Association between the number of pregnancies and hearing loss: NHANES 1999-2018.

BACKGROUND

Hearing loss represents an escalating global health concern with profound implications for individuals and society. While prior studies suggest that reproductive factors may influence women's auditory health, the specific association between the number of pregnancies and auditory function remains inadequately understood. This research aimed to investigate the association between the number of pregnancies and hearing loss in U.S. women.

METHODS

We conducted a cross-sectional analysis of 5,269 U.S. women aged 20 years and older from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Reproductive health data, including the number of pregnancies, were obtained via self-reported questionnaires. Hearing loss was defined as a pure-tone average ≥ 25 dB HL at speech frequencies (0.5, 1, 2, and 4 kHz) in the better-hearing ear. All analyses incorporated NHANES sample weights. Weighted multivariable logistic regression and restricted cubic spline regression were employed to evaluate the relationship between the number of pregnancies and hearing loss. Subgroup and sensitivity analyses were used to test the consistency and robustness of the association. And mediation analyses explored the roles of white blood cells and high-density lipoprotein in this association.

RESULTS

A total of 5,269 adult women were included in the analysis, of whom 624 (9.81%) exhibited hearing loss. After adjusting for confounders, the number of pregnancies was significantly associated with hearing loss (OR: 1.12; 95% CI: 1.05-1.20; P < 0.001). Conversely, the use of birth control pills was associated with lower odds of hearing loss (OR: 0.67; 95% CI: 0.47-0.94; P < 0.05). Restricted cubic spline regression demonstrated a linear increase in the odds of hearing loss with a greater number of pregnancies. This positive association was consistent across most subgroups. Mediation analyses revealed that white blood cells and high-density lipoprotein partially mediated this association. Sensitivity analyses, including alternative definitions of hearing loss and multiple imputation for missing covariates, confirmed the robustness of the results.

CONCLUSION

Our findings demonstrated that a higher number of pregnancies was significantly associated with hearing loss, while birth control pill use appeared protective. These findings highlight the importance of recognizing potential auditory health implications associated with multiple pregnancies and may inform future public health strategies aimed at supporting women's hearing health across the reproductive lifespan.