Association between dietary iron intake and pelvic inflammatory disease in women from the US: Findings from the 2013 to 2020 NHANES dataset.

Pelvic inflammatory disease (PID), a prevalent gynecological ailment compromising women's health, demonstrates established risk mitigation from dietary trace minerals. However, iron's role in PID pathogenesis remains unestablished. The National Health and Nutrition Examination Survey collected data on dietary iron intake and PID through dietary intake questionnaires and reproductive health questionnaires. We utilized data from 2013 to 2020 and employed multiple logistic regression to explore this relationship. This was further enhanced by smooth curve fitting and threshold analysis to determine linear and nonlinear relationships. Subgroup analyses based on various demographic characteristics were also executed. Our cohort comprised 5034 women between the ages of 20 and 59. Findings from the multivariate logistic regression suggested a protective effect of higher iron consumption against PID. Subgroup analyses underscored a marked reduction in PID risk among women who were cohabiting, diabetic, and nonsmokers. The application of smoothed curve fitting illustrated a U-shaped curve describing the relationship between iron intake and PID risk. Threshold analysis indicated a decrease in PID risk by 3% per unit increase in iron intake below 27 mg/day. Additional univariate and multivariate logistic regression analyses of other common dietary trace elements and vitamins revealed no significant independent association with PID risk after full covariate adjustment, which highlighted the specific protective role of dietary iron in PID among dietary trace elements. Our analysis revealed a significant inverse association between iron intake and PID development, particularly when iron consumption was below 27 mg/day. These findings emphasize the crucial role of trace minerals in enhancing gynecological health and propose that augmenting dietary iron could be a strategic approach to prevent PID.