Researchers have long known that reasons for smoking include social pressure and other environmental factors, as well as genetic factors based on results of previous twin studies. Now a more comprehensive study of twins by researchers at the University of Southern California (USC) has provided a better understanding of these complex influences. They found that women are far more likely than men to start smoking because of environmental factors, whereas genetic factors appear to play a larger role in influencing men to start smoking.

However, the study, which appears in the current issue of the journal Cancer Epidemiology, Biomarkers and Prevention, found no differences between the sexes in factors related to continued smoking, which appeared to be strongly influenced by genetics. The study, entitled "Gender Differences In Determinants of Smoking Initiation and Persistence in California Twins," looked at factors that influenced twins to start smoking and to continue smoking.

With regard to starting smoking, there was a significant difference between men and women, said Ann Hamilton, assistant professor of preventive medicine at the Keck School of Medicine of USC and lead author on the study. "Heritability, which reflects factors related to genetic effects, was stronger in men; however, among men who communicated with each other at least weekly, the heritable effect was reduced. This may indicate that the heritable effect in men could be overestimated or able to be affected by environmental factors."

But when it comes to continuing to smoke, the study found little difference in causal factors between males and females or between those who communicated with each other often and those who did not. "Of those who smoke, it seems that there's a resistance to stopping that has a genetic component," Hamilton says.

"The study suggests that society can have the most impact in preventing people from smoking in the first place," Hamilton
'"/>

Contact: Kathleen O'Neil
kathleen.oneil@usc.edu
323-442-2830
University of Southern California
23-Jun-2006

Page: 1 2
Related biology news :

1. New study warns limited carbon market puts 20 percent of tropical forest at risk
2. Clones on task serve greater good, evolutionary study shows
3. Pollution causes 40 percent of deaths worldwide, study finds
4. A study by the MUHC and McGill University opens a new door to understanding cancer
5. New study suggests Concord grape juice may provide protection against breast cancer
6. Preclinical study links gene to brain aneurysm formation
7. In limiting life span, study finds booming bacteria innocent
8. Multicenter study nets new lung tumor-suppressor gene
9. MIT study: Maturity brings richer memories
10. Chickadee, nutchatch presence in conifers increases tree growth, says CU-Boulder study
11. Phase II study of therapeutic vaccine shows efficacy in patients with metastatic colorectal cancer