Research Quarterly for Exercise and Sport
ISSN: 0270-1367 (Print) 2168-3824 (Online) Journal homepage: http://www.tandfonline.com/loi/urqe20
Public Health Surveillance of Physical Activity Caroline A. Macera & Michael Pratt To cite this article: Caroline A. Macera & Michael Pratt (2000) Public Health Surveillance of Physical Activity, Research Quarterly for Exercise and Sport, 71:sup2, 97-103, DOI: 10.1080/02701367.2000.11082792 To link to this article: http://dx.doi.org/10.1080/02701367.2000.11082792
Published online: 13 Feb 2015.
Submit your article to this journal
Article views: 8
View related articles
Citing articles: 33 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=urqe20 Download by: [Central Michigan University]
Date: 06 November 2015, At: 00:51
Macera
Research Quarterly for ExerciseandSport ©2000 bythe American Alliancefor Health, Physical Education, Recreation and Dance Vol. 71, No.2, pp. 97-103
Public Health Surveillance of Physical Activity
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Caroline A. Macera and Michael Pratt
Keywords: exercise, moderate, sedentary, vigorous
Physical Activity as a Public Health Issue
T
h e importance of physical activity in maintaining health throughout life is well-recognized (USDHHS, 1996). Low levels of physical activity are associated with increased incidence of coronary heart disease and have been implicated in the mortality associated with the leading causes of death (Hahn, Teutsch, Rothenberg, & Marks, 1990; McGinnis & Foege, 1993; Powell, Thompson, Caspersen, & Kendrick, 1987). These studies suggest that the cost of physical inactivity is high, with one study suggesting that between $4.3 and $5.6 million would be saved annually if 10 percent of sedentary adults began a walking program (Jones & Eaton, 1994). The direct costs of physical inactivity are more than $24 million annually (Colditz, 1999). From a public health perspective, the increased mortality and morbidity associated with physical inactivity suggests that public health action is warranted. In addition, high medical and societal costs attributable to physical inactivityjustify increased attention to this behavior on both a national and community level. According to the Surgeon General's Report on Physical Activity and Health, less than 30 percent of adults are sufficiently active to achieve the full range of health benefits (USDHHS, 1996). Physical inactivity has a relative
Caroline A. Macera and Michael Pratt are with the Physical Activity & Health Branch Division of Nutrition & PhysicalActivity Centers for Disease Control & Prevention.
RDES: June 2000
risk for coronary heart disease mortality (about 1.9) comparable with cigarette smoking, a long recognized risk factor (Powell et al., 1987). However, the prevalence of inactivity is much higher than that of smoking (more than 70 percent compared with 30 percent). Because physical inactivity is a modifiable behavior, the potential for change is large. Targeted interventions that use stagesof-change approaches are successful at moving people along the physical activity continuum (Marcus et al., 1992). The Institute of Medicine (1988) report, a comprehensive review of the status of public health systems and training in the United States, emphasized the need for surveillance of chronic disease. It outlined for chronic disease the basic public health components that have been used to make outstanding advances in controlling communicable diseases. One of the highlights of the report was the essential role for surveillance of risk factors that were threats to public health because of high prevalence, high risk of mortality, and preventability. Physical inactivity meets all of the criteria for surveillance: it has a high prevalence, is associated with high rates of morbidity and mortality, has high direct and indirect costs, and is preventable. To accurately monitor physical activity levels on a population level requires a solid, stable surveillance system. Characteristics of a disease-based surveillance system as applied to physical activity are shown in Table 1. Among the many advantages of an effective surveillance system are that it allows researchers to establish baseline data to guide policy and programs, to track the prevalence of physical activity, and to evaluate interventions or policies. One of the key features of a surveillance system that distinguishes it from other data collection activities is that it is a stimulus for action.
97
Macera
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Public Health Surveillance Surveillance systems are useful and important tools in public health practice. Using surveillance methods to gather data on risk behaviors is relatively new. However, methods for surveillance of various diseases have been established for many years. The key aspect of a surveillance system is the timely dissemination of data to agencies or organizations that can undertake effective prevention and control activities. The elements of a surveillance system and a brief definition are shown in Table 2. The flow of information, also called a surveillance cycle, is illustrated in Figure 1. Surveillance systems differ from research studies and census measurement in several ways. A surveillance system obtains prevalence estimates of a disease or risk factor, whereas a research study has a specific question to answer about the etiology of a disease or risk factor. A census is a count of all members of a population by such demographic characteristics as age, sex, or race/ ethnicity. A surveillance system collects data at regular, frequent intervals (e.g., annually) on an ongoing basis in contrast to most research studies, which collect data once or a limited number of times. The case definition for surveillance has to be standard and easy to determine and report, whereas for a research study the case defini-
Table 1. Objectives of Public Health Surveillance for Diseases and for Physical Activity Disease Surveillance •
•
• •
•
estimate the magnitude of a public health problem understand the natural history of a disease
•
detect outbreaks or epidemics documentthe distribution/spread of disease evaluate control strategies
•
•
•
•
•
detect changes in health practice
•
•
identify research needs
•
•
facilitate planning
•
•
stimulate action
•
98
Physical Activity Surveillance identify baseline prevalence of physical activity/inactivity track physical activity patternsthroughoutthe lifespan identify subgroups at high risk maintain trends over time;track national/state objectives determine effect of interventions; evaluate policy and programs analyze systemic changes in counseling, environmental design specify dose-response and measurement issues ensure public health resources are available develop populationspecific physical activity interventions
tion may require many tests and conditions and can vary from study to study. Complex or detailed measurements are not feasible for a surveillance system, yet they are highly desirable for a research study. A research study may focus on particular subpopulations, whereas surveillance systems generally produce population-based prevalence data. Census data are obtained from everyone in a population (ideally), whereas surveillance data are obtained from a statisticallyrepresentative sample and, after appropriate weighting, population estimates can be derived.
Surveillance of Physical Activity in the United States In the United States, two major surveillance systems for adults collect information on physical activity. The National Health Interview Survey (NHIS) is conducted annually and collects information on vigorous and moderate-intensity physical activity (National Center for Health Statistics, 1999). NHIS data are used to track national health objectives, and the Behavioral Risk Factor Surveillance System (BRFSS), a state-based program, is used to track state objectives and programs (USDHHS, 2000). In the BRFSS, each state uses the same protocol, the same set of core questions, and random-digit-dialing to obtain data on a representative sample of the state's adult population. When state data are combined and weighted, national estimates are obtained. Data on physical activity are collected every other year; the last year for which such data are available for analysis is 1998. The surveillance data presented here are on 146,993 non-institutionalized U.S. adults who participated in the BRFSS telephone survey in 1998. All data are age-adjusted to the 2000 standard population.
Table 2. KeyElements in a Surveillance System •
Case definition
•
•
Reporting sources
•
•
Data management and analysis Dissemination
•
•
•
Program implementation and evaluation Feedback
•
•
System modification
•
•
•
•
Must be reliable andvalid; easyto identify and report Surveys at state, national,or local level Produce summary statistics andtrends To organizations that plan programs andto the general public Use to choose programs to implement and monitor program effectiveness Is the case definition appropriate? Are data released in a timely manner? System must be flexible to adjustto changing needs
ROES: June 2000
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Definition
Prev, fenCfl
Physical acthity is classified by intensiry. frequen cy, a nd duration to reflect major com pone nu of heahh-related fitn ess. Su rvey respondents are categorized according to whether they engage in the recommended amount of ac tivi ty, an insuffi cient am ount of activity, or no activity. Those in the rrrommmtW-attivity category report participating in moderate- in tensity activities for 30 or mo re minutes on 5 or more daY' per week ervigoroue-intensity act ivities for 20 o r more minutes o n 3 or more d ays pe r wee k. In the 1998 BRFSS. on ly two activities d uring th e month be fo re (he survey a re co unted toward s meeting these recommendations. Moderat e-inte nsity activities a re those tha t cause some increase in breathing or hea rt rat e, such as brisk walking. vigorous-irnenetry acti vities are those that ca use large in creases in breathing o r hea rt rat e. such as aerobic dancing or running. Those in the inJufft rim t- activity ca tegory report doi ng some activity (vigo ro us or moderate ) but not for the recommended duration o r frequen cy. and those in the no attivil1 cat egory report no lei sure-time activity. Those who monitor H ealthy People Objectives ( USDH HS, 20(0) ca n track moderate-intensity activity separately from vigorousinte nsity acti\iry.
Overall. data from the 1998 BRFSS indicate that 29 percent of adults report no leisure-time physical activi ry, 27 pe rcent achieve recommended levels of physical activiry, and 44 percent report some acti\ity but not enou gh to ac hieve recommended levels. Among the adulu meeting recommended activity levels. I ~ pe rce nt pe rform moderate intensity activities only and 8 pe rcent perform a combination of moderate- a nd vigorous-i ntensity activities. O nly 6 percent reach recom me nded activity levels on the basis of vigorous acti vity alone (Figure 2) . T he distribution of physical activity patte rn s by demogra phic ca tegories in cluding sex, age group. a nd race/ eth n icity indicate a highe r p revale nce of recommended levels of activity among men, young pe ople. and whites com pared with women. older people, and people from minority races or ethnic groups (Table 3) . Like-wise. college educated people a nd those in high income brackets also have a higher prevalence of recommended levels of activi ty than th ose with lower educational o r income levels. In addition, those living in the west have a higher prevalence of recommended activity than those in o ther pam of the Un ited States. Using cutpoirns based o n body mass in dex (BMI: weight in kilograms divided by height in metersl ) , the prevalence of recommended levels of physical activity is lo we r for adults w ho a re ove rweight (BMI 25 .0.29.9) or obese (BMI ~ 30) than for normal .....eight adults (Table 4) . Trends
~lodiftC"llt:io n
Reoporting
r
,
SoU T't"f'S
e, .8RFSS · 1
" "
~
Data AD a.I~S
"·-1 ' "ftDdI ,: \i
'/
For states that have part icipated in the BRFSS each year since (he survey began. the pro po rtion of U.S. adults who re po rt doing no leisure-time activity has not changed much in the decade from 1988 to 1998. The prevalence has remained a round 30 pe rcent. In contrast, those .....ho meet reco m mended level s of activity incr eased from around 22 percent in 198610 around 27 percent in 1992 bu t has been level from 1992 to 1998 (Figu re ~) .
_.. .
-~
-.«
Poliry
es . HP 2010 Ob)«ll_ AI"" 1.Information Row in A State·Based Surveillince System for Physical Activity
ROES: Ju.. 2IIDD
...,..AI" 1. Physicel Activity, U,S. Adults, BRFSS, 1998
Macera
50 ~---------------------------------
40 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
........
---------.-
....
'Y....
II-.---t.
-~.--II-------------/-
. -.....
•
------1--------
Downloaded by [Central Michigan University] at 00:51 06 November 2015
20 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
10 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
0+---,----,----,---,------,------,---.----,------,----,--...----,-----,
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
I-+- Inactive --- Recommended I Figure 3.AdultsAged 18+ Years Participation in Physical Activity in PastMonth, BRFSS, 1986-1998
Table 3. Participation in Physical Activity, U.S. AdultsAged 18 +, BRFSS 1998 Weighted and Age-Adjusted to the Year 2000 Standard Population
Demographic Group Overall Men Women Age (year) Men • 18-29 • 30-44 • 45-64 • 65-74 • 75+ Women • 18-29 • 30-44 • 45-64 • 65-74 • 75+ Race/Ethnicity White Black Hispanic Asian/Pacific Islander American Indian
Inactive 29.1 27.1 30.9
Insufficient 44.3 45.5 43.1
Recommended* 26.6 27.5 26.0
18.4 24.5 30.6 31.4 41.4
52.0 50.9 42.8 37.5 28.1
29.6 24.6 26.6 31.1 30.5
25.7 27.9 31.5 36.1 48.6
47.5 45.1 42.5 37.7 30.6
26.8 27.0 26.0 26.2 20.8
26.5 35.4 40.9 29.5 33.8
45.8 41.5 37.4 44.3 40.5
27.7 23.1 21.7 26.2 25.7
*Performs moderate intensityactivity 5 or more days/week; 30or more minutes per day, or vigorous intensityactivity 3 or more days/week; 20 or more minutes per day, or both.
100
ROES: June 2000
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Macera
Limitations of the BRFSS
A Case Study in Modifying Surveillance Systems: the BRFSS
The physical activity questions in the current BRFSS (used in the 1984-1998 surveys) have several limitations that restrict their usefulness. These questions assess only leisure-time physical activity (no occupational, household, or transportation-related activity); their focus is on sports rather than on moderate-intensity daily activities and allow respondents to report a maximum of two activities during the previous month. These limitations were recognized several years ago when the health benefits of moderate-intensity physical activity became well-established (Pate, eta!., 1995;USDHHS, 1996). Because moderate-intensity activity can occur in situations other than sports-related settings, and is possible in some occupational settings, the need to expand the scope of the BRFSS physical activity questions was explored at a 1997 BRFSS coordinators' meeting attended by state BRFSS representatives. Since then, considerable work has been done to develop questions that address some of these limitations.
Because a surveillance system needs to be flexible enough to adapt to new scientific findings and stable enough to monitor trends, the process involved in updating a surveillance system is complex. Although it is extremely valuable to use the same questions over time so that trends can be tracked it is also necessary to adjust to scientific developments so that the information collected is relevant to current scientific knowledge and community programs. The BRFSS physical activity questions were recently modified to meet the need to broaden the scope of the data collected. The process for identifying when surveillance items need to be changed and the process for developing new items lends itself to a case study. When updating a surveillance system, it is important to ensure that the new items are consistent with national objectives and current scientific knowledge. When questions on physical activity questions were first included in the BRFSS in the early 1980s, monitoring the 1990 health
Table 4. Participation in Physical Activity, U.S. AdultsAged 18+, BRFSS 1998 Weighted and Age-Adjusted to the Year 2000 Standard Population Insufficient Recommended* Demographic Group Inactive Education 51.1 32.6 16.3
ISSN: 0270-1367 (Print) 2168-3824 (Online) Journal homepage: http://www.tandfonline.com/loi/urqe20
Public Health Surveillance of Physical Activity Caroline A. Macera & Michael Pratt To cite this article: Caroline A. Macera & Michael Pratt (2000) Public Health Surveillance of Physical Activity, Research Quarterly for Exercise and Sport, 71:sup2, 97-103, DOI: 10.1080/02701367.2000.11082792 To link to this article: http://dx.doi.org/10.1080/02701367.2000.11082792
Published online: 13 Feb 2015.
Submit your article to this journal
Article views: 8
View related articles
Citing articles: 33 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=urqe20 Download by: [Central Michigan University]
Date: 06 November 2015, At: 00:51
Macera
Research Quarterly for ExerciseandSport ©2000 bythe American Alliancefor Health, Physical Education, Recreation and Dance Vol. 71, No.2, pp. 97-103
Public Health Surveillance of Physical Activity
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Caroline A. Macera and Michael Pratt
Keywords: exercise, moderate, sedentary, vigorous
Physical Activity as a Public Health Issue
T
h e importance of physical activity in maintaining health throughout life is well-recognized (USDHHS, 1996). Low levels of physical activity are associated with increased incidence of coronary heart disease and have been implicated in the mortality associated with the leading causes of death (Hahn, Teutsch, Rothenberg, & Marks, 1990; McGinnis & Foege, 1993; Powell, Thompson, Caspersen, & Kendrick, 1987). These studies suggest that the cost of physical inactivity is high, with one study suggesting that between $4.3 and $5.6 million would be saved annually if 10 percent of sedentary adults began a walking program (Jones & Eaton, 1994). The direct costs of physical inactivity are more than $24 million annually (Colditz, 1999). From a public health perspective, the increased mortality and morbidity associated with physical inactivity suggests that public health action is warranted. In addition, high medical and societal costs attributable to physical inactivityjustify increased attention to this behavior on both a national and community level. According to the Surgeon General's Report on Physical Activity and Health, less than 30 percent of adults are sufficiently active to achieve the full range of health benefits (USDHHS, 1996). Physical inactivity has a relative
Caroline A. Macera and Michael Pratt are with the Physical Activity & Health Branch Division of Nutrition & PhysicalActivity Centers for Disease Control & Prevention.
RDES: June 2000
risk for coronary heart disease mortality (about 1.9) comparable with cigarette smoking, a long recognized risk factor (Powell et al., 1987). However, the prevalence of inactivity is much higher than that of smoking (more than 70 percent compared with 30 percent). Because physical inactivity is a modifiable behavior, the potential for change is large. Targeted interventions that use stagesof-change approaches are successful at moving people along the physical activity continuum (Marcus et al., 1992). The Institute of Medicine (1988) report, a comprehensive review of the status of public health systems and training in the United States, emphasized the need for surveillance of chronic disease. It outlined for chronic disease the basic public health components that have been used to make outstanding advances in controlling communicable diseases. One of the highlights of the report was the essential role for surveillance of risk factors that were threats to public health because of high prevalence, high risk of mortality, and preventability. Physical inactivity meets all of the criteria for surveillance: it has a high prevalence, is associated with high rates of morbidity and mortality, has high direct and indirect costs, and is preventable. To accurately monitor physical activity levels on a population level requires a solid, stable surveillance system. Characteristics of a disease-based surveillance system as applied to physical activity are shown in Table 1. Among the many advantages of an effective surveillance system are that it allows researchers to establish baseline data to guide policy and programs, to track the prevalence of physical activity, and to evaluate interventions or policies. One of the key features of a surveillance system that distinguishes it from other data collection activities is that it is a stimulus for action.
97
Macera
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Public Health Surveillance Surveillance systems are useful and important tools in public health practice. Using surveillance methods to gather data on risk behaviors is relatively new. However, methods for surveillance of various diseases have been established for many years. The key aspect of a surveillance system is the timely dissemination of data to agencies or organizations that can undertake effective prevention and control activities. The elements of a surveillance system and a brief definition are shown in Table 2. The flow of information, also called a surveillance cycle, is illustrated in Figure 1. Surveillance systems differ from research studies and census measurement in several ways. A surveillance system obtains prevalence estimates of a disease or risk factor, whereas a research study has a specific question to answer about the etiology of a disease or risk factor. A census is a count of all members of a population by such demographic characteristics as age, sex, or race/ ethnicity. A surveillance system collects data at regular, frequent intervals (e.g., annually) on an ongoing basis in contrast to most research studies, which collect data once or a limited number of times. The case definition for surveillance has to be standard and easy to determine and report, whereas for a research study the case defini-
Table 1. Objectives of Public Health Surveillance for Diseases and for Physical Activity Disease Surveillance •
•
• •
•
estimate the magnitude of a public health problem understand the natural history of a disease
•
detect outbreaks or epidemics documentthe distribution/spread of disease evaluate control strategies
•
•
•
•
•
detect changes in health practice
•
•
identify research needs
•
•
facilitate planning
•
•
stimulate action
•
98
Physical Activity Surveillance identify baseline prevalence of physical activity/inactivity track physical activity patternsthroughoutthe lifespan identify subgroups at high risk maintain trends over time;track national/state objectives determine effect of interventions; evaluate policy and programs analyze systemic changes in counseling, environmental design specify dose-response and measurement issues ensure public health resources are available develop populationspecific physical activity interventions
tion may require many tests and conditions and can vary from study to study. Complex or detailed measurements are not feasible for a surveillance system, yet they are highly desirable for a research study. A research study may focus on particular subpopulations, whereas surveillance systems generally produce population-based prevalence data. Census data are obtained from everyone in a population (ideally), whereas surveillance data are obtained from a statisticallyrepresentative sample and, after appropriate weighting, population estimates can be derived.
Surveillance of Physical Activity in the United States In the United States, two major surveillance systems for adults collect information on physical activity. The National Health Interview Survey (NHIS) is conducted annually and collects information on vigorous and moderate-intensity physical activity (National Center for Health Statistics, 1999). NHIS data are used to track national health objectives, and the Behavioral Risk Factor Surveillance System (BRFSS), a state-based program, is used to track state objectives and programs (USDHHS, 2000). In the BRFSS, each state uses the same protocol, the same set of core questions, and random-digit-dialing to obtain data on a representative sample of the state's adult population. When state data are combined and weighted, national estimates are obtained. Data on physical activity are collected every other year; the last year for which such data are available for analysis is 1998. The surveillance data presented here are on 146,993 non-institutionalized U.S. adults who participated in the BRFSS telephone survey in 1998. All data are age-adjusted to the 2000 standard population.
Table 2. KeyElements in a Surveillance System •
Case definition
•
•
Reporting sources
•
•
Data management and analysis Dissemination
•
•
•
Program implementation and evaluation Feedback
•
•
System modification
•
•
•
•
Must be reliable andvalid; easyto identify and report Surveys at state, national,or local level Produce summary statistics andtrends To organizations that plan programs andto the general public Use to choose programs to implement and monitor program effectiveness Is the case definition appropriate? Are data released in a timely manner? System must be flexible to adjustto changing needs
ROES: June 2000
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Definition
Prev, fenCfl
Physical acthity is classified by intensiry. frequen cy, a nd duration to reflect major com pone nu of heahh-related fitn ess. Su rvey respondents are categorized according to whether they engage in the recommended amount of ac tivi ty, an insuffi cient am ount of activity, or no activity. Those in the rrrommmtW-attivity category report participating in moderate- in tensity activities for 30 or mo re minutes on 5 or more daY' per week ervigoroue-intensity act ivities for 20 o r more minutes o n 3 or more d ays pe r wee k. In the 1998 BRFSS. on ly two activities d uring th e month be fo re (he survey a re co unted toward s meeting these recommendations. Moderat e-inte nsity activities a re those tha t cause some increase in breathing or hea rt rat e, such as brisk walking. vigorous-irnenetry acti vities are those that ca use large in creases in breathing o r hea rt rat e. such as aerobic dancing or running. Those in the inJufft rim t- activity ca tegory report doi ng some activity (vigo ro us or moderate ) but not for the recommended duration o r frequen cy. and those in the no attivil1 cat egory report no lei sure-time activity. Those who monitor H ealthy People Objectives ( USDH HS, 20(0) ca n track moderate-intensity activity separately from vigorousinte nsity acti\iry.
Overall. data from the 1998 BRFSS indicate that 29 percent of adults report no leisure-time physical activi ry, 27 pe rcent achieve recommended levels of physical activiry, and 44 percent report some acti\ity but not enou gh to ac hieve recommended levels. Among the adulu meeting recommended activity levels. I ~ pe rce nt pe rform moderate intensity activities only and 8 pe rcent perform a combination of moderate- a nd vigorous-i ntensity activities. O nly 6 percent reach recom me nded activity levels on the basis of vigorous acti vity alone (Figure 2) . T he distribution of physical activity patte rn s by demogra phic ca tegories in cluding sex, age group. a nd race/ eth n icity indicate a highe r p revale nce of recommended levels of activity among men, young pe ople. and whites com pared with women. older people, and people from minority races or ethnic groups (Table 3) . Like-wise. college educated people a nd those in high income brackets also have a higher prevalence of recommended levels of activi ty than th ose with lower educational o r income levels. In addition, those living in the west have a higher prevalence of recommended activity than those in o ther pam of the Un ited States. Using cutpoirns based o n body mass in dex (BMI: weight in kilograms divided by height in metersl ) , the prevalence of recommended levels of physical activity is lo we r for adults w ho a re ove rweight (BMI 25 .0.29.9) or obese (BMI ~ 30) than for normal .....eight adults (Table 4) . Trends
~lodiftC"llt:io n
Reoporting
r
,
SoU T't"f'S
e, .8RFSS · 1
" "
~
Data AD a.I~S
"·-1 ' "ftDdI ,: \i
'/
For states that have part icipated in the BRFSS each year since (he survey began. the pro po rtion of U.S. adults who re po rt doing no leisure-time activity has not changed much in the decade from 1988 to 1998. The prevalence has remained a round 30 pe rcent. In contrast, those .....ho meet reco m mended level s of activity incr eased from around 22 percent in 198610 around 27 percent in 1992 bu t has been level from 1992 to 1998 (Figu re ~) .
_.. .
-~
-.«
Poliry
es . HP 2010 Ob)«ll_ AI"" 1.Information Row in A State·Based Surveillince System for Physical Activity
ROES: Ju.. 2IIDD
...,..AI" 1. Physicel Activity, U,S. Adults, BRFSS, 1998
Macera
50 ~---------------------------------
40 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
........
---------.-
....
'Y....
II-.---t.
-~.--II-------------/-
. -.....
•
------1--------
Downloaded by [Central Michigan University] at 00:51 06 November 2015
20 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
10 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
0+---,----,----,---,------,------,---.----,------,----,--...----,-----,
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
I-+- Inactive --- Recommended I Figure 3.AdultsAged 18+ Years Participation in Physical Activity in PastMonth, BRFSS, 1986-1998
Table 3. Participation in Physical Activity, U.S. AdultsAged 18 +, BRFSS 1998 Weighted and Age-Adjusted to the Year 2000 Standard Population
Demographic Group Overall Men Women Age (year) Men • 18-29 • 30-44 • 45-64 • 65-74 • 75+ Women • 18-29 • 30-44 • 45-64 • 65-74 • 75+ Race/Ethnicity White Black Hispanic Asian/Pacific Islander American Indian
Inactive 29.1 27.1 30.9
Insufficient 44.3 45.5 43.1
Recommended* 26.6 27.5 26.0
18.4 24.5 30.6 31.4 41.4
52.0 50.9 42.8 37.5 28.1
29.6 24.6 26.6 31.1 30.5
25.7 27.9 31.5 36.1 48.6
47.5 45.1 42.5 37.7 30.6
26.8 27.0 26.0 26.2 20.8
26.5 35.4 40.9 29.5 33.8
45.8 41.5 37.4 44.3 40.5
27.7 23.1 21.7 26.2 25.7
*Performs moderate intensityactivity 5 or more days/week; 30or more minutes per day, or vigorous intensityactivity 3 or more days/week; 20 or more minutes per day, or both.
100
ROES: June 2000
Downloaded by [Central Michigan University] at 00:51 06 November 2015
Macera
Limitations of the BRFSS
A Case Study in Modifying Surveillance Systems: the BRFSS
The physical activity questions in the current BRFSS (used in the 1984-1998 surveys) have several limitations that restrict their usefulness. These questions assess only leisure-time physical activity (no occupational, household, or transportation-related activity); their focus is on sports rather than on moderate-intensity daily activities and allow respondents to report a maximum of two activities during the previous month. These limitations were recognized several years ago when the health benefits of moderate-intensity physical activity became well-established (Pate, eta!., 1995;USDHHS, 1996). Because moderate-intensity activity can occur in situations other than sports-related settings, and is possible in some occupational settings, the need to expand the scope of the BRFSS physical activity questions was explored at a 1997 BRFSS coordinators' meeting attended by state BRFSS representatives. Since then, considerable work has been done to develop questions that address some of these limitations.
Because a surveillance system needs to be flexible enough to adapt to new scientific findings and stable enough to monitor trends, the process involved in updating a surveillance system is complex. Although it is extremely valuable to use the same questions over time so that trends can be tracked it is also necessary to adjust to scientific developments so that the information collected is relevant to current scientific knowledge and community programs. The BRFSS physical activity questions were recently modified to meet the need to broaden the scope of the data collected. The process for identifying when surveillance items need to be changed and the process for developing new items lends itself to a case study. When updating a surveillance system, it is important to ensure that the new items are consistent with national objectives and current scientific knowledge. When questions on physical activity questions were first included in the BRFSS in the early 1980s, monitoring the 1990 health
Table 4. Participation in Physical Activity, U.S. AdultsAged 18+, BRFSS 1998 Weighted and Age-Adjusted to the Year 2000 Standard Population Insufficient Recommended* Demographic Group Inactive Education 51.1 32.6 16.3
