The checkmark association between gamma glutamyl-transpeptidase and body mass index in a large Chinese population.

Background: Obesity has long been regarded as a risk factor for abnormal liver function, although the quantitative relationship between them is not clear. This study aimed to investigate the relationship between body mass index (BMI) and gamma-glutamyl transpeptidase (GGT) in different gender populations.

Methods: The cross-sectional study included 221,934 people aged over 18 years and under 90 years who underwent physical examinations at Yijishan Hospital in Wuhu City from 2011 to 2016. t-test and Chi-square test were used to compare the differences in demographic characteristics and biochemical indexes between men and women. Linear regression model and smooth curve method were used to investigate the relationship between BMI and GGT.

Results: The smooth curve shows a checkmark association between GGT and BMI. After adjusting for confounders, the cut-off BMI for the whole population was 19.5 kg/m2. When BMI was less than 19.5 kg/m2, GGT levels decreased with increasing BMI, and when BMI was greater than 19.5 kg/m2, GGT levels increased with increasing BMI. After gender stratification, there was a checkmark association between male and female GGT levels and BMI, but the trend of male GGT levels changing with BMI was more obvious than that of females.

Conclusions: Our investigation demonstrated that the GGT level in obese Chinese people is significantly higher than that in non-obese people living in Wuhu City. BMI level can be considered as an early warning index for diseases related to liver function injury in the clinic, although the influence of gender difference should be specifically considered.