Serum lipoprotein(a) levels and insulin resistance have opposite effects on fatty liver disease

Background and aims: High lipoprotein(a) [Lp(a)] levels are associated with increased risk of cardiovascular disease. However, the association between Lp(a) and fatty liver disease (FLD) remains controversial. Therefore, we analyzed the relationship between FLD and serum Lp(a) levels in Korean adults. Methods: A total of 22,534 participants who underwent a routine health screening program at Kangbuk Samsung Hospital in 2010 and 2014 were enrolled. Anthropometric and biochemical parameters, including Lp(a), were measured. The presence of FLD was assessed using abdominal ultrasonography. Odds ratios (ORs) for the presence of FLD were analyzed in quartile groups of serum Lp(a) levels using logistic regression. We divided the participants into four groups according to the median values of Lp(a) and homeostasis model assessment for insulin resistance (HOMA-IR). Results: Among the total study population, 3030 (13.4%) participants had fatty liver disease. The mean Lp(a) level was lower in subjects with FLD than in those without (70.0 vs 73.8 nmol/L, p < 0.001). The OR for FLD was the lowest in the fourth Lp(a) quartile group, using the first quartile group as the reference group after adjusting for confounding factors [0.815; 95% confidence interval (CI) 0.725-0.916]. When the OR for FLD was analyzed in four groups divided by the median values of Lp(a) and HOMA-IR, the low Lp(a)-high HOMA-IR group had the greatest OR for FLD, using the high Lp(a)-low HOMA-IR group as the reference (1.903; 95% CI 1.679-2.158). Conclusions: Serum Lp(a) levels were inversely associated with the presence of FLD. Subjects with low Lp(a) and high insulin resistance (IR) showed higher risk of FLD than those with high Lp(a) and low IR, suggesting the opposite associations of Lp(a) and IR with FLD.