Underrepresentation of females and the elderly with type 1 diabetes in clinical exercise trials: A call to action

AIMS: The aims of this review were to (1) estimate the ratio of male and female participants with type 1 diabetes (T1D) in clinical exercise studies, (2) ascertain the degree to which menstruation has been considered and (3) characterize the number of studies in which the elderly have been included. MATERIALS AND METHODS: Original clinical exercise research articles in individuals with T1D from 1985 to 2025 on PubMed were screened. The number and age of participants were analysed. A standardized menstrual-status tiering system was used to assess the quality of menstrual cycle (MC) information of females: Gold, Silver and Bronze were awarded based on the level of methodological control, including verification of MC characteristics and hormonal profiling. RESULTS: Of a total of 315 included studies, the majority (81%) contained a mixed-sex population with an overall male dominance in participant ratio (57% males vs 43% females). Since 1985, there have been six studies conducted exclusively in females compared to the 54 studies done in men, with six times fewer total participants (n = 99 vs n = 671, respectively). Across all studies, the mean age of participants was 29 ± 7 years, with only one study conducted solely in post-menopausal females. MC status was reported in 30 studies, 6 of which were graded Bronze and 3 Silver. None achieved Gold. CONCLUSIONS: Females and the elderly are under-represented in clinical exercise trials conducted in people with T1D. These data highlight the need for intensified efforts to bridge the current sex-and age-data gaps so as to improve practical implementation and clinical translation.