Fewer and fewer Americans are at low risk for cardiovascular disease, according to an important and frightening new report on long term trends from the National Health and Nutrition Examination Surveys (NHANES) of adults 25-74 years of age.
In the most recent survey (1999-2004) only about 8% of US adults had a low risk profile, despite favorable trends in reducing smoking and cutting cholesterol. The overall increase in risk was due to the increased prevalence of diabetes, obesity, and hypertension, said the CDC’s Earl Ford, and his colleagues, in their report in Circulation.
Of major concern, the long term trend observed by the study was troubling. Following the early 1970s, when very few people had low risk factor profiles, progress appeared to be made, as the survey found substantial increases in the proportion of people with low risk profiles in the late 1980s and early 1990s. But then the hopeful trend reversed in the mid 1990s, apparently in accord with the increase in obesity and diabetes
Low risk was defined as
- not currently smoking
- total cholesterol <200 mg/dL and not using cholesterol-lowering drugs
- blood pressure <120/80 mm Hg and not using antihypertensive drugs
- BMI <25 kg/m²
- no previous diagnosis of diabetes
The overall trends were apparent in various subgroups, though a greater proportion of women than men had low risk profiles, and whites had more favorable profiles than blacks or Hispanics.
The authors discussed the implications of their findings:
Our analysis suggests that achieving low risk status for most US adults remains a distant and challenging goal. Unfortunately, the limited strides that were made toward this goal during the 1970s and 1980s were eroded by the increases in excess weight, diabetes mellitus, and hypertension during more recent decades. Because prevention offers potentially great opportunities for lessening the burden of cardiovascular disease, it is critical that the percentages of US adults who have optimal blood pressure, who have never developed diabetes mellitus, and who have optimal body weight be improved.
An accompanying editorial by Harvard researchers Rob van Dam and Walter Willett considers the broad implications of the gloomy findings. The situation may even get far worse, they note, since “these trends do not yet reflect the effects of the current epidemic of childhood obesity, which causes an early onset of type 2 diabetes, hypertension, and dyslipidemia. Because the complications of diabetes mellitus increase strongly with duration, by 40 years of age, the affected children will have accrued several decades of exposure that will greatly elevate risks of not just coronary heart disease and stroke but also microvascular complications that can eventually lead to amputations, blindness, and kidney failure.”
The editorialists calculate the impact of obesity in young people and conclude “that the current epidemic of obesity in children will have a substantial impact on life expectancy in the coming decades,” leading to declines in life expectancy in many parts of the country.
Van Dam and Willet argue that efforts to control obesity can not be addressed through a “traditional high-risk medical approach,” but instead must be addressed at the population level:
Creating an environment that promotes health requires not only a high priority in health policy but also fundamental changes in agricultural, transportation, urban design, and educational policies. Much potential exists to reverse ominous trends in cardiovascular risk factors and mortality in the United States, but this is unlikely to occur without making prevention of overweight and obesity a clear national priority.
Here is the American Heart Association press release:
The proportion of Americans rated low on key heart disease risk factors expanded during the 1980s and 1990s, but is now declining, according to national surveys.
Only about 1 in 12 U.S. adults had a low risk profile for cardiovascular disease during 1994-2004.
While fewer adults are smoking, an increasing proportion are developing high blood pressure or diabetes or becoming overweight or obese.
Less than 10 percent of Americans have low risk for heart disease
DALLAS,Sept. 14, 2009 — After two decades of improvement, the percentage of Americans without major heart disease risk factors is dropping, according to a report in Circulation: Journal of the American Heart Association.
“From a preventive health point of view, it’s important that individuals achieve as many of these goals as possible, and it’s disappointing that less than 10 percent of Americans are meeting them all,” said Earl S. Ford, M.D., M.P.H., lead author of the study and medical officer of the U.S. Public Health Services at theCenters for Disease Control and Prevention (CDC) in Atlanta, Ga.
“Our analysis suggests that achieving low risk status for most U.S. adults remains a distant and challenging goal. Unfortunately, the limited strides that were made towards this goal during the 1970s and 1980s were eroded by the increases in excess weight, diabetes and hypertension during more recent decades.”
Researchers tracked data on adults aged 25-74 in four national surveys, examining several low-risk criteria:
Never or former smoker;
Total cholesterol below 200 milligrams per deciliter (mg/dL) and not using cholesterol-lowering drugs;
Blood pressure below 120/80 millimeters of mercury (mmHg) without using blood pressure-lowering medication;
Not overweight or obese, as reflected in a body mass index (BMI) less than 25 kg/m2; and
Never diagnosed with diabetes.
In numerous studies, people without risk factors have lower healthcare costs and are far less likely to develop cardiovascular disease.
In the National Health and Nutrition Examination Surveys (NHANES):
- 4.4 percent of adults had all five of the low-risk factors in NHANES I, 1971-75;
- 5.7 percent had all five in NHANES II, 1976-1980;
- 10.5 percent of adults rated low risk on all factors in NHANES III, 1988-94; and
- only 7.5 percent of adults rated low risk on all factors in the 1999-2004 survey.
“Until the early 90s, we were moving in a positive direction, but then it took a turn and we’re headed in a negative direction,” Ford said. “When you look at the individual factors, tobacco use is still headed in the right direction and so are cholesterol levels, although that has leveled off. The problem is that blood pressure, BMI and diabetes are all headed in the wrong direction.”
An imbalance in the amount of energy consumed in food and the amount expended in physical activity is likely a major culprit in the negative risk factor trends, Ford said.
“Addressing this imbalance, by people becoming more active and eating less, would reduce overweight and obesity which in turn would help to lower blood pressure and prevent diabetes,” Ford said.
The trends over time are similar in men and women, although in every survey significantly more women than men had across-the-board low risk factors.
Furthermore, whites had a significantly higher prevalence of low risk factors than African Americans in all but one survey (1976-1980). A larger percentage of whites had a low risk factor burden compared to Mexican Americans during 1988-1994 and 1999-2004 surveys.
Results of the study illustrate a great need for prevention, “thus, healthcare providers should have adequate resources, time and reimbursement to engage in the prevention of cardiovascular disease in patients,” researchers said. “Such efforts by clinicians need to be complemented by efforts by state and national agencies that have the responsibility to develop effective public health interventions.”
Potential targets for such interventions include work sites and schools where large numbers of people can be targeted and where evidence-based interventions can be implemented.
In an accompanying editorial, Rob M. van Dam, Ph.D. and Walter C. Willett, M.D., Ph.D. of Harvard Medical School and Brigham and Women’s Hospital said the findings are disturbing because the trends among younger age groups have occurred in the presence of unprecedented availability of evidence-based heart disease treatment and even more worrisome because the trends do not yet reflect the effects of the current epidemic of childhood obesity.
The findings provide an important signal that the health of Americans is at a crossroad, they noted. “Much potential exists to reverse ominous trends in cardiovascular risk factors and mortality in the United States, but this is unlikely to occur without making prevention of overweight and obesity a clear national priority.”
Ford’s co-authors are: Chaoyang Li, M.D., Ph.D.; Guixiang Zhao, M.D., Ph.D.; William S. Pearson, Ph.D.; and Simon Capewell, M.D. Author disclosures are on the manuscript.
Here is the European Society of Cardiology press statement:
Increase in cardiovascular risk factors, heralds epidemic of cardiovascular disease
Commenting on a study published today in Circulation 1, showing after two decades of improvement, the percentage of Americans without risk factors for heart disease was falling, Professor Guy De Backer, from the Division of Cardiology at the University of Gent, Belgium, said that with the rising levels of obesity in the US such findings could hardly be considered surprising.
“Over the next few years it’s likely that this observed decline in the proportion of people with low cardiovascular risks will translate into increased cardiovascular disease,” said Professor De Backer, a former chair of the European Society of Cardiology (ESC) Joint Prevention Committee. “This paper should act as a wake-up call in Europe as well as the US, since overall European risk factors are not so different. While obesity may be higher in the US, Europe has been less successful in reducing smoking and cutting blood pressure.”
Indeed, the EuroAspire survey(2), which reviewed risk factors in patients with established coronary heart disease from 22 European countries, found that only 6 % of men and 4 % women were achieving lifestyle, risk factor and therapeutic targets for prevention.
“Health surveillance is essential for the development of good health policy. We need to know exactly what are the problems we are facing to determine the best ways of counteracting them,” said Professor De Backer.
Commenting last week at the EuroHeart Conference (Brussels, Belgium Thursday September 10, 2009), a meeting organised by the European Heart Network and the ESC as part of Work Package 5 of the EuroHeart Project, Professor De Backer said that it is a major issue that no overall surveillance initiatives have been put in place in Europe to review changing trends in cardiovascular risk factors for the general European population.“While different countries may be running their own initiatives there needs to be a standardised approach to allow meaningful comparisons, and enable countries to learn from each other” said Professor De Backer, adding that the European Union needs to be taking a greater lead in advising its member states on cardiovascular disease prevention.
Professor Torben Jorgensen, an ESC Spokesperson on prevention from the Research Centre for Prevention (Glostrup. Denmark), said that the study by Earl S Ford and colleagues in Circulation indicated that the current strategy of targeting individuals at high risk of heart disease for prevention was not working.
“Evidence suggests that you can get people to change their attitudes for short periods, but that this is not long enough to prevent obesity, diabetes and high blood pressure,” he said. “Instead society as a whole needs to foster a general environment which encourages healthy eating and physical activity, including adaptations to towns and cities that favour pedestrians and cyclists. Such initiatives should start in schools and the work place, and will require good collaboration between politicians and doctors for success.”
Evidence, he added, shows that just small life-style changes made in society as a whole have a tremendous impact on obesity and diabetes. “Our present unlucky situation is due to changes in society that have occurred over the past decades – so future “medicine” must look into improving society’s infrastructure,” he said.
1. Less than 10 percent of Americans have low risk for heart disease, Earl S. Ford, with co-authors Chaoyang Li, Guixiang Zhao, William S. Pearson and Simon Capewell, Circulation, 2009
2. Kotseva K, Wood D, De Backer G, et al. EUROASPIRE III: A survey on the lifestyle, risk factors and use of cardioprotective drug therapies in coronary patients from twenty-two European countries. Eur J Cardiovasc Prev Rehabil 2009; doi: 10.1097/HJR.0b013e3283294b1d
3. EuroHeart projectThe EuroHeart project , is a joint initiative of the European Society of Cardiology (ESC) and the European Heart Network, set up to address the significant burden of CVD in Europe and to determine specific areas of intervention to contribute to preventing avoidable deaths and disability. The project, which involves partners in 21 countries and receives funding from the European Commission Public Health Programme, has five major objectives: 1. Mobilise broad support for cardiovascular health (CVH) promotion and cardiovascular disease prevention with a view to achieving stronger cross sector cooperation (Work Package 4, 2. Map and analyze national plans, policies and measures impacting on cardiovascular health promotion and cardiovascular disease prevention. (Work Package 5), 3. Investigate issues concerning CVD in women (Work Package 6), 4. Improve prevention practices at primary care level (Work Package 7), 5. Implement and adapt European guidelines on CVD prevention to national situations (Work Package 8).