Abstract
BACKGROUND: Cardio-metabolic risk factors (CMRFs) represent the accumulation of metabolic abnormalities, significantly increasing the likelihood of cardiovascular diseases. Although studies assessed the independent association of single-child status and lifestyle risk factors with components of CMRFs or clustered CMRFs, little has been known about the combined effect of single-child status and lifestyles on clustered CMRFs as well as sex differences. MATERIALS AND METHODS: Data was collected from a cross-sectional survey conducted in September 2013 in China. A total of 13,859 children and adolescents aged 7-18 years with blood samples were included. Anthropometric measurements and serum biochemical indexes were collected to assess clustered CMRFs, while questionnaires were used to obtain single-child status, lifestyle information, and characteristics of children and their parents. Mixed effect logistic regression was applied to analyze the independent and the combined effects of single-child status and ideal lifestyle category on clustered CMRFs. RESULTS: The prevalence of clustered CMRFs was 3.4%, with a higher prevalence in boys (4.0%) than girls (2.7%). Children and adolescents with clustered CMRFs had a higher proportion of single children (76.6 vs. 69.7%) and unfavorable lifestyles (62.1 vs. 29.2%) compared with their peers with non-clustered CMRFs. Both single children (OR = 1.67, 95% CI: 1.32-2.11) and unfavorable lifestyles (OR = 9.03, 95% CI: 6.26-13.02) were associated with an increased risk of clustered CMRFs. The risk of clustered CMRFs increased significantly (OR = 12.79, 95% CI: 6.67-24.52) when single children and an unfavorable lifestyle were combined, which was almost neutralized (OR = 1.33, 95% CI: 0.63-2.82) when single children adhered to a favorable lifestyle. However, no sex differences were observed in this study. CONCLUSION: Single children with unfavorable lifestyles were associated with an obvious risk of clustered CMRFs, which might be partially offset by expanding family size (the number of siblings) or establishing a favorable lifestyle. A birth-friendly social environment as well as a family environment with a favorable lifestyle are encouraged in China.