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Age-related macular degeneration and 5-year incidence of impaired activities of daily living
Maturitas 77 (2014) 263–266
Contents lists available at ScienceDirect
Maturitas journal homepage: www.elsevier.com/locate/maturitas
Age-related macular degeneration and 5-year incidence of impaired activities of daily living Bamini Gopinath ∗ , Gerald Liew, George Burlutsky, Paul Mitchell Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, NSW, Australia
a r t i c l e
i n f o
Article history: Received 29 August 2013 Received in revised form 14 November 2013 Accepted 3 December 2013 Keywords: Age-related macular degeneration Activities of daily living Blue Mountains Eye Study Older adults
a b s t r a c t Objectives: We aimed to assess the prospective association between age-related macular degeneration (AMD) and impaired activities of daily living (ADL) among a large cohort of older adults. Study design: Functional status was determined by the Older Americans Resources and Services ADL scale from 2002–2004 to 2007–2009 among 761 participants aged 60+ years. AMD was assessed from retinal photographs. Results: After adjusting for age, sex, living status, self-rated poor health, smoking, body mass index, visual impairment, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores, having any AMD or late AMD increased the risk of incident impaired total ADL 5 years later, odds ratio, OR 2.87 (95% confidence intervals, CI 1.44–5.71) and OR 12.95 (95% CI 3.78–44.35), respectively. Having any AMD increased the risk of developing instrumental ADL disability over the 5 years, multivariable-adjusted OR 2.06 (95% CI 1.11–3.83). Conclusions: This study shows that the presence of AMD could independently signal an increased risk of functional disability, particularly in performing instrumental ADL tasks. © 2013 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Age-related macular degeneration (AMD) is the leading cause of blindness and low vision among older adults [1]. Loss of central vision in AMD means that everyday activities such as reading and driving cannot be performed [2]. The resulting severe disability involves enormous personal costs and is a massive burden on health resources [3]. Activities of daily living (ADL) measures are commonly used to assess older adults for disability in carrying out daily functions including basic ADL (BADL) such as eating, and instrumental ADL (IADL) required to function in the community, such as shopping [4]. However, there is a paucity of population-based studies that have prospectively assessed the associations between AMD and risk of ADL. Recently, a retrospective US study of 47 AMD subjects showed that visual acuity loss in AMD was associated with self-reported difficulties in IADLs [5]. Given that AMD is an important cause of blindness, a more comprehensive understanding of the impact of AMD on an individual’s functional status is needed. In particular, prospective studies studying the link between AMD and future functional impairment are
∗ Corresponding author at: Centre for Vision Research, University of Sydney, Westmead Hospital, Hawkesbury Road, Westmead, NSW 2145, Australia. Tel.: +61 2 9845 5551; fax: +61 2 9845 8345. E-mail address: [email protected] (B. Gopinath). 0378-5122/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.maturitas.2013.12.001
needed to provide important data which could assist in the longterm planning of health services and policies [6]. Therefore, using a relatively large cohort of adults aged ≥55 years we aimed to investigate whether there is a prospective association between AMD and functional status as assessed by a generic ADL scale. 2. Methods 2.1. Study population The Blue Mountains Eye Study (BMES) is a population-based cohort study of common eye diseases and other health outcomes in a suburban Australian population located west of Sydney. Study methods and procedures have been described elsewhere [7]. Baseline examinations of 3654 residents aged >49 years were conducted during 1992–1994 (BMES-1, 82.4% participation rate). Surviving baseline participants were invited to attend examinations after 5- (1997–1999, BMES-2), 10- (2002–2004, BMES-3), and 15 years (2007–2009, BMES-4). At BMES-2, -3 and -4, 2334 (75.1% of survivors), 1952 participants (75.6% of survivors) and 1149 (55.4% of survivors) with complete data were re-examined, respectively. All study participants provided written informed consent. 2.2. Assessment of AMD We took two 30◦ stereoscopic color retinal photographs of the macula of both eyes, which were graded for presence of early and
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B. Gopinath et al. / Maturitas 77 (2014) 263–266
Table 1 Participant’s response to activities of daily living (ADL) questions stratified by the presence of AMD at the Blue Mountains Eye Study in 2002–2004 (n = 1288). Without AMD n 1. Can you use the telephone? 1057 No help 21 Some help/completely unable 2. Can you get to places out of walking distance? No help 1011 Some help/completely unable 68 3. Can you go shopping for groceries or clothes? 1012 No help 66 Some help/completely unable 4. Can you prepare your own meals? No help 1002 Some help/completely unable 75 5. Can you do your housework? 813 No help 259 Some help/completely unable 6. Can you take your own medications? 1042 No help 23 Some help/completely unable 7. Can you handle your own money? No help 1054 25 Some help/completely unable 8. Can you eat? 1075 No help 8 Some help/completely unable 9. Can you dress and undress yourself? 1071 No help Some help/completely unable 11 10. Can you take care of your own appearance? No help 1077 5 Some help/completely unable 11. Can you walk? No help 1058 24 Some help/completely unable 12. Can you get in and out of bed? 1077 No help 4 Some help/completely unable 13. Can you take a bath or shower? 1061 No help Some help/completely unable 20 14. Do you ever have trouble getting to bathroom on time? No 961 119 Yes or has a colostomy/catheter
late AMD using the Wisconsin AMD Grading System [8,9]. Interand intra-grader reliability showed good agreement for grading of specific AMD lesions with quadratic weighted kappa values ranging from 0.64 to 0.93 and 0.54 to 0.94 respectively [10]. The detailed methodology of AMD ascertainment in this population has been previously reported [8,9]. Early AMD was defined as the absence of late AMD and presence of either: (1) large (>125-m diameter) indistinct soft or reticular drusen or (2) both large distinct soft drusen and retinal pigmentary abnormalities (hyperpigmentation or hypopigmentation) in either eye [9]. Similarly, late AMD was defined as the presence of neovascular AMD or geographic atrophy in either eye [9]. Any AMD was defined as having early or late AMD. A retinal specialist (P.M.) adjudicated all uncertain retinal pathology and confirmed all late AMD cases. 2.3. Assessment of ADL disability The Older American Resources and Services (OARS) ADL scale [11] includes 14 items: seven items assess BADL (eating, dressing and undressing, grooming, walking, getting in and out of bed, bathing, and toileting), and seven items assess IADL (using the telephone, travel, shopping, meal preparation, housework, taking medicine, and management of finances). The OARS ADL scale was only administered at the 10- (2002–2004) and 15-year BMES examinations (2007–2009). Hence, we assessed the association between
With AMD
p value
%
n
%
98.1 2.0
179 18
90.9 9.1
93.7 6.3
174 23
88.3 11.7
93.9 6.1
169 28
85.8 14.2
93.0 7.0
173 24
87.8 12.2
0.01
75.8 24.2
127 70
64.5 35.5
0.001
97.8 2.2
186 5
97.4 2.6
0.69
97.7 2.3
183 15
92.4 7.6
99.3 0.7
198 1
99.5 0.5
0.71
99.0 1.0
197 3
98.5 1.5
0.55
99.5 0.5
198 1
99.5 0.5
0.94
97.8 2.2
191 8
96.0 4.0
0.13
99.6 0.4
196 2
99.0 1.0
0.23
98.2 1.9
194 5
97.5 2.5
0.53
89.0 11.0
170 30
85.0 15.0
0.11
<0.0001
0.01
<0.0001
<0.0001
AMD and the 5-year incidence of impaired ADL. Each item was rated on a 3-point scale: performs the activity without help (2), performs the activity with some help (1), or completely unable to perform the activity (0), hence, the higher the score the more independent the person is. Three summary scales were computed by summing the scores of items: (1) a total score, the sum of all 14 items (range 0–28), (2) a BADL score, the sum of the 7 BADL items (range 0–14), and (3) an IADL score, the sum of the 7 IADL items (range 0–14). Participants reporting that they needed help with any of the activities or were completely unable to perform any of the activities were considered to have impaired ADL. 2.4. Information on covariates At face-to-face interviews with trained interviewers, information about participant’s socio-economic characteristics and their medical history and lifestyle was collected. Level of education obtained was also ascertained and classified as lower than tertiary (i.e. did not attain any qualifications past high school) or tertiary and higher. Participants were also asked whether they received a pension. Participants self-reported history of smoking as never, past, or current smoking. Current smokers included those who had stopped smoking within the past year. Body mass index (BMI) was calculated as weight divided by height squared (kg/m2 ). Criteria for a diagnosis of diabetes were: self-reported diabetes history and
B. Gopinath et al. / Maturitas 77 (2014) 263–266 Table 2 Longitudinal association between AMD and total impaired Activities of Daily Living (ADL) at Blue Mountains Eye Study in 2004–2009 (n = 761). Presence of AMD
Mean ADL score (SD)
Total impaired ADLOR (95% CI) Multivariable-adjusteda
No AMD (n = 667) Any AMD (n = 94) Early AMD (n = 78) Late AMD (n = 16)
27.00 (2.3) 26.11 (3.3) 26.34 (3.3) 25.20 (3.1)
1.0 (reference) 2.87 (1.44–5.71) 1.74 (0.77–3.94) 12.95 (3.78–44.35)
a Adjusted for age, sex, living status, self-rated poor health, smoking, body mass index, best corrected visual acuity in better eye, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores.
current use of diabetic medications; or a fasting plasma glucose concentration ≥7.0 mmol/L [12]. Subjects were defined as having hypertension if they had systolic blood pressure greater than 140 mm Hg or diastolic blood pressure more than 90 mm Hg or were on anti-hypertensive medications [13]. Self-rated health was assessed by asking: ‘for somebody your age, would you say your health is excellent, very good, good, fair, or poor?’ Low self-rated health was defined as fair or poor. Walking difficulty or use of a cane, walker or wheelchair was subjectively observed by a trained examiner and categorized as ‘disability in walking’. Visual acuity was measured wearing current glasses, using a LogMar chart, and was followed by subjective refraction [7]. For each eye, visual acuity was recorded as the number of letters read correctly from 0 (<6/60) to 70 (6/3). Visual impairment was defined as visual acuity of less than 39 letters (<6/12) in the better eye after subjective refraction. Cognitive function was assessed using the mini-mental state exam (MMSE) administered at both the baseline and follow-up visits. MMSE scores range from 0 to 30 [14], with scores <24 indicating cognitive impairment. The 10item version of the Center for Epidemiologic Studies Depression Scale (CES-D-10) measures depressive feelings and behaviors experienced in the past week [15]. A cut-off score of ≥10 out of a total possible score of 30 was used to define participants with significant depressive symptoms [15].
2.5. Statistical analyses SAS software (SAS Institute, Cary, NC) version 9.2 was used for analyses including t-tests, 2 -tests and logistic regression. Multivariable logistic regression analysis was used to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI) to demonstrate the association between any, early or late AMD (dependent variables) and incidence of ADL disability, falls and fractures (independent variables), while adjusting for potential confounders.
3. Results Among BMES participants examined in 2002–2004, 1288 had complete ‘baseline’ AMD and ADL data, and were included in this study. Further, for incidence analyses, we included 761 participants who had baseline information on AMD and 5-year follow-up ADL data. A significantly higher proportion of persons with any AMD compared to those without AMD reported difficulties in performing six out of the seven IADL tasks (Table 1). Those with AMD at baseline, 26 (41.3%) reported impaired IADL 5 years later compared to 113 (22.1%) participants with no AMD. After multivariableadjustment, having any AMD or late AMD increased the risk of incident impaired total ADL by ∼3-fold and 13-fold, respectively (Table 2). Table 3 shows that any AMD was independently associated with the incidence of impaired IADL, OR 2.06 (95% CI
265
Table 3 Longitudinal association between AMD and Impaired Instrumental Activities of Daily Living (IADL) at Blue Mountains Eye Study in 2002–2004 (n = 761). Presence of AMD
Mean IADL score (SD)
Impaired IADL OR (95% CI) Multivariableadjusteda
No AMD (n = 667) Any AMD (n = 94) Early AMD (n = 78) Late AMD (n = 16)
13.40 (1.3) 12.83 (2.0) 13.09 (1.7) 11.83 (2.5)
1.0 (reference) 2.06 (1.11–3.83) 1.92 (1.00–3.71) 2.93 (0.56–15.23)
a Adjusted for age, sex, living status, self-rated poor health, smoking, body mass index, best corrected visual acuity in better eye, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores.
1.11–3.83). AMD was not associated with incident BADL disability (data not shown).
4. Discussion We show that having any AMD or late AMD increased the risk of experiencing total ADL impairment by 3- and 13-fold, respectively, 5 years later. We need to advise caution, however, as there was a very small number of late AMD participants who had impaired total ADL 5 years later (n = 8), this could explain the wide 95% CI observed in relation to late AMD and incident ADL. Nevertheless, participants with any AMD compared to those with no AMD had ∼2-fold higher risk of incident IADL disability, i.e. were more likely to report difficulties in activities such as shopping, housework and using the telephone. Non-significant associations were observed between AMD and BADL incidence, which is in agreement with the notion that vision loss (except for extreme cases) is unlikely to lead to the inability to conduct simpler self-care tasks such as bathing and toileting [5]. However, AMD could still impact on functional status due to the need to depend on others for more complex tasks that characterize IADLs. Indeed, cross-sectional data from a small, US clinic-based study [5] showed that after multivariable adjustment, AMD was associated with IADL disability (p = 0.02). These findings concur with the 2-fold increased risk of incident IADL disability observed 5 years later among our participants with any AMD. Impaired mobility could be a potential pathway by which AMD could lead to IADL disability [5]. Individuals with AMD could become increasingly dependent on others for specific tasks such as grocery shopping, which requires a means of transportation or the ability to walk. Reduced accuracy for reaching or grasping objects in persons with AMD [16] could lead to disability with doing household chores/cooking as a result of difficulties in mobility and/or a fear of dropping heavy objects around the house. Finally, the inability to use the telephone and manage money is likely to be the result of reading difficulties caused by AMD [5]. We need to highlight that observed associations were independent of the influence of best corrected visual impairment in better eye, suggesting that AMD increases risk of ADL disability by other pathways. These data underscore the importance of developing rehabilitation interventions to target specific functional deficits in older adults with AMD. In summary, AMD increased the risk of experiencing IADL disability among older adults. The functional disability associated with AMD could come with great personal and societal costs [5]; hence, effective rehabilitation interventions that target older adults with AMD are important in order to maintain their functional independence.
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Contributors Study concept and design: BG and PM, Acquisition of subjects and data: PM. Analysis and interpretation of data: BG, GL, GB and PM. Preparation of Manuscript: BG. Important critical revision: BG, GL, GB and PM. Competing interests All authors have no conflict of interest and declare no financial interest. Funding The Blue Mountains Eye Study was supported by the Australian National Health and Medical Research Council (grant nos. 974159, 991407, 211069, 262120), and Westmead Millennium Institute. Bamini Gopinath is supported by a Macular Degeneration Foundation and Blackmores Dr. Paul Beaumont Fellowship. Ethical approval The University of Sydney and the Western Sydney Area Human Ethics Committees approved the study, and written, informed consent was obtained from all participants at each examination. References [1] Foran S, Wang JJ, Mitchell P. Causes of visual impairment in two older population cross-sections: the Blue Mountains Eye Study. Ophthalmic Epidemiol 2003;10:25–15.
[2] Lim LS, Mitchell P, Seddon JM, Holz FG, Wong TY. Age-related macular degeneration. Lancet 2012;379:38–1728. [3] Guymer RH, Chong EW. Modifiable risk factors for age-related macular degeneration. Med J Aust 2006;184:58–455. [4] McCusker J, Bellavance F, Cardin S, Belzile E. Validity of an activities of daily living questionnaire among older patients in the emergency department. J Clin Epidemiol 1999;52:30–1023. [5] Hochberg C, Maul E, Chan ES, et al. Association of vision loss in glaucoma and age-related macular degeneration with IADL disability. Invest Ophthalmol Vis Sci 2012;53:6–3201. [6] Kemper P. The use of formal and informal home care by the disabled elderly. Health Serv Res 1992;27:51–421. [7] Attebo K, Mitchell P, Smith W. Visual acuity and the causes of visual loss in Australia. The Blue Mountains Eye Study. Ophthalmology 1996;103:64–357. [8] Wang JJ, Rochtchina E, Lee AJ, et al. Ten-year incidence and progression of age-related maculopathy: the Blue Mountains Eye Study. Ophthalmology 2007;114:92–8. [9] Klein BE, Moss SE, Magli YL, Klein R, Hoyer C, Johnson J. Optic disc cupping: prevalence findings from the WESDR. Invest Ophthalmol Vis Sci 1989;30:9–304. [10] Mitchell P, Smith W, Attebo K, Wang JJ. Prevalence of age-related maculopathy in Australia. The Blue Mountains Eye Study. Ophthalmology 1995;102:1450–60. [11] Duke University Centre for the Study of Aging and Human Development. OARS Multidimensional Functional Assessment Questionnaire, 1975; 1988. [12] World Health Organization. Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1. Diagnosis and classification of diabetes mellitus. World Health Organization; 1999. [13] 2003 World Health Organization (WHO)/International Society of Hypertension (ISH) statement on management of hypertension. J Hypertens 2003;21:1983–92. [14] Folstein MF, Folstein SE, McHugh PR. “Mini-Mental State”: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189–98. [15] Andresen EM, Malmgren JA, Carter WB, Patrick DL. Screening for depression in well older adults: evaluation of a short form of the CES-D (Center for Epidemiologic Studies Depression Scale). Am J Prev Med 1994;10:77–84. [16] Timberlake GT, Omoscharka E, Quaney BM, Grose SA, Maino JH. Effect of bilateral macular scotomas from age-related macular degeneration on reachto-grasp hand movement. Invest Ophthalmol Vis Sci 2011;52:2540–50.
Contents lists available at ScienceDirect
Maturitas journal homepage: www.elsevier.com/locate/maturitas
Age-related macular degeneration and 5-year incidence of impaired activities of daily living Bamini Gopinath ∗ , Gerald Liew, George Burlutsky, Paul Mitchell Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, NSW, Australia
a r t i c l e
i n f o
Article history: Received 29 August 2013 Received in revised form 14 November 2013 Accepted 3 December 2013 Keywords: Age-related macular degeneration Activities of daily living Blue Mountains Eye Study Older adults
a b s t r a c t Objectives: We aimed to assess the prospective association between age-related macular degeneration (AMD) and impaired activities of daily living (ADL) among a large cohort of older adults. Study design: Functional status was determined by the Older Americans Resources and Services ADL scale from 2002–2004 to 2007–2009 among 761 participants aged 60+ years. AMD was assessed from retinal photographs. Results: After adjusting for age, sex, living status, self-rated poor health, smoking, body mass index, visual impairment, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores, having any AMD or late AMD increased the risk of incident impaired total ADL 5 years later, odds ratio, OR 2.87 (95% confidence intervals, CI 1.44–5.71) and OR 12.95 (95% CI 3.78–44.35), respectively. Having any AMD increased the risk of developing instrumental ADL disability over the 5 years, multivariable-adjusted OR 2.06 (95% CI 1.11–3.83). Conclusions: This study shows that the presence of AMD could independently signal an increased risk of functional disability, particularly in performing instrumental ADL tasks. © 2013 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Age-related macular degeneration (AMD) is the leading cause of blindness and low vision among older adults [1]. Loss of central vision in AMD means that everyday activities such as reading and driving cannot be performed [2]. The resulting severe disability involves enormous personal costs and is a massive burden on health resources [3]. Activities of daily living (ADL) measures are commonly used to assess older adults for disability in carrying out daily functions including basic ADL (BADL) such as eating, and instrumental ADL (IADL) required to function in the community, such as shopping [4]. However, there is a paucity of population-based studies that have prospectively assessed the associations between AMD and risk of ADL. Recently, a retrospective US study of 47 AMD subjects showed that visual acuity loss in AMD was associated with self-reported difficulties in IADLs [5]. Given that AMD is an important cause of blindness, a more comprehensive understanding of the impact of AMD on an individual’s functional status is needed. In particular, prospective studies studying the link between AMD and future functional impairment are
∗ Corresponding author at: Centre for Vision Research, University of Sydney, Westmead Hospital, Hawkesbury Road, Westmead, NSW 2145, Australia. Tel.: +61 2 9845 5551; fax: +61 2 9845 8345. E-mail address: [email protected] (B. Gopinath). 0378-5122/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.maturitas.2013.12.001
needed to provide important data which could assist in the longterm planning of health services and policies [6]. Therefore, using a relatively large cohort of adults aged ≥55 years we aimed to investigate whether there is a prospective association between AMD and functional status as assessed by a generic ADL scale. 2. Methods 2.1. Study population The Blue Mountains Eye Study (BMES) is a population-based cohort study of common eye diseases and other health outcomes in a suburban Australian population located west of Sydney. Study methods and procedures have been described elsewhere [7]. Baseline examinations of 3654 residents aged >49 years were conducted during 1992–1994 (BMES-1, 82.4% participation rate). Surviving baseline participants were invited to attend examinations after 5- (1997–1999, BMES-2), 10- (2002–2004, BMES-3), and 15 years (2007–2009, BMES-4). At BMES-2, -3 and -4, 2334 (75.1% of survivors), 1952 participants (75.6% of survivors) and 1149 (55.4% of survivors) with complete data were re-examined, respectively. All study participants provided written informed consent. 2.2. Assessment of AMD We took two 30◦ stereoscopic color retinal photographs of the macula of both eyes, which were graded for presence of early and
264
B. Gopinath et al. / Maturitas 77 (2014) 263–266
Table 1 Participant’s response to activities of daily living (ADL) questions stratified by the presence of AMD at the Blue Mountains Eye Study in 2002–2004 (n = 1288). Without AMD n 1. Can you use the telephone? 1057 No help 21 Some help/completely unable 2. Can you get to places out of walking distance? No help 1011 Some help/completely unable 68 3. Can you go shopping for groceries or clothes? 1012 No help 66 Some help/completely unable 4. Can you prepare your own meals? No help 1002 Some help/completely unable 75 5. Can you do your housework? 813 No help 259 Some help/completely unable 6. Can you take your own medications? 1042 No help 23 Some help/completely unable 7. Can you handle your own money? No help 1054 25 Some help/completely unable 8. Can you eat? 1075 No help 8 Some help/completely unable 9. Can you dress and undress yourself? 1071 No help Some help/completely unable 11 10. Can you take care of your own appearance? No help 1077 5 Some help/completely unable 11. Can you walk? No help 1058 24 Some help/completely unable 12. Can you get in and out of bed? 1077 No help 4 Some help/completely unable 13. Can you take a bath or shower? 1061 No help Some help/completely unable 20 14. Do you ever have trouble getting to bathroom on time? No 961 119 Yes or has a colostomy/catheter
late AMD using the Wisconsin AMD Grading System [8,9]. Interand intra-grader reliability showed good agreement for grading of specific AMD lesions with quadratic weighted kappa values ranging from 0.64 to 0.93 and 0.54 to 0.94 respectively [10]. The detailed methodology of AMD ascertainment in this population has been previously reported [8,9]. Early AMD was defined as the absence of late AMD and presence of either: (1) large (>125-m diameter) indistinct soft or reticular drusen or (2) both large distinct soft drusen and retinal pigmentary abnormalities (hyperpigmentation or hypopigmentation) in either eye [9]. Similarly, late AMD was defined as the presence of neovascular AMD or geographic atrophy in either eye [9]. Any AMD was defined as having early or late AMD. A retinal specialist (P.M.) adjudicated all uncertain retinal pathology and confirmed all late AMD cases. 2.3. Assessment of ADL disability The Older American Resources and Services (OARS) ADL scale [11] includes 14 items: seven items assess BADL (eating, dressing and undressing, grooming, walking, getting in and out of bed, bathing, and toileting), and seven items assess IADL (using the telephone, travel, shopping, meal preparation, housework, taking medicine, and management of finances). The OARS ADL scale was only administered at the 10- (2002–2004) and 15-year BMES examinations (2007–2009). Hence, we assessed the association between
With AMD
p value
%
n
%
98.1 2.0
179 18
90.9 9.1
93.7 6.3
174 23
88.3 11.7
93.9 6.1
169 28
85.8 14.2
93.0 7.0
173 24
87.8 12.2
0.01
75.8 24.2
127 70
64.5 35.5
0.001
97.8 2.2
186 5
97.4 2.6
0.69
97.7 2.3
183 15
92.4 7.6
99.3 0.7
198 1
99.5 0.5
0.71
99.0 1.0
197 3
98.5 1.5
0.55
99.5 0.5
198 1
99.5 0.5
0.94
97.8 2.2
191 8
96.0 4.0
0.13
99.6 0.4
196 2
99.0 1.0
0.23
98.2 1.9
194 5
97.5 2.5
0.53
89.0 11.0
170 30
85.0 15.0
0.11
<0.0001
0.01
<0.0001
<0.0001
AMD and the 5-year incidence of impaired ADL. Each item was rated on a 3-point scale: performs the activity without help (2), performs the activity with some help (1), or completely unable to perform the activity (0), hence, the higher the score the more independent the person is. Three summary scales were computed by summing the scores of items: (1) a total score, the sum of all 14 items (range 0–28), (2) a BADL score, the sum of the 7 BADL items (range 0–14), and (3) an IADL score, the sum of the 7 IADL items (range 0–14). Participants reporting that they needed help with any of the activities or were completely unable to perform any of the activities were considered to have impaired ADL. 2.4. Information on covariates At face-to-face interviews with trained interviewers, information about participant’s socio-economic characteristics and their medical history and lifestyle was collected. Level of education obtained was also ascertained and classified as lower than tertiary (i.e. did not attain any qualifications past high school) or tertiary and higher. Participants were also asked whether they received a pension. Participants self-reported history of smoking as never, past, or current smoking. Current smokers included those who had stopped smoking within the past year. Body mass index (BMI) was calculated as weight divided by height squared (kg/m2 ). Criteria for a diagnosis of diabetes were: self-reported diabetes history and
B. Gopinath et al. / Maturitas 77 (2014) 263–266 Table 2 Longitudinal association between AMD and total impaired Activities of Daily Living (ADL) at Blue Mountains Eye Study in 2004–2009 (n = 761). Presence of AMD
Mean ADL score (SD)
Total impaired ADLOR (95% CI) Multivariable-adjusteda
No AMD (n = 667) Any AMD (n = 94) Early AMD (n = 78) Late AMD (n = 16)
27.00 (2.3) 26.11 (3.3) 26.34 (3.3) 25.20 (3.1)
1.0 (reference) 2.87 (1.44–5.71) 1.74 (0.77–3.94) 12.95 (3.78–44.35)
a Adjusted for age, sex, living status, self-rated poor health, smoking, body mass index, best corrected visual acuity in better eye, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores.
current use of diabetic medications; or a fasting plasma glucose concentration ≥7.0 mmol/L [12]. Subjects were defined as having hypertension if they had systolic blood pressure greater than 140 mm Hg or diastolic blood pressure more than 90 mm Hg or were on anti-hypertensive medications [13]. Self-rated health was assessed by asking: ‘for somebody your age, would you say your health is excellent, very good, good, fair, or poor?’ Low self-rated health was defined as fair or poor. Walking difficulty or use of a cane, walker or wheelchair was subjectively observed by a trained examiner and categorized as ‘disability in walking’. Visual acuity was measured wearing current glasses, using a LogMar chart, and was followed by subjective refraction [7]. For each eye, visual acuity was recorded as the number of letters read correctly from 0 (<6/60) to 70 (6/3). Visual impairment was defined as visual acuity of less than 39 letters (<6/12) in the better eye after subjective refraction. Cognitive function was assessed using the mini-mental state exam (MMSE) administered at both the baseline and follow-up visits. MMSE scores range from 0 to 30 [14], with scores <24 indicating cognitive impairment. The 10item version of the Center for Epidemiologic Studies Depression Scale (CES-D-10) measures depressive feelings and behaviors experienced in the past week [15]. A cut-off score of ≥10 out of a total possible score of 30 was used to define participants with significant depressive symptoms [15].
2.5. Statistical analyses SAS software (SAS Institute, Cary, NC) version 9.2 was used for analyses including t-tests, 2 -tests and logistic regression. Multivariable logistic regression analysis was used to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI) to demonstrate the association between any, early or late AMD (dependent variables) and incidence of ADL disability, falls and fractures (independent variables), while adjusting for potential confounders.
3. Results Among BMES participants examined in 2002–2004, 1288 had complete ‘baseline’ AMD and ADL data, and were included in this study. Further, for incidence analyses, we included 761 participants who had baseline information on AMD and 5-year follow-up ADL data. A significantly higher proportion of persons with any AMD compared to those without AMD reported difficulties in performing six out of the seven IADL tasks (Table 1). Those with AMD at baseline, 26 (41.3%) reported impaired IADL 5 years later compared to 113 (22.1%) participants with no AMD. After multivariableadjustment, having any AMD or late AMD increased the risk of incident impaired total ADL by ∼3-fold and 13-fold, respectively (Table 2). Table 3 shows that any AMD was independently associated with the incidence of impaired IADL, OR 2.06 (95% CI
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Table 3 Longitudinal association between AMD and Impaired Instrumental Activities of Daily Living (IADL) at Blue Mountains Eye Study in 2002–2004 (n = 761). Presence of AMD
Mean IADL score (SD)
Impaired IADL OR (95% CI) Multivariableadjusteda
No AMD (n = 667) Any AMD (n = 94) Early AMD (n = 78) Late AMD (n = 16)
13.40 (1.3) 12.83 (2.0) 13.09 (1.7) 11.83 (2.5)
1.0 (reference) 2.06 (1.11–3.83) 1.92 (1.00–3.71) 2.93 (0.56–15.23)
a Adjusted for age, sex, living status, self-rated poor health, smoking, body mass index, best corrected visual acuity in better eye, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores.
1.11–3.83). AMD was not associated with incident BADL disability (data not shown).
4. Discussion We show that having any AMD or late AMD increased the risk of experiencing total ADL impairment by 3- and 13-fold, respectively, 5 years later. We need to advise caution, however, as there was a very small number of late AMD participants who had impaired total ADL 5 years later (n = 8), this could explain the wide 95% CI observed in relation to late AMD and incident ADL. Nevertheless, participants with any AMD compared to those with no AMD had ∼2-fold higher risk of incident IADL disability, i.e. were more likely to report difficulties in activities such as shopping, housework and using the telephone. Non-significant associations were observed between AMD and BADL incidence, which is in agreement with the notion that vision loss (except for extreme cases) is unlikely to lead to the inability to conduct simpler self-care tasks such as bathing and toileting [5]. However, AMD could still impact on functional status due to the need to depend on others for more complex tasks that characterize IADLs. Indeed, cross-sectional data from a small, US clinic-based study [5] showed that after multivariable adjustment, AMD was associated with IADL disability (p = 0.02). These findings concur with the 2-fold increased risk of incident IADL disability observed 5 years later among our participants with any AMD. Impaired mobility could be a potential pathway by which AMD could lead to IADL disability [5]. Individuals with AMD could become increasingly dependent on others for specific tasks such as grocery shopping, which requires a means of transportation or the ability to walk. Reduced accuracy for reaching or grasping objects in persons with AMD [16] could lead to disability with doing household chores/cooking as a result of difficulties in mobility and/or a fear of dropping heavy objects around the house. Finally, the inability to use the telephone and manage money is likely to be the result of reading difficulties caused by AMD [5]. We need to highlight that observed associations were independent of the influence of best corrected visual impairment in better eye, suggesting that AMD increases risk of ADL disability by other pathways. These data underscore the importance of developing rehabilitation interventions to target specific functional deficits in older adults with AMD. In summary, AMD increased the risk of experiencing IADL disability among older adults. The functional disability associated with AMD could come with great personal and societal costs [5]; hence, effective rehabilitation interventions that target older adults with AMD are important in order to maintain their functional independence.
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Contributors Study concept and design: BG and PM, Acquisition of subjects and data: PM. Analysis and interpretation of data: BG, GL, GB and PM. Preparation of Manuscript: BG. Important critical revision: BG, GL, GB and PM. Competing interests All authors have no conflict of interest and declare no financial interest. Funding The Blue Mountains Eye Study was supported by the Australian National Health and Medical Research Council (grant nos. 974159, 991407, 211069, 262120), and Westmead Millennium Institute. Bamini Gopinath is supported by a Macular Degeneration Foundation and Blackmores Dr. Paul Beaumont Fellowship. Ethical approval The University of Sydney and the Western Sydney Area Human Ethics Committees approved the study, and written, informed consent was obtained from all participants at each examination. References [1] Foran S, Wang JJ, Mitchell P. Causes of visual impairment in two older population cross-sections: the Blue Mountains Eye Study. Ophthalmic Epidemiol 2003;10:25–15.
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