Heart disease, stroke-related deaths in developed countries on the rise due to obesity
High and increasing obesity, among other risk factors such as smoking, high blood pressure, and diabetes, are jeopardizing further CVD-death declines in many countries
The rate of decline in the number of people dying because of heart disease and stroke has slowed down significantly, and shockingly even reversed in younger populations, in many high-income countries. This is most apparent between ages 35 and 74 years, where cardiovascular disease (CVD)-death rates have increased in the US (males and females) and Canada (females), researchers from the University of Melbourne say.
“Cardiovascular diseases (CVDs) collectively are the leading cause of death globally, and also the leading cause of premature deaths, as assessed by the Global Burden of Disease (GBD) Study. Since the 1970s, some countries have seen the number of deaths from cardiovascular disease – mostly heart disease and stroke – fall by 40% to 80%. In high-income countries, this very substantial decline in CVD mortality over the past half-century has been a major, yet often unheralded, global public-health achievement. However, our study has found that cardiovascular disease mortality rates have almost stopped declining in many high-income countries, including Australia. We found that in some parts of the world, rates have even started to rise,” said the researchers in their findings published in the International Journal of Epidemiology.
The research team analyzed trends in cardiovascular disease deaths in 23 high-income countries since 2000. The primary source of data for the analysis was the World Health Organization (WHO) mortality database.
Researchers found cardiovascular disease deaths for people aged 35 to 74-years-old are now barely declining, or are increasing, in 12 out of the 23 countries studied. The analysis shows that CVD deaths increased from 2016 to 2017 for seven countries, which includes Australia, Germany, the USA and the UK (males and females), Greece and New Zealand (males) and the Netherlands (females). In the USA and for Canadian females, cardiovascular disease death rates have increased in the most recent year, while in Australia, the UK and New Zealand, annual declines in deaths from cardiovascular disease are now only 20-50% of what they were in the 2000s.
An estimated 17.9 million people died from CVDs in 2016, representing 31% of all global deaths, say the World Health Organization (WHO). Of these deaths, 85% were due to heart attack and stroke.
“In the most recent year, CVD death rates for females appear to have increased slightly in the US, were steady in Italy and declined only marginally (by less than 2%) in Belgium, the Netherlands, and New Zealand. For men, they were unchanged in the US and declined only marginally (by less than 2%) in Australia, Germany, Israel, Italy, and Spain. The average annual rate of decline of CVD mortality in the US since 2010 has been about 1% for both males and females, compared with about 3.5% over the previous decade. Average annual declines in CVD mortality between 2000 and 2010 were at least 3% in every country (and only slightly less so in Japan), averaging 4.1% for males and 3.9% for females, compared with 3.2% (males and females) since 2010. This pattern of slowing CVD-mortality declines is even more evident at ages 35–74 years,” says the study.
Detailed assessment shows that in several other countries, the rate of decline for both sexes has slowed to less than 2% - Germany, Italy, Spain, and the UK - and for at least one sex in others (males: Australia, Canada, France, and Greece; females: Austria, Denmark and New Zealand). There are few exceptions, states the study, which says that the largest average annual declines in CVD mortality over the decade to 2010 were observed in Ireland (5.4% males, 5.0% females), the UK (5.2% males, 5.0% females), Denmark males (4.9%), Norway males (4.9%) and Singapore females (5.2%).
This slowing decline in the reduction of deaths from the disease has major implications for life expectancy, say experts. According to the researchers, each of the countries - where the CVD-deaths have either slowed dramatically or reversed - have very high obesity levels. Obesity, or at least poor diet, say the researchers, could have been a significant contributor to the slowdown in the decline of cardiovascular disease deaths.
“Each of these countries has very high levels of obesity. In Australia, close to one-third of adults are obese. These increases in obesity levels mean that a significant portion of the population has been exposed to the cardiovascular disease risks associated with being overweight for several decades. Evidence shows a clear increase in cardiovascular disease mortality risks with increasing obesity. One study shows the risks for people who are extremely obese are similar to those for smokers. This suggests that obesity, or at least poor diet, may have been a significant contributor to the slowdown in the decline of cardiovascular disease deaths,” says the paper.
However, say the researchers, obesity is only one of many risk factors for cardiovascular disease mortality; others include smoking, high blood pressure, high cholesterol, and diabetes. For example, say the researchers, obesity levels are low in Italy and France, where the slowdown in cardiovascular disease mortality in recent years is among the most notable of all countries.
According to the research team, the implication for policy is that the effect of successful public health interventions on cardiovascular disease mortality over the past 50 years is diminishing, and that “CVD mortality has reached such low levels that further gains will be very difficult to achieve” without much more targeted and strategic public-health measures. The researchers recommend significant investment in preventive health measures, particularly those aimed at increasing physical activity, improving diet, and reducing obesity.
“Examination of trends in risk factors such as tobacco smoking, obesity, high cholesterol, high blood pressure, and diabetes, as well as access to health care, can provide insight into causes of recent CVD-mortality change,” says the team.
They add, “We also need to continue efforts to reduce rising inequalities in cardiovascular disease risk factors and to improve access to health care across the population. 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.”