Association between albumin-bilirubin (ALBI) score and metabolically healthy obesity among US adults: findings from NHANES 2005–2018

BACKGROUND: The albumin-bilirubin (ALBI) score is an objective assessment of liver function. Given that the liver plays a key role in obesity-related metabolic regulation and that different metabolic phenotypes may be accompanied by different hepatic characteristics, this study aimed to investigate the relationship between ALBI score and metabolically healthy obesity (MHO). METHODS: Multivariable weighted logistic regression, restricted cubic spline, threshold effects analysis, subgroup analysis, and interaction tests were used to examine the relationship between ALBI score and MHO based on data from the 2005–2018 National Health and Nutrition Examination Survey (NHANES). RESULTS: A significant nonlinear positive association between ALBI score and MHO was found among 9,934 obese US adults. In a fully adjusted model, participants in the highest quartile of ALBI scores (with relatively poor liver function) had 105% higher odds of MHO than those in the lowest quartile [OR = 2.05, (95% CI: 1.33, 3.16)]. Threshold analysis identified an inflection point of −2.65, ALBI ≤ −2.65 was significantly positively associated with MHO, and ALBI > −2.65 no significant association was observed. This positive association was more pronounced in individuals older than 50 years (P for interaction = 0.018). CONCLUSIONS: In obese US adults, ALBI score was positively associated with MHO status (particularly significant when ALBI < −2.65), and this association was moderated by age. Our findings suggest that ALBI score can help to reveal MHO-related hepatic characteristics.