Metabolically healthy obese subjects are at risk of fatty liver but not of pre-clinical atherosclerosis

Abstract

Backgrounds and aims: Whether obesity increases risk of cardiovascular disease (CVD) and fatty liver because of the co-existence of other risk factors is uncertain. We investigated odds ratios (ORs) for: a) a measure of pre-clinical atherosclerosis and b) fatty liver, in metabolically healthy obese (MHO) subjects, metabolically abnormal obese (MAO) subjects and metabolically abnormal non obese subjects (MANO), using a metabolically healthy non obese (MHNO) group as the reference.

Methods and results: 14,384 South Koreans from an occupational cohort underwent cardiac computed tomography (CT) estimation of CAC score, liver ultrasound determination of fatty liver, and measurement of cardiovascular risk factors. Pre-clinical atherosclerosis was defined by a CAC score >0. We used logistic regression to determine ORs for CAC >0, and fatty liver in MHO, MAO and MANO subjects (reference group MHNO). There was no increase in OR for CAC score >0 (OR = 0.93, [95% CIs 0.67,1.31], p = 0.68), in the MHO group, whereas there was an increase in the ORs for CAC score >0 in the MAO, and MANO groups (OR = 1.64 [95% CI 1.36,1.98], p < 0.001) and (OR = 1.38 [95% CI 1.17,1.64], p < 0.001), respectively. In contrast, for fatty liver, there was an increase in OR in each group (OR = 3.63 [95% CI 3.06, 4.31] p < 0.001); (OR = 5.89 [5.18,6.70] p < 0.001); and (OR = 1.83 [95% CI 1.69,2.08]) in the MHO, MAO group and MANO groups respectively.

Conclusion: MHO subjects are at risk of fatty liver but attenuated risk of pre-clinical atherosclerosis. Both MAO and MANO subjects are at risk of fatty liver and pre-clinical atherosclerosis.

Keywords: Atherosclerosis; Cardio-metabolic risk factors; Coronary artery calcium (CAC) score; Fatty liver; Metabolic syndrome (MetS); Metabolically healthy obese; Non alcoholic fatty liver disease (NAFLD).