Diet, visceral adiposity, and impaired lung function in postmenopausal women: a mediation analysis

Preserved Ratio Impaired Spirometry (PRISm) is a high-risk respiratory phenotype whose pathophysiology in postmenopausal women remains poorly understood. Although diet quality is known to influence lung health, its association with PRISm and the potential mediating role of visceral adiposity after menopause remain poorly characterized.

This cross-sectional study included 1130 postmenopausal women from the National Health and Nutrition Examination Survey (NHANES, 2007-2012). Survey-weighted multivariable logistic and linear regression models were applied to assess the associations of the Healthy Eating Index (HEI) and Dietary Inflammatory Index (DII) with PRISm, as well as with the Visceral Adiposity Index (VAI) and Triglyceride-Glucose Index (TyG). Mediation analysis was used to quantify indirect effects.

In fully adjusted models, higher HEI scores (OR = 0.97, 95% CI 0.96-0.99) were significantly associated with lower PRISm prevalence, whereas higher DII (indicating a more pro-inflammatory diet) was associated with higher PRISm prevalence (OR = 1.30, 95% CI 1.08-1.57). Both dietary indices were associated with VAI and TyG (p < 0.05), which in turn were positively associated with PRISm (VAI: OR = 1.12, 95%CI 1.03-1.22; TyG: OR = 2.22, 95%CI 1.43-3.45). Mediation analysis further demonstrated that the associations between dietary indices and PRISm prevalence were partially mediated by visceral adiposity and insulin resistance. Specifically, VAI accounted for 2.25% of the observed association between HEI and PRISm and 8.04% of the association between DII and PRISm, whereas TyG mediated 2.58% and 9.58% of the HEI-PRISm and DII-PRISm associations, respectively.

Among postmenopausal women, a healthier, less inflammatory diet is associated with lower odds of PRISm, partly explained by lower levels of visceral adiposity and insulin resistance. These findings suggest that dietary patterns associated with lower visceral adiposity may be relevant for lung health preservation during the menopausal transition.