Context: Cystic fibrosis-related diabetes is primarily due to a defect in insulin secretion. Women with cystic fibrosis (CF) are at higher risk of developing CF-related diabetes.
Objective: The objective of the study was to examine sex differences in insulin and glucose homeostasis. We hypothesized that in CF, women would display lower insulin secretion than men.
Design: This was a study based on an ongoing observational CF cohort with a mean follow-up of 19.9 ± 5.2 months.
Setting: The study was conducted at the CF clinic of the Centre Hospitalier de l'Université de Montréal (Québec, Canada).
Patients: From 230 adults with CF (123 men, 107 women) of similar age and functional pulmonary status, 104 retested after the follow-up. Age-matched healthy individuals (25 men, 19 women) were included in the study.
Interventions: Participants underwent a 2-hour oral glucose tolerance test with 30-minute interval sample measurements.
Main outcome measure: Plasma insulin and glucose levels were measured.
Results: Women with CF had higher overall insulin secretion as compared with men with CF (P ≤ .05) but similar to healthy women (P = .606). Men with CF had lower overall insulin secretion than healthy men (P = .020) and higher insulin sensitivity (P = .009) than women with CF. PATIENTS with CF displayed higher overall glucose excursions than healthy patients. Sex-related differences were still observed in the CF cohort after follow-up.
Conclusions: Surprisingly, in CF, adult women presented higher insulin secretion than adult men at a comparable level with what is observed in healthy individuals. Potential implications of this sex dimorphism in CF remain to be established.