[Association between body mass index and quality of life in Chinese adults]

To assess the relationship between body mass index and quality of life (QOL) in Chinese adults.

83 347 subjects from database of 2010 Chronic Non-communicable Disease and Risk Factor Surveillance in China were included in this study. Questionnaire was used to collect general information and health status. WHO QOL-BREF was adopted as an instrument to measure the quality of life among all the subjects. Weight and height of each subject were measured, and then body mass index (BMI) was calculated. Kruskal-Wallis test was used to compare QOL from different BMI classifications. Multiple logistic regression analysis was used to assess the association of QOL with BMI in different sex.

Among 83 347 subjects, when compared with normal weight adults, their QOL scores were relatively low for those underweight, overweight and obese adults. Scores of psychological and environment domains in the overweight adult groups were higher than other groups. The highest score of social relationship domain was for obese group and the lowest score was seen in the underweight group. Differences on the above said groups were significant (P < 0.000 1). When compared to normal weight adults, after adjusting for other factors, OR impaired QOLs in physical (OR = 1.38, 95% CI:1.12-1.70), mental (OR = 1.29, 95% CI:1.08-1.54), social relationship and (OR = 1.26, 95% CI:1.08-1.47) and environment domains (OR = 1.37, 95% CI:1.12-1.67) all increased among men in the underweight group. However, ORs of impaired QOL in physical (OR = 0.88, 95%CI:0.82-0.94; OR = 0.90, 95%CI: 0.82-0.98), psychological (OR = 0.88, 95% CI:0.83-0.94; OR = 0.83, 95% CI:0.77-0.90), social relationship (OR = 0.89, 95%CI:0.84-0.94; OR = 0.78, 95%CI:0.71-0.85) and environment domains (OR = 0.85, 95%CI:0.80-0.92; OR = 0.79, 95%CI:0.73-0.86) decreased among both overweight and obese men, respectively. For women,ORs of impaired QOL in social relationship (OR = 0.92, 95%CI: 0.85-0.98) and environment domains (OR = 0.91, 95%CI:0.80-0.92) both decreased in the overweight group. And the ORs decreased also in impaired QOL in social relationship domain (OR = 0.86, 95%CI: 0.78-0.95) for obese women.

QOLs of the four domains were different for adults with different BMl classification. Underweight men showed poor QOL on these four domains while overweight and obese men had better QOLs. For women, overweight group had better QOLs in both relationship and environment domains but obese women had better relationship QOL.