Physical activity had significant association with lower body fat percentage among middle-aged adults: China Health and Nutrition Survey in 2015

Abstract

Background As with the unprecedented economic and social development in China, physical activity (PA) have decreased dramatically and body fat percentage (BF%) have varied. In the lasted large scale field investigation, we described the distribution of PA and BF%, and their association across the entire percentiles. Methods Based on data from China Health and Nutrition Surveys (CHNS) in 2015, 5763 participants aged 40-64 years coming from 15 provinces were included. PA was calculated as metabolic equivalent task hours per day (MET·h/d). BF% was measured by bioelectrical impedance analysis (BIA). Kruskal-Wallis test was used to test the difference of PA among gender, age, BMI groups, education, income, region and urbanization. Gender-Body mass index (BMI)-stratified quantile regression (QR) analyses were utilized to describe the association between PA and BF% distribution. Results A part of non-overweight/obese participants had high body fat. Older adults, overweight/obese group, higher education, higher income, residents of central China and higher urbanization had lower PA. Participants who engaged in vigorous PA had median BF% 2.0% and 1.5% lower than the slightly PA group (23.4%, 34.8%) for men and women, respectively. For every additional hour of moderate PA (4.5 MET·h/d), the total BF% was reduced by a median of 0.0290%, 0.0539% and 0.0699% in the 50th, 75th and 90th percentiles respectively, and 0.0490%, 0.0854% and 0.0998% in trunk BF% at the correspondingly percentiles respectively. The association between PA and total BF% was the strongest in normal weight obesity participants than others. Females and the non-overweight/obese group had more statistical significant coefficients at multiple percentiles than males and the overweight/obese group, respectively. Conclusions In middle-aged adults in China, a part of normal weight obesity persons were in non-overweight/obese group and women prone to gain fat mass with BMI increasing but muscle in men. Individuals with vigorous PA had lower BF% comparing with slightly active ones, and an extra moderate leisure PA per day was recommended, especially for normal weight obesity and abdominal adipose individuals.