Background: China has seen a burgeoning epidemic of obesity in recent decades, but few studies reported nationally on obesity across socio-demographic subgroups. We sought to assess the prevalence and socio-demographic associations of obesity nationwide.
Methods: We assessed the prevalence of overall obesity (body mass index ≥28 kg/m2) and abdominal obesity (waist circumference ≥85/90 cm for women/men) among 2.7 million community-dwelling adults aged 35 to 75 years in the China PEACE Million Persons Project from 2014 to 2018 and quantified the socio-demographic associations of obesity using multivariable mixed models.
Results: Age-standardized rates of overall and abdominal obesity were 14.4% (95% CI, 14.3%-14.4%) and 32.7% (32.6%-32.8%) in women and 16.0% (15.9%-16.1%) and 36.6% (36.5%-36.8%) in men. Obesity varied considerably across socio-demographic subgroups. Older women were at higher risk for obesity (eg, adjusted relative risk [95% CI] of women aged 65-75 versus 35-44 years: 1.29 [1.27-1.31] for overall obesity, 1.76 [1.74-1.77] for abdominal obesity) while older men were not. Higher education was associated with lower risk in women (eg, adjusted relative risk [95% CI] of those with college or university education versus below primary school: 0.47 [0.46-0.48] for overall obesity, 0.61 [0.60-0.62] for abdominal obesity) but higher risk in men (1.07 [1.05-1.10], 1.17 [1.16-1.19]).
Conclusions: In China, over 1 in 7 individuals meet criteria for overall obesity, and 1 in 3 for abdominal obesity. Wide variation exists across socio-demographic subgroups. The associations of age and education with obesity are significant and differ by sex. Understanding obesity in contemporary China has broad domestic policy implications and provides a valuable international reference.
Keywords: body mass index; demography; obesity; prevalence; socioeconomic factors; waist circumference.