activity. In this respect, we cannot completely exclude that this reverse causation may play an important role in the relationship between low walking activity level and elevated mortality risk observed in our sample. Reverse causation is particularly likely with diseases with a long natural history preceding death, such as chronic obstructive pulmonary disease, dementia, and arthritis. However, because of the use of an extensive multidimensional assessment instrument, the present study could comprehensively investigate the different domains of elderly status influencing walking activity and survival. For this reason and to rule out the effect of large number of potential confounders, we incorporated in our model a large number of variables, including comorbidities and measures of cognitive status. In addition, as in all cohort studies, selective survival before entry the cohort has to be taken into account. In this longitudinal observational study, results may be confounded by unmeasured factors. In the absence of randomization, it is likely that there are significant, not considered differences between the evaluation groups that may have biased the study results and conclusions. For example, we were not able to identify the specific site of arthritis (spine, hip, or knee). Furthermore, it can be hypothesized that subjects with a higher level of walking activity had an easier access to medical care service compared to sedentary subjects. Another limitation of the present study is determined by the lack of any documentation concerning the cause of death. However, we were interested in characterizing the impact of walking activity itself on all-cause mortality. In this respect, it is important to underline that we can only hypothesize that the elders enrolled in our study walked for an hour each day for years and
Fig. 1. Survival curves for patients stratified across levels of walking time per day at baseline assessment. Sedentary: subjects walking less than 1 h per day; Active: subjects walking 1 h or more per day.
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that this was not a new activity. Similarly, the classification of walking activity used in the present study (i.e. of those walking 30 min–1 h/ day) could affect the results observed. Finally, the ilSIRENTE sample population was composed by persons aged 80 years or older, so our results may not be applicable to other age groups. In conclusion, our results expand the knowledge that moderate physical activity carried out as part of everyday activities can be of substantial benefit even to frail and older persons. Vigorous exercise is not always required, while regular leisure activities – such as walking, gardening, or housekeeping – seem to be enough to reach considerable benefits. Older people are repeatedly told about the benefits of physical exercise. Encouragement of older men and women to maintain or increase their walking activity can help lose weight, lower blood pressure, improve cholesterol levels, lower blood sugar and slow down osteoporosis. All these positive effects help maintain mobility, prolong independence, and reduce the risk of all-cause mortality. In this respect, health educational authorities and health care organizations together with primary care physicians should encourage all the older people to be physically active even during the extreme ages of life (Brown et al., 2003; Malmberg et al., 2005; Schutzer et al., 2004). Conflict of interest statement None.
Acknowledgments First of all, we thank all the participants for their enthusiasm in participating to the project and their patience during the assessments. We are grateful to all the persons working as volunteers in the “Protezione Civile” and in the Italian Red Cross of Abruzzo Region for their support. We sincerely thank the “Comunità Montana Sirentina” and in particular its President, who promoted and strongly supported the development of the project. The ilSIRENTE Study Group is composed as follows: Steering Committee: R. Bernabei, F. Landi Coordination: A. Russo, M. Valeri, G. Venta Writing Panel: C. Barillaro, M. Cesari, L. Ferrucci, G. Onder, M. Pahor, V. Zamboni, E. Capoluongo Participants: Comune di Fontecchio: P. Melonio, G. Bernabei, A. Benedetti; Comune di Fagnano: N. Scarsella, A. Fattore, M. Fattore; Comune di Tione: M. Gizzi; Comune di Ovindoli: S. Angelosante, E. Chiuchiarelli; Comune di Rocca di Mezzo: S. Pescatore; Comune di Rocca di Cambio: G. Scoccia; Comune di Secinaro: G. Pizzocchia; Comune di Molina Aterno: P. Di Fiore; Comune di Castelvecchio: A. Leone; Comune di Gagliano Aterno: A. Petriglia; Comune di Acciano: A. Di Benedetto; Comune di Goriano Sicoli: N. Colella; Comune di Castel di Ieri: S. Battista; RSA Opera Santa Maria della Pace: A. De Santis, G. Filieri, C. Gobbi, G. Gorga, F. Cocco, P. Graziani. References Abell, J.E., Hootman, J.M., Zack, M.M., Moriarty, D., Helmick, C.G., 2005. Physical activity and health related quality of life among people with arthritis. J. Epidemiol. Community Health 59, 380–385. Aijo, M., Heikkinen, E., Schroll, M., Steen, B., 2002. Physical activity and mortality of 75year-old people in three Nordic localities: a five-year follow-up. Aging Clin. Exp. Res. 14, S83–S89. Brown, D.W., Balluz, L.S., Heath, G.W., et al., 2003. Associations between recommended levels of physical activity and health-related quality of life Findings from the 2001 Behavioral Risk Factor Surveillance System (BRFSS) survey. Prev. Med. 37, 520–528. Church, T.S., Earnest, C.P., Skinner, J.S., Blair, S.N., 2007. Effects of different doses of physical activity on cardiorespiratory fitness among sedentary, overweight or obese postmenopausal women with elevated blood pressure: a randomized controlled trial. JAMA 297, 2081–2091. Cohen-Mansfield, J., Marx, M.S., Biddison, J.R., Guralnik, J.M., 2004. Socio-environmental exercise preferences among older adults. Prev. Med. 38, 804–811. Cress, M.E., Buchner, D.M., Questad, K.A., Esselman, P.C., deLateur, B.J., Schwartz, R.S., 1999. Exercise: effects on physical functional performance in independent older adults. J. Gerontol. A. Biol. Sci. Med. Sci. 54, M242–M248.
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