Type 1 diabetes onset before menarche shortens reproductive window
Women who had type 1 diabetes onset before menarche have a reproductive period nearly 3 years shorter than women without diabetes, according to a study published in Menopause.
“Studies have provided discrepant findings on the issue of early menopause in women with type 1 diabetes,” Tina Costacou, PhD, an associate professor of epidemiology at the University of Pittsburgh, told Healio. “Our results suggest that the discrepancies may relate to whether the type 1 diabetes diagnosis precedes menarche or not, something that previous investigations did not examine.”
Costacou and colleagues compared the number of reproductive years for women with type 1 diabetes enrolled in the Pittsburgh Epidemiology of Diabetes Complications (EDC) study with a control group consisting of women without diabetes from the Study of Women’s Health Across the Nation (SWAN). EDC participants were women who had childhood-onset type 1 diabetes diagnosed at UPMC Children’s Hospital of Pittsburgh from 1950 to 1980. Participants were reexamined biennially for up to 10 years and completed biennial surveys for up to 30 years of follow-up. The surveys included reproductive history information such as age at menarche and menopause status. SWAN participants were women aged 42 to 52 years who had a menstrual period within the past 3 months of enrollment and at least one intact ovary. Demographic data, medical history and reproductive history on SWAN participants were collected at baseline. Covariate data for EDC participants were taken from the follow-up visit preceding menopause in which chronological age was closest to the mean baseline age in SWAN, since women in EDC were younger at study entry.
Reproductive history with diabetes
There were 105 women with type 1 diabetes from EDC and 178 SWAN participants without diabetes included in the analysis. The diabetes cohort was younger than the group without diabetes (42.8 years vs. 46 years; P = .002). There was a greater proportion of non-Hispanic white women in the diabetes cohort vs. those without diabetes (96.2% vs. 67.4%; P < .0001). Women with type 1 diabetes were less likely to smoke and had a lower BMI, diastolic blood pressure, total cholesterol, LDL cholesterol and triglyceride concentrations, and higher HDL cholesterol than the group without diabetes.
After adjusting for race, women with type 1 diabetes had a delay in age at menarche of 0.5 years compared with women without diabetes (P = .002). After adjusting for age, race, BMI, smoking status, hypertension, HDL cholesterol, having ever taken oral contraceptives and number of pregnancies, the diabetes group had natural menopause 2 years younger than the group without diabetes (P < .0001). Those with type 1 diabetes had 2.5 fewer reproductive years compared with women without diabetes.
Onset before, after menarche
Researchers divided the diabetes group into those who had type 1 diabetes onset before and after menarche. There was no significant difference in age at menarche, age at natural menopause or reproduction period length between women with type 1 diabetes onset after menarche and the group without diabetes, whereas participants with type 1 diabetes onset before menarche had 2.9 fewer reproductive years compared with those without diabetes (P < .0001).
Researchers noted only 25 women in the EDC cohort had type 1 diabetes onset after menarche and the small sample size “may undermine the statistical power to detect a difference.”
“Another possible explanation regarding these findings being restricted to women whose type 1 diabetes onset occurred prior to menarche may be that type 1 diabetes occurring before menarche leads to a greater disruption of the female reproductive system compared with type 1 diabetes occurring after menarche,” the researchers wrote.
Costacou said future research should examine the factors behind why women with type 1 diabetes at menarche have a shorter reproduction period.
“It would be important to determine factors, especially modifiable risk factors, responsible for the shorter reproductive period in women with a type 1 diabetes diagnosis preceding menarche,” Costacou said. “Such knowledge could point to pathways to improve the length of the reproductive period of these women.”
For more information:
Tina Costacou, PhD, can be reached at firstname.lastname@example.org.