Body Mass Index and Mortality in Chinese Older Adults -New Evidence from a Large Prospective Cohort in China.

objectivesTo comprehensively evaluate the association between BMI and death risk in people aged 65 years and over in Shenzhen, China, and suggest the optimal range of body mass index (BMI) for the older adults.

designA prospective cohort study.

settingA population-based study of elderly adults in Shenzhen, China.

participants359044 Shenzhen Healthy Ageing Research participants aged 65 and over with 4682 deaths during a mean of 1.5 years of follow-up were included in this analysis. MEASURES: Hazard ratio of all-cause and cause specific mortality risks associated with BMI categories. The association between BMI and all-cause and cause specific mortality were independently estimated by Cox regression model.

resultsRegardless of gender, BMI of 24 -29.9 kg/m2 was a protective factor for death in all ages, while BMI above 30 kg/m2 was still a protective factor for older adults under 70 years old. Regardless of age, BMI at 24-25.9 kg/m2 was associated with lower mortality in men, while BMI at 26-27.9 kg/m2 was associated with lower mortality in women. For the older adults without chronic diseases, BMI at 24-25.9 kg/m2 was also significantly associated with lower mortality. In the analysis of BMI and cause of death, we also found that BMI of 24-25.9 kg/m2 was significantly associated with the lower mortality from cardiovascular disease, cancer, chronic respiratory disease and digestive system disease in China.

conclusionBMI in the range of 24-25.9 kg/m2 may be protective for mortality in Chinese older adults. Additional more large-scale, multicenter and long-term follow-up studies are needed to confirm these findings in different populations.