The prevalence of a low-risk profile for cardiovascular disease among adults in the U.S. population has decreased in recent years, suggesting the “huge potential” for preventing cardiovascular disease is far from being realized, according to an analysis of NHANES.
Using data from four National Health and Nutrition Examination Surveys, Dr. Earl S. Ford, medical officer of the U.S. Public Health Service at the Centers for Disease Control and Prevention in Atlanta, and colleagues tracked cardiovascular risk data for American adults aged 25-75 years during 1971-1975, 1976-1980, 1988-1994, and 1999-2004, and showed that the prevalence of a low-risk profile increased from 4.4% at the time of the first survey to 10.5% by the third survey, but then decreased to 7.5% in the fourth survey (1999-2004).
The low-risk-factor profile incorporated the following variables: not currently smoking; total cholesterol less than 200 mg/dL without cholesterol-lowering medications; systolic blood pressure less than 120 mm Hg and diastolic blood pressure less than 80 mm Hg without antihypertensive medications; body mass index less than 25 kg/m
“The limited strides that were made toward achieving low-risk status during the 1970s and 1980s have more recently been negated by the obesity epidemic and increased rates of hypertension and diabetes,” Dr. Ford said in an interview. According to the results, “fewer than 10% of Americans are meeting the low-risk goals.”
The low-risk factor patterns were similar for men and women, but the prevalence of low-risk profiles was higher in women than in men in each of the surveys, the authors reported. Similarly, the low-risk-factor burden was much higher among survey respondents aged 25-44 years than among those aged 45-64 or 65-74 years in all the surveys, and it was higher among whites than blacks during each survey except 1976-1980. During 1988-1994 and 1999-2004 only, a larger percentage of whites had a low-risk-factor burden compared with Mexican Americans, they wrote.
An analysis of the individual risk categories showed favorable trends for not currently smoking (60% at the time of the first survey and 74% by the fourth survey) and low concentrations of total cholesterol (35% and 43%, respectively). For blood pressure, the low-risk percentage was higher for the period 1988-1994 than for the 1971-1975 period, but it decreased for the period 1999-2004, “which is worrisome,” the authors wrote.
Similarly, “the distribution of body mass index progressively deteriorated over time,” they reported, adding that the unfavorable trends “argue for vigorous population-based approaches to reverse the unhealthy shift in the distributions of blood pressure and body mass index and to sustain or accelerate the improvement in the distribution of total cholesterol.”
Because the NHANES surveyed only noninstitutionalized adults, the true risk-factor burdens “may be even worse” than those reported, which is one of the limitations of the study, the authors noted. Additional limitations include the exclusion of physical activity and a dietary index as part of the risk determination, and changes in the wording of questions for use of current antihypertensive medication and physician-diagnosed diabetes that could potentially have affected the estimates, they wrote.
Despite the possible limitations, “our results clearly demonstrate a great need for prevention; thus, health care providers should have adequate resources, time, and reimbursement to engage in the prevention of cardiovascular disease in individuals,” the authors wrote.
In an accompanying editorial, Rob M. van Dam, Ph.D., of the Harvard School of Public Health, Boston, and Dr. Walter C. Willett of Brigham and Women's Hospital in Boston, said that the trajectory of the risk factor trends is even more worrisome considering the analyses “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” (Circulation 2009 [doi:10.1161/CIRCULATIONAHA.109.891507]).
The authors reported having no financial disclosures related to this report.