HELSINKI, Finland, Oct. 15 (UPI) -- New research suggests a gene variant of a neuropeptide once linked with alcoholism could in fact hold down the evolution of that disease.
The study by Finish scientists lends another twist to the ever-shifting scientific quest to understand the interplay between genes and alcoholism.
"This is an interesting finding, a potential sign that (a gene variant of the neuropeptide Y or NPY) might retard progression of alcoholism," said Hannu Alho, a specialist in addiction medicine at the National Public Health Institute in Helsinki.
Alho was lead author of the study, published in the journal Alcoholism: Clinical & Experimental Research.
Researchers said teasing apart causal relations between a person's genetic makeup and the tendency to hit the bottle is a convoluted task. Studies are often conflicting and the disease is polygenetic, meaning the result of a confluence of complicated genetic factors.
Alho told United Press International he and fellow researchers initiated the study after reading about a previous one that proposed a link between a gene variant of NPY and higher alcohol consumption.
Peptides form the constituent parts of proteins, and neuropeptides are peptides found in neural tissue.
Specifically, the earlier study found the gene variant was linked with a 34 percent higher average alcohol consumption. But Alho said that study did not identify whether subjects were alcoholics.
Surprisingly, in their subsequent study, Alho and fellow researchers found a higher prevalence of the NPY variant in social drinkers, not alcoholics. They also found the variant was associated with a decreased risk of alcoholism. That fact lead them to speculate the gene variant may actually suppress rather than persuade the evolution of alcoholism, though they were careful to caution that larger scale studies are needed.
Alho's team assembled two test groups using 122 alcoholics -- 101 male, 21 female -- and 59 social drinkers -- 34 male, 25 female. Social drinkers are defined as people who intake less than 30 grams of pure alcohol a day or about three American beers, Alho said.
The alcoholics used were divided into two groups based on their type of alcoholism. Type 1 alcoholism is associated with anxiety and occurs later in an individual's life. Type 2 is presumed to be heavily genetically influenced and is characterized by behavioral disorders and early onset of the disease, usually around the age of 15.
The gene variant was associated with a decreased threat from both Types 1 and 2.
"There are a number of problems with this kind of study and researchers must be sure that the controls and alcoholics are both sub-sampled from the same larger population," said Thomas E. Johnson, a behavioral geneticist at The University of Colorado at Boulder. "Except for that caveat, this seems to be a solid and very believable piece of research."
Johnson said alcohol genetics is very difficult because "there are so many genes and variants at those genes that probably dispose to alcoholism. Numerous neurochemical pathways are involved in alcohol action, (so many that) it is more probable that an effect on a given neurochemical will be observed after alcohol exposure, rather than not being observed."
(Reported by Kelly Hearn in Washington)
