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Biomedical subjects

Sandra A Ham

Publications and source records attributed to Sandra A Ham.

10 recordsLinked to original sources
PubMed2007

Discrepancies between methods of identifying objectively determined physical activity.

UNLABELLED: Current methods for validating physical activity (PA) questionnaires typically use accelerometers as objective measures for comparison with questionnaire responses and obtain low correlations or agreement. PURPOSE: We examined possible reasons for weak associations in validation studies by comparing published ActiGraph accelerometer intensity cut points with cut points based on intensity thresholds for heart rate response to PA. METHODS: Twelve adults (five men, seven women; age 31.0 +/- 14.3 yr) wore an ActiGraph accelerometer and a Polar Vantage NV heart watch simultaneously for seven consecutive days during their waking hours. We identified PA bouts from the minute-by-minute ActiGraph data using published accelerometer thresholds for defining moderate- and vigorous-intensity PA. We then compared PA bout intensities identified with these criteria with intensity classifications of the PA bouts using mean percent heart rate reserve (HRR). RESULTS: Most of the moderate-intensity PA bouts identified by the Freedson (78.3%), Swartz (88.0%), and Hendelman (94.7%) ActiGraph cut points were associated with a mean %HRR < 45% (very light and light intensities). The estimated mean frequency with which study participants engaged in moderate-intensity PA varied with the cut points and type of bouts used and ranged from 1.1 d.wk(-1) (45-60%HRR) to 7.0 d.wk(-1) (Hendelman cut points). The mean total duration on active days ranged from 17.9 min.d(-1)(45-60%HRR) to 139.2 min.d(-1) (Hendelman cut points). Fewer bouts of vigorous PA were found in the accelerometer data, and most were in the vigorous-intensity category of > or = 60%HRR. CONCLUSIONS: The method used for analyzing ActiGraph activity data can result in large differences in the summary measure of minutes of moderate- to vigorous-intensity activity.

Adult↗
PubMed2006

Dog walking and physical activity in the United States.

INTRODUCTION: Dog walking is a purposeful physical activity that may have health benefits for humans and canines. A descriptive epidemiology of the contribution of dog walking to physically active lifestyles among dog walkers in the United States has not been previously reported. METHODS: Data on youth and adults who reported walking for pet care trips (N = 1282) on the National Household Travel Survey 2001 were analyzed for number of trips, proportion walking a dog for at least 10 minutes on one trip, and accumulation of 30 minutes or more in 1 day of walks lasting at least 10 minutes. RESULTS: In 1 day, 58.9% of dog walkers took two or more walks, 80.2% took at least one walk of 10 minutes or more, and 42.3% accumulated 30 minutes or more from walks lasting at least 10 minutes each. There were no significant differences by sex, family income, or categories of urbanization. CONCLUSION: Walking a dog may contribute to a physically active lifestyle and should be promoted as a strategy that fits within the framework set forth by the Task Force on Community Preventive Services for Physical Activity.

Adolescent↗
PubMed2005

Trends in walking for transportation in the United States, 1995 and 2001.

INTRODUCTION: The purpose of this study was to examine trends in walking for transportation among U.S. adults and youth for Healthy People 2010 objective 22-14. The objective calls for increasing the proportion of trips of 1 mile or less made by walking to 25% for adults and 50% for youth. National transportation surveys are used to track national health objectives, but data interpretation and caveats to use have not been discussed in the public health literature to date. METHODS: Cross-sectional analyses at two time points used data from the 1995 Nationwide Personal Transportation Survey and the subsequent 2001 National Household Travel Survey. The populations of interest were U.S. civilian noninstitutionalized adults (aged 18 years and older) and youth (aged 5 to 15 years). Trends were reported for the percentage of walking trips of 1 mile or less for transportation (adults) and walking trips of 1 mile or less to school (youth) using 86,286 trips (1995) and 119,462 trips (2001) made by adults and 3114 trips (1995) and 4073 trips (2001) made by youth. RESULTS: Of trips of 1 mile or less, adults reported more walking in 2001 (21.2%; 95% confidence interval [CI], 20.5-21.9) than in 1995 (16.7%; CI, 15.9-17.5). For trips to school of 1 mile or less, youths also increased walking from 1995 (31.3%; CI, 27.9-34.4) to 2001 (35.9%; CI, 33.0-38.8). Changes in survey methodology affected the interpretation of the Healthy People 2010 trends. CONCLUSION: In spite of small increases in walking between 1995 and 2001 accompanying a change in survey methodology, U.S. adults and youth fall short of meeting Healthy People 2010 walking objectives for trips of 1 mile or less.

Adolescent↗
PubMed2005

Prevalence of physical activity in the United States: Behavioral Risk Factor Surveillance System, 2001.

INTRODUCTION: The health benefits of regular cardiovascular exercise are well-known. Such exercise, however, has traditionally been defined as vigorous physical activity, such as jogging, swimming, or aerobic dance. Exercise of moderate intensity also promotes health, and many U.S. adults may be experiencing the health benefits of exercise through lifestyle activities of moderate intensity, such as yard work, housework, or walking for transportation. Until recently, public health surveillance systems have not included assessments of this type of physical activity, focusing on exercise of vigorous intensity. We used an enhanced surveillance tool to describe the prevalence and amount of both moderate-intensity and vigorous-intensity physical activity among U.S. adults. METHODS: We analyzed data from the 2001 Behavioral Risk Factor Surveillance System, a state-based, random-digit-dialed telephone survey administered to U.S. adults aged 18 years and older (n = 82,834 men and 120,286 women). Physical activity behavior was assessed using questions designed to quantify the frequency of participation in moderate- or vigorous-intensity physical activities performed during leisure time or for household chores and transportation. RESULTS: Overall, 45% of adults (48% of men and 43% of women) were active at recommended levels during nonworking hours (at least 30 minutes five or more days per week in moderate-intensity activities, equivalent to brisk walking, or at least 20 minutes three or more days per week in vigorous activities, equivalent to running, heavy yard work, or aerobic dance). Less than 16% of adults (15% of men and 17% of women) reported no moderate or vigorous activity in a usual week. CONCLUSION: Integrating surveillance of lifestyle activities into national systems is possible, and doing so may provide a more accurate representation of the prevalence of recommended levels of physical activity. These results, however, suggest that the majority of U.S. adults are not active at levels associated with the promotion and maintenance of health.

Adult↗
PubMed2005

Physical activity among adults >or=50 yr with and without disabilities, BRFSS 2001.

PURPOSE: Before 2001, the Behavioral Risk Factor Surveillance System (BRFSS), a national survey of health behaviors, assessed only leisure-time physical activity. In 2001, the BRFSS used newly developed physical activity items to evaluate combined leisure-time, household, and transportation activities. Using BRFSS 2001 data, this cross-sectional study describes the prevalence of inactivity and insufficient and recommended physical activity for older adults (i.e., aged >or=50 yr). METHODS: BRFSS 2001 data were analyzed using prevalence estimates and logistic regression to assess physical activity patterns among older adults (N=74,960) stratified by disability status, and select sociodemographic and health status characteristics. RESULTS: A total of 43.4, 39.1, and 17.5% of respondents without disabilities were active at a recommended level, insufficiently active, and inactive, respectively, taking into account nonoccupational physical activities. A total of 28.8% of older adults with disabilities were active at a recommended level, 35.7% insufficiently active, and 35.5% inactive. Among persons with and without disabilities, groups with the highest odds of inactivity and insufficient activity were women, persons aged >or=75 yr, blacks, persons with lower education levels and low incomes, and those who were obese. CONCLUSIONS: Not all persons with disabilities can be active at recommended levels, but it is possible for the vast majority to do some types of physical activity, even if at insufficient levels. Thus, it may be possible for the prevalence of inactivity among persons with and without disabilities to be similar. This was not found. At the start of the new millennium, almost 60% of older adults without disabilities and 70% with disabilities were not obtaining a recommended amount of combined leisure-time, transportation, and household physical activity.

Activities of Daily Living↗
PubMed2004

Descriptive epidemiology of pedometer-determined physical activity.

PURPOSE: The dual purposes of this study were: 1) to provide preliminary descriptive epidemiology data representing pedometer-determined physical activity (PA) and 2) to explore sources of intra-individual variability in steps per day. METHODS: All participants (76 males, age = 48.4 +/- 16.3 yr, body mass index (BMI) = 27.1 +/- 5.1 kg x m(-2); 133 females, age = 47.4 +/- 17.5 yr, BMI = 26.9 +/- 5.7 kg x m(-2)) resided in Sumter County, SC, and were recruited by telephone to receive a mailed kit to self-monitor PA for 1 wk. Statistical analyses compared mean steps per day between sexes, races, age groups, education and income levels, and BMI categories. Mean steps per day were also compared between: 1) weekdays versus weekend days, 2) workdays versus nonworkdays, and 3) days of sport/exercise versus no participation. RESULTS: The entire sample took 5931 +/- 3664 steps x d(-1) (males = 7192 +/- 3596 vs females = 5210 +/- 3518 steps x d(-1), t = 7.88, P < 0.0001). Significant differences were also indicated by race, age, education, income, and BMI. In addition, weekdays were significantly higher than weekend days, workdays were higher than nonworkdays, and sport/exercise days were higher than nonsport/exercise days. CONCLUSIONS: The large standard deviations reflect a wide distribution of ambulatory behavior. Regardless, important differences are still evident by demographic characteristics, BMI categories, day of the week, and reported engagement in work or sport/exercise.

Adolescent↗
PubMed2004

Ranking of cities according to public health criteria: pitfalls and opportunities.

Popular magazines often rank cities in terms of various aspects of quality of life. Such ranking studies can motivate people to visit or relocate to a particular city or increase the frequency with which they engage in healthy behaviors. With careful consideration of study design and data limitations, these efforts also can assist policymakers in identifying local public health issues. We discuss considerations in interpreting ranking studies that use environmental measures of a city population's public health related to physical activity, nutrition, and obesity. Ranking studies such as those commonly publicized are constrained by statistical methodology issues and a lack of a scientific basis in regard to design.

Cities↗
PubMed2003

Assessment of physical activity by telephone interview versus objective monitoring.

PURPOSE: To compare different methods of quantifying time in physical activity (PA). METHODS: Twenty-five participants (12 male, 13 female) volunteered to be monitored for seven consecutive days, during which different PA patterns were measured by the simultaneous heart-rate motion sensor technique (HR+M). At the end of the 7th day, participants completed questions taken from the 2001 Behavioral Risk Factor Surveillance System (BRFSS) PA module telephone survey, in which they recalled the amount of time spent walking, and in moderate and vigorous activities. The results of the BRFSS PA module were then compared with those of the HR+M. RESULTS: No significant group differences were found in the amount of time spent in moderate and vigorous activities between methods. However, individual differences were greater for time spent in moderate activities (SE +/- 7.36 min x d(-1); range -70 to 77 min x d(-1)) than for time spent in vigorous activities (SE +/- 3.57 min x d(-1); range -39 to 33 min x d(-1). Spearman correlation coefficients between the HR+M and the BRFSS were significant for vigorous activities (r = 0.54, P < 0.01). There was 80% agreement between the two methods of classifying individuals who either: (a) met the recommendations (through moderate and/or vigorous PA) or (b) did not meet the recommendations. CONCLUSION: The BRFSS and HR+M methods yielded similar group estimates of PA, but individual assessments of moderate activity differed more than those of vigorous activity. BRFSS estimations of group compliance with national PA recommendations were similar to those of the HR+M.

Adult↗
PubMedDate not supplied

Increasing stair use in a worksite through environmental changes.

PURPOSE: This study assessed the impact on stair use of four sequential environmental interventions: (1) installing new carpet and painting the walls, (2) adding framed art-work on stair landings, (3) displaying motivational signs throughout the building, and (4) adding a stereo system and playing various types of music in the stairwell. METHODS: We conducted a longitudinal study with no comparison group to evaluate the impact of environmental changes on stairway use. The setting was the main stairwell in the Centers for Disease Control and Prevention's (CDC) Rhodes Building in Atlanta, Georgia. Proximity sensors were installed in each stairwell entry to monitor traffic. The subjects were 554 permanent CDC employees and 110 temporary employees. Changes in stairwell use by intervention were evaluated. RESULTS: Both motivational signs and music significantly increased stair use by 8.9% over baseline (p < .05). The increase in sign use occurred in the first 3 months of the intervention, whereas the increase in music occurred after the first 3 months. DISCUSSION: These data suggest that physical improvements to a stairwell, signage that encourages stair use, and music may increase physical activity among building occupants.

Centers for Disease Control and Prevention, U.S.↗