However, it was also observed that circadian gene variants could also affect risk factors strictly in non-overweight subjects, as it was shown in a Japanese cohort that C allele in the CLOCK rs1801260 SNP was associated with the prevalence of type 2 diabetes in non-overweight subjects, but not in overweight subjects, after adjusting for potential confounding factors, including age, sex, research area, BMI, smoking habit, alcohol drinking status, leisure time exercise, energy intake and family history of diabetes [71]. This evidence concerns the gene CLOCK and type 2 diabetes mellitus.