The association of body mass index (BMI) with all-cause mortality in older Taiwanese: Results of a national cohort study

In older adults, underweight has been shown to be associated with increased all-cause mortality, but the association with excessive weight is inconclusive. The study aimed to determine the association of weight status with subsequent all-cause mortality risk in older Taiwanese. The study analyzed the dataset of the Survey of Health and Living Status of the Elderly in Taiwan, a nationally representative longitudinal cohort study. Baseline BMI calculated from self-reported weight and height (kg/m(2)) was used to predict all-cause mortality risk during subsequent four years in 2462 >= 53 years old Taiwanese. Cox-regression analysis was performed to determine the significance of the association of weight status with all-cause mortality during follow-up four-years controlled for demographic, lifestyle and health-related variables. Results showed that underweight was associated with increased risk of mortality risk in all age ranges examined, but excessive weight was not significantly associated with increased risk of mortality. Results suggest that the association between BMI status and all-cause mortality is L-shaped and obesity paradox may indeed exist in these specific age groups in Taiwanese over 65 years old. However, some uncertainty remains because confounding factors could not be totally controlled. Large scale prospective studies with better control of confounding factors are needed to resolve this important public health issue. (C) 2011 Elsevier Ireland Ltd. All rights reserved.