Sydney, Aug 5 (IANS): Heart disease and stroke mortality rates have almost stopped declining in many high-income countries and are even increasing in some countries, reveals a new study.

For the study, published in the International Journal of Epidemiology, researchers from the University of Melbourne analysed trends in cardiovascular disease mortality, which consists of mainly heart disease and stroke -- in 23 high-income countries since the year 2000.

The study found that cardiovascular disease mortality rates for people aged 35 to 74 years are now barely declining, or are increasing, in 12 of the 23 countries.

Cardiovascular disease mortality rates have increased in the most recent years in US and Canadian females, while in Australia, the UK and New Zealand annual declines in deaths from cardiovascular diseases are now 20 to 50 per cent.

"Research suggests that obesity, or at least poor diet, may have been a significant contributor to the slowdown in the decline of cardiovascular disease deaths," said Alan Lopez, Professor at the University of Melbourne.

"Each of these countries have very high levels of obesity. In Australia, close to one-third of adults are obese," Lopez said.

The researchers observed that obesity is the main risk factors for cardiovascular disease mortality -- others include smoking, high blood pressure, high cholesterol and diabetes.

"Failure to address these issues could confirm the end of the long-term decline in cardiovascular disease deaths and threaten future gains in life expectancy." concluded study's co-author Tim Adair, a researcher at the varsity.