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AMSTERDAM -- In the bleak midwinter, the risk of alcoholic cirrhosis might increase.

That's the conclusion of an analysis that links cooler temperatures and less sunshine to increased alcohol use and therefore to alcohol-associated liver disease, according to Neil Shah, MD, of the University of North Carolina in Chapel Hill.

The findings support the "not uncommon notion that people drink to stay warm" and lay themselves open to all the consequences of alcohol use, Shah said at the International Liver Congress, the annual meeting of the European Association for the Study of the Liver (EASL).

But Shah cautioned that although climate and alcohol-related liver disease were associated in the study, that doesn't mean that one causes the other.

Indeed, the analysis is based on a "very original idea ... but possibly there are many factors of confusion," commented Helena Cortez-Pinto, MD, PhD, of the University of Lisbon, who was not part of the study but who co-moderated the EASL session at which it was presented.

Among other things, she said, statistics in different countries -- especially death certificates -- are not equally reliable, which might affect the accuracy of the analysis.

The data are "provocative (and) provide a strong argument in favor of the hypothesis that the amount of alcohol intake, and, as a result, the risk of alcohol-related cirrhosis, depends on latitude," commented Francesco Negro, MD, of the University Hospital of Geneva in Switzerland.

But, like Cortez-Pinto, he cautioned that confounding factors abound. "It remains to be seen to what extent other factors, such as ethnic, cultural, and religious backgrounds, may attenuate this association," he said.

Shah noted that heavy alcohol intake can give the perception of warmth -- a fact that leads to the assumption that people in countries with colder weather drink more and might therefore have increased prevalence of alcoholic liver diseases.

And it's known that hours of sunlight are related to both temperature and depression and therefore also could influence alcohol use, he added.

But the assumptions have not been tested using global epidemiological data, he said.

To help fill the gap, Shah's group used databases for a total of 193 countries to get data on such things as daily alcohol use, liver disease, cirrhosis, and percentage of binge drinkers.

Climate data came from databases maintained by the and included such things as average temperature, latitude, most prominent climate type, and average hours of yearly sunshine.

Using regression analysis, they looked for associations between climate and both the alcohol-attributable fraction (AAF) of cirrhosis and the age-standardized death rate (ASDR) from cirrhosis, Shah said.

In an exploratory univariate analysis, there were no associations between climate data and the ASRD, he reported, so the researchers did not continue on that line.

But the analysis showed significant links between the AAF and average temperature, mean annual sunshine hours, and latitude, so Shah's group conducted a further multivariate analysis, adjusting for the percentage of binge drinkers among active drinkers and average alcohol consumption.

That analysis showed average temperature and sunshine hours remained independently associated with AAF, Shah said. For instance, for every degree Celsius increase in temperature there is an observed 0.3% decrease in AAF.

Although there are likely many other factors that come into play, Shah said, one possible implication of the study is that public policy measures to prevent alcohol cirrhosis should be especially active in colder climates.

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