Work

The mediating role of BMI in the association between composite dietary antioxidant index and infertility in women: a nationwide population-based study

Year: 2025

Type: article

Abstract: BACKGROUND: The composite dietary antioxidant index (CDAI) reflects dietary antioxidant intake. Preliminary studies indicate that higher CDAI levels are associated with a lower prevalence of female infertility. However, the underlying mechanisms linking CDAI to infertility remain unclear. This study aims to investigate the relationship between CDAI and infertility in women, as well as the mediating effect of BMI in this association. METHODS: A total of 1,806 women aged 20 to 45 years were recruited from the National Health and Nutrition Examination Survey (NHANES, 2013-2018). CDAI was calculated based on the intake of six dietary antioxidants: vitamins A, C, and E, selenium, zinc, and carotenoids. We employed weighted logistic regression models, mediation analysis, and subgroup analyses. RESULTS: Among participants, 211 (11.68%) reported infertility. For each unit increase in CDAI, the likelihood of female infertility decreased by 11% (OR = 0.89, 95% CI: 0.84 to 0.94, P < 0.001). Conversely, for each unit increase in BMI, the prevalence of female infertility increased by 6% (OR = 1.06, 95% CI: 1.03 to 1.09, P < 0.001). Exploratory mediation analysis identified an indirect association of BMI in the relationship between CDAI and infertility (indirect effect = -0.0005, 95% CI: -0.0011 to -0.0001), accounting for 6.2% of the total effect. Subgroup analyses indicated that in women aged 20-30 years, the mediating effect of BMI accounted for 9.8% of the total effect, while in women aged 30-40 years, it accounted for 9.96%. Moreover, notable indirect effects were - 0.000887 (11.3%) in those with irregular menstruation, and - 0.0057 (7.97%) in women with menarche age ≥ 11 years, highlighting the complex interplay of these factors. CONCLUSION: BMI plays significant role in the relationship between CDAI and female infertility. Our findings suggest a potential associative pathway through which antioxidant intake may correlate with reproductive health via weight-related factors, providing novel insights for nutritional interventions aimed at preventing female infertility.

Source: BMC Women s Health

DOI: 10.1186/s12905-025-04062-x