Excess mortality in mothers of patients with polycystic ovary syndrome

Do diabetic parents of patients with polycystic ovary syndrome (PCOS) encounter excess mortality compared with the mortality of men and women with type 2 diabetes, recruited without selection for PCOS? Type 2 diabetes among mothers of PCOS patients results in excess mortality compared with women with diabetes from the general population. Insulin resistance is a prominent feature of PCOS. Because of the heritable nature of PCOS, parents of these patients are also prone to develop type 2 diabetes mellitus, which might influence their life expectancy. This reverse parent-offspring study included 946 mothers and 902 fathers of patients with PCOS. The medical history of the parents was primarily obtained during the initial screening of each patient and updated via questionnaires. Mortality data of these parents were compared with the mortality rates of the general Dutch population and with mortality rates of a control population consisting of 1353 men and women diagnosed with type 2 diabetes mellitus. The standardized mortality ratio (SMR) was calculated as the ratio of the observed mortality of the parents to the expected mortality in the general Dutch population. The mortality of parents with type 2 diabetes mellitus relative to controls with diabetes but not related to anyone with PCOS was standardized for age, gender and calendar period using Poisson regression. In total, 302 parents were deceased in 62 693 person-years. Mothers above age 60 had a significant excess mortality of 1.50 (95% CI 1.15-1.92) compared with the general Dutch population. Moreover, mothers with diabetes had two-times higher mortality risk compared with control women with diabetes (RR 2.0, 95% CI 1.19-3.41). No excess mortality among fathers of PCOS patients was observed. Although recall bias for family history was previously demonstrated to be minimal for long-term chronic diseases, the prevalence of diabetes in the parents was based on their daughter's self-report and was not clinically confirmed. Also, no other additional clinical data regarding the parent population were available. Prospective long-term follow-up studies should be conducted to confirm this excess mortality. Our findings justify screening for type 2 diabetes mellitus among the mothers with a daughter suffering from PCOS to ensure that timely preventive and therapeutic measures according to the appropriate guidelines can be taken. No particular funding was received for this study. Y.V.L., M.E.R.-S., N.K., J.R.v.L., M.v.d.B., H.J.G.B. and E.J.G.S. do not have any conflict of interest. J.S.E.L. has received fees and grant support from the following companies (in alphabetic order): Ferring, Genovum, Merck-Serono, Organon, Schering Plough and Serono. B.C.J.M.F. has received fees and grant support from the following companies (in alphabetic order): Andromed, Ardana, Ferring, Genovum, Merck Serono, Organon, Pantharei Bioscience, PregLem, Schering, Schering Plough, Serono, and Wyeth. These companies had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.