Abstract
BACKGROUND: Gestational diabetes mellitus (GDM) is a common pregnancy complication closely associated with increased oxidative stress. The Oxidative Balance Score (OBS) integrates dietary and lifestyle factors influencing oxidative stress, yet its relationship with GDM remains unclear. METHODS: In this case-control study, 150 pregnant women with GDM and 170 healthy controls were recruited from primary healthcare centers in Urmia, Iran. Dietary intake was assessed using a validated 168-item Food Frequency Questionnaire (FFQ), and OBS was calculated based on dietary and lifestyle pro-oxidant and antioxidant components. Logistic regression models were used to examine the association between OBS tertiles and GDM risk, adjusting for potential confounders. RESULTS: Women with GDM had significantly lower total OBS (18.37 ± 8.77 vs. 20.64 ± 10.98, p = 0.041) and dietary OBS (16.1 ± 6.46 vs. 17.89 ± 8.66, p = 0.036) compared to controls. key antioxidant nutrient intake, including riboflavin, folate, magnesium, and zinc, were significantly lower in the GDM group (p < 0.05). In contrast, lifestyle OBS was significantly higher in the GDM group (4.05 ± 1.4 vs. 3.65 ± 1.62, p = 0.018). Women in the highest OBS tertile had a 23% lower risk of GDM (aOR = 0.77; 95% CI: 0.48-0.92). Higher dietary and lifestyle OBS were also inversely associated with GDM risk. CONCLUSION: A higher OBS, particularly in its dietary and lifestyle components, is associated with a reduced risk of GDM. These findings highlight the importance of antioxidant-rich diets and lifestyle modifications in GDM prevention.