Insulin Sensitivity among College Athletes with Smoking Behavior

Abstract

It has been shown that athletes have higher smoking rate than regular college students. But the association between smoking behavior and insulin sensitivity in college athletes is still unclear. The purpose of this cross-sectional study was to investigate the smoking behavior on insulin sensitivity in college athletes. Five hundred and fifty two nonsmoking and ninety eight smoking (8.4 ± 0.7 cigarette per day) athletes were recruited for this study. Indices of glucose metabolism (glucose, insulin, HbA1c), inflammation (white blood cells, WBC) and liver function test markers (alanine aminotransferase [ALT], aspartate aminotransferase [AST]) were measured for all subjects under fasting condition. We found that gender-, alcohol consumption- and age-adjusted insulin, HOMA-IR (homeostasis model assessment of insulin resistance), HOMA-β (homeostasis model assessment β-cell function) and WBC number were higher in smokers than nonsmokers in ANCOVA. QUICKI (quantitative insulinsensitivity check index) and AST levels were lower in smokers compared to nonsmokers. Simple linear regression and multiple linear regression analyses were used to determine whether the smoking amount was associated with markers in metabolism. We found that smoking amount was positively associated with serum insulin, HOMAIR, HOMA-β, HbA1c and WBC count, and negatively associated with QUICKI before and after adjusting the gender, alcohol consumption and age. Smoking was also negatively related with adjusted AST. However, WBC is positively correlated with HOMA-IR and HOMA-β, and negatively correlated with QUICKI. These findings conclude that athletes with smoking behavior have low insulin sensitivity; the possible reason might be due to the increased chronic low-grade inflammation.