Association between body mass index and body fat measured by dual-energy X-ray absorptiometry (DXA) in China: a systematic review and meta-analysis

Objective: We examined the association between body mass index (BMI) and body fat percentage (BF%) measured by dual-energy X-ray absorptiometry (DXA) among adults and children in China. Methods: We searched four databases–PubMed, China National Knowledge Infrastructure, Wanfang, and Vip for studies published in the past 22 years. Meta-analysis was conducted using random- or fixed-effect models. Results: In total of 21 studies met inclusion criteria and were included in review, and 17 ot them in meta-analysis. They were conducted across China. Their sample size ranged from 62 to 5 726, and participants’ age ranged from 6‒80 years. Meta-analysis revealed strong associations between BMI and BF% measured by DXA in adults (pooled r = 0.71, 95% CI: 0.66 to 0.74) and children (pooled r = 0.60, 95% CI: 0.52 to 0.68). The association was stronger in Northern China than in East China in children (β = −0.40, 95% CI: −0.65 to −0.14) and in Central China in adults (β = −0.25; 95% CI: −0.51 to −0.01). Urban children's BMI was strongly associated with BF% than rural (β = 0.19; 95% CI: 0.04 to 0.35), whereas it was stronger in adults living in rural than in urban (β = −0.35; 95% CI: −0.66 to −0.05). Conclusions: BMI was strongly associated with BF% measured by DXA, and the association in children and adults in China varied by residence and region.