Moderate Drinking May Protect Heart By Improving Insulin Resistance, Study Suggests

Analysis of a large Italian database by UB epidemiologists showed thatthe prevalence of a condition precipitated by insulin resistance called SyndromeX, which is characterized by abnormal levels of triglycerides, HDL cholesterol,blood pressure and glucose--all risk factors for heart disease--wassignificantly higher among non-drinkers than drinkers.

Results also showed that Syndrome X incidence declined as alcoholconsumption increased and that the effect seemed to be more pronounced in womenthan in men. The apparent beneficial effect of drinking peaked at the 3-to-4drinks-per-day level for both men and women, however. Syndrome X incidencebegan to climb in women who consumed more than four drinks per day, findingsshowed.

Results of the study by Jian Liu, M.D. and Maurizio Trevisan, M.D., ofUB's Department of Social and Preventive Medicine, were presented here today byLiu (June 26, 1998) at the annual meeting of the Society for EpidemiologicResearch.

Insulin resistance is a condition in which the pancreas producessufficient amounts of the hormone, but cells absorb it more slowly than normal,causing sugar (glucose) and insulin to accumulate in the blood. Insulinresistance may be exacerbated by a bad diet, lack of physical activity, geneticpredisposition and being overweight, Trevisan said.

The symptoms that characterize Syndrome X put a severe strain on theheart and arteries, he noted. Knowing that moderate drinking lowers the risk ofheart attack, the UB researchers sought to determine if a relationship existedbetween alcohol consumption and insulin sensitivity, using Syndrome X as amarker.

The results could shed light on one possible mechanism through whichalcohol may lower the risk of heart disease, Trevisan said.

Trevisan and Liu analyzed data collected from 37,991 Italian men andwomen in nine epidemiologic studies that comprise the Risk Factor and LifeExpectancy Group. Their analysis included information on the amount of alcoholconsumed per day, along with measurements of blood pressure, triglycerides, HDLcholesterol and blood glucose, variables all related to insulin resistance.

Persons with Syndrome X were defined as having all of the following:

• Blood pressure greater than 140/90 mmHg, or taking anti-hypertensivemedicine
• Triglycerides greater than 175 mg/dl for men and 133 mg/dl for women,or taking lipid-lowering medicine
• Blood glucose higher than 100 mg/dl for men and 95 mg/dl for women, ortaking diabetes medicines, and
• HDL levels lower than 40 mg/dl for men and 46 mg/dl for women.

Alcohol consumption was rated as light (1-2 drinks per day), moderate(3-4 drinks per day) or heavy (more than 5 drinks per day). A drink was definedas 11.7 grams (about four ounces) of alcohol.

Results showed that of the 21,612 men in the study, 2.9 percent ofdrinkers fit the Syndrome X definition, compared to 3.6 percent of thenon-drinkers. Among 16,379 women, the percentages of drinkers versusnon-drinkers classified with Syndrome X were 2.79 percent versus 3.95 percent,respectively.

Trevisan said if these results are confirmed in follow-up studies, thenext step will be to determine the mechanism by which moderate alcoholconsumption increases insulin sensitivity.