Changes in the Genetic Influences on Smoking over a 50-Year Period

Jason D. Boardman, University of Colorado at Boulder
Casey Blalock, University of Colorado at Boulder

We describe trends in the genetic influences on regular smoking across multiple cohorts of U.S. adults born between 1925 and 1970. We estimate that 36% of the variance in regular smoking is due to additive genetic influences. We also show that the timing of the first Surgeon General’s Report coincides with an increase in the genetic influences on regular smoking, but subsequent legislation prohibiting smoking in public places caused a significant reduction in the genetic causes for regular smoking. We argue that systematic variation in genetic influences across periods makes it difficult to estimate genetic effects on health behaviors using data obtained from a single point in time. Without properly describing the location of the sample within the larger epidemiological trend, the results from genetic studies are difficult to interpret and may lead to erroneous conclusions about the genetic and social factors that may underlie complex behaviors like smoking.