Genes may explain why churchgoers drink, smoke less - report

Churchgoers drink and smoke less than adults who spend their Sundays elsewhere but a US study has found it may not be church attendance itself that explains this - it could be their genes.

The study of nearly 1,800 adult male twins found in adolescence, the relationship between church attendance and lower rates of drinking and smoking appeared largely due to "shared" environment, the factors influencing both members of a twin pair.

That is, teenagers who attended church regularly were more likely to want to follow their parents' wishes and conform to community expectations.

By adulthood, however, those environmental influences had faded, the researchers found. Instead, genes seemed to account for the relationship between church-going and lesser alcohol and nicotine use.

In this case, genes may enter the picture via their influence over a person's natural temperament, the researchers wrote in the American Journal of Psychiatry.

Many adults who continue to regularly go to church, they speculated, may also be the type who would limit their drinking and avoid smoking.

"Church attendance is one of the strongest correlates of substance abuse," said researcher Kenneth Kendler, of the Virginia Commonwealth University School of Medicine in Richmond.

"Understanding the underlying nature of this association is important because of what it tells us about the causes of substance use."

The study included 469 identical twin pairs and 287 pairs of fraternal twins, all of whom were interviewed twice over six years. The men were asked about their current church attendance and smoking and drinking habits, as well as their habits during adolescence.

Twin studies like these allow researchers to disentangle the effects of genes, shared environment like home life and parenting practices, and non-shared environment such as friendships and other factors unique to an individual, on a given behaviour or disease risk.

Identical twins share all of their genes, while fraternal twins share about half of their genes, on average. So if genes, for example, hold a stronger influence over a particular behaviour than shared environment does, identical twins would be more similar in that behaviour than fraternal twins would be.

Dr Kendler's team found that when it came to the link between church-going and substance use, the roles of environment changed over time. By adulthood, shared environment seemed to have almost no role.

Instead, genes largely explained the relationship, with some role of non-shared environmental factors also being apparent.