Health-Related Quality of Life Surveillance --- United States,
1993--2002
Hatice S. Zahran, MD
Rosemarie Kobau, MPH
David G. Moriarty
Matthew M. Zack, MD
James Holt, PhD
Ralph Donehoo, MPH Division of Adult and Community Health
National Center for Chronic Disease Prevention and Health Promotion
The material in this report originated in the National Center for Chronic Disease Prevention and Health Promotion, Janet Collins, PhD, Director, and the Division
of Adult and Community Health, Wayne H. Giles, MD, Acting Director.
Corresponding author: David G. Moriarty, Division of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion,
4770 Buford Highway, NE, Atlanta, GA 30334, MS
K-51; Telephone: 770-488-5455; Fax: 770-488-5964; E-mail:
dgm1@cdc.gov.
Abstract
Problem/Condition: Population-based surveillance of health-related quality of life (HRQOL) is needed to
promote the health and quality of life of U.S. residents and to monitor progress in achieving the two overall
Healthy People 2010 goals: 1) increase the quality and years of healthy life and 2) eliminate health disparities.
Reporting Period: This report examines surveillance-based HRQOL data from 1993 through 2002.
Description of System: Survey data from a validated set of HRQOL measures (CDC HRQOL-4) were
analyzed for 1993--2001 from the Behavioral Risk Factor Surveillance System (BRFSS) surveys for the 50 states and
the District of Columbia (DC) and for 2001--2002 from the National Health and Nutrition Examination
Survey (NHANES). These measures assessed self-rated health; physically unhealthy days (i.e., the number of days
during the preceding 30 days for which physical health, including physical illness and injury, was not good);
mentally unhealthy days (i.e., the number of days during the preceding 30 days for which mental health, including
stress, depression, and problems with emotions, was not good); and days with activity limitation (i.e., number of
days during the preceding 30 days that poor physical or mental health prevented normal daily activities). A
summary measure of overall unhealthy days also was computed from the sum of a respondent's physically unhealthy
and mentally unhealthy days, with a maximum of 30 days.
Results and Interpretation: During 1993--2001, the mean number of physically unhealthy days,
mentally unhealthy days, overall unhealthy days, and activity limitation days was higher after 1997 than before 1997.
During 1993--1997, the percentage of respondents with zero overall unhealthy days was stable (51%--53%) but declined
to 48% by 2001. The percentage of respondents with
>14 overall unhealthy days increased from 15%--16%
during 1993--1997 to 18% by 2001. Adults increasingly rated their health as fair or poor and decreasingly rated it
as excellent or very good. Women, American Indians/Alaska Natives, persons of "other races," separated or
divorced persons, unmarried couples, unemployed persons, those unable to work, those with a <$15,000 annual
household income, and those with less than a high school education reported worse HRQOL (i.e., physically unhealthy
days, mentally unhealthy days, overall unhealthy days, and activity limitation days). Older adults reported more
physically unhealthy days and activity limitation days, whereas younger adults reported more mentally unhealthy days.
A seasonal pattern was observed in physically unhealthy days and overall unhealthy days.
During 1993--2001, BRFSS respondents in 13 states reported increasing physically unhealthy days; respondents
in 13 states and DC reported increasing mentally unhealthy days; respondents in Alabama, Connecticut, Maine,
New Jersey, New Mexico, North Carolina, and Oregon reported both increasing physically and mentally unhealthy
days; and respondents in 16 states and DC reported increasing activity limitation days. During 2001--2002,
NHANES respondents with one or more medical conditions (e.g., arthritis or stroke) reported worse HRQOL than
those
without such conditions, and those with an increasing number of medical conditions reported increasingly
worse HRQOL.
Public Health Action: Policy makers and researchers should continue to monitor HRQOL and its correlates in
the U.S. population. In addition, public health professionals should expand monitoring to populations currently
missed by existing surveys, including institutionalized and homeless persons, adolescents, and children. A key aspect is
to study and identify the personal and community determinants of HRQOL in prevention research and
population studies, to understand how to improve HRQOL, and to reduce HRQOL disparities. In addition, population
health assessment professionals should continue to refine and validate HRQOL, functional status, and self-reported
health measures.
Introduction
Population-based surveillance of physical and mental health is an important component of tracking population
trends, identifying health disparities, and monitoring progress in achieving the two overall national health goals for
Healthy People 2010: 1) increase the quality and years of healthy life and 2) eliminate health disparities
(1). CDC developed a set of standard health-related quality of life (HRQOL) measures (CDC HRQOL-4) used in Behavioral Risk Factor Surveillance
System (BRFSS) surveys since 1993 and, since 2000, in the National Health and Nutrition Examination Survey (NHANES) to
track the HRQOL of adults (2,3). For this surveillance report, HRQOL was defined as perceived physical and mental health
over time (2).
The CDC HRQOL-4 measures (also known as the Healthy Days measures) have demonstrated reliability and validity
for population health surveillance (4--6). The measures predict morbidity, health-care use, and mortality, and are associated
with chronic diseases, disability, risky health behaviors, and sociodemographic factors
(7--10).
The CDC HRQOL-4 measures include questions regarding self-rated health and the number of recent days when
physical health was impaired, mental health was impaired, and activities were limited because of poor health. Additional
optional BRFSS questions regarding recent days of pain, depression, anxiety, sleeplessness, and vitality are available for states to
use (http://www.cdc.gov/hrqol).
This report summarizes the perceived physical and mental health of the U.S. population, assesses HRQOL among
adults with different sociodemographic characteristics, identifies vulnerable populations, examines seasonal patterns and
geographic variations, and evaluates HRQOL among persons with chronic medical conditions. The report also provides data on
U.S. adult HRQOL so community groups and clinicians can compare their HRQOL findings with state and national
populations.
Methods
Questionnaires
For this analysis, data were derived from the 1993--2001 BRFSS surveys and the 2001--2002 NHANES. BRFSS is
an ongoing, random-digit--dialed telephone survey of the noninstitutionalized, U.S. civilian population aged
>18 years conducted in all 50 states and the District of Columbia (DC). BRFSS monitors the prevalence of key health- and
safety-related behaviors and characteristics of the U.S. population. Details regarding design and content of BRFSS are available
at http://www.cdc.gov/brfss.
NHANES is an ongoing series of cross-sectional surveys on health and nutrition designed to be nationally representative
of the noninstitutionalized, U.S. civilian population by using a complex, multistage probability design. The
2001--2002 NHANES oversampled low-income persons, persons aged
12--19 years, persons aged >60 years, non-Hispanic blacks,
and Mexican Americans. NHANES includes a household interview and health examination component. The health
examination component was performed in a mobile examination center (MEC) and included the MEC interview, physical
examination, and laboratory examination (11). During the household interview, NHANES participants aged
>20 years were asked to self-report whether they had ever been diagnosed with a chronic medical condition. The CDC
HRQOL-4 questions were asked
during the MEC interview. Details regarding design and content of NHANES are available at
http://www.cdc.gov/nchs/nhanes.htm.
Health-Related Quality of Life Measures
The CDC HRQOL-4 measures included in BRFSS and NHANES
(11,12) were
Would you say that in general your health is excellent, very good, good, fair, or poor? (self-rated health)
Now thinking about your physical health, which includes physical illness and injury, for how many days during the
past 30 days was your physical health not good? (physically unhealthy days)
Now thinking about your mental health, which includes stress, depression, and problems with emotions, for how
many days during the past 30 days was your mental health not good? (mentally unhealthy days)
During the past 30 days, for about how many days did poor physical or mental health keep you from doing your
usual activities, such as self-care, work, school,* or recreation? (activity limitation days)
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Analytical Sample and Comparison Populations
During 1993--2001, a total of 1,291,986 persons (52% female) participated in BRFSS. The median state response
rate† ranged from 71.4% in 1993 to 51.1% in 2001
(12).
During 2001--2002, a total of 13,156 persons were selected for the NHANES sample; of these, 11,039 (83.9%)
completed the household interview, and 10,480 (79.7%) completed the health examination component. Data for respondents aged
>18 years who were asked the Healthy Days measures
(n = 5,130; 52% female) at the MEC were analyzed
(11).
BRFSS contains only a limited number of self-reported chronic health conditions, and not all conditions are
assessed annually. Therefore, to assess perceived disease burden, the associations between HRQOL and chronic medical
conditions were examined among NHANES respondents aged
>20 years who were asked questions regarding common
medical conditions during the household interview
(12).
To compare HRQOL reported by BRFSS respondents with that from NHANES respondents, comparable age
and sociodemographic groups and periods were examined from each surveillance system. Because BRFSS included the
HRQOL questions in only 21 states in 2002, data for 2002 were excluded from the comparative analysis. Only data from the
2001 BRFSS were examined.
Data Analysis
BRFSS 1993--2001
The following characteristics for the Healthy Days measures were examined: time trends, sociodemographic
characteristics, month (seasonality), and state of residence. Percentages, means, and 95% confidence intervals (CIs) were calculated, as well
as percentages of responses to the self-rated health measure. Self-rated health was dichotomized into two groups (i.e., fair or
poor versus excellent, very good, or good); calculated percentages in these categories have been reported previously
(1,2). Overall unhealthy days were calculated, which is the sum of each respondent's physically or mentally unhealthy days, with a
maximum of 30 unhealthy days (2). For those respondents who reported no physically and mentally unhealthy days, activity
limitation days were imputed as zero. Although Healthy Days measures were categorized into responses indicating zero days, 1--13
days, and >14 days of physically unhealthy days, mentally unhealthy days, overall unhealthy days, and activity limitation days,
only the percentages of persons with zero days and
>14 days were assessed (13,14).
The pattern of responses to the Healthy Days measures across sociodemographic groups was consistent regardless
of interview year or state of residence. For example, persons with less than a high school degree reported more overall
unhealthy days than those with a college degree, regardless of interview year or state of residence. Therefore, to increase the reliability
of estimates, aggregate data were used from 1993 through 2001 to examine HRQOL. For BRFSS data, 95% CIs were
calculated by using the z distribution (point estimates
+ [standard error X 1.96]).
To examine seasonal patterns and monthly differences, a 3-month moving average was calculated from monthly
BRFSS 1993--2001 HRQOL data for physically unhealthy days, mentally unhealthy days, overall unhealthy days, and
activity limitation days for each year during 1998--2001 and for comparable monthly periods during the previous 5 years
(15). Data
were weighted to estimate population means and percentages and age-standardized to the 2000 U.S. standard
population. Trends were analyzed by using multiple linear and logistic regression analyses that controlled for sex, age,
race/ethnicity, education, income, marital status, employment status, and health insurance status. Unadjusted, multivariable-adjusted,
age-standardized values, and 95% CIs were calculated by using SUDAAN to account for the complex survey
design.
County-level estimates were obtained from BRFSS and temporally aggregated into two periods: 1993--1997 and
1998--2001. Data were age-standardized to the 2000 U.S. standard population. Data were spatially smoothed using a
nonparametric median smoothing technique
(16--18). Data values were then classified into six ranges with substantively meaningful
break points, corresponding to whole-day values. The geographically varying nature of the mean number of unhealthy days
reported by adults during the two periods was
determined.
NHANES 2001--2002
Means and 95% CIs were calculated by sociodemographic characteristics, chronic medical conditions, and number
of medical conditions. Self-rated health was dichotomized into two groups (i.e., fair or poor versus excellent, very good,
or good), and crude and age-standardized (to the 2000 U.S. standard population) percentages were calculated in these
categories by chronic medical conditions and by number of medical conditions. For NHANES data, 95% CIs were calculated by
using the Student's t-distribution with 15 degrees of freedom to account for sample clustering. Data were weighted to
estimate population means and percentages, and SUDAAN was used to account for the complex survey design.
NHANES responses to the CDC HRQOL-4 questions were compared with those from the 2001 BRFSS
by sociodemographic characteristics. Substantial differences in HRQOL between NHANES and BRFSS data sets
were assessed by examining nonoverlapping 95% CIs. Only
significant differences were documented.
Results
BRFSS 1993--2001
After multivariable adjustment, trend analysis indicated that, during 1993--2001, the percentage of respondents
who reported poor health increased from 3.3% to 4.1%; fair health, from 9.7% to 11.4%; and good health, from 27.2% to
29.8%. The percentage of respondents who reported excellent health decreased from 25.8% to 21.7%, and those who reported
very good health decreased from 34.1% to 33.0% (Table 1). Age-standardized results also indicated increases in the percentage
of respondents who reported poor, fair, and good health and a decrease in the percentage of respondents who reported
excellent health (Table 1, Figure 1).
During the same period, multivariable adjusted mean number of physically unhealthy days increased from 2.9 to
3.4, mentally unhealthy days increased from 2.9 to 3.5, overall unhealthy days increased from 5.2 to 6.1, and activity
limitation days increased from 1.6 to 2.0 (Table 2). The increases in the age-standardized mean number of physically unhealthy,
mentally unhealthy, overall unhealthy, and activity limitation days were significant (Table 2, Figure 2).
The multivariable adjusted percentage of respondents with zero physically unhealthy days, mentally unhealthy days,
overall unhealthy days, or activity limitation days decreased, whereas the multivariable adjusted percentage of respondents with
>14 days of physically unhealthy days, mentally unhealthy days, overall unhealthy days, or activity limitation days increased
(Table 3, Figure 3).
HRQOL by Selected Sociodemographic Subgroups
Sex. A higher percentage of women reported fair or poor health (15.5%) compared with men (13.3%) (Table 4).
Regardless of race/ethnicity, when compared with men, women reported significantly more physically unhealthy days (3.6 versus
2.7), mentally unhealthy days (3.5 versus 2.5), overall unhealthy days (6.3 versus 4.6), and activity limitation days (2.0 versus
1.6) (Table 5). Similarly, compared with men, a higher percentage of women reported
>14 physically unhealthy days (10.8%
versus 8.0%), mentally unhealthy days (10.6% versus 7.2%), overall unhealthy days (19.1% versus 13.4%), and activity
limitation days (6.0% versus 4.9%) (Table 6).
Age. A total of 33.2% of older adults (i.e., aged
>75 years) reported fair or poor health, whereas only 7.5% of young
adults (i.e., aged 18--24 years) reported fair or poor health (Table 4). Adults aged
>75 years reported the highest numbers
of
physically unhealthy days (6.0), overall unhealthy days (6.9), and activity limitation days (3.0). Adults aged 18--24
years reported the highest number of mentally unhealthy days (3.7)
(Table 5). As age increased, mean number of
physically unhealthy days, overall unhealthy days, and activity limitation days increased, and mentally unhealthy days decreased.
Adults aged >75 years reported the highest percentage with
>14 physically unhealthy days (20.3%), overall unhealthy
days (22.7%), and activity limitation days (10.3%). Adults aged 18--24 years reported the highest percentage of
>14 mentally unhealthy days (10.5%) (Table 6).
Race/Ethnicity. Compared with non-Hispanic whites (12.8%), more Hispanics (21.9%), American Indians/Alaska
Natives (21.1%), and non-Hispanic blacks (19.8%) reported fair or poor health, and fewer Asians/Pacific Islanders (9.0%)
reported fair or poor health (Table 4). The percentages of Hispanic men (19.6%), American Indian/Alaska Native men (19.2%),
and black men (17.3%) with fair or poor health were higher and the percentage of Asian/Pacific Islander men (8.8%) with fair
or poor health was lower than that of white men (12.0%) (Table 7). Similarly for women, percentages of Hispanic
women (24.2%), American Indian/Alaska Native women (23.1%), and black women (21.6%) with fair or poor health were
higher and the percentage of Asian/Pacific Islander women (9.2%) with fair or poor health was lower than that of white
women (13.6%).
Reported mean number of physically unhealthy days was higher among American Indian/Alaska Native men (3.9)
than among men of "other races" (3.1), and black (3.0), white (2.7), and Hispanic (2.7) men (Table 8). American
Indian/Alaska Native women (4.9) and women of "other races" (4.1) reported more mean number of physically unhealthy days than
black (3.8), Hispanic (3.8), and white (3.5) women. Asian/Pacific Islander men and women reported the fewest physically
unhealthy days (1.8 and 2.2, respectively).
Reported mean number of mentally unhealthy days was higher among American Indian/Alaska Native men (4.1) and
men of "other races" (3.5) than Hispanic (2.9), black (2.7), and white (2.4) men (Table 8). American Indian/Alaska Native
women (5.0) and women of "other races" (4.9) reported more mentally unhealthy days than Hispanic (4.0), black (3.8), and
white (3.5) women. Asian/Pacific Islander men and women reported the fewest mentally unhealthy days (2.1 and 2.6, respectively).
In addition, American Indian/Alaska Native men (6.7) and men of "other races" (5.8) reported more overall unhealthy
days than black (4.9), Hispanic (4.9), and white (4.5) men (Table 8). American Indian/Alaska Native women (8.4) and women
of "other races" (7.9) reported more overall unhealthy days than black (6.7), Hispanic (6.7), and white (6.2) women.
Asian/Pacific Islander men and women reported the fewest overall unhealthy days (3.6 and 4.5, respectively).
Reported activity limitation days were higher among American Indian/Alaska Native men (2.6) than among men of
"other races" (2.1), and black (1.9), white (1.6), and Hispanic (1.6) men (Table 8). American Indian/Alaska Native women (3.1)
and women of "other races" (2.9) also reported more activity limitation days than black (2.4), Hispanic (2.1), and white
(1.9) women. Asian/Pacific Islander men and women reported the fewest activity limitation days (1.1 and 1.2, respectively).
More American Indians/Alaska Natives (13.5%) reported
>14 physically unhealthy days and fewer Asians/Pacific
Islanders (5.1%) reported >14 physically unhealthy days than persons of "other races" (10.9%), blacks (10.5%), Hispanics
(10.0%), and whites (9.3%) (Table 6). More American
Indians/Alaska Natives (14.4%) and persons of "other races" (12.9%)
reported >14 mentally unhealthy days and fewer Asians/Pacific Islanders (6.2%) reported
>14 mentally unhealthy days than whites (8.6%), blacks (10.3%), and Hispanics (10.5%). In addition, more American Indians/Alaska Natives (23.8%) and persons
of "other races" (20.4%) reported
>14 overall unhealthy days and fewer Asians/Pacific Islanders (10.6%) reported
>14 overall unhealthy days than Hispanics (18.1%), blacks (18.0%), and whites (16.0%).
The percentages of persons who reported
>14 activity limitation days were higher among American Indians/Alaska
Natives (9.2%), persons of "other races" (7.6%), and blacks (6.9%) and were lower among Asians/Pacific Islanders (2.9%)
than Hispanics (5.7%) and whites (5.2%) (Table 6). In comparison, the percentages of blacks and Hispanics with
>14 physically unhealthy days, mentally unhealthy days, and overall unhealthy days did not differ but were higher than whites.
Marital status. Higher percentages of widowed (31.1%), separated (23.1%), and divorced (18.5%) persons reported fair
or poor health, compared with married persons (13.0%) (Table 4). Widowed (5.7), separated (4.5), and divorced (4.2)
persons reported the most mean number of physically unhealthy days (Table 5). Mean number of overall unhealthy days and
activity limitation days was higher among separated (8.8 and 3.0), divorced (7.3 and 2.7), and widowed (7.3 and 3.0) persons
than among married persons (4.9 and 1.6), never married persons (5.4 and 1.5), and unmarried couples (6.5 and 1.7).
Separated (5.9), divorced (4.4), and unmarried couples (4.4) also reported more mentally unhealthy days than never married
(3.5), widowed (2.9), and married (2.5) persons.
The same patterns were observed among groups reporting
>14 physically unhealthy days, overall unhealthy days,
mentally unhealthy days, and activity limitation days. Higher percentages of widowed (19.1%), separated (14.1%), and
divorced (13.2%) persons reported >14 physically unhealthy days, compared with married persons (8.7%), unmarried couples
(7.8%), and never married persons (5.9%) (Table 6). More separated (28.3%), widowed (23.9%), and divorced (22.8%)
persons reported >14 overall unhealthy days than unmarried couples (19.1%), never married persons (15.1%), and married
persons (14.3%). More separated (19.4%), divorced (13.9%), and unmarried couples (12.9%) reported
>14 mentally unhealthy days, and more widowed (10.0%), separated (9.6%), and divorced (8.6%) persons reported
>14 activity limitation days than other groups.
Education. The percentage of adults with less than a high school education (34.6%) who reported fair or poor health
was higher than that of high school graduates (15.7%), those with some college (10.7%), and college graduates (6.1%)
who reported fair or poor health (Table 4). Those with less than a high school education reported more physically unhealthy
days (5.5), mentally unhealthy days (3.9), overall unhealthy days (7.8), and activity limitation days (3.2) than those of
higher education. High school graduates reported 3.2 physically unhealthy days, 3.1 mentally unhealthy days, 5.7 overall
unhealthy days, and 1.8 activity limitation days, whereas college graduates reported 2.1 physically unhealthy days, 2.3
mentally unhealthy days, 4.0 overall unhealthy days, and 1.1 activity limitation days (Table 5).
Compared with other education subgroups, higher percentages of persons with less than a high school education
reported >14 physically unhealthy days (18.2%), mentally unhealthy days (13.0%), overall unhealthy days (25.8%), and
activity limitation days (10.8%) (Table 6). Lower percentages of persons with a college education reported
>14 physically unhealthy days (5.3%), mentally unhealthy days (6.0%), overall unhealthy days (10.6%), and activity limitation days (2.9%).
Annual household income. The percentage of adults with an annual household income of <$15,000 who reported fair
or poor health (31.5%) was significantly higher than adults with annual household incomes of $15,000--$24,999
(19.9%), $25,000--$49,999 (10.3%), and >$50,000 (5.1%) (Table 4). Persons with an annual household income of <$15,000
reported more physically unhealthy days (5.9), mentally unhealthy days (4.8), overall unhealthy days (8.8), and activity limitation
days (3.8), whereas those with an annual household income of
>$50,000 reported fewer physically unhealthy days (1.9),
mentally unhealthy days (2.3), overall unhealthy days (4.0), and activity limitation days (1.0) (Table 5). Similarly, more adults with
a <$15,000 annual household income reported
>14 physically unhealthy days (19.3%),
>14 mentally unhealthy days (15.6%),
>14 overall unhealthy days (28.5%), and
>14 activity limitation days (12.6%) than adults in higher income households
(Table 6).
Employment status. Persons who were retired (27.6%), unemployed for <1 year (15.8%), unemployed for
>1 year (27.2%), and unable to work (67.0%) more often reported fair or poor health than adults employed for wages (7.8%)
and self-employed adults (8.4%) (Table 4). In addition, persons who were retired (5.0), unemployed for <1 year
(3.5), unemployed for >1 year (5.6), and unable to work (16.5) reported more physically unhealthy days than adults employed
for wages (1.9) and self-employed adults (2.1) (Table 5). Persons who were unemployed for <1 year (5.1), unemployed for
>1 year (5.9), and unable to work (9.7) reported more mentally unhealthy days than other groups. The mean number of
overall unhealthy days was comparatively high among persons who were retired (6.1), unemployed for <1 year (7.6), unemployed
for >1 year (9.5), and those unable to work (19.8). Activity limitation days were also comparatively high among retired
persons (2.5), <1 year unemployed persons (2.8),
>1 year unemployed persons (4.5), and those unable to work (13.4).
However, retired persons reported the fewest mentally unhealthy days (2.0), whereas persons who were self-employed and employed
for wages reported the fewest physically unhealthy days (2.1 and 1.9), overall unhealthy days (4.3 and 4.4), and activity
limitation days (1.0 and 0.9), compared with persons with other employment status.
Compared with persons with any other employment status, more retired persons (16.7%), unemployed persons
(10.6%--18.7%), and those unable to work (58.2%) reported
>14 physically unhealthy days; more retired persons
(19.7%), unemployed persons (23.9%--30.5%), and those unable to work (67.8%) reported
>14 overall unhealthy days; and more retired persons (8.5%), unemployed persons (8.5%--15.8%), and those unable to work (47.7%) reported
>14 activity limitation days (Table 6). Conversely, significantly fewer retired persons (6.1%) reported
>14 mentally unhealthy days, and more unemployed persons (16.1%--19.3%) and those unable to work (34.3%) reported
>14 mentally unhealthy days.
Health-care plan status. Except for physically unhealthy days, all measures were associated with not having
health insurance. Adults without health insurance (18.5%) more
often reported fair or poor health (Table 4) and more
mentally unhealthy days (4.3), overall unhealthy days (6.6), and activity limitation days (2.0) than adults with health insurance
(Table
5). The percentage of adults without health insurance with
>14 mentally unhealthy days (13.4%), overall unhealthy
days (20.2%), and activity limitation days (6.2%) was higher than those with health insurance (8.3%, 15.7%, and
5.3%, respectively) (Table 6).
Seasonality
Although mean number of mentally unhealthy days (Figure 4) and activity limitation days (Figure 5) did not
change seasonally, mean number of physically unhealthy days (Figure 6) and overall unhealthy days (Figure 7) during winter
months exceeded that during summer months. Furthermore, for these measures, the monthly means for the months during
1998--2001 exceeded that for the previous 5 years (Figures 4--7).
Associations Between Self-Rated Health and HRQOL
Self-rated health was strongly associated with unhealthy days in both BRFSS and NHANES data. In BRFSS, persons
with excellent health reported the least number of physically unhealthy days (0.9), mentally unhealthy days (1.7), overall
unhealthy days (2.5), and activity limitation days (0.5) (Table 9). Persons with fair or poor health reported substantially more
physically unhealthy days (11.8), mentally unhealthy days (6.5), overall unhealthy days (14.8), and activity limitation days (6.9).
Similar patterns were observed in NHANES data (Table 10).
Comparison of NHANES 2001--2002 and BRFSS 2001
Mean number of physically unhealthy days, mentally unhealthy days, overall unhealthy days, and activity limitation
days among different sociodemographic subgroups was generally comparable among 2001--2002 NHANES respondents and
2001 BRFSS respondents. For example, in both data sets, women, persons with less than a high school education, and persons
with a <$15,000 annual household income reported worse HRQOL than men and those with more education and
annual household income (Tables 10 and 11).
HRQOL by Medical Condition (NHANES 2001--2002)
During 2001--2002, NHANES respondents with one or more chronic medical condition reported worse HRQOL
than those without such conditions. Compared with persons without any chronic medical conditions, persons with such
conditions more often reported fair or poor health. For example, whereas only 7.1% of those without any chronic medical
conditions reported fair or poor health, 27.5% of those with arthritis reported fair or poor health. An increasing number of
medical conditions increased the percentage of those reporting fair or poor health (age-standardized) (Table 12). For example,
13.6% of those with one medical condition, 21.4% of those with two conditions, 29.4% of those with three conditions, 44.9%
of those with four conditions, and 75.4% of those with five conditions reported fair or poor health.
Persons with any chronic medical condition reported significantly more physically unhealthy days, mentally unhealthy
days, overall unhealthy days, and activity limitation days than those without such a condition. For example, compared with
those without any chronic conditions, those with arthritis reported an average of 6.7 (versus 2.2) physically unhealthy days,
5.1 (versus 2.9) mentally unhealthy days, 10.0 (versus 4.8) overall unhealthy days, and 2.9 (versus 0.9) activity limitation
days (Table 13). As the number of medical conditions increased, the mean number of physically unhealthy days,
mentally unhealthy days, overall unhealthy days, and activity limitation days increased. Persons with five or more conditions
reported mentally unhealthy days and overall unhealthy days two times more; physically unhealthy days, three times more; and
activity limitation days, at least four times more than those with one chronic medical condition.
HRQOL Trends Within States (BRFSS 1993--2001)
During 1993--2001, age-standardized mean number of physically unhealthy days increased in 13
states§ and remained stable in all other states (Table 14). The median
age-standardized mean number of physically unhealthy days for all states
over all years and both sexes was 3.2, with state means ranging from 2.4 to 3.9. In all but three states (Arizona, Louisiana, and
West Virginia) and DC, women reported significantly more physically unhealthy days (median: 3.4 days; range: 2.4--4.1 days)
than men (median: 2.8 days; range: 2.1--3.8 days) (Table 15).
During the same period, an increase was observed in mentally unhealthy days in 13
states¶ and DC, and a decrease was observed in North Dakota (Table 16). The median
age-standardized mean number of mentally unhealthy days for all
states over all years and both sexes was 3.0, with state means ranging from 2.2 to 4.3. Women reported more mentally
unhealthy days (median: 3.5 days; range: 2.7--5.2 days) than men (median: 2.3 days; range: 1.8--3.4 days), regardless of their state
of residence (Table 17).
During 1993--2001, a total of 17 states** and DC had increasing levels of overall unhealthy days (Table 18). Only
North Dakota had a significant decline in overall unhealthy days. The median age-standardized mean number of overall
unhealthy days for all states over all years and both sexes was 5.3, with state means ranging from 4.1 to 6.8. In every state,
women reported more overall unhealthy days (median: 6.2 days; range: 4.6--7.7 days) than men (median: 4.6 days; range:
3.6--5.8 days) (Table 19).
The age-standardized mean number of activity limitation days increased in 16
states†† and DC (Table 20). The median
age-standardized mean number of activity limitation days for all states over all years and both sexes was 1.7, with state
means ranging from 1.2 to 2.8. In 22 states, women reported more activity limitation days (median: 1.9 days; range: 1.3--2.8
days) than men (median: 1.6 days; range: 1.1--2.8 days) (Table 21).
During 1993--2001, significant increases were observed in mean number of physically unhealthy days, mentally
unhealthy days, overall unhealthy days, and activity limitation days in six census divisions (i.e., Middle Atlantic, New England,
East North Central, East South Central, South Atlantic, and West South Central). Among these six divisions, the East
South Central region (i.e., Alabama, Kentucky, Mississippi, and Tennessee) had the worst HRQOL (Tables 15,
17, 19, and 21).
From 1993--1997 to 1998--2001, mean overall unhealthy days increased nationally; the majority of states had
more areas that averaged six or more overall unhealthy days during 1998--2001 than during 1993--1997 (Figures 8 and
9).
The percentage of all counties that averaged six or more overall unhealthy days (age-standardized) increased from
29% during 1993--1997 to 42% during 1998--2001.
Discussion
The findings in this report indicate that, during 1993--2001, the perceived physical and mental health of U.S.
adults worsened. Mean number of unhealthy days, activity limitation days, and self-rated health substantially differed
among socioeconomic and demographic subgroups. Women; American
Indians/Alaska Natives; persons of "other races,"
non-Hispanics; persons with a <$15,000 annual household income; persons with less than a high school degree; persons
without health insurance; and persons who were divorced, separated, or widowed reported more days of impaired physical and
mental health. These findings are consistent with previously reported findings among the U.S. adult population
(2,3,19,20). The aging of the U.S. population does not explain these worsening trends because age standardization did not alter
these findings (7).
Women reported more unhealthy days and activity limitation days than men, consistent with previous studies
(2,3,7). Unique physiologic (e.g., reproductive cycle and pregnancy), psychologic (e.g., willingness to disclose mental health
distress), socioeconomic status (e.g., education, income, and occupation), and social factors (e.g., work and child or adult care
giving stress, lack of social support) might explain these differences
(21,22).
Consistent with previous study findings, older adults reported more physically unhealthy days and activity limitation
days, whereas younger adults reported more mentally unhealthy days
(2,3). Older adults are more likely to have chronic
diseases that impair their physical health. The greater number of mentally unhealthy days among young adults is of public
health concern because they might indicate an increased risk for adoption of risky behaviors (e.g., cigarette smoking, alcohol use,
and violence) that have serious consequences for impaired health as young adults age
(23,24). Young adults might be at increased risk for psychological distress because they are adjusting to new social roles (e.g., occupation and parenthood), have
less resilience in dealing with stressful life events, and might have fewer financial resources to buffer them from stress
(25--30). However, older adults who might benefit from the additional resources conferred with age (e.g., income and wealth, access
to Social Security and Medicare) also might have successfully resolved stressful life events that account for greater
psychologic distress (28,31,32). In addition, this observed age difference in mentally unhealthy days is limited to
community-dwelling older adults and underrepresents older adults who are more likely to reside in institutions and who might have poor
cognitive or psychologic outcomes. Therefore, mentally unhealthy days might have been underestimated in older adults
(9,10).
Among racial/ethnic populations, worse HRQOL among American Indians/Alaska Natives might be partly attributed
to factors such as income, education, occupation, disease
status, behavioral risk factors, social and cultural factors
(e.g., disenfranchisement and discrimination) that can impair perceived physical and mental health. The percentage
of Hispanics who reported fair or poor health was as high as American Indians/Alaska Natives; however, Hispanics
reported fewer mean number of physically unhealthy days, mentally unhealthy days, overall unhealthy days, and activity limitation
days than American Indians/Alaska Natives. The differences in HRQOL by race/ethnicity might be associated with
cultural differences (33) or with the difference in the nature of information obtained by the self-rated health question and
Healthy Days questions (34). For example, the "days" questions refer to physical or mental distress within the preceding 30
days, whereas self-rated health is a measure of perceived health that can include a broad period
(34). Although Hispanics might not report recent physical or mental health distress, they might be more likely to report lifetime impaired health associated with
a number of health and psychosocial factors. This finding warrants further study.
The findings in this report provide additional evidence regarding the strong associations between HRQOL and
marital status, socioeconomic status (i.e., employment, income, and education), and health insurance status
(19,20,35). HRQOL responses among the respondents with similar socioeconomic and demographic characteristics did not differ substantially
from the 2001 BRFSS to the 2001--2002 NHANES. This indicates the comparability of responses to the Healthy Day
measures across the surveys.
Although only North Dakota had fewer mentally unhealthy days and overall unhealthy days over time, the remaining
states and DC either had increases or no changes in mean number of physically unhealthy days, mentally unhealthy days,
overall unhealthy days, and activity limitation days. The geographic maps indicate increasingly more areas with six or more
overall unhealthy days within the majority of states. Environmental, economic, and social differences among and within states
might account for these HRQOL differences and warrant
future studies and possible intervention to improve HRQOL.
A seasonal pattern was observed in physical health; the mean number of physically unhealthy days during winter
months was higher than during summer months. This might be attributable, in part, to the increased incidence of medical
conditions (e.g., influenza) or to the exacerbation of existing chronic conditions (e.g., pulmonary and cardiovascular
disease) (36--40).
For respondents with at least one chronic medical condition, findings indicated that both their perceived physical health
and mental health were impaired, consistent with other findings
(7--10,41). As the number of chronic medical
conditions increased, mean number of physically unhealthy days, mentally unhealthy days, and activity limitation days also
increased. Stress, anxiety, depression, and uncertainty often occur with chronic illness, as illness can affect a person's ability to cope
with daily activities. Furthermore, psychologic distress might lead to adoption of unhealthy coping behaviors, further
impairing physical health. The high number of mentally unhealthy days among persons with chronic medical conditions
warrants further examination. The strong associations between self-rated health and the HRQOL measures provide additional
evidence of the validity of the HRQOL measures described in this report.
Limitations
The findings in this report are subject to at least six limitations. First, because NHANES and BRFSS surveys include
only noninstitutionalized adults, persons in institutions, persons in households without telephones, and the homeless
(i.e., populations that might have worse HRQOL than others) were excluded
(9,10). Second, because NHANES and BRFSS surveys are cross-sectional surveys, HRQOL and the characteristics studied (e.g., unemployment, inability to work,
and marital status) were assessed at a single point in time. Thus, determining whether the association of some of
these characteristics with HRQOL preceded or followed these HRQOL responses was not possible. Third, because the results
for the selected sociodemographic subgroups were crude estimates, adjusting for these sociodemographic characteristics
might have changed the results. Fourth, other variables not studied such as risky health behaviors, the physical and the
social environment (e.g., air pollution, poor housing, and violence), functional status, stressful life events, and
unmeasured socioeconomic factors (e.g., wealth and type of employment) might account for additional HRQOL differences
among population subgroups. Fifth, although evidence exists indicating good measurement properties for the HRQOL
measures (http://www.cdc.gov/hrqol/measurement_properties/index.htm), reliability might vary by subgroups (e.g., age, income
level, race/ethnicity, and acculturation), by scaling methods used (e.g., grouping responses into categories of 0, 1--13,
>14 days), and by response shift (e.g., changes in health perceptions after the onset of a chronic illness or injury), affecting judgment
and
responses to the Healthy Days questions (42). Finally, the HRQOL mental health measure was not validated for detection
of mental illness with clinical psychiatric examinations.
Public Health Action
Findings from ongoing national surveillance of HRQOL are useful for identifying vulnerable subpopulations,
tracking population trends, and monitoring progress in achieving
Healthy People 2010 goals. The findings in this report indicate
that women, the youngest adults, older adults, those with annual household incomes of <$15,000, those with less than a
high school education, American Indians/Alaska Natives, and those without health-care coverage are vulnerable populations
that could benefit from interventions designed to reduce their burden of impaired HRQOL. Because interventions
on diet, physical activity, and smoking have indicated improved health outcomes, the evidenced-based programs in the
Guide to Community Preventive Services (http://www.thecommunityguide.org) might be useful in improving HRQOL. Examples
of how national, state, and local programs have used Healthy Days measures are documented on the CDC HRQOL
website (http://www.cdc.gov/hrqol) and in previously published reports
(43,44).
Population HRQOL tracking with the Healthy Days measures is recommended to assess the perceived physical and
mental health needs of adults, prioritize population health needs and disparities, and document the health effects of policies
and interventions. Although the Healthy Days measures have been used in studies with adolescents
(45--47), more research is needed to assess validity and reliability of these and similar measures in populations aged <18 years.
To develop a more comprehensive population HRQOL surveillance system, additional self-rated health and HRQOL
data from other national surveys such as the National Health Interview Survey (NHIS), the Medical Expenditure Panel
Survey (MEPS), and Current Population Survey should also be analyzed and evaluated. Where sample size permits,
additional analysis of Healthy Days surveillance data at the metropolitan area, county, and sub-county levels is recommended to
identify community-level factors that influence population health. Assessing the perceived physical and mental health effects of
natural and man-made disasters in collaboration with federal, state, and community partners should be a priority. Healthy
Days surveillance data currently available from the 2001--2002 NHANES for adolescents aged
>12 years should also be analyzed, as well as older adult Healthy Days data currently available from the 2003 and later Center for Medicare and Medicaid
Services Health Outcome Study (48).
The CDC HRQOL-4 measures, recently recommended as standard cross-cutting measures for chronic disease
surveillance (49), should be continued each year in the core BRFSS and in NHANES. When feasible, these and other
HRQOL measures should also be included in other key national, state, and local surveillance systems (e.g., NHIS, MEPS, the
General Social Survey, and the Youth Risk Behavior Survey) to permit direct HRQOL comparisons across major surveillance
systems and to help identify health-related behaviors, policies, and interventions that can improve population health and reduce
health disparities. In addition, population health assessment professionals should continue to refine and validate HRQOL,
functional status, and self-reported health measures.
Acknowledgments
State Behavioral Risk Factor Surveillance System coordinators and the National Center for Health Statistics, Division of
Health Examination Statistics contributed data for this report. The project was supported through a cooperative agreement between CDC
and the Association of Teachers of Preventive Medicine, Washington, DC, and through an interagency agreement between CDC and the
U.S. Department of Energy and administered by the Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee.
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* School was included in only NHANES.
† According to the methodology of the Council of American Survey Research Organizations, the response rate includes the number of
completed interviews in the numerator and an estimate of interviewees and those whose eligibility is undetermined in the denominator.
§ Alabama, Alaska, Connecticut, Maine, Michigan, Mississippi, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Oregon,
and South Carolina.
¶ Alabama, Arkansas, Connecticut, Kentucky, Maine, New Jersey, New Mexico, North Carolina, Oregon, South Dakota, Texas, Utah,
and Virginia.
** Alabama, Alaska, Arkansas, Connecticut, Kentucky, Maine, Michigan, Mississippi, New Jersey, New Mexico, New York, North
Carolina, Oregon, South Dakota, Utah, Virginia, and Washington.
†† Alabama, Connecticut, Florida, Idaho, Louisiana, Maine, New Mexico, New York, North Carolina, Ohio, Oregon, South Carolina,
Tennessee, Virginia, Washington, and Wyoming.
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