Association Between Dietary Fiber and Female Fertility: a NHANES-Based Study

This study aimed to evaluate whether dietary fiber content and density were associated with female infertility in the USA. Data on current dietary fiber and current or past female infertility were collected from the National Health and Nutrition Examination Surveys (NHANES) in 2013-2014, 2015-2016, and 2017-2018 cycles. Infertility was identified with the question "Have you ever tried a year to become pregnant: ever attempted to become pregnant over a period of at least a year without becoming pregnant?" The association between dietary fiber and female infertility was analyzed by weighted multivariate logistic regression. Subgroup analysis was performed based on the body mass index (BMI) of women. False discovery rate (FDR)-adjusted P values (q values) < 0.05 indicated statistical significance. Totally 2370 women were eligible for analysis. Dietary fiber content was negatively associated with female infertility [odds ratio (OR) = 0.643, 95% confidence interval (CI) = 0.480-0.861, P = 0.004, q = 0.020]. Dietary fiber density was not associated with the odds of female infertility (OR = 0.734, 95% CI = 0.573-0.941, P = 0.016, q = 0.079). Subgroup analysis exhibited that dietary fiber content was not associated with infertility in underweight and normal-weight (OR = 0.620, 95% CI = 0.332-1.157, P = 0.130, q = 0.467) and overweight (OR = 0.764, 95% CI = 0.523-1.117, P = 0.160, q = 0.553) women; dietary fiber content was inversely associated with infertility in obese women (OR = 0.610, 95% CI = 0.443-0.841, P = 0.003, q = 0.015). There were no significant associations between dietary fiber density and female infertility in underweight and normal-weight (OR = 0.673, 95% CI = 0.393-1.153, P = 0.146, q = 0.410), overweight (OR = 0.769, 95% CI = 0.534-1.107, P = 0.153, q = 0.523), and obese (OR = 0.753, 95% CI = 0.581-0.975, P = 0.032, q = 0.160) populations. In conclusion, a negative association was found between dietary fiber content and female infertility especially among obese women. Future studies are warranted to confirm our findings and the causal relationship between dietary fiber, obesity, and female infertility.