14 June 2010

Unhealthy people blame genes

A survey shows that the deluge of scientific discoveries of links between specific genes and many chronic diseases provids some unhealthy people an excuse for their medical woes.


A new survey shows that the recent deluge of scientific discoveries of links between specific genes and many chronic diseases might be providing the least healthy people with something they don't need: an excuse for their medical woes.

"We wanted to know if people are going to use genetics as a way to kind of get off the hook, rather than change their behavior and be healthy," explained study co-author Suzanne C. O'Neill, an assistant professor with the Cancer Control Program at Lombardi Comprehensive Cancer Centre at Georgetown University in Washington, DC.

"But the bottom line is that most people aren't doing that. It's only when you look at people with a number of behavioural risk factors that you run into trouble," she said.

"People, for example, who are smokers and have a poor diet and don't exercise as much as they should. Those people are more likely to think that diseases are caused by genetics, and are not interested in information on behavioural change. So, the people we want to reach the most are the ones we are going to have the most trouble with," O'Neill added.

How the research was done

O'Neill, who conducted her research while a postdoctoral student at the social and behavioral research branch of the National Human Genome Research Institute at the US National Institutes of Health, and colleagues reported the survey results in the June 8 online edition of the Annals of Behavioural Medicine.

According to the CDC Foundation, humans are 99.9% identical, genetically speaking. It is the minute 0.1% remainder that accounts for differences ranging from traits as innocuous as hair color to pre-dispositions for a wide variety of diseases.

With this in mind, the authors set out to assess behaviour-related health risk by asking almost 2 000 survey respondents about their daily routines with respect to diet, exercise, smoking, drinking, sun exposure, multivitamin use, body mass index (BMI), and educational background.

In turn, participants were asked to indicate how strongly they believed their behavior, on the one hand, and their genetic background, on the other, would influence disease risk. All were also asked how important it was to them to learn more about healthy behaviours versus genetic risk.

Finally, all participants were asked to outline their family history with respect to eight typically preventable diseases: diabetes, osteoporosis, heart disease, high cholesterol, high blood pressure, and lung, colon and skin cancers.

What the study showed

Evenly split between men and women, more than one-third of the poll participants were college graduates, and nearly two-thirds were married. One-quarter were smokers, one-quarter said they were physically active less than five days a week, and more than one-third reported being obese, the study authors found.

About half of those surveyed said they had a family history with every disease covered by the poll, with the exception of high blood pressure (which touched 83 percent of participants) and osteoporosis (15%).

The research team found genetic risk was more likely to be cited as the cause for diabetes, heart disease, high cholesterol, high blood pressure and colon cancer among those with a family history of these diseases.

Those engaged in behaviours that posed the most risk to their health were more likely to attribute cancer risk and high blood pressure risk to genetics, the study authors noted.

Overall, those with the poorest behavior were also the least likely to want more guidance on how healthy behavior could lower disease risk, except with regards to lung cancer, O'Neill and colleagues found.

'Some people don't want to know'

Nevertheless, while 57% of respondents said they wanted more information on genetic risk, 67% said they wanted more information on healthy habits.

"It's important to note that the public as a whole isn't overly deterministic about genetics," O'Neill said. "At the same time, it's not totally surprising that there is this subset of people who are really having a harder time. Both from experience and from the literature, we know that people often don't want to hear information that is threatening," she explained.

"But the fact that some people do place a high value on genetic information may actually open up a novel way to talk to them," O'Neill suggested. "We can introduce the information they are most receptive to - information about genetics - while at the same time getting out the message that behaviour does play a huge role in health risk. So, there are ways to approach this problem."

Lona Sandon, an assistant professor of nutrition at the University of Texas Southwestern Medical Center in Dallas, said that those who might be too quick to point to genetics to explain their health predicament are struggling with the so-called "health-belief mode."

"First, you have to believe there is a health problem before you can acknowledge there's something you can do to change that problem," she explained. "And certainly people who work in public health would say that individual behaviour, as well as environmental influences, are the strongest determinants of health outcomes, and that genetics and the medical care we get actually play a very small role in health outcomes, because we typically don't get to the health-care point until we have disease," Sandon continued.

"So it's disease prevention and health promotion where we need to make healthy lifestyle choices, and early on in life," she said. "We have to prevent it before we're in our 60s, not after." - (HealthDay News, June 2010)


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