Alcohol consumption and the incidence of type II diabetes.
BACKGROUND
This study examines the relation between alcohol and type II diabetes and the possible mediating effects of HDL-cholesterol and serum insulin.


METHODS
Prospective study of 5221 men aged 40-59 years with no history of coronary heart disease, diabetes, or stroke drawn from general practices in 18 British towns.


RESULTS
During the mean follow up of 16.8 years there were 198 incident cases of type II diabetes. Occasional drinkers were the reference group. A non-linear relation was seen between alcohol intake and age adjusted risk of diabetes, with risk lowest in light and moderate drinkers and highest in heavy drinkers (quadratic trend p=0.03). Further adjustment for body mass index decreased risk in heavy drinkers. After additional adjustment for physical activity, smoking, and (undiagnosed) pre-existing coronary heart disease, only moderate drinkers showed significantly lower risk than occasional drinkers (RR=0.66 95% CI 0.44 to 0.99). Alcohol intake was inversely associated with serum insulin and positively associated with HDL-cholesterol. Adjustment for these factors reduced the "protective" effect in moderate drinkers (adjusted RR=0.73 95% CI 0.48 to 1.10) but the quadratic trend remained significant (p=0.02).


CONCLUSIONS
There is a non-linear relation between alcohol intake and the risk of type II diabetes. Serum insulin and HDL-cholesterol explained a small amount (20%) of the reduction in risk of type II diabetes associated with moderate drinking. The adverse effect of heavy drinking seemed to be partially mediated through its effect on body weight.
Wannamethee
S G
SG
Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, UK. goya@pcps.ucl.ac.uk
Shaper
A G
AG
Perry
I J
IJ
Alberti
K G M M
KG
D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D008076:Cholesterol, HDL / Q000097:blood; D003327:Coronary Disease / Q000453:epidemiology / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007328:Insulin / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology
D001786:Blood Glucose; D008076:Cholesterol, HDL; D007328:Insulin