Prevalence and epidemiological determinants of metabolically obese but normal-weight in Chinese population

There is metabolic heterogeneity in normal-weight individuals, however, there has been limited research in the Chinese population. This study aimed to investigate the prevalence, distribution and epidemiological determinants of metabolically obese but normal-weight (MONW) in a Chinese population.

A total of 17,876 normal-weight individuals were recruited from 37,815 individuals in Zhejiang province in southeastern China. Normal-weight was defined as a body mass index (BMI) of 18.5-23.9 kg/m². Metabolically abnormal traits were assessed by metabolic syndrome criteria from the International Diabetes Federation (IDF) in 2015. MONW was defined as individuals who had at least two metabolically abnormal trait but normal weight. Multiple logistic regression was used to investigate MONW risk factors, adjusting for potential confounders.

The prevalence of metabolic abnormality was 34.1% in normal-weight individuals, and the overall prevalence of MONW was 16.1% in the general population. Different MONW distributions were found between men and women depending on age. Compared with women, men had a significantly higher MONW prevalence among those aged < 45 years old, and there was a lower prevalence for those aged ≥50 years old. Higher BMI or waist circumference (WC), central obesity, menopause, and family histories of hypertension, diabetes, and cardiovascular diseases, increased MONW risk. Higher education levels, regular alcohol drinking, and balanced or vegetarian food preferences reduced MONW risk.

Normal-weight individuals have metabolic heterogeneity in China. The MONW distribution between men and women depends on age. BMI, WC, dietary factors, and family history of chronic diseases, are associated with metabolic status.