Association between nutritional status indices and non-alcoholic fatty liver disease in older adults: insights from the National Health and Nutrition Examination Survey 2017-2018

While previous studies have identified a relationship between dietary intake and the risk of non-alcoholic fatty liver disease (NAFLD), the influence of overall nutritional status on NAFLD development has not been thoroughly investigated. This study sought to explore the association between different nutritional status indicators and NAFLD among the older adults. Nutritional status was evaluated using controlling nutritional status (CONUT), prognostic nutritional index (PNI) and nutritional risk index (GNRI), while NAFLD was identified based on a controlled attenuation parameter ≥ 285 dB/m, measured using transient elastography. The analysis included multivariate regression, receiver operating characteristic analysis, eXtreme Gradient Boosting and subgroup analysis to investigate the relationships between nutritional status indices and NAFLD. The study enrolled 1409 participants for the main analysis, with an NAFLD prevalence of 44·7 %. After accounting for potential confounders, a positive association between PNI and NAFLD was observed. Participants in the third and fourth quartiles of PNI showed increased odds of NAFLD compared with the lowest quartile (Q3: OR = 1·45, 95 % CI (1·03, 2·05); Q4: OR = 2·27, 95 % CI (1·59, 3·24)). Similarly, higher GNRI quartiles were significantly associated with greater odds of NAFLD (Q4 v. Q1: aOR = 1·84; 95 % CI (1·28, 2·65)). Conversely, higher CONUT values were linked to a reduced prevalence of NAFLD (OR = 0·65, 95 % CI (0·48, 0·87)). This study highlights that suboptimal nutritional status, indicating overnutrition as evaluated by PNI, GNRI and CONUT, is positively linked with the risk of NAFLD in individuals aged 50 years and above.