Association Between Body-Mass Index and Risk of Death in More Than 1 Million Asians

Study Questions:

Is body mass index (BMI) associated with increased mortality risk among Asian men and women?

Methods:

Subjects enrolled in 19 studies, all from Asia, were included in this pooled analysis. Subjects with missing data on age, BMI, vital status, and age under 18 years were excluded. Additional exclusion criteria included those with a BMI over 50 kg/m2. Over 1.1 million adults were followed over a mean follow-up period of 9.2 years. Cox regression models were used to adjust for potential confounding factors.

Results:

A total of 1,141,609 subjects (535,199 men and 606,410 women) were included in this analysis. The overall mean BMI was 22.9 ± 3.6 (range, 19.8-23.7 kg/m2). Approximately 120,700 deaths were recorded (35.7% from cardiovascular disease, and 29.9% from cancer). The lowest risk of death was observed among persons with a BMI in the range of 22.6-27.5 kg/m2. Risk for death was increased for those with a BMI under or over that range. For those with a BMI of 35 kg/m2 or greater, the increased risk was 50%. For subjects with a BMI of 15 kg/m2 or less, the risk of death ranged from 2.0-2.8. A similar U-shaped association was observed between BMI and risk for death from cancer, from cardiovascular disease, and from other causes. In cohorts comprising Indians and Bangladeshis, the risk of death from any cause and from causes other than cancer or cardiovascular disease was increased among persons with a BMI of 20 kg/m2 or less, as compared to those with a BMI between 22.6 and 25 kg/m2. No increased risk of death for this group was noted with a higher BMI.

Conclusions:

The investigators concluded that underweight was associated with an increased risk of death in all Asian populations, and increase in BMI was associated with an increased risk of death for East Asians, but not for Indians and Bangladeshis.

Perspective:

This large-scale study suggests that BMI is an important marker for health; being underweight is a significant indicator of increased all-cause mortality. Factors associated with being underweight may identify opportunities for intervention. Among those populations with increased mortality risk associated with increased BMI, a similar analysis will assist public health efforts in areas of preventive care.

Keywords: Risk, Follow-Up Studies, Thinness, Body Mass Index, Cardiovascular Diseases, Asian Continental Ancestry Group


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