Alcohol use and fasting glucose in a developing southern Chinese population: the Guangzhou Biobank Cohort Study

In observational studies, mainly from Western Caucasian populations, moderate alcohol use has been shown to be associated with a lower risk of diabetes. However, whether the protection is due to the attributes of alcohol or to those of moderate alcohol users is difficult to disentangle. A population with a different distribution of alcohol consumption and diabetes prevalence from Western populations was studied as a counterfactual comparison.

Baseline data from the Guangzhou Biobank Cohort Study phases 1 and 2 (2003-6) were used to examine the adjusted associations, using multivariable censored linear regression, of alcohol use with fasting blood glucose in older (> or =50 years) men (n = 5740) and women (n = 14 274) from southern China. Moderate alcohol use was defined as weekly drinking of < or =210 g alcohol in men and < or =140 g in women. The expected associations of alcohol with high-density lipoprotein (HDL) cholesterol and blood pressure were also checked.

Moderate alcohol users had very similar fasting glucose levels to never users, adjusted for age, sex, socioeconomic status, smoking and physical activity. In contrast, moderate alcohol users had higher HDL-cholesterol by 0.05 mmol/litre (95% CI 0.02 to 0.07). Excessive (more than moderate) alcohol users had higher fasting glucose.

In an understudied population with a different pattern of alcohol use from the populations usually studied, the biologically expected effects of moderate alcohol use were seen, but there was little effect on fasting glucose. Although cross-sectional studies cannot be conclusive, this pattern of findings, if confirmed, suggests that moderate alcohol use may not affect fasting glucose, although excessive use may be a risk factor.