Individuals who stand to gain the most from changing their behaviors are the most likely to defensively downplay that fact and instead blame genetics, a new study suggests.
The researchers surveyed nearly 2,000 healthy American adults on their behavioral risk factors, family history, beliefs about causes of common diseases, and their preferences for one type of health information over another.
The physical factors included physical activity, dietary habits, smoking, alcohol consumption, sun exposure, multivitamin use and body mass index.
Prompted by the "tsunami of genetic data" made possible by the completion of the Human Genome Project and the still as-yet unpracticed possibility of wide genetic testing, the study sought to understand the psychosocial effects of a public faced with never-before apprehended information about their genetic susceptibility to common health conditions.
Originally, scientists feared that individuals would attach too much weight to genetic predisposition, undermining public health efforts to promote lifestyle changes as counteractive measures, the researchers wrote in a paper published in a forthcoming issue of the Annals of Behavioral Medicine.
A majority of respondents indicated behavioral factors were more important than genetics in causing eight largely preventable diseases (diabetes, osteoporosis, heart disease, high cholesterol, hypertension, lung, colon and skin cancers).
But for those respondents who themselves engaged in more risky habits, their tendency to downplay behavioral information increased significantly. Such behaviors included smoking, types of diet and physical activity, risky alcohol consumption, and sun exposure.
One explanation for this way of overvaluing genetic information is that it allows individuals with risky behavior an excuse for not changing their bad habits, the researchers suggest.
"It may also be that they've tried standard behavioral advice in the past and it hasn't worked for them, or they're fatigued to hearing this advice from family, friends, doctors and the media," researcher Suzanne O’Neill of Georgetown University told Livescience.
The results offer "very valuable information" for the scientific community in the way it may communicate the duality of factors behind common diseases, O’Neill said.
With the exception of hereditary illnesses, compared to genetics, behavior plays "a very important part, maybe more important" in the origins of disease, she told LiveScience. "But we don’t really know for sure yet."