Association Between Female Reproductive Factors and Laryngopharyngeal Reflux: A National Population-Based Study

Background: The association between female reproductive factors and laryngopharyngeal reflux (LPR) remains poorly understood. This study investigated the relationship between reproductive history and LPR risk in women using a large nationally representative cohort. Methods: We conducted a nested case-control study using linked data from the Korean National Health and Nutrition Examination Survey and the National Health Insurance Service database (2007-2017). Among 57,559 participants, 1347 women diagnosed with LPR were matched 1:1 with 1347 controls without reflux disease using propensity score matching based on age, income, and education level. Multivariable logistic regression analyses were performed to evaluate the associations between reproductive factors and LPR risk after adjustment for metabolic and lifestyle variables. Results: Women with a first childbirth at age ≥27 years had a significantly higher risk of LPR than those with earlier childbirth (adjusted odds ratio [aOR] 1.33, 95% confidence interval [CI] 1.08-1.63; p = 0.007). A menarche-to-first-birth interval of ≥17 years was also associated with an increased risk of LPR (aOR 1.56, 95% CI 1.15-2.15; p = 0.005). In addition, breastfeeding for <12 months was independently associated with a higher risk of LPR (aOR 1.26, 95% CI 1.04-1.53; p = 0.019). These associations remained significant after adjustment for potential confounders. Conclusions: Female reproductive factors potentially reflecting cumulative hormonal exposure were independently associated with LPR risk in this nationally representative cohort. First delivery at age ≥27 years, a menarche-to-first-birth interval ≥17 years, and breastfeeding <12 months were associated with LPR, suggesting that reproductive history should be considered when evaluating women with reflux-related symptoms.