Association between alpha-1-acid glycoprotein and infertility in the NHANES 2015–2020

Infertility is a prevalent reproductive disorder, with local and systemic inflammatory responses potentially playing a pivotal role in its etiology. Alpha-1-acid glycoprotein (AGP), an acute-phase glycoprotein, has been implicated in inflammatory processes. This study set out to find out the relationship between AGP levels and infertility among American women. A cross-sectional survey was used for analyzing the National Health and Nutrition Examination Survey data from 2015 to 2020. For study of the relationship between AGP and infertility, multiple logistic regression models were utilized. Smoothed curve fitting and threshold effects were implemented to describe the nonlinear relationship between the two. The study consisted of 2229 female volunteers between the years of 18 and 45, with 262 cases of infertility. Both Model 1 (OR = 2.97, 95% CI: 1.76, 5.00), which was not adjusted for covariates, and Model 2 (OR = 2.60, 95% CI: 1.50, 4.49), which was corrected for age and race, revealed a significant positive association between AGP and infertility. However, after controlling for all variables, this positive relationship was insignificant in model 3 (OR = 1.44, 95% CI: 0.68, 3.08). The link between AGP and infertility failed to significantly depend on the impact of each subgroup (P for all interaction tests > 0.05). A positive nonlinear link between AGP and infertility was identified utilizing smooth curve fitting. Furthermore, threshold effect analysis exhibited an inverted U-shaped connection with an inflection point of 0.76 g/L between AGP and infertility in women elderly 35 and above. According to our research, AGP and infertility are associated positively. It might inspire novel approaches to clinical care, but additional investigation is required to comprehend the underlying mechanisms.