The study found that drinkers in the highest category of intensity have a 60 percent greater risk of developing metabolic syndrome than those in the lowest category.
The metabolic syndrome is a cluster of cardiovascular disease risk factors which include high blood pressure, elevated triglycerides, low levels of high-density lipoprotein (HDL), impaired fasting glucose and excess abdominal fat. A diagnosis of metabolic syndrome is made if you have three out of five of these risk factors. Having metabolic syndrome increases the risk for cardiovascular disease.
"Lifetime cumulative effects of alcohol consumption on cardiovascular risk factors comprising the metabolic syndrome have been largely unknown, but our study found that drinking patterns independently predict the risk of metabolic syndrome," said lead author Amy Z. Fan, M.D., Ph.D.
Fan and her co-author Marcia Russell, Ph.D., conducted the study at the Prevention Research Center, Pacific Institute for Research and Evaluation, Berkeley, Calif. Russell is a senior scientist at the Prevention Research Center, while Fan is a cardiovascular epidemiologist with the Centers for Disease Control and Prevention in Atlanta, Ga.
"Intensity and frequency of alcohol consumption is important, not just the volume of drinking over a lifetime," said Fan. "It's the historical pattern of drinking that matters."
Russell's research has led to a new way to examine the complex multi-dimensional patterns of drinking over a lifetime. Total volume is the total number of drinks in a lifetime; frequency is the total lifetime drinking days; intensity is volume divided by frequency or drinks per drinking day, averaged over a lifetime.
Researchers studied lifetime drinking patterns using a large population-based sample from northwestern New York state, developed and maintained by University of Buffalo researchers. The database provided healthy controls for case-control studies of chronic disease, with 2,817 individuals, 35 to 79 years old who drank at least once a month for at least six months during their lifetime.
Fan used multivariate regression analysis to determine whether measures of lifetime drinking patterns predict metabolic syndrome. She found the effect of drinking patterns is independent of age, race, gender, family history of heart disease and diabetes, smoking, physical activity and other risk factors.
The prevalence of metabolic syndrome was 25 percent in the study population. The highest quartile category of intensity represented females who consumed an average of four drinks per drinking day and males who consumed an average of six drinks per drinking day. These drinkers are at 60 percent greater risk for metabolic syndrome than the lowest intensity drinkers. The lowest intensity drinkers represent females who consume an average of one drink per drinking day and males who consume an average of 1.3 drinks per drinking day. Those in the second quartile category had a 23 percent higher risk, and those in the third quartile category had a 43 percent higher risk, compared to those in the low-intensity group.
"Individuals who had an early peak of drinking behavior are at higher risk of metabolic syndrome compared to those who have initiated drinking later in life and maintained a low moderate level through life," said Fan. The early group peaked drinking at about age 20-30; then sharply dropped as they age. Among women, the former early-peak-drinkers have a 52 percent higher risk of metabolic syndrome than current low-level drinkers.
"A history of heavy, episodic drinking carries a greater risk of developing metabolic syndrome, regardless of gender," said Fan. "Young people who tend to become involved in episodic drinking rather than moderate drinking should be discouraged."
The researchers concluded that it is healthier to drink smaller amounts per drinking day than to drink more on fewer days, in line with current guidelines on moderate drinking. "The drinking pattern of one drink per day is much healthier than seven drinks on a weekend," said Fan.
Co-authors are: Marcia Russell, Ph.D., M.P.H.; Joan Dorn, Ph.D.; Jo L. Freudenheim, Ph.D., M.S.; Paola Muti, M.D.; Thomas Nochajski, Ph.D.; Kathy Hovey, M.S.; and Maurizio Trevisan, M.D., M.S.
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