Abstract
BACKGROUND: Evidence suggests that there is some relationship between circadian clock gene variants and obesity. However, there are few examinations supporting this observation in human subjects. This study was aimed to investigate the interaction between Cry1 circadian gene polymorphism and major dietary patterns on obesity measurements. METHODS: Healthy overweight and obese women aged 18-53 years old were recruited from health centers in Tehran, Iran by a multistage cluster random sampling method (n = 377). Major dietary patterns were elicited after assessing the intake of 16 food groups using a valid and reliable 147-item food frequency questionnaire (FFQ). Anthropometric measurements were performed for each and every participant. Body composition was analyzed using bioelectrical impedance analysis (BIA). Socio-demographic and physical activity data were also collected by a validated Farsi demographic questionnaire and the international physical activity questionnaire (IPAQ). The Cry1 rs2287161 polymorphism were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Generalized linear models were used for interaction analysis. RESULTS: Two major dietary patterns, including healthy and unhealthy dietary pattern (HDP and UDP, respectively) were determined using factor analysis. Our study showed a significant higher weight (P = 0.003), body mass index (BMI) (P = 0.042), hip circumference (P = 0.052), and body fat mass (P = 0.028) in carriers of C allele compared with G allele. Moreover, a significant gene-diet interaction was observed between being a carrier of C allele and BMI (P = 0.099 for CC genotype; P = 0.1 for CG genotype) and fat mass (P = 0.1 for CG genotype). CONCLUSIONS: The current study suggests a significant interaction of Cry1 rs2287161 gene polymorphisms in people following a healthy dietary pattern on BMI and fat mass among carriers of C allele compared to carriers of G allele.