Association between KCNQ1 genetic variants and obesity in Chinese patients with type 2 diabetes

We recruited 6,667 and 6,606 diabetic case–control samples from Shanghai and Hong Kong, respectively. Of the samples, 7.5% and 6.3% were excluded because of genotyping failure or data missing in the association analyses of rs2237892 and rs2237895 with obesity/BMI, respectively.

We found that rs2237892 was associated with lower BMI and lower incidence of overweight/obesity in diabetic patients from Hong Kong (BMI, β = −0.0060 per diabetes risk C allele for log₁₀BMI [95% CI −0.0088, −0.0032; p = 2.83 × 10⁻⁵]; overweight/obesity, OR 0.880 for C allele [95% CI 0.807, 0.960; p = 0.004]) and in the meta-analysis of cases from the two regions (BMI, combined β = −0.0048 per C allele for log₁₀BMI [95% CI −0.0070, −0.0026; p = 2.20 × 10⁻⁵]; overweight/obesity, combined OR 0.890 for C allele [95% CI 0.830, 0.955; p = 0.001]). rs2237895 was also related to decreased BMI (combined β = −0.0042 per diabetes risk C allele for log₁₀BMI [95% CI −0.0062, −0.0022; p = 4.30 × 10⁻⁵]). A significant association with waist circumference was detected for rs2237892 in the pooled analyses (β = −0.0026 per C allele for log₁₀[waist circumference] [95% CI −0.0045, −0.0007; p = 0.007]). However, neither an association with the risk of being overweight or obese nor associations with quantitive traits were detected for rs2237892 or rs2237895 in controls.