Smaller Reproductive Window With Type 1 Diabetes

Developing type 1 diabetes (T1D) in childhood was significantly associated with a shorter opportunity for childbearing, a new study showed.

Women diagnosed with T1D in childhood had an average 2.5 fewer reproductive years compared with their nondiabetic counterparts (95% CI -3.6 to -1.5, P<0.0001), reported Tina Costacou, PhD, of the University of Pittsburgh, and colleagues.

Shortening of the reproductive window occurred on both sides, the researchers wrote in Menopause, the journal of the North American Menopause Society (NAMS).

Specifically, women with T1D were an average 0.5 years older at the time of menarche and tended to be younger at the time of natural menopause onset, by 2 years on average. This was following adjustment for age, race, BMI, smoking status, hypertension, HDL cholesterol levels, history of oral contraceptives, and number of pregnancies.

The findings only applied to women diagnosed with T1D prior to menarche. Women who developed diabetes after menarche didn’t see a significant shortening of their reproductive window, according to a small sub-analysis of 25 women.

“Due to the important role of insulin in maintaining the normal function of the female [hypothalamic-pituitary-ovarian] axis, the disruption in insulin regulation in women with type 1 diabetes may underlie our findings of delayed menarche and premature ovarian aging compared with the general population,” Costacou’s group explained.

In a statement, NAMS medical director Stephanie Faubion, MD, MBA, of the Mayo Clinic in Rochester, Minnesota, pointed out that health risks associated with early-onset T1D in women are not only limited to premature ovarian aging.

“They are also at increased risk for cardiovascular disease, osteoporosis, and early mortality because of early natural menopause,” said Faubion, who was not involved with the study. “Understanding these risks and targeting appropriate risk-reducing strategies are key to optimizing the health and quality of life of these women.”

The analysis from Costacou and colleagues included 105 women from the Epidemiology of Diabetes Complications study, who from 1950 to 1980 were diagnosed with T1D (at age 9 on average). This group was compared with 178 women without diabetes from the Pittsburgh site of the Study of Women’s Health Across the Nation.

Women who underwent a hysterectomy/oophorectomy before menopause or had received hormone therapy during the menopausal transition were excluded.

The T1D group tended to be younger, more white, and less likely to smoke or have a history of smoking compared with the nondiabetic group. They also had a lower BMI (25.2 vs 26.5, respectively) and higher HDL cholesterol (61.0 mg/dL vs 54.0 mg/dL).

Women with T1D were less likely to have ever used oral contraceptives (63.5% vs 77.5%) and were also less likely to have ever been pregnant (72.4% vs 91.0%). Among women with a history of pregnancy, those with T1D had fewer pregnancies on average and fewer live births than their nondiabetic counterparts.