In patients with cystic fibrosis, adult women demonstrate higher insulin secretion than their male counterparts, suggesting a potential sex dimorphism in this disease, recent study data found.
Moreover, women with cystic fibrosis had insulin secretion levels comparable to those of healthy women, whereas men with cystic fibrosis had significantly lower insulin levels than healthy men.
To investigate the role of sex on insulin homeostasis and cystic fibrosis-related diabetes (CFRD), the researchers recruited 230 patients (123 men, 107 women) with cystic fibrosis from the Montreal Cystic Fibrosis Cohort. All patients were of comparable age and had normal lung function.
In addition, 44 healthy controls (25 men, 19 women), matched for age and BMI, were recruited from the Institut de Recherches Cliniques de Montréal.
All study participants underwent a 2-hour oral glucose tolerance test after an overnight fast. In less than 5 minutes, they drank 1.75 g glucose/kg of body weight, with a maximum of 75 g, based on guidelines from the Canadian Diabetes Association. The researchers then obtained blood samples at 0, 30, 60, 90 and 120 minutes to assess plasma glucose and insulin levels.
The researchers found that the overall insulin secretion of female participants with cystic fibrosis was higher than those of men with cystic fibrosis (P<.05) and similar to the insulin secretion of healthy women (P=.606). Conversely, men with cystic fibrosis had lower overall insulin concentrations than healthy men (P=.02) and higher insulin sensitivity (P=.009) than female patients with cystic fibrosis. The overall glucose fluctuations of patients with cystic fibrosis were higher than in healthy patients.
The gender-based differences remained consisted in the patients with cystic fibrosis after follow-up.
The researchers said these findings ran counter to their hypothesis, and their full implications are not yet clear.
“Contrary to our hypothesis, adult women with [cystic fibrosis] are characterized by higher insulin secretion than men with [cystic fibrosis],” the researchers wrote. “This data should be confirmed in other [cystic fibrosis] populations and the potential implications of this sex difference (eg, CFRD risk, lung function and/or weight maintenance) remain to be established.”
Disclosure: The researchers report no relevant financial disclosures.