Nearly 20 percent of adults at the highest risk of having an MI did not believe they needed to improve their physical health, according to a population-based study in Canada.

The researchers found that smoking, obesity and low physical activity were the risk factors most strongly associated with an individual’s perceived need to improve their physical health (PNIPH). Diabetes and hypertension were not associated with PNIPH after the researchers adjusted for potential confounders.

Lead researcher F. Daniel Ramirez, MD, of the University of Ottawa Heart Institute, and colleagues published their results online in the Journal of the American Heart Association on May 3.

“Understanding what motivates changes in behavior is key to improving the health of individuals and communities,” Ramirez said in a news release. “Our study sheds light on how knowledge of personally modifiable risk factors for heart attack, such as quitting smoking and exercising, affects people’s perception of the need to improve their health.”

A previous study found the following nine potentially modifiable risk factors (PMRFs) accounted for at least 90 percent of the population attributable risk for acute MI, according to the researchers: smoking, history of hypertension, diabetes, abdominal obesity, psychosocial factors, daily consumption of fruits and vegetables, regular alcohol consumption, regular physical activity and a raised apolipoprotein (Apo)B/ApoA1 ratio.

For this study, residents of six Canadian provinces completed a cross-sectional survey that assessed all of the PMRFs except for the apolipoprotein (Apo)B/ApoA1 ratio. The national combined household- and person-level survey response rate was 68.4 percent.

The researchers evaluated PNIPH based on an affirmative response to the question, “Do you think there is anything you should do to improve your physical health?.”

A total of 45,443 individuals responded to the survey. The researchers said the sample represented 96.8 percent of the adult population of the six provinces and 40.9 percent of the entire country.

The mean number of PMRFs was 2.5, while the mean body mass index was 26.1 kg/m².

In all, 73.6 percent of individuals reported PNIPH, of which 81.1 percent reported an intention to improve their health in the upcoming year. However, 17.7 percent of people with five or more risk factors did not feel a need to improve their health.

Of the people who endorsed PNIPH, 99.8 percent said a specific behavioral change was important to improve their physical health. Of those who identified a specific change, 90.7 percent said they wanted to exercise more, lose weight, improve their dietary habits or quit/reduce smoking.

A multivariable analysis found that smoking, obesity and low physical activity were most strongly associated with PNIPH and that self-reported hypertension, diabetes and excessive alcohol consumption were not associated with PNIPH. There was a smaller association with PINPH for high stress and low fruit and vegetable consumption.

Among the individuals with PINPH, 55.9 percent said they had a barrier to adopting positive health changes. The most common barriers were a lack of will power or self-discipline, work schedule and family responsibilities.

The researchers acknowledged a few limitations of the study, including that the outcome variable (PNIPH) was imperfect and likely did not capture nuances in health perceptions. They said a panel of questions targeting different aspects of health perceptions and determinants of lifestyle behavioral change could have led to a more robust analysis. In addition, they collected data via self-reports, which could have led to recall bias. Further, they grouped culture or racial origins into white, visible minority and not stated, which limited them from assessing sociocultural influences on health perceptions.

“The cumulative burden of PMRFs is positively associated with PNIPH; however, individually, PMRFs are differentially associated with this perception,” the researchers wrote. “A substantial proportion of individuals at risk for cardiovascular events do not feel a need to improve their physical health, indicating an urgent need to identify means to modify public health perceptions and behaviors.”