Association between cardiometabolic index and infertility risk: a cross-sectional analysis of NHANES data (2013–2018)

The cardiometabolic index (CMI), a novel measure of obesity that integrates lipid profiles and indicators of abdominal adiposity, has emerged as a promising marker of metabolic health. However, its relationship with infertility remains largely unexplored. Using data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2018, this study investigated the potential association between CMI and infertility risk. We utilized weighted multivariate logistic regression to examine the association between CMI and infertility and employed a restricted cubic spline model to explore potential non-linear relationships. Interaction tests and subgroups analyses were conducted to assess heterogeneity across different subgroups. The analysis included a nationally representative cohort of 1,142 women. After controlling for potential confounders, a positive association was identified between CMI and infertility risk (OR: 1.47; 95% CI: 1.05-2.06; p = 0.028). The restricted cubic spline model revealed a non-linear relationship (p = 0.0109), with an inflection point at a CMI value of 0.341. Our findings provides evidence of a positive association between CMI and infertility risk among U.S. adults. These results suggest that CMI could serve as a simple and effective surrogate marker for infertility risk assessment, offering valuable insights for reproductive health management.