Associations Between Dietary Iron, SNP rs2794720, and Metabolic Syndrome Risk in Chinese Males and Females: A Community-Based Study in a Chinese Metropolis.

Background: Metabolic syndrome, a cardiovascular risk cluster, is recognized as a global health priority influenced by gene-diet interactions. The rs2794720 polymorphism has not been previously reported in relation to metabolic syndrome. This study examined the associations between dietary iron, SNP rs2794720, and metabolic syndrome in Chinese metropolitan population, with a focus on sex-specific and genotype-specific effects. Methods: A community-based cross-sectional study enrolled 2639 adults (1254 males, 1385 females) from Shanghai, China. Anthropometric measurements, laboratory analyses, and genotyping for the participants were performed. Dietary assessment utilized the 3-day 24 h dietary recall method. Metabolic syndrome was identified by the presence of at least three out of five metabolic abnormalities according to the NCEP-ATP III criteria. Results: After adjusting for confounders, in males, metabolic syndrome risk was associated with dietary iron (p = 0.002) but not with rs2794720 (p = 0.731). In females, metabolic syndrome risk was associated with rs2794720 (p = 0.014) and dietary iron (p = 0.016), with a significant interaction observed between rs2794720 and dietary iron (p = 0.047). Stratified by rs2794720, among females lacking the C allele, there was a linear trend between dietary iron and metabolic syndrome risk (p = 0.048). Compared to the reference group (lowest-intake GG homozygotes), the Q2-Q4 Ors (95% CI) were 5.31 (1.08, 39.52), 5.50 (1.16, 40.28), and 8.40 (1.80, 41.44)), while the major allele carriers did not show this trend (p = 0.704); compared to the reference group, the Q1-Q4 ORs(95% CI) were 6.13 (1.68, 39.66), 7.53 (2.06, 48.86), 8.10 (2.20, 52.60), and 7.84 (2.07, 51.70)). Conclusions: Our study first identified rs2794720 as a novel SNP associated with metabolic syndrome in Chinese females. The association between dietary iron and metabolic syndrome risk was unique to GG homozygotes (the minority), whereas CC/CG genotypes (the majority) showed no such association.