No effect by the common gene variant rs10830963 of the melatonin receptor 1B on the association between sleep disturbances and type 2 diabetes: results from the Nord-Trondelag Health Study

Genetic variation in the melatonin receptor 1B (MTNR1B) is associated with type 2 diabetes. Melatonin contributes to the regulation of sleep, and sleep problems are a documented risk factor for type 2 diabetes. The aim of this study was to investigate whether the MTNR1B gene variant rs10830963 is associated with sleep problems and whether this variant contributes to the association between sleep disturbances and type 2 diabetes. This was a case-control study nested within the population-based Nord-Trondelag Health Study, including 1,322 prevalent cases of type 2 diabetes and 1,447 controls. In addition, prospective data were available for 838 incident cases and 1,133 controls. Genotyping was done by TaqMan single-nucleotide polymorphism allelic discrimination analysis. ORs and 95% CIs were calculated using logistic regression models. Our findings confirm an association between sleep disturbances and type 2 diabetes (OR 1.69, 95% CI 1.22-2.33, p = 0.0016) and between the risk allele of rs10830963 and type 2 diabetes (OR 1.12, 95% CI 1.00-1.27, p = 0.0579). There was a tendency for an association between the risk allele and prevalence of sleep problems (specifically early awakening). However, the risk allele did not influence the association of sleep problems with diabetes, which was unaltered after adjustment for the MTNR1B risk allele (OR 1.69, 95% CI 1.23-2.34, p = 0.0014). Results based on prospective data were similar, although non-significant. Our findings do not support participation of the MTNR1B gene variant rs10830963 in the well documented association between sleep disturbances and type 2 diabetes.