Association of Serum Alkaline Phosphatase with the TG/HDL Ratio and TyG Index in Korean Adults

Alkaline phosphatase (ALP) has long been considered a marker of hepatobiliary and bone disorders, but recent studies have shown that increased ALP activity is correlated with various cardio-metabolic diseases. Thus, we investigated the association of serum ALP level with surrogate markers of insulin resistance such as triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C ratio) and triglyceride and glucose (TyG) index in the general population. The study included 12,868 men and women aged 19 years and older. Participants were categorized into four groups based on serum ALP level (U/L) as follows: Q1: 55–190 U/L, Q2: 191–224 U/L, Q3: 225–265 U/L, and Q4: 266–923 U/L for men, Q1: 48–161 U/L, Q2: 162–198 U/L, Q3: 199–245 U/L, Q4: 246–790 U/L for women. The insulin resistance cut-off levels were defined corresponding to the 75th percentile of the TyG index and TG/HDL-C ratio in the current samples. Odds ratios (ORs) with 95% confidence intervals (CIs) of insulin resistance according to quartile of serum ALP level were calculated using weighted multivariate logistic regression analysis. Compared with Q1, the adjusted OR (95% CI) for insulin resistance of the Q4 serum ALP group was 1.517 (1.234–1.866) in men and 1.881 (1.399–2.528) in women using the TG/HDL-C ratio and 1.374 (1.093–1.728) in men and 2.047 (1.468–2.855) in women using the TyG index after adjusting for confounding variables. Serum ALP levels are independently and positively associated with surrogate markers of insulin resistance in Korean adults.