Waist circumference shows a significant association with the risk of noncommunicable diseases: a cross-sectional study from a large community sample in Southeast China.

objectiveTo study the magnitude and pattern of the cross-sectional associations of body mass index (BMI) and waist circumference (WC) with the prevalence of hypertension (HTN), type 2 diabetes (T2DM), and dyslipidemia in a large community-dwelling population in Southeast China.

methodsA total of 135,352 permanent residents aged 35-75 years were recruited using multistage stratified cluster random sampling from Fujian Province, China (2018-2021). Physical measurements included height, weight, WC, and blood pressure. Fasting fingertip blood samples were tested for plasma glucose and lipid profiles. Overweight/obesity was defined as BMI ≥ 24 kg/m², and central obesity was defined as WC ≥ 85 cm for males and ≥ 80 cm for females. Multiple linear regression with Z-score standardization was used to directly compare standardized effect sizes of BMI and WC on continuous metabolic parameters. Modified Poisson regression with robust error variance was applied to estimate adjusted risk ratios (aRR) for HTN, T2DM, dyslipidemia, and multimorbidity burden, adjusting for sociodemographic and lifestyle factors.

resultsAmong 135,352 participants (mean age 56.7 ± 9.9 years; 59.5% female), the prevalence of HTN, T2DM, and dyslipidemia was 46.2%, 18.3%, and 16.6%, respectively. After Z-score standardization, every 1-SD increase in WC was associated with a larger increase in systolic blood pressure (β = 0.132 vs. β = 0.115 for BMI) and far larger elevations in fasting plasma glucose (β = 0.130 vs. β = 0.020) and triglycerides (β = 0.176 vs. β = 0.091), as well as a stronger inverse association with HDL-C (β=-0.185 vs. β=-0.147). All obesity subtypes independently increased risks of HTN (mixed obesity aRR = 1.926, isolated elevated BMI aRR = 1.434, isolated elevated WC aRR = 1.358), T2DM (mixed obesity aRR = 1.574, isolated elevated WC aRR = 1.495, isolated elevated BMI aRR = 1.143), and dyslipidemia (mixed obesity aRR = 1.402, isolated elevated BMI aRR = 1.304, isolated elevated WC aRR = 1.102). Elevated WC alone (aRR = 1.432), elevated BMI alone (aRR = 1.409), and mixed obesity (aRR = 1.973) independently raised the multimorbidity burden. Age was the strongest independent correlate of all outcomes. Smoking showed a spurious "protective" association, likely due to healthy survivor bias and residual confounding.

conclusionsBoth BMI and WC are independently associated with HTN, T2DM, and dyslipidemia, with WC notably associated with T2DM. Mixed obesity poses a high risk and nearly doubles multimorbidity burden. Integrating WC into routine screening alongside BMI is recommended to identify central obesity risks. Targeted interventions should focus on high-risk groups. Future studies are needed to establish causality and evaluate WC-centered programs for reducing the NCD burden.