Objective: To investigate the familial aggregation of metabolic syndrome (MetS) and its components in the Chinese.
Methods and procedures: A total of 17,954 subjects from 5,224 families with multiple siblings aged 25-64 years old (mean age 45.8 years, 51.6% male) were enrolled from a rural area of Anhui Province of China during 2004-2005. Anthropometric measurement, body composition, blood pressure, plasma lipids, and fasting glucose and insulin, as well as a questionnaire interview, were obtained from each participant.
Results: Significant correlations among siblings were observed in all the traits examined, including BMI, waist circumference, total body and abdominal fat percentage, fasting plasma glucose (FPG) and insulin, insulin resistance index of homeostatic model assessment (HOMA-IR), total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and blood pressure, after adjustment for age, gender and some other covariates. The correlation coefficients varied from 0.18 for FPG to 0.42 for HDL-C. In stratified analyses, we found siblings with a smaller age gap among them had higher intraclass correlation coefficients (ICCs) for most of the above phenotypes than those with a greater age difference, and the correlation of systolic blood pressure (SBP) was stronger in male siblings than that in female. If the eldest sibling is affected by MetS or any of its components, younger siblings bear a twofold to threefold higher risk for developing MetS or any of its components than those with a healthy eldest sibling.
Discussion: Our study demonstrated a significant familial resemblance as regards MetS and its components among the Chinese. Further studies are warranted to investigate specific genetic and environmental factors related to MetS in this population.