Body mass index and related attribution to all-cause mortality in adults of Family Cohort of Nutrition and Chronic Diseases in Shanxi province / 中华流行病学杂志

ABSTRACT

Objective@#To assess the relationship between body mass index (BMI) and mortality in adults of Shanxi, China.@*Methods@#Baseline data were from the '2002 China Nutrition and Health Survey’ in Shanxi province. All the death-related investigation and follow-up visits were carried out from December 2015 to March 2016. The follow-up program covered 5 360 people from all the 7 007 participants aged 18 years and over that having complete core information, with a rate as 76.5%. Participants of this study were divided into eight groups, according to the appearance of BMI. Taking the group with the lowest mortality density as the reference group, Cox regression model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) of deaths by the whole population, gender and age groups (≥60 years, <60 years). Results were then adjusted by age, gender, smoking, alcohol use and education level from the baseline survey. Sensitivity analysis was also conducted.@*Results@#Results from the study showed that among the total number of 67 129 person- years from the average period of 12.5 years, there were 615 deaths occurred, with the mortality density as 916 per 100 000 person-years. Taking the BMI range of 26.0-27.9 kg/m2 as the reference, the aHRs of death increased to 1.90 (95%CI 1.26-2.86), 1.68 (95%CI 1.15-2.45), 1.49 (95%CI 1.08-2.06) and 1.72 (95%CI 1.07-2.76) after the multivariate adjustment, in these four groups (BMI<18.5, 18.5-19.9, 22.0-23.9 and ≥30.0 kg/m2), respectively. Low body weight (BMI<18.5 kg/m2) was associated with higher risks of death in the elderly of ≥60 years, with the aHR of death as 1.94 (95%CI 1.20-3.15).@*Conclusions@#When BMI appeared as ≤19.9 kg/m2, 22.0-23.9 kg/m2 and ≥30.0 kg/m2, the risks of death would increase. In addition to programs that focusing on obesity, special attention should be paid to the high risk of mortality which was caused by low-weight and malnutrition in the elderly.