Regional variation of alanine aminotransferase serum levels in the People's Republic of China

The regional variation of the blood concentration of alanine aminotransferase (ALT), a sensitive predictor of liver damage, was studied in the People's Republic of China with reference to its potential association with environmental variables and geographic location. The research results presented are based on 121,977 blood samples from healthy adults in 93 cities in the country using correlation analysis, ridge regression estimation and trend surface analysis that were applied to explore if there was any tendency of spatial variation. A regression formula using a simulation equation under the condition of known local geographic factors was used. Statistical significance was set at P<0.05. A positive correlation between ALT concentration altitude and sunshine hours and a negative correlation between ALT concentration and temperature, humidity and precipitation were found. With respect to geographical location, there was a negative correlation between ALT concentration and longitude. Higher ALT values were found in western China compared to eastern regions, dividing the country into three different regions with respect to serum ALT levels.