Association between Waist-Hip Ratio and Female Infertility in the United States: Data from National Health and Nutrition Examination Survey 2017-2020

Abstract

Introduction: Obesity has previously been correlated with an elevated risk of reproductive system diseases in women. The waist-hip ratio (WHR) has been shown to be correlated with visceral fat, making it one of the most commonly used indicators of abdominal obesity. However, little is known about the relationship between WHR and infertility. Therefore, the aim of this study was to evaluate the effect of the WHR on infertility in women of childbearing age.

Methods: The study used cross-sectional data from women aged 20-45 who participated in the National Health and Nutrition Examination Survey (NHANES), which was conducted between 2017 and 2020. We collected details of their waist circumference, hip circumference, fertility status, and several other essential variables. We used multivariate logistic regression analysis and subgroup analyses to assess the association between WHR and infertility.

Results: There were 976 participants, with 12.0% (117/976) who experienced infertility. After adjusting for potential confounding factors, our multivariate logistic regression analysis revealed that every 0.1 unit increase in WHR resulted in a more than 35% higher risk of infertility (odds ratio [OR; 95% confidence interval [CI]: 1.35 [1.01∼1.81], p = 0.043). Compared to the group with WHR <0.85, the risk of infertility increased in the group with WHR ≥0.85, with an adjusted OR of 1.74 (95% CI: 1.06∼2.85). When WHR was treated as a continuous variable, it was observed that each 0.1 unit increase in WHR was associated with a relatively high risk in the secondary infertility population after adjusting all covariates, with an OR of 1.66 (95% CI: 1.14∼2.40, p = 0.01). When WHR was analyzed as a categorical variable, the group with WHR ≥0.85 exhibited a significantly higher risk of secondary infertility than the group with WHR <0.85, with the OR of 2.75 (95% CI: 1.35-5.59, p = 0.01) after adjusting for all covariates. Furthermore, the interaction analysis indicated that there was a significant interaction between age status on WHR and the risk of infertility.

Conclusion: WHR showed a positive correlation with the risk of infertility. This study highlights the importance of effectively managing abdominal fat and promoting the maintenance of optimal WHR levels to mitigate the progression of infertility, particularly for younger women.

Keywords: Cross-sectional analysis; Infertility; NHANES; Obesity; Waist-hip ratio.

Fig. 1.

Flowchart of the study population enrollment. WHR, waist-hip ratio.

Fig. 2.

Stratified multivariable analysis of the association between WHR and infertility according to baseline characteristics. Each stratification adjusts for all factors (age, ethnicity, educational level, marital status, family poverty income ratio, physical activity, dietary supplements taken, smoking status, alcohol drinking status, hypertension, diabetes, regular menstrual periods, and trouble sleeping) except for the stratification factor itself. The likelihood ratio test was used to examine interactions among subgroups and WHR and statistical significance was set at a two-tailed p value of <0.05. PIR, family poverty income ratio; WHR, waist-hip ratio.