INS and type 2 diabetes mellitus: According to a Chinese study, T2DM incidence dropped by two years for every year when menopause was delayed [39]. All the aforementioned studies implicate the role of estrogen as well as the interplay of estrogen and insulin in women achieving menopause in a natural way at a normal age. An in-vivo study conducted in female insulin-resistant rats concluded that insulin levels play a role in maintaining menstrual cycle health throughout a woman’s life cycle.