The prevalence of heart disease and its attendant risk factors — hypertension, diabetes, and obesity — are increasing in all age groups and most income groups in Canada, according to a study published Monday in the Canadian Medical Association Journal.

The increasing prevalence of heart disease is likely because of earlier detection and better survival, as more Canadians are living through a first heart attack, said researchers with Institute for Clinical Evaluative Sciences and the Peter Munk Cardiac Centre, both in Toronto.

The study's authors base their conclusions on data from the National Health Population Survey and the Canadian Community Health Survey from 1994 to 2005 for those aged 12 and older and including all socio-economic and ethnic groups.

The study found an estimated 1.29 million Canadians reported having heart disease in 2005, representing a nearly 20 per cent increase in men and just over a two per cent increase in women compared with 1994.

Although people in lower income groups were at greatest risk, hypertension prevalence nearly doubled and obesity increased over time in all income groups. Diabetes is also increasing in almost all income groups, although the gap between the richest and the poorest is widening.

The authors found that hypertension and diabetes are increasing most in those who were obese or overweight.

"There is great potential for more cardiovascular disease and worsening disparities in the future unless preventative efforts are directed toward these vulnerable groups," the authors write.

Lead author Dr. Douglas Lee of the Institute for Clinical Evaluative Sciences, says projections suggest the rising prevalence of obesity in the current generation of adolescents will increase the prevalence of coronary heart disease by five to 16 per cent in 2035.

He went so far as to warn that it may also "for the first time in two centuries significantly reduce life expectancy in the 21st century."