The number of pregnancies in this population ranged from 0 to 7 and we found a statistically significant interaction with the MTNR1B-rs10830963 polymorphism in determining type-2 diabetes, in such a way that a greater number of pregnancies increased the risk of type-2 diabetes in allele G carrying women (additive model). Here, MTNR1B is linked to type 2 diabetes mellitus.