This report provides state-specific estimates of and characterizes adults who
report having no known major risk factors for CHD.
Data were analyzed from 91,428 persons aged greater than or equal to 18
years who resided in 48 states and the District of Columbia and participated
in the 1992 Behavioral Risk Factor Surveillance System (BRFSS), a random-
digit-dialed telephone survey. The analysis examined survey responses
regarding the following risk factors: current cigarette smoking (smoked at
least 100 cigarettes in their lifetime and now smoking), physical inactivity
(no or irregular leisure-time physical activity), overweight (body mass index
greater than or equal to 27.3 for women and greater than or equal to 27.8 for
men), high blood pressure (told more than once by a health professional he/she
has high blood pressure or is currently taking antihypertensive medications),
high blood cholesterol (ever told by a health professional he/she has high
blood cholesterol), and diabetes (ever told by a doctor he/she has diabetes).
Persons who reported having none of these risk factors were defined as having
no known risk factors for CHD.
The results were weighted to account for the distribution of demographic
characteristics in each state. To determine the actual prevalence of adults in
each state with no known CHD risk factors, state-specific estimates were not
standardized to a referent population. For data aggregated from all states,
census data for the 1980 U.S. population were used to standardize comparisons
by age, race, and educational status; aggregated analyses were restricted to
black and white respondents for whom the age, race, and education
distributions of the population were known. SESUDAAN was used to calculate the
standard errors for the prevalence estimates (2).
Of the 91,428 respondents, 18% reported having none of the six major CHD
risk factors; 35% reported having one risk factor; 29%, two risk factors; 13%,
three risk factors; and 5%, four to six risk factors. In every state, less
than 30% of the population had no known risk factors. The state specific
proportion of respondents with no known risk factors varied minimally; in 45
(92%) of the states, the proportion ranged from 14% to 26% (Table 1).
For both males and females, the percentage of respondents with no known
risk factors was highest for 18-34-year-olds. Among males, the percentage was
lowest for those aged 50-64 years, and among females, the percentage varied
inversely with age (Table 2). The prevalence of no known risk factors for CHD
increased directly with increasing level of education.
Results
The finding in this report that, in 1992, only 18% of adults
reported having no known risk factors for CHD indicates that, despite
improvements in the treatment and control of CHD-related conditions, a
substantial percentage of adults continue to be at risk for CHD. This low
prevalence underscores the need for primary prevention efforts that focus on
achieving behavioral changes that prevent the occurrence of risk factors.
Several of the year 2000 national health objectives target the primary
prevention of specific risk factors for CHD, including overweight (objective
15.10), physical inactivity (objective 15.11), high blood cholesterol
(objective 15.7), and cigarette smoking (objective 15.12) (3).
Achievement of these objectives should increase the number of U.S.
adults who have no known major risk factors for CHD and further
reduce CHD- associated mortality.
The prevalences of two risk factors--cigarette smoking and high blood
cholesterol--have decreased substantially. In 1965, approximately 40% of U.S.
adults smoked cigarettes; in comparison, by 1991, 26% smoked cigarettes (4).
In addition, from the second National Health and Nutrition Examination Survey
(NHANES II) (1976-1980) to NHANES III (1988-1991), the proportion of adults
with high blood cholesterol levels (greater than or equal to 240 mg/dL)
decreased from 26% to 20% (5). For other risk factors, however, prevalences
have remained constant or increased. For example, when compared with 1987, the
proportion of adults who engaged in no leisure-time physical activity (24%) in
1991 was unchanged, and the proportion who engaged in moderate physical
activity five or more times per week increased only slightly (22% in 1987 and
24% in 1991) (6). From 1987 through 1991, the proportion of U.S. adults who
were overweight increased from 26% to 28%, respectively (6). Finally, despite
substantial improvements in the awareness, treatment, and control of
hypertension, hypertension continues to affect an estimated 50 million persons
in the United States (7).
Although the findings in this report assist in targeting efforts to
reduce specific risk factors for CHD, these findings are subject to at least
two limitations. First, because BRFSS estimates are based on self reports, the
prevalence of most risk factors, especially overweight and current smoking
status, are likely to be underreported. Second, risk factors for which
awareness is low are underreported; for example, only an estimated 29% of
adults know their cholesterol level (8). Therefore, this report most likely
overestimates the proportion of adults without CHD risk factors.
To assist in reducing the prevalence of CHD risk factors, health programs
and organizations have intensified advocacy of primary prevention strategies.
For example, the National High Blood Pressure Education Program has developed
policy recommendations for implementing primary prevention interventions for
hypertension (9), and the National Cholesterol Education Program has made
dietary recommendations to reduce cholesterol levels (10). The need for the
primary prevention of CHD risk factors also is important because education or
treatment of persons with established risk factors may not reduce their risk
to the level of persons who never have the risk factor; for example, persons
who effectively control their hypertension remain at higher risk for CHD than
do persons who never develop hypertension (9).
References
1. American Heart Association. 1993 Heart and stroke facts statistics. Dallas:
American Heart Association, 1992.
2. Shah BV. SESUDAAN: standard errors program for computing of standardized
rates from sample survey data. Research Triangle Park, North Carolina:
Research Triangle Institute, 1981.
3. Public Health Service. Healthy people 2000: national health promotion and
disease prevention objectives--full report, with commentary. Washington, DC:
US Department of Health and Human Services, Public Health Service, 1991; DHHS
publication no. (PHS)91-50212.
4. CDC. Cigarette smoking among adults--United States, 1991. MMWR 1993;42:230-
3.
5. Sempos CT, Cleeman JI, Carroll MD, et al. Prevalence of high blood
cholesterol among US adults: an update based on guidelines from the second
report of the National Cholesterol Education Program Adult Treatment Panel.
JAMA 1993;269:3009-14.
6. CDC. Health, United States, 1992, and healthy people 2000 review.
Hyattsville, Maryland: US Department of Health and Human Services, Public
Health Service, 1993; DHHS publication no. (PHS)93-1232.
7. Joint National Committee on Detection, Evaluation, and Treatment of High
Blood Pressure. The fifth report of the Joint National Committee on Detection,
Evaluation, and Treatment of High Blood Pressure (JNC V). Arch Intern Med
1993;153:154-83.
8. CDC. Cholesterol screening and awareness--Behavioral Risk Factor
Surveillance System, 1990. MMWR 1992;41:669,675-8.
9. National High Blood Pressure Education Program Working Group. National High
Blood Pressure Education Program Working Group report on primary prevention of
hypertension. Arch Intern Med 1993;153:186-208.
10. Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Summary of the second report of the National
Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation,
and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II).
JAMA 1993;269:3015-23.