Obesity Research & Clinical Practice (2013) 7, e401—e406
ORIGINAL ARTICLE
BMI percentile curves for Japanese men and women aged 20—79 years who underwent a health checkup in 1980 and 2005 Yukako Tatsumi a,∗ , Yuko Ohno a , Akiko Morimoto a , Yoshio Nishigaki b , Shoichi Mizuno c, Shaw Watanabe d a
Department of Mathematical Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan b Saku Central Hospital, Nagano, Japan c National Institute of Health and Nutrition, Tokyo, Japan d Life Science Promoting Association, Tokyo, Japan Received 10 November 2011 ; received in revised form 20 April 2012; accepted 5 May 2012
KEYWORDS BMI; Percentile curve; LMS method; Japanese; Sex
Summary Objective: To establish body mass index (BMI) percentile curves for adults and to compare these in 1980 with those in 2005 among Japanese men and women. Methods: Participants included 8080 community residents aged 20—79 years who had a health check-up in 1980 and 5616 community residents aged 20—79 years who had a health check-up in 2005. Sex-specific percentile curves for BMI were constructed using the LMS method. We presented the 3rd, 5th, 15th, 25th, 50th, 75th, 85th, 95th, and 97th percentile curves. Results: From 1980 to 2005, the BMI percentile values of men increased, especially the 95th and 97th percentile values in men aged 20—39 years. The BMI distribution of young men in 2005 was wider than that in 1980. From 1980 to 2005, the 50th percentile values of women in 2005 were lower than those in 1980. However, the 95th percentile values of women increased among women aged less than 50 years. Conclusion: We were able to confirm the existence of BMI percentile values depending on date, age, and sex by establishing BMI percentile curves. © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
∗
Corresponding author at: 1-7 Yamadaoka, Suita, Osaka 5650871, Japan. Tel.: +81 6 6879 2526; fax: +81 6 6879 2524. E-mail address: [email protected] (Y. Tatsumi).
Introduction Obesity is a major risk factor for not only the metabolic syndrome and type 2 diabetes mellitus
1871-403X/$ — see front matter © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.orcp.2012.05.004
e402 but also cardiovascular disease, the leading cause of death worldwide [1,2]. Because the obesity rate increases yearly, prevention of obesity is becoming a worldwide problem [3]. At the same time, being underweight is associated with a substantially increased risk of death in Asian populations [4]. Therefore, it is important to control body weight appropriately. Population indexes for body weight control are usually the average body mass index (BMI) and the obesity rate. However, healthcare professionals should conceptualize BMI values according to age and sex. In addition, individuals should check their own BMI values to control their body weight. The BMI percentile curve, which can track BMI values visually, is a tool used in health education and guidance for school-aged children and adolescents. In 2007, the World Health Organization released new growth references for school-aged children and adolescents [5], and the US Centers for Disease Control and Prevention released updated growth charts [6]. Both updates included BMI percentiles to evaluate obesity in school-aged children and adolescents. The BMI percentile curve may be an effective tool to manage BMI in adults as well. In addition, a BMI percentile curve may make it possible to evaluate body weight control in a specific population. However, no study has created BMI percentile curves for adults. The aims of the present study were to establish BMI percentile curves for adults and to compare BMI percentile curves in 1980 with those in 2005 among Japanese men and women.
Methods Study participants Data came from health check-ups from a single central hospital in a rural area of Nagano Prefecture in Japan. Participants were 8080 community residents (3191 men and 4889 women) aged 20—79 years who had a health check-up in 1980 and 5616 community residents (2016 men and 3600 women) aged 20—79 years who had a health check-up in 2005. We excluded 162 participants in 1980 and 18 in 2005 who did not have their body weight and/or height measured. Consequently, the remaining 7918 (3145 men and 4773 women) participants in 1980 and 5598 (2009 men and 3589 women) in 2005 were included in the analysis. The Ethical Committee of Saku Central Hospital approved the study (21—15).
Y. Tatsumi et al.
Data collection Nurses measured weight and height. Participants were weighed while wearing light clothing, and height was measured without shoes. The BMI (kg/m2 ) was calculated as weight (kg) divided by the square of height (m). A self-administered questionnaire included in the health check-up allowed for collection of demographic information. Cardiometabolic outcomes included blood pressure, total cholesterol, and triglycerides. Total cholesterol was measured by the cholesterol oxidase — DAOS method, while triglycerides were measured by the ultraviolet method.
Statistical analysis To compare baseline characteristics, we used analysis of variance for age and BMI, and the general linear model with adjustments for age for systolic blood pressure, total cholesterol, and triglycerides. We made sex-specific percentile curves for BMI with the LMS method developed by Cole and Green [8]. Details of this method and its application have been described [7,8]. Briefly, the distribution at BMI values was summarized by three parameters: the mean, skew, and kurtosis. The Box—Cox power (L), the median (M), and the coefficient of variation (S). The three parameters are constrained to change smoothly as the BMI changes, and can, similar to centiles, be plotted against BMI. Thus, one advantage of the LMS method is that the three curves, L, M, and S, completely summarize the measurement’s distribution over the range of BMI. In this study, we used the Akaike minimum ABIC method for smoothing [9]. We calculated and presented the smoothed L, M, and S values for each age- and sex-specific point. Table 1 shows the number of participants and smoothed L, M, and S values by age and sex in 1980 and 2005. The equation for the LMS is: Z=
(measurement/M)L−1 LS
where Z is the z-score that corresponds to a percentile. We presented the following BMI percentile curves for men and women aged 20—79 years: 3rd, 5th, 15th, 25th, 50th, 75th, 85th, 95th, and 97th.
Results Table 2 summarizes participants’ characteristics according to sex and year. The average age rose from 1980 to 2005 among both sexes. The estimated
Body mass index-for-age and LMS parameters of men and women aged 20—79 years in 1980 and 2005.
Age (year)
1980
2005
Men (n = 3145) 20—24 25—29 30—34 35—39 40—44 45—49 50—54 55—59 60—64 65—69 70—74 75—79
Women (n = 4773)
n
M
L
S
124 253 283 258 315 419 428 346 278 243 135 63
21.95 22.16 22.80 23.08 23.39 23.25 23.22 22.95 22.30 22.38 22.13 22.04
−1.458 −1.033 −0.530 −0.552 −0.312 −0.307 −0.313 −0.441 −0.578 −0.596 −0.409 −0.366
0.107 0.109 0.114 0.110 0.109 0.111 0.112 0.115 0.115 0.117 0.121 0.118
n 390 287 332 388 457 592 665 667 477 318 146 54
Men (n = 2009)
Women (n = 3589)
M
L
S
n
M
L
S
n
M
L
S
21.30 21.10 21.79 22.83 23.15 23.65 23.75 24.01 23.78 23.66 22.85 22.82
−1.530 −1.284 −0.947 −0.631 −0.586 −0.538 0.124 0.339 0.343 0.233 0.071 −0.210
0.109 0.110 0.113 0.117 0.117 0.118 0.122 0.128 0.136 0.142 0.145 0.145
36 52 75 70 103 133 167 160 224 284 364 341
22.70 22.92 23.68 23.65 23.62 23.61 23.74 23.70 23.98 23.58 23.36 23.26
−1.059 −0.755 −1.187 −0.351 −0.221 −0.329 −0.687 −0.049 0.080 0.371 0.487 0.841
0.134 0.141 0.137 0.137 0.124 0.117 0.115 0.117 0.108 0.121 0.124 0.123
23 75 136 186 222 262 288 329 439 520 591 518
20.83 20.38 20.40 21.16 21.49 22.29 22.48 22.69 23.15 23.08 23.64 23.42
−2.994 −2.735 −2.391 −0.825 −1.584 −1.706 −0.826 −0.164 −0.026 −0.121 0.135 0.694
0.121 0.121 0.123 0.132 0.134 0.130 0.129 0.138 0.132 0.134 0.136 0.138
BMI percentile curves in 1980 and 2005
Table 1
M, for the median. L, for the power in the Box—Cox transformation. S, for the coefficient of variation. BMI, body mass index.
Table 2
Participants’ characteristics according to sex and year. 1980
n Age (year)a Body mass index (kg/m2 )a 20—29 years 30—39 years 40—49 years 50—59 years 60—69 years 70—79 years Systolic blood pressure (mmHg)b Total cholesterol (mg/dl)b Triglycerides (mg/dl)b a
p-Value
Men (1)
Women (2)
Men (3)
Women (4)
1 vs. 2
1 vs. 3
2 vs. 4
3 vs. 4
3145 48.8 ± 14.6
4773 48.2 ± 15.3
2009 60.3 ± 14.8
3589 59.6 ± 14.1
0.888
ORIGINAL ARTICLE
BMI percentile curves for Japanese men and women aged 20—79 years who underwent a health checkup in 1980 and 2005 Yukako Tatsumi a,∗ , Yuko Ohno a , Akiko Morimoto a , Yoshio Nishigaki b , Shoichi Mizuno c, Shaw Watanabe d a
Department of Mathematical Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan b Saku Central Hospital, Nagano, Japan c National Institute of Health and Nutrition, Tokyo, Japan d Life Science Promoting Association, Tokyo, Japan Received 10 November 2011 ; received in revised form 20 April 2012; accepted 5 May 2012
KEYWORDS BMI; Percentile curve; LMS method; Japanese; Sex
Summary Objective: To establish body mass index (BMI) percentile curves for adults and to compare these in 1980 with those in 2005 among Japanese men and women. Methods: Participants included 8080 community residents aged 20—79 years who had a health check-up in 1980 and 5616 community residents aged 20—79 years who had a health check-up in 2005. Sex-specific percentile curves for BMI were constructed using the LMS method. We presented the 3rd, 5th, 15th, 25th, 50th, 75th, 85th, 95th, and 97th percentile curves. Results: From 1980 to 2005, the BMI percentile values of men increased, especially the 95th and 97th percentile values in men aged 20—39 years. The BMI distribution of young men in 2005 was wider than that in 1980. From 1980 to 2005, the 50th percentile values of women in 2005 were lower than those in 1980. However, the 95th percentile values of women increased among women aged less than 50 years. Conclusion: We were able to confirm the existence of BMI percentile values depending on date, age, and sex by establishing BMI percentile curves. © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
∗
Corresponding author at: 1-7 Yamadaoka, Suita, Osaka 5650871, Japan. Tel.: +81 6 6879 2526; fax: +81 6 6879 2524. E-mail address: [email protected] (Y. Tatsumi).
Introduction Obesity is a major risk factor for not only the metabolic syndrome and type 2 diabetes mellitus
1871-403X/$ — see front matter © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.orcp.2012.05.004
e402 but also cardiovascular disease, the leading cause of death worldwide [1,2]. Because the obesity rate increases yearly, prevention of obesity is becoming a worldwide problem [3]. At the same time, being underweight is associated with a substantially increased risk of death in Asian populations [4]. Therefore, it is important to control body weight appropriately. Population indexes for body weight control are usually the average body mass index (BMI) and the obesity rate. However, healthcare professionals should conceptualize BMI values according to age and sex. In addition, individuals should check their own BMI values to control their body weight. The BMI percentile curve, which can track BMI values visually, is a tool used in health education and guidance for school-aged children and adolescents. In 2007, the World Health Organization released new growth references for school-aged children and adolescents [5], and the US Centers for Disease Control and Prevention released updated growth charts [6]. Both updates included BMI percentiles to evaluate obesity in school-aged children and adolescents. The BMI percentile curve may be an effective tool to manage BMI in adults as well. In addition, a BMI percentile curve may make it possible to evaluate body weight control in a specific population. However, no study has created BMI percentile curves for adults. The aims of the present study were to establish BMI percentile curves for adults and to compare BMI percentile curves in 1980 with those in 2005 among Japanese men and women.
Methods Study participants Data came from health check-ups from a single central hospital in a rural area of Nagano Prefecture in Japan. Participants were 8080 community residents (3191 men and 4889 women) aged 20—79 years who had a health check-up in 1980 and 5616 community residents (2016 men and 3600 women) aged 20—79 years who had a health check-up in 2005. We excluded 162 participants in 1980 and 18 in 2005 who did not have their body weight and/or height measured. Consequently, the remaining 7918 (3145 men and 4773 women) participants in 1980 and 5598 (2009 men and 3589 women) in 2005 were included in the analysis. The Ethical Committee of Saku Central Hospital approved the study (21—15).
Y. Tatsumi et al.
Data collection Nurses measured weight and height. Participants were weighed while wearing light clothing, and height was measured without shoes. The BMI (kg/m2 ) was calculated as weight (kg) divided by the square of height (m). A self-administered questionnaire included in the health check-up allowed for collection of demographic information. Cardiometabolic outcomes included blood pressure, total cholesterol, and triglycerides. Total cholesterol was measured by the cholesterol oxidase — DAOS method, while triglycerides were measured by the ultraviolet method.
Statistical analysis To compare baseline characteristics, we used analysis of variance for age and BMI, and the general linear model with adjustments for age for systolic blood pressure, total cholesterol, and triglycerides. We made sex-specific percentile curves for BMI with the LMS method developed by Cole and Green [8]. Details of this method and its application have been described [7,8]. Briefly, the distribution at BMI values was summarized by three parameters: the mean, skew, and kurtosis. The Box—Cox power (L), the median (M), and the coefficient of variation (S). The three parameters are constrained to change smoothly as the BMI changes, and can, similar to centiles, be plotted against BMI. Thus, one advantage of the LMS method is that the three curves, L, M, and S, completely summarize the measurement’s distribution over the range of BMI. In this study, we used the Akaike minimum ABIC method for smoothing [9]. We calculated and presented the smoothed L, M, and S values for each age- and sex-specific point. Table 1 shows the number of participants and smoothed L, M, and S values by age and sex in 1980 and 2005. The equation for the LMS is: Z=
(measurement/M)L−1 LS
where Z is the z-score that corresponds to a percentile. We presented the following BMI percentile curves for men and women aged 20—79 years: 3rd, 5th, 15th, 25th, 50th, 75th, 85th, 95th, and 97th.
Results Table 2 summarizes participants’ characteristics according to sex and year. The average age rose from 1980 to 2005 among both sexes. The estimated
Body mass index-for-age and LMS parameters of men and women aged 20—79 years in 1980 and 2005.
Age (year)
1980
2005
Men (n = 3145) 20—24 25—29 30—34 35—39 40—44 45—49 50—54 55—59 60—64 65—69 70—74 75—79
Women (n = 4773)
n
M
L
S
124 253 283 258 315 419 428 346 278 243 135 63
21.95 22.16 22.80 23.08 23.39 23.25 23.22 22.95 22.30 22.38 22.13 22.04
−1.458 −1.033 −0.530 −0.552 −0.312 −0.307 −0.313 −0.441 −0.578 −0.596 −0.409 −0.366
0.107 0.109 0.114 0.110 0.109 0.111 0.112 0.115 0.115 0.117 0.121 0.118
n 390 287 332 388 457 592 665 667 477 318 146 54
Men (n = 2009)
Women (n = 3589)
M
L
S
n
M
L
S
n
M
L
S
21.30 21.10 21.79 22.83 23.15 23.65 23.75 24.01 23.78 23.66 22.85 22.82
−1.530 −1.284 −0.947 −0.631 −0.586 −0.538 0.124 0.339 0.343 0.233 0.071 −0.210
0.109 0.110 0.113 0.117 0.117 0.118 0.122 0.128 0.136 0.142 0.145 0.145
36 52 75 70 103 133 167 160 224 284 364 341
22.70 22.92 23.68 23.65 23.62 23.61 23.74 23.70 23.98 23.58 23.36 23.26
−1.059 −0.755 −1.187 −0.351 −0.221 −0.329 −0.687 −0.049 0.080 0.371 0.487 0.841
0.134 0.141 0.137 0.137 0.124 0.117 0.115 0.117 0.108 0.121 0.124 0.123
23 75 136 186 222 262 288 329 439 520 591 518
20.83 20.38 20.40 21.16 21.49 22.29 22.48 22.69 23.15 23.08 23.64 23.42
−2.994 −2.735 −2.391 −0.825 −1.584 −1.706 −0.826 −0.164 −0.026 −0.121 0.135 0.694
0.121 0.121 0.123 0.132 0.134 0.130 0.129 0.138 0.132 0.134 0.136 0.138
BMI percentile curves in 1980 and 2005
Table 1
M, for the median. L, for the power in the Box—Cox transformation. S, for the coefficient of variation. BMI, body mass index.
Table 2
Participants’ characteristics according to sex and year. 1980
n Age (year)a Body mass index (kg/m2 )a 20—29 years 30—39 years 40—49 years 50—59 years 60—69 years 70—79 years Systolic blood pressure (mmHg)b Total cholesterol (mg/dl)b Triglycerides (mg/dl)b a
p-Value
Men (1)
Women (2)
Men (3)
Women (4)
1 vs. 2
1 vs. 3
2 vs. 4
3 vs. 4
3145 48.8 ± 14.6
4773 48.2 ± 15.3
2009 60.3 ± 14.8
3589 59.6 ± 14.1
0.888
