Alanine aminotransferase (ALT) is a cytosolic enzyme specific to hepatocytes, and its elevated level in the peripheral blood denotes liver cell injury. Detection of persistently elevated ALT levels during routine health check-up in asymptomatic or symptomatic individuals provides a window of opportunity to explore the causes of liver cell damage and for the timely institution of appropriate treatment. This was a retrospective study using a subset of the data from a previous community-based prospective study done for the estimation of the prevalence of celiac disease (CD) in India, during which estimation of ALT levels in the blood samples of participants was also carried out. Of the 11,053 individuals (4399 [39.8%] males; mean age 37.9 ± 13.3 years) screened, 6209 consented to provide blood samples for testing for CD. Of these, assessment of serum ALT levels was done in 6083 (2235 [36.7%] males) patients. ALT was elevated above the upper limit of normal (ULN) (> 40 IU/L) in 1246 (20.5%) of the participants and > 1.5 times (> 60 IU/L) in 329 (5.4%) participants. The ALT levels were elevated more frequently in men as compared to women (29.4% vs. 15.3%, p < 0.001). There was a significant positive correlation (Pearson correlation coefficient [r] = 0.25, p < 0.0001) between ALT levels and body mass index (BMI). With increasing age, there was a significant decrease in the proportion of subjects with ALT ≥ 1.5× ULN (p < 0.001). Our results suggest that a high proportion (20.5%) of individuals otherwise considered healthy have values of ALT level in the serum above the "normal" range/cut-off suggesting likely ongoing underlying liver damage. There is a need for measures to evaluate and, if found, treat the underlying cause for the same.
Keywords: Alanine transaminase; Body mass index; Celiac disease; Hepatocytes; Metabolic syndrome; Non-alcoholic fatty liver disease; Obesity; Prevalence; Public health; Tissue transglutaminase.