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Epidemiologic survey of locomotive syndrome in Japan
Journal of Orthopaedic Science 21 (2016) 222e225
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Original article
Epidemiologic survey of locomotive syndrome in Japan Atsushi Seichi a, *, Atsushi Kimura b, Shinichi Konno c, Shoji Yabuki c a
Department of Orthopaedic Surgery, Mitsui Memorial Hospital, Tokyo, Japan Department of Orthopaedics, Jichi Medical University, Tochigi, Japan c Department of Orthopaedic Surgery, Fukushima Medical University, Fukushima, Japan b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 30 September 2015 Received in revised form 3 December 2015 Accepted 14 December 2015 Available online 21 January 2016
Background: The authors have developed a screening tool, the 25-Geriatric Locomotive Function Scale (GLFS-25), for the early detection of locomotive syndrome (LS). However, few studies have examined the prevalence of LS in the general population. This study estimated the prevalence of LS in Japan using the GLSF-25 and investigated age specific mean values for this scale. Methods: A nationwide cross-sectional questionnaire survey was conducted to reveal standard values for the GLFS-25 and to estimate the total number of individuals with LS in Japan. Subjects were individuals selected from residents aged 40e79 years in Japan by a stratified, two-stage random sampling method in 2014. The survey period was from February to March 2014. A total of 9028 subjects were invited to participate. The GLFS-25 was used to estimate the prevalence of LS. We also investigated the degree of recognition of LS. Results: Answers for the questionnaire were obtained from 5162 subjects (57.2%); 22.1% of responders had heard of LS. According to the GLSF-25, 614 subjects were regarded as having LS, representing a prevalence of 11.9%. When standardizing this value with the age distribution of the Japanese population, the total number of individuals with LS between the 40s and 70s in Japan was estimated to be approximately 7.5 million. Age specific standard values on the GLFS-25 were 4.4 in the 40s, 5.5 in the 50s, 7.1 in the 60s, and 12.7 in the 70s. The prevalence of LS increased with age and was particularly high in subjects aged 70e79. Conclusions: The degree of recognition of LS was 22%. This study demonstrated sex- and age specific standard values of the GLFS-25 and estimated the total number of individuals with LS in Japan based on a representative population. © 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
1. Introduction With the advent of the “super-aged society,” the number of elderly who need nursing care is increasing sharply, leading to a heavy financial burden on society [1,2]. To reduce the number of elderly people requiring nursing care, the Japanese Orthopaedic Association (JOA) proposed a new concept of locomotive syndrome (LS) in 2007 [2]. LS refers to conditions under which the elderly will require nursing care service in the near future because of functional deterioration in the locomotive organs.
* Corresponding author. Department of Orthopaedic Surgery, Mitsui Memorial Hospital, 1 Kandaizumicho, Chiyoda-ku, Tokyo 101-8643, Japan. Tel.: þ81 3 3862 9111; fax: þ81 3 3862 9140. E-mail address: [email protected] (A. Seichi).
The authors have developed a screening tool, the 25-question Geriatric Locomotive Function Scale (GLFS-25), for the purpose of early detection of LS [3]. GLFS-25 is a self-administered, relatively comprehensive measure that consists of 25 questions regarding activities of daily living, social functioning, and mental health during the last month. In GLFS-25, the 25 items are graded using a 5-point scale ranging from no impairment (0 points) to severe impairment (4 points), and then added to produce a total score (minimum 0, maximum 100). Higher scores are associated with worse locomotive function. A previous study confirmed the validity and reliability of GLFS-25, and an optimal cutoff for identifying LS was set at 16 [3,4]. Several studies have investigated the mean values of GLFS-25 [5,6]; however, these values were obtained from relatively small community-based studies, and little is known of the nationwide prevalence of LS. We showed the standard value of GLFS-25 and estimated the total number of individuals with LS in Japan based on a nationwide, cross-sectional, Internet survey [7].
http://dx.doi.org/10.1016/j.jos.2015.12.012 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
223
Those results can help provide epidemiologic information for the Japanese government to decide on a policy regarding LS. However, there is some criticism against Internet-based surveys because of the selection bias introduced based on the non-representative nature of Internet population samples. To provide more exact epidemiologic information on LS, we conducted a cross-sectional survey involving a representative sample selected from Japanese residents. This study aimed to clarify the prevalence of LS in Japan, describe the degree of recognition of LS, and determine age-specific mean values for the GLSF-25.
Communications), data were standardized using the direct method to estimate the prevalence of LS in Japan. We also investigated agespecific mean values for the GLSF-25. Differences in group comparisons were determined by the ManneWhitney U test or KruskaleWallis test (Bonferroni collection). Probability values less than 0.05 were considered statistically significant. SPSS version 18.0 for Windows (SPSS Inc., Chicago, IL, USA) was used for all statistical analyses.
2. Materials and methods
A total of 9028 individuals were invited to participate in this survey, and answers for the questionnaire from 5162 were analyzed. Written informed consent was obtained from all the responders. Reasons for the 3866 non-responders included refusal to take part in the survey (n ¼ 2458), absence during the investigation period (n ¼ 657), sickness (n ¼ 92), and other (n ¼ 659). There were no statistical differences in gender or age distribution between responders and non-responders. Distributions of responders' sex, age, and geographic location are shown in Table 2.
2.1. Subjects This study was part of the JOA-Subsidized Science Project Research 2013 and conducted on commission from the JOA. The protocol was approved by the Institutional Review Boards of the JOA and Jichi Medical University. The study population consisted of all residents aged 40e79 years in Japan who were able to respond to questionnaires. Sampling was performed by a stratified, two-stage random sampling method [8e10]. As a first step, the nation was divided into 45 layers through a 9-area distribution (Hokkaido, Tohoku, Kanto, Hokuriku, Tokai, Kinki, Chugoku, Shikoku, and Kyushu area) and 5-city size distribution (1; 21 largest cities in Japan (Table 1), 2; cities of 200,000, 3; cities of 100,000, 4; cities of <100,000, 5; rural districts), and 350 points were selected on the basis of the population of each regional block and/or city-scale-classified layer. The number of sampling points for each group was determined by the population ratio (Table 1). As a second step, 24 subjects per point were randomly selected from “the Basic Resident Registration” in 2013 to obtain more than 4500 effective representative samples [7,8]. We conducted a cross-sectional survey involving questionnaire placement along with visits to the subjects' homes. The survey was handed to respondents by a trained data collector (Nippon Research Center, Ltd, Tokyo, Japan) who collected the completed survey 1 week later. The survey period was from February to March 2014. The questionnaires included the GFLS-25 [3] and one question about the name value of LS (Question: Do you know what LS is? Answer: 1. I know what it is; 2. I have only heard its name; 3. I do not know what it is).
3. Results
3.1. Name value of locomotive syndrome in early 2014 Of 5162 responders, 309 (6.0%) knew what LS was, 829 (16.1%) knew the name of LS, and 4024 (78.0%) did not know what LS was (Table 3). The recognition rate for LS was 22.1%. Recognition was highest in females in their 60s. 3.2. Standard values of the 25-question Geriatric locomotive function The sex- and age-specific standard values of GFLS-25 are summarized in Table 4. The age-specific standard values with 95% confidence intervals (95% CI) of GLFS-25 were 4.4 (95% CI: 4.1, 4.8) in the 40s, 5.5 (95% CI: 5.0, 6.0) in the 50s, 7.1 (95% CI: 6.6, 7.7) in the 60s, and 12.7 (95% CI: 11.6, 13.8) in the 70s, showing an increase with age. The standard value of GLFS-25 in the 70s was significantly higher than that in other age groups (P < 0.001, KruskaleWallis test, Bonferroni collection). The standard value of GLFS-25 in women was significantly higher than that in men (P < 0.001, ManneWhitney U test).
2.2. Statistical analysis
3.3. Prevalence of locomotive syndrome
On the basis of the population with regard to age in Japan in 2013 (Statistics Bureau, Ministry of Internal Affairs and
The age-specific prevalence of locomotive syndrome defined by GLFS-25 with a cutoff value of 16 is shown in Fig. 1. The prevalence of LS was 4.6% in the 40s and gradually increased up to 24.5% in the 70s. The overall mean prevalence of LS was 11.9% (614/5162).
Table 1 Number of survey points in Japan (total number ¼ 350). Area
Hokkaido Tohoku Kanto Hokuriku Tokai Kinki Chugoku Shikoku Kyushu
Population size of the cities 21 largest citiesa
200,000
100,000
100,000
Rural areas
5 3 45 2 10 17 5 0 8
2 7 29 5 9 17 5 4 8
3 3 23 2 9 8 5 2 5
3 8 20 6 9 11 4 4 12
3 5 7 1 3 3 2 2 6
a The 21 largest cities in Japan are Sapporo, Sendai, Saitama, Chiba, Tokyo, Yokohama, Kawasaki, Sagamihara, Niigata, Shizuoka, Hamamatsu, Nagoya, Kyoto, Osaka, Sakai, Kobe, Okayama, Hiroshima, Kitakyushu, Kumamoto, and Fukuoka.
Table 2 Distribution of responders' sex, age, and geographic location. Area
Hokkaido Tohoku Kanto Hokuriku Tokai Kinki Chugoku Shikoku Kyushu
Males by age
Females by age
40s
50s
60s
70s
40s
50s
60s
70s
21 37 235 41 68 104 27 7 74
32 53 174 28 64 81 47 19 70
38 48 235 44 94 81 49 32 112
24 38 200 23 47 69 42 14 64
34 43 227 41 94 110 41 17 86
36 67 203 27 74 84 45 28 73
29 76 262 36 79 123 51 34 94
30 51 206 35 79 96 33 20 62
224
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
Table 3 Degree of recognition of locomotive syndrome. Total (%)
Raw data (%)
I know what it is
I have only heard its name
I do not know it what it is
5162 (100.0)
309 (6.0)
829 (16.1)
4024 (78.0)
40s 50s 60s 70s
614 568 733 521
(100.0) (100.0) (100.0) (100.0)
23 31 26 16
(3.7) (5.5) (3.5) (3.1)
55 68 95 76
(9.0) (12.0) (13.0) (14.6)
536 469 612 429
(87.3) (82.6) (83.5) (82.3)
40s 50s 60s 70s
693 637 784 612
(100.0) (100.0) (100.0) (100.0)
43 48 84 38
(6.2) (7.5) (10.7) (6.2)
114 127 171 123
(16.5) (19.9) (21.8) (20.1)
536 462 529 451
(77.3) (72.5) (67.5) (73.7)
Males
Females
Table 4 Mean value of GLFS-25 and estimated number of individuals with LS. Sex Males
Age Number of subjects Mean value of GLFS-25 (95% CI) Estimated prevalence of LS Census population in 2013 Estimated number of individuals with LS
40s 50s 60s 70s All Females 40s 50s 60s 70s All All 40s 50s 60s 70s All
614 518 733 521 2436 693 637 784 612 2726 1307 1205 1517 1133 5162
4.5 5.3 7.1 11.8 7.0 4.4 5.5 7.1 12.7 7.6 4.4 5.5 7.1 12.7 7.3
(3.8e5.1) (4.6e6.1) (6.2e7.9) (10.2e13.5) (6.5e7.5) (3.9e4.9) (5.0e6.4) (6.4e7.9) (12.0e15.0) (7.1e8.0) (4.1e4.8) (5.0e6.0) (6.6e7.7) (11.6e13.8) (6.8e7.8)
4.4% 7.2% 11.5% 21.1% 10.8% 4.8% 8.3% 12.5% 27.5% 12.9% 4.6% 7.8% 12.0% 24.5% 11.9%
8,994,315 7,691,160 8,879,308 6,118,744 31,683,527 8,704,303 7,660,021 9,337,244 7,383,124 33,084,692 17,698,618 15,351,181 18,216,552 13,501,868 64,768,219
395,750 553,764 1,021,120 1,291,055 3,261,689 417,807 635,782 1,167,156 2,030,359 4,251,103 813,556 1,189,545 2,188,276 3,321,414 7,512,792
GLF25; 25-question Geriatric locomotive Function Scale; LS; Locomotive syndrome.
3.4. Estimated number of individuals with LS in Japan
4. Discussion
The number of individuals with LS was estimated based on the prevalence of LS and the national population census from “the Basic Resident Registration” in 2013. The total number of individuals with LS between 40s and 70s in Japan was estimated to be approximately 7.5 million (Table 4).
The concept of LS has emerged as a potential solution to the issue of rapidly increasing nursing care for the elderly in Japan [2]. A nationwide epidemiologic study of LS is an essential first step to take effective countermeasures against LS. Our Internet survey showed that there are approximately 6.5 million individuals with LS between their 40s and 70s in Japan [7]. There was a difference of 1 million between the previous Internet survey and the present study. Because of a higher quality of the study design, the result of this study is more reliable. One limitation of an Internet survey is sampling bias. In this study, a sample representing the Japanese population was selected by a stratified, two-stage random sampling method [8e10]. This method has been accepted as the best epidemiologic method. For example, clinical tests of validity of the Japanese Short-Form-36 health survey including validation of its scoring algorithms have been conducted using this sampling method [9]. The effective collection rate of 57.2% in this study was excellent for this kind of study, and there were no statistical differences in gender or age distribution between responders and non-responders. The results of this study can be generalized to Japanese people aged 40e79 years. This study demonstrated sex- and age-specific standard values of GLFS-25 and estimated the total number of individuals with LS in Japan using a reliable survey methods and a large sample size. The current results provide reference values of GFLS-25 for future studies and useful information for designing preventive strategies against the epidemic of LS.
Fig. 1. Prevalence of locomotive syndrome. The prevalence increased with age. The overall mean prevalence was 11.9% (614/5162).
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
The present study also showed that there are approximately 7.5 million of individuals with LS aged between 40 and 70 in Japan. This figure demonstrates the magnitude of the problem associated with nursing care in an aging society, and supports the idea that it is financially acceptable for the Japanese government to plan preventive strategies against LS. LS is highly prevalent in Japan. Increasing awareness of these findings is important for medical professionals and patients to gain a better understanding of LS and how to manage this disorder. The degree of recognition of LS was only 22.1% in this nationwide survey. The goal is to increase awareness of LS in Japan to more than 80% by 2024. Future studies and promotional activities should explore not only the treatment-seeking behaviors of individuals with LS but also the rapid, nationwide spread of the importance of recognizing the impact of this disorder. Conflict of interest This work was financially supported by a JOA Research Grant (2013-2) and a Japanese Society for Musculoskeletal Medicine Research Grant (No. 2013-4). All authors declare that they have no competing interests; each author certifies that no commercial relationships exist (e.g., consultancies, stock ownership, equity interests, patent/licensing arrangements, etc.) which might pose a conflict of interest in connection with this article.
225
References [1] Nakamura K. The concept and treatment of locomotive syndrome: its acceptance and spread in Japan. J Orthop Sci 2011;16:489e91. [2] Nakamura KA. “Super-aged” society and the “locomotive syndrome”. J Orthop Sci 2008;13:1e2. [3] Seichi A, Hoshino Y, Doi T, Akai M, Tobimatsu Y, Iwaya T. Development of a screening tool for risk of locomotive syndrome in the elderly: the 25-question Geriatric locomotive function Scale. J Orthop Sci 2012;17:163e72. [4] Seichi A, Hoshino Y, Doi T, Akai M, Tobimatsu Y, Kita K, Iwaya T. Determination of the optimal cutoff time to use when screening elderly people for locomotive syndrome using the one-leg standing test (with eyes open). J Orthop Sci 2014:620e6. [5] Muramoto A, Imagama S, Ito Z, Hirano K, Ishiguro N, Hasegawa Y. Physical performance tests are useful for evaluating and monitoring the severity of locomotive syndrome. J Orthop Sci 2012;17:782e8. [6] Muramoto A, Imagama S, Ito Z, Hirano K, Tauchi R, Ishiguro N, Hasegawa Y. Threshold values of physical performance tests for locomotive syndrome. J Orthop Sci 2013;18:618e26. [7] Kimura A, Seichi A, Konno S, Yabuki S, Hayashi K. Prevalence of locomotive syndrome in Japan: a nationwide, cross-sectional internet survey. J Orthop Sci 2014;19:792e7. [8] Yabuki S, Fukumori N, Takegami M, Onishi Y, Otani K, Sekiguchi M, Wakita T, Kikuchi S, Fukuhara S, Konno S. Prevalence of lumbar spinal stenosis, using the diagnostic support tool, and correlated factors in Japan: a population-based study. J Orthop Sci 2013;18:893e900. [9] Fukuhara S, Ware JE, Kosinski M, Wada S, Gandek B. Psychometric and clinical tests of validity of the Japanese SF-36 health survey. J Clin Epidemiol 1998;51: 1045e53. [10] Homma Y, Yamaguchi O, Hayashi K. Epidemiologic survey of lower urinary tract symptoms in Japan. Adult Urol 2006;68:560e4.
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Original article
Epidemiologic survey of locomotive syndrome in Japan Atsushi Seichi a, *, Atsushi Kimura b, Shinichi Konno c, Shoji Yabuki c a
Department of Orthopaedic Surgery, Mitsui Memorial Hospital, Tokyo, Japan Department of Orthopaedics, Jichi Medical University, Tochigi, Japan c Department of Orthopaedic Surgery, Fukushima Medical University, Fukushima, Japan b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 30 September 2015 Received in revised form 3 December 2015 Accepted 14 December 2015 Available online 21 January 2016
Background: The authors have developed a screening tool, the 25-Geriatric Locomotive Function Scale (GLFS-25), for the early detection of locomotive syndrome (LS). However, few studies have examined the prevalence of LS in the general population. This study estimated the prevalence of LS in Japan using the GLSF-25 and investigated age specific mean values for this scale. Methods: A nationwide cross-sectional questionnaire survey was conducted to reveal standard values for the GLFS-25 and to estimate the total number of individuals with LS in Japan. Subjects were individuals selected from residents aged 40e79 years in Japan by a stratified, two-stage random sampling method in 2014. The survey period was from February to March 2014. A total of 9028 subjects were invited to participate. The GLFS-25 was used to estimate the prevalence of LS. We also investigated the degree of recognition of LS. Results: Answers for the questionnaire were obtained from 5162 subjects (57.2%); 22.1% of responders had heard of LS. According to the GLSF-25, 614 subjects were regarded as having LS, representing a prevalence of 11.9%. When standardizing this value with the age distribution of the Japanese population, the total number of individuals with LS between the 40s and 70s in Japan was estimated to be approximately 7.5 million. Age specific standard values on the GLFS-25 were 4.4 in the 40s, 5.5 in the 50s, 7.1 in the 60s, and 12.7 in the 70s. The prevalence of LS increased with age and was particularly high in subjects aged 70e79. Conclusions: The degree of recognition of LS was 22%. This study demonstrated sex- and age specific standard values of the GLFS-25 and estimated the total number of individuals with LS in Japan based on a representative population. © 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
1. Introduction With the advent of the “super-aged society,” the number of elderly who need nursing care is increasing sharply, leading to a heavy financial burden on society [1,2]. To reduce the number of elderly people requiring nursing care, the Japanese Orthopaedic Association (JOA) proposed a new concept of locomotive syndrome (LS) in 2007 [2]. LS refers to conditions under which the elderly will require nursing care service in the near future because of functional deterioration in the locomotive organs.
* Corresponding author. Department of Orthopaedic Surgery, Mitsui Memorial Hospital, 1 Kandaizumicho, Chiyoda-ku, Tokyo 101-8643, Japan. Tel.: þ81 3 3862 9111; fax: þ81 3 3862 9140. E-mail address: [email protected] (A. Seichi).
The authors have developed a screening tool, the 25-question Geriatric Locomotive Function Scale (GLFS-25), for the purpose of early detection of LS [3]. GLFS-25 is a self-administered, relatively comprehensive measure that consists of 25 questions regarding activities of daily living, social functioning, and mental health during the last month. In GLFS-25, the 25 items are graded using a 5-point scale ranging from no impairment (0 points) to severe impairment (4 points), and then added to produce a total score (minimum 0, maximum 100). Higher scores are associated with worse locomotive function. A previous study confirmed the validity and reliability of GLFS-25, and an optimal cutoff for identifying LS was set at 16 [3,4]. Several studies have investigated the mean values of GLFS-25 [5,6]; however, these values were obtained from relatively small community-based studies, and little is known of the nationwide prevalence of LS. We showed the standard value of GLFS-25 and estimated the total number of individuals with LS in Japan based on a nationwide, cross-sectional, Internet survey [7].
http://dx.doi.org/10.1016/j.jos.2015.12.012 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
223
Those results can help provide epidemiologic information for the Japanese government to decide on a policy regarding LS. However, there is some criticism against Internet-based surveys because of the selection bias introduced based on the non-representative nature of Internet population samples. To provide more exact epidemiologic information on LS, we conducted a cross-sectional survey involving a representative sample selected from Japanese residents. This study aimed to clarify the prevalence of LS in Japan, describe the degree of recognition of LS, and determine age-specific mean values for the GLSF-25.
Communications), data were standardized using the direct method to estimate the prevalence of LS in Japan. We also investigated agespecific mean values for the GLSF-25. Differences in group comparisons were determined by the ManneWhitney U test or KruskaleWallis test (Bonferroni collection). Probability values less than 0.05 were considered statistically significant. SPSS version 18.0 for Windows (SPSS Inc., Chicago, IL, USA) was used for all statistical analyses.
2. Materials and methods
A total of 9028 individuals were invited to participate in this survey, and answers for the questionnaire from 5162 were analyzed. Written informed consent was obtained from all the responders. Reasons for the 3866 non-responders included refusal to take part in the survey (n ¼ 2458), absence during the investigation period (n ¼ 657), sickness (n ¼ 92), and other (n ¼ 659). There were no statistical differences in gender or age distribution between responders and non-responders. Distributions of responders' sex, age, and geographic location are shown in Table 2.
2.1. Subjects This study was part of the JOA-Subsidized Science Project Research 2013 and conducted on commission from the JOA. The protocol was approved by the Institutional Review Boards of the JOA and Jichi Medical University. The study population consisted of all residents aged 40e79 years in Japan who were able to respond to questionnaires. Sampling was performed by a stratified, two-stage random sampling method [8e10]. As a first step, the nation was divided into 45 layers through a 9-area distribution (Hokkaido, Tohoku, Kanto, Hokuriku, Tokai, Kinki, Chugoku, Shikoku, and Kyushu area) and 5-city size distribution (1; 21 largest cities in Japan (Table 1), 2; cities of 200,000, 3; cities of 100,000, 4; cities of <100,000, 5; rural districts), and 350 points were selected on the basis of the population of each regional block and/or city-scale-classified layer. The number of sampling points for each group was determined by the population ratio (Table 1). As a second step, 24 subjects per point were randomly selected from “the Basic Resident Registration” in 2013 to obtain more than 4500 effective representative samples [7,8]. We conducted a cross-sectional survey involving questionnaire placement along with visits to the subjects' homes. The survey was handed to respondents by a trained data collector (Nippon Research Center, Ltd, Tokyo, Japan) who collected the completed survey 1 week later. The survey period was from February to March 2014. The questionnaires included the GFLS-25 [3] and one question about the name value of LS (Question: Do you know what LS is? Answer: 1. I know what it is; 2. I have only heard its name; 3. I do not know what it is).
3. Results
3.1. Name value of locomotive syndrome in early 2014 Of 5162 responders, 309 (6.0%) knew what LS was, 829 (16.1%) knew the name of LS, and 4024 (78.0%) did not know what LS was (Table 3). The recognition rate for LS was 22.1%. Recognition was highest in females in their 60s. 3.2. Standard values of the 25-question Geriatric locomotive function The sex- and age-specific standard values of GFLS-25 are summarized in Table 4. The age-specific standard values with 95% confidence intervals (95% CI) of GLFS-25 were 4.4 (95% CI: 4.1, 4.8) in the 40s, 5.5 (95% CI: 5.0, 6.0) in the 50s, 7.1 (95% CI: 6.6, 7.7) in the 60s, and 12.7 (95% CI: 11.6, 13.8) in the 70s, showing an increase with age. The standard value of GLFS-25 in the 70s was significantly higher than that in other age groups (P < 0.001, KruskaleWallis test, Bonferroni collection). The standard value of GLFS-25 in women was significantly higher than that in men (P < 0.001, ManneWhitney U test).
2.2. Statistical analysis
3.3. Prevalence of locomotive syndrome
On the basis of the population with regard to age in Japan in 2013 (Statistics Bureau, Ministry of Internal Affairs and
The age-specific prevalence of locomotive syndrome defined by GLFS-25 with a cutoff value of 16 is shown in Fig. 1. The prevalence of LS was 4.6% in the 40s and gradually increased up to 24.5% in the 70s. The overall mean prevalence of LS was 11.9% (614/5162).
Table 1 Number of survey points in Japan (total number ¼ 350). Area
Hokkaido Tohoku Kanto Hokuriku Tokai Kinki Chugoku Shikoku Kyushu
Population size of the cities 21 largest citiesa
200,000
100,000
100,000
Rural areas
5 3 45 2 10 17 5 0 8
2 7 29 5 9 17 5 4 8
3 3 23 2 9 8 5 2 5
3 8 20 6 9 11 4 4 12
3 5 7 1 3 3 2 2 6
a The 21 largest cities in Japan are Sapporo, Sendai, Saitama, Chiba, Tokyo, Yokohama, Kawasaki, Sagamihara, Niigata, Shizuoka, Hamamatsu, Nagoya, Kyoto, Osaka, Sakai, Kobe, Okayama, Hiroshima, Kitakyushu, Kumamoto, and Fukuoka.
Table 2 Distribution of responders' sex, age, and geographic location. Area
Hokkaido Tohoku Kanto Hokuriku Tokai Kinki Chugoku Shikoku Kyushu
Males by age
Females by age
40s
50s
60s
70s
40s
50s
60s
70s
21 37 235 41 68 104 27 7 74
32 53 174 28 64 81 47 19 70
38 48 235 44 94 81 49 32 112
24 38 200 23 47 69 42 14 64
34 43 227 41 94 110 41 17 86
36 67 203 27 74 84 45 28 73
29 76 262 36 79 123 51 34 94
30 51 206 35 79 96 33 20 62
224
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
Table 3 Degree of recognition of locomotive syndrome. Total (%)
Raw data (%)
I know what it is
I have only heard its name
I do not know it what it is
5162 (100.0)
309 (6.0)
829 (16.1)
4024 (78.0)
40s 50s 60s 70s
614 568 733 521
(100.0) (100.0) (100.0) (100.0)
23 31 26 16
(3.7) (5.5) (3.5) (3.1)
55 68 95 76
(9.0) (12.0) (13.0) (14.6)
536 469 612 429
(87.3) (82.6) (83.5) (82.3)
40s 50s 60s 70s
693 637 784 612
(100.0) (100.0) (100.0) (100.0)
43 48 84 38
(6.2) (7.5) (10.7) (6.2)
114 127 171 123
(16.5) (19.9) (21.8) (20.1)
536 462 529 451
(77.3) (72.5) (67.5) (73.7)
Males
Females
Table 4 Mean value of GLFS-25 and estimated number of individuals with LS. Sex Males
Age Number of subjects Mean value of GLFS-25 (95% CI) Estimated prevalence of LS Census population in 2013 Estimated number of individuals with LS
40s 50s 60s 70s All Females 40s 50s 60s 70s All All 40s 50s 60s 70s All
614 518 733 521 2436 693 637 784 612 2726 1307 1205 1517 1133 5162
4.5 5.3 7.1 11.8 7.0 4.4 5.5 7.1 12.7 7.6 4.4 5.5 7.1 12.7 7.3
(3.8e5.1) (4.6e6.1) (6.2e7.9) (10.2e13.5) (6.5e7.5) (3.9e4.9) (5.0e6.4) (6.4e7.9) (12.0e15.0) (7.1e8.0) (4.1e4.8) (5.0e6.0) (6.6e7.7) (11.6e13.8) (6.8e7.8)
4.4% 7.2% 11.5% 21.1% 10.8% 4.8% 8.3% 12.5% 27.5% 12.9% 4.6% 7.8% 12.0% 24.5% 11.9%
8,994,315 7,691,160 8,879,308 6,118,744 31,683,527 8,704,303 7,660,021 9,337,244 7,383,124 33,084,692 17,698,618 15,351,181 18,216,552 13,501,868 64,768,219
395,750 553,764 1,021,120 1,291,055 3,261,689 417,807 635,782 1,167,156 2,030,359 4,251,103 813,556 1,189,545 2,188,276 3,321,414 7,512,792
GLF25; 25-question Geriatric locomotive Function Scale; LS; Locomotive syndrome.
3.4. Estimated number of individuals with LS in Japan
4. Discussion
The number of individuals with LS was estimated based on the prevalence of LS and the national population census from “the Basic Resident Registration” in 2013. The total number of individuals with LS between 40s and 70s in Japan was estimated to be approximately 7.5 million (Table 4).
The concept of LS has emerged as a potential solution to the issue of rapidly increasing nursing care for the elderly in Japan [2]. A nationwide epidemiologic study of LS is an essential first step to take effective countermeasures against LS. Our Internet survey showed that there are approximately 6.5 million individuals with LS between their 40s and 70s in Japan [7]. There was a difference of 1 million between the previous Internet survey and the present study. Because of a higher quality of the study design, the result of this study is more reliable. One limitation of an Internet survey is sampling bias. In this study, a sample representing the Japanese population was selected by a stratified, two-stage random sampling method [8e10]. This method has been accepted as the best epidemiologic method. For example, clinical tests of validity of the Japanese Short-Form-36 health survey including validation of its scoring algorithms have been conducted using this sampling method [9]. The effective collection rate of 57.2% in this study was excellent for this kind of study, and there were no statistical differences in gender or age distribution between responders and non-responders. The results of this study can be generalized to Japanese people aged 40e79 years. This study demonstrated sex- and age-specific standard values of GLFS-25 and estimated the total number of individuals with LS in Japan using a reliable survey methods and a large sample size. The current results provide reference values of GFLS-25 for future studies and useful information for designing preventive strategies against the epidemic of LS.
Fig. 1. Prevalence of locomotive syndrome. The prevalence increased with age. The overall mean prevalence was 11.9% (614/5162).
A. Seichi et al. / Journal of Orthopaedic Science 21 (2016) 222e225
The present study also showed that there are approximately 7.5 million of individuals with LS aged between 40 and 70 in Japan. This figure demonstrates the magnitude of the problem associated with nursing care in an aging society, and supports the idea that it is financially acceptable for the Japanese government to plan preventive strategies against LS. LS is highly prevalent in Japan. Increasing awareness of these findings is important for medical professionals and patients to gain a better understanding of LS and how to manage this disorder. The degree of recognition of LS was only 22.1% in this nationwide survey. The goal is to increase awareness of LS in Japan to more than 80% by 2024. Future studies and promotional activities should explore not only the treatment-seeking behaviors of individuals with LS but also the rapid, nationwide spread of the importance of recognizing the impact of this disorder. Conflict of interest This work was financially supported by a JOA Research Grant (2013-2) and a Japanese Society for Musculoskeletal Medicine Research Grant (No. 2013-4). All authors declare that they have no competing interests; each author certifies that no commercial relationships exist (e.g., consultancies, stock ownership, equity interests, patent/licensing arrangements, etc.) which might pose a conflict of interest in connection with this article.
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