Sept. 16, 2009 -- The percentage of Americans without major heart disease risk factors rose during the 1980s and 1990s, but our health is declining again, a study shows.
Though the percentage of smokers is still heading south, the number of people with obesity, diabetes, and high blood pressure is increasing, shows the study published in Circulation: Journal of the American Heart Association.
"It's not good news," study researcher Earl S. Ford, MD, MPH, of the U.S. Public Health Services at the CDC, tells WebMD. "The effect of all this stuff is going to be determined by the balance of the risk factors."
In a news release, Ford says that "from a preventive health point of view, it's important that individuals achieve as many of these [low-risk] goals as possible, and it's disappointing that less than 10 percent of Americans are meeting them all."
Trends in Heart Disease Risk Factors
About one in 12 adults in the U.S. had a low-risk profile for cardiovascular disease during the 1994-2004 period, he tells WebMD, and that needs to improve.
Ford adds in the news release that the study "suggests that achieving low risk status for most U.S. 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 and hypertension during more recent decades."
Ford's team analyzed data on adults aged 25-74 in four national surveys, examining the prevalence of a low-risk profile for heart disease, which includes all of the following:
- Never smoked, or former smoker.
- Total cholesterol below 200 and not using cholesterol-lowering drugs.
- Blood pressure below 120/80 without using blood pressure-lowering medications.
- Not overweight or obese, as reflected in a body mass index (BMI) less than 25.
- Never diagnosed with diabetes.
In the present analysis, they found that 4.4% of adults had all five of the low-risk factors between 1971 and 1975. That rose to 5.7% in the 1976-1980 National Health and Nutrition Examination Survey, and rose again to 10.5% in 1988-1994. But the trend did not continue and the proportion of adults rating at low risk in 1999-2004 fell to 7.5%.
"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 says in a news release. "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."
Physical Activity and Obesity
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 says. "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."
The study also shows that:
- Trends are similar for men and women, though more women in every survey had across-the-board low-risk factors.
- Whites had a significantly higher prevalence of low-risk factors than African-Americans in all but the 1976-1980 survey.
- A larger percentage of whites had a low-risk factor burden than Mexican-Americans in 1988-1994 and 1999-2004 surveys.
- Vigorous population-based approaches are needed to reverse the unhealthy shift in risk factor measures.
- Health care providers should have adequate time, resources, and reimbursement to engage in prevention efforts.
- Work and school represent settings where interventions to reduce risk factors could be deployed.
Rob M. van Dam, PhD, and Walter Willett, MD, PhD, of Harvard Medical School and Brigham and Women's Hospital, say in an accompanying editorial that the findings of this latest survey are disturbing, especially since they don't yet reflect the effects of the current epidemic of childhood obesity.
"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," they write.