Pre-Pregnancy Fitness and Risk of Gestational Diabetes: A Longitudinal Analysis
To assess the associations of pre-pregnancy cardiorespiratory fitness, moderate-to vigorous-intensity physical activity (MVPA), and time spent watching television with subsequent development of gestational diabetes mellitus (GDM).Methods
Participants were 1,333 women enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study who did not have diabetes either at baseline (1985-86) or prior to births occurring after baseline. Baseline fitness was estimated using a graded symptom-limited maximal exercise treadmill test and expressed in metabolic equivalent (MET) units. Baseline MVPA (exercise units/day) was measured using the CARDIA physical activity history questionnaire, and television viewing (hours/day) was assessed by self-report in 1990-91. Logistic regression analysis was used to derive odds ratios (OR) and 95% confidence intervals (CI), adjusting for time from baseline to delivery and baseline study center, age, race, education, parity, family history of diabetes, smoking, alcohol, saturated fat intake, waist circumference, HOMA-IR, and HDL-Cholesterol.Results
Over 25 years of follow up, 164 women developed GDM. The odds of developing GDM were 21% lower for each 1 standard deviation increment in baseline level of fitness (2.3 METs; OR 0.79, 95% CI 0.65, 0.96). Pre-pregnancy MVPA and television viewing were not statistically associated with the development of GDM.Conclusion
Study findings indicate that objectively assessed pre-pregnancy fitness, but not self-reported MVPA or television time, is associated with GDM. Clinicians should counsel women on the benefits of improving fitness in the pre-conception period, particularly among women at greater risk for GDM.