Gender-dependent association of body mass index and waist circumference with disability in the Chinese oldest old.
OBJECTIVE
To explore associations of BMI and waist circumference (WC) with disability among the Chinese oldest old.


METHODS
The 5,495 oldest old in the sixth wave of Chinese Longitudinal Healthy Longevity Study conducted in 2011 were included in this study. Disability was assessed by activities of daily living (ADL); height and weight for BMI and WC were measured; information including socio-demographics, lifestyles, and health status was collected.


RESULTS
Generalized additive models analysis showed that the association of BMI/WC with ADL disability was nonlinear. Among the males, logistic regression results supported a "J" shape association between ADL disability with BMI/WC-the highest tertile group in BMI or WC was significantly associated with an increased risk of ADL disability: odds ratio 1.78 (95% confidence interval (CI): 1.26-2.52) for BMI and 2.01 (95% CI: 1.44-2.82) for WC. Among females, an inverse "J" shape association was found, only the lowest tertile group before the cutoff point had an increased risk of ADL disability: odds ratio 1.42 (95%CI: 1.02-1.97) for BMI and 1.47 (95% CI:1.06-2.04) for WC.


CONCLUSIONS
Associations of BMI and WC with ADL disability are significant even in the oldest old, but differ between the genders.
Division of Non-communicable Diseases Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing, China.
Zhaoxue
Z
Yin
Division of Non-communicable Diseases Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing, China.
Xiaoming
X
Shi
Department of Medicine, Duke University School of Medicine, Durham, NC, USA.
Virginia B
VB
Kraus
Department of Sociology, Dickinson College, Carlisle, PA, USA.
Melanie Sereny
MS
Brasher
Center for the study of Aging and Human Development and the Geriatric Division of School of Medicine, Duke University, Durham, NC, USA.
Huashuai
H
Chen
Center for Study of Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China.
Yuzhi
Y
Liu
Division of Non-communicable Diseases Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing, China.
Yuebin
Y
Lv
Center for the study of Aging and Human Development and the Geriatric Division of School of Medicine, Duke University, Durham, NC, USA.|Center for Study of Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China.
Yi
Y
Zeng
D000203:Activities of Daily Living; D000369:Aged, 80 and over; D044466:Asian People; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002681:China; D006233:Persons with Disabilities; D005260:Female; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008136:Longevity; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D012737:Sex Factors; D055105:Waist Circumference