People living in colder regions with less sunlight are more likely to consume more alcohol than their warmer-weather counterparts, according to a new study published online in the journal Hepatology.
Researchers at the University of Pittsburgh’s Division of Gastroenterology found that as temperature and sunlight hours drop, alcohol consumption tends to increase. Climate factors were also linked to binge drinking and the prevalence of alcoholic liver disease, one of the main causes of death in patients with long-term excessive alcohol use.
“It’s something that everyone has assumed for decades, but no one has scientifically demonstrated it. Why do people in Russia drink so much? Why in Wisconsin? Everybody assumes that’s because it’s cold,” said senior author Ramon Bataller, M.D., Ph.D., chief of hepatology at the University of Pittsburgh Medical Center (UPMC).
“But we couldn’t find a single paper linking climate to alcoholic intake or alcoholic cirrhosis. This is the first study that systematically demonstrates that worldwide and in America, in colder areas and areas with less sun, you have more drinking and more alcoholic cirrhosis,” said Bataller, also a professor of medicine at Pitt, and associate director of the Pittsburgh Liver Research Center.
Alcohol is a vasodilator, meaning it increases the flow of warm blood to the skin, which is full of temperature sensors. This would bring a sense of warmth to those living in cold climates. Drinking also is linked to depression, which tends to be worse when sunlight is scarce and there’s a chill in the air.
Using data from the World Health Organization, the World Meteorological Organization and other large, public data sets, the research team found a clear negative correlation between climate factors (average temperature and sunlight hours) and alcohol consumption.
Alcohol consumption was measured as total alcohol intake per capita, percent of the population that drinks alcohol, and the incidence of binge drinking.
The researchers also found evidence that climate contributed to a higher incidence of alcoholic liver disease. These trends were true both when comparing across countries around the world and also when comparing across counties within the United States.
“It’s important to highlight the many confounding factors,” said lead author Meritxell Ventura-Cots, Ph.D., a postdoctoral researcher at the Pittsburgh Liver Research Center. “We tried to control for as many as we could. For instance, we tried to control for religion and how that influences alcohol habits.”
With much of the desert-dwelling Arab world abstaining from alcohol, it was important to confirm that the findings would hold up even when excluding these Muslim-majority countries. Likewise, within the U.S., Utah has regulations that limit alcohol intake, which have to be taken into account.
While looking for patterns of cirrhosis, the team had to control for health factors that might worsen the effects of alcohol on the liver like viral hepatitis, obesity and smoking.
In addition to settling an age-old debate, the new findings suggest that policy initiatives focused on lowering the burden of alcoholism and alcoholic liver disease should target geographic areas where alcohol is more likely to be problematic.