Supplementary Material for: A Novel Polymorphism (rs35612982) in CDKAL1 Is a Risk Factor of Type 2 Diabetes: A Case-Control Study

Background: The interaction of environmental factors and genetic factors may contribute to the risk of type 2 diabetes (T2D). We aimed to investigate whether age, gender, body mass index (BMI) and lifestyle factors have an effect on the association between the CDKAL1 polymorphisms and T2D. Methods: Eight single nucleotide polymorphisms in CDKAL1 were genotyped by Agena MassARRAY in 508 T2D patients and 503 controls. The association between the CDKAL1 polymorphisms and T2D was evaluated using logistic regression model by calculating OR and 95% CIs. Results: We found a significant association between CDKAL1 polymorphisms (rs4712523, OR 1.42, p = 9.44 × 10^–5; rs4712524, OR 1.38, p = 3.28 × 10^–4; rs10946398, OR 1.43, p = 6.21 × 10^–5; rs7754840, OR 1.43, p = 6.33 × 10^–5; rs35612982, OR 1.34, p = 0.0010; and rs10440833, OR 1.32, p = 0.0018) and T2D risk among the Han population from Northwest China. We also found that genetic variants of CDKAL1 could modify the risk of T2D that might be influenced by age, BMI and the status of smoking and drinking. Besides, rs35612982-CT (p = 0.038) and rs10440833-AT (p = 0.044) genotypes were higher insulin level. Conclusion: CDKAL1 rs35612982 (C/T) polymorphism, as a new polymorphism, was associated with the increased risk of T2D in the Han Chinese population. Moreover, the contribution of CDKAL1 polymorphisms to T2D risk seems to be associated with age, gender, BMI, smoking and drinking.