Nonlinear relationship associations between a lipid composite index and asthma in middle-aged women: a cross-sectional study from NHANES 2007-2016

BackgroundAsthma demonstrates pronounced sex-based disparities, with adult females exhibiting a disproportionately higher disease burden. Although aberrant lipid metabolic profiles have been mechanistically linked to asthma pathogenesis, the specific association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and asthma risk in women remains unclear. This study aims to investigate the relationship between NHHR and asthma risk in middle-aged women using a nationally representative U.S. population.MethodsData were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. A variety of statistical methods, such as multivariate logistic regression, smoothed curve fitting, threshold effects, and subgroup analyses, were applied to explore the relationship between NHHR and asthma risk.ResultsA total of 7,337 participants aged 30-65 years were included, with an asthma prevalence of 16.82%. After full adjustment for demographic, socioeconomic, lifestyle, and clinical factors, higher NHHR levels were positively associated with asthma risk (OR = 1.26, 95% CI: 1.01, 1.58). Smooth curve fitting demonstrated a nonlinear relationship with a threshold inflection point at Log10(NHHR) = 0.07 (corresponding to NHHR ≈ 1.17). Above this threshold, asthma risk increased significantly (OR = 1.78, 95% CI: 1.24-2.54). Subgroup analyses indicated a significant interaction by education level, with stronger associations observed among women with lower educational attainment.ConclusionsElevated NHHR is independently and nonlinearly associated with asthma risk in middle-aged women. The findings suggest that dysregulated lipid metabolism may contribute to asthma susceptibility, highlighting NHHR as a potential biomarker for metabolic-inflammatory crosstalk and in women's respiratory health.