The effect of social desirability and social approval on self-reports of physical activity

Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study

BACKGROUND

The health benefits of leisure-time physical activity are well known, but whether less exercise than the recommended 150 min a week can have life expectancy benefits is unclear. We assessed the health benefits of a range of volumes of physical activity in a Taiwanese population.

METHODS

In this prospective cohort study, 416,175 individuals (199,265 men and 216,910 women) participated in a standard medical screening programme in Taiwan between 1996 and 2008, with an average follow-up of 8·05 years (SD 4·21). On the basis of the amount of weekly exercise indicated in a self-administered questionnaire, participants were placed into one of five categories of exercise volumes: inactive, or low, medium, high, or very high activity. We calculated hazard ratios (HR) for mortality risks for every group compared with the inactive group, and calculated life expectancy for every group.

FINDINGS

Compared with individuals in the inactive group, those in the low-volume activity group, who exercised for an average of 92 min per week (95% CI 71-112) or 15 min a day (SD 1·8), had a 14% reduced risk of all-cause mortality (0·86, 0·81-0·91), and had a 3 year longer life expectancy. Every additional 15 min of daily exercise beyond the minimum amount of 15 min a day further reduced all-cause mortality by 4% (95% CI 2·5-7·0) and all-cancer mortality by 1% (0·3-4·5). These benefits were applicable to all age groups and both sexes, and to those with cardiovascular disease risks. Individuals who were inactive had a 17% (HR 1·17, 95% CI 1·10-1·24) increased risk of mortality compared with individuals in the low-volume group.

INTERPRETATION

15 min a day or 90 min a week of moderate-intensity exercise might be of benefit, even for individuals at risk of cardiovascular disease.

FUNDING

Taiwan Department of Health Clinical Trial and Research Center of Excellence and National Health Research Institutes.

Physical activity and breast cancer risk in Chinese women

Background:

The influence of different types and intensities of physical activity on risk for breast cancer is unclear.

Methods:

In a prospective cohort of 73 049 Chinese women (40–70 years), who had worked outside the home, we studied breast cancer risk in relation to specific types of self-reported and work history-related physical activity, including adolescent and adult exercise and household activity and walking and cycling for transportation. Occupational sitting time and physical activity energy expenditure were assigned based on lifetime occupational histories.

Results:

In all, 717 incident breast cancer cases were diagnosed. Breast cancer risk was lower for women in the lowest quartile of average occupational sitting time and in the highest quartile of average occupational energy expenditure (adjusted hazard ratio (HR): 0.81 and 0.73, respectively, P⩽0.05). Adult exercise at or above the recommended level (8 metabolic equivalent (MET) h per week per year) was associated with lower risk (adjusted HR: 0.73, P<0.05) in post-menopausal women. Analysis of joint effects showed that having both an active job and exercise participation did not confer an additional benefit. Other common daily activities were not associated with lower risk.

Interpretation:

These findings suggest that both exercise and occupational activity are associated with lower breast cancer risk, which supports current health promotion campaigns promoting exercise.

Posthospital Heart-Healthy Behaviors in Adults With Comorbid Diabetes

The purpose of these secondary analyses was to examine relationships between patient factors and patient-provider decision-making style (PDM) on heart-healthy behavior changes in 142 adults with diabetes after hospitalization for an acute coronary syndrome (ACS). A clinical trial randomized adults to either control or a telephone coaching intervention. Generalized estimating equations were used to analyze the relationship between patient factors and PDM style on longitudinal postdischarge changes in three heart-healthy behaviors, avoiding high fat foods, weight loss, and increased physical activity. Neither PDM style nor telephone coaching intervention affected heart-healthy behaviors in this population. Although adults with diabetes preferred collaborative patient-provider decision-making, present levels of provider engagement were not sufficient to support behavior change. Results suggest the need for sustained and tailored nursing interventions to facilitate heart-healthy behavior changes in adults with diabetes after ACS hospitalization.

Association between school- and nonschool-based activity programs and physical activity in adolescent girls

BACKGROUND

Some researchers have questioned if activity programs would be more effective if based outside school (eg, community leagues) rather than within schools. This study compared participation in activity programs based within and outside of school, and estimated the associations between participation and moderate-vigorous physical activity (MVPA) among adolescent girls.

METHODS

Within the Trial of Activity for Adolescent Girls, independent samples of 1559 6th-grade girls (age 11 to 12) and 3282 8th-grade girls (age 13 to 14) reported program participation using questionnaires. MVPA was measured using accelerometers. Linear mixed models accounted for school and site clustering.

RESULTS

Sixth-grade girls reported 5 times as many programs outside school as within school (4.1 vs. 0.8); daily MVPA was 0.29 minutes higher (1.2% of the mean) for each additional program outside school. Compared with 6th-grade girls, 8th-grade girls participated in 1.3 fewer programs outside school, while programs' association with MVPA was unchanged. Conversely, school programs' association with MVPA was greater in 8th grade. Daily MVPA was 1.33 minutes higher per school program, and participation declined 0.13.

CONCLUSION

Programs within and outside schools can both increase activity among adolescent girls. Intervention research should focus on increasing participation in school programs, and increasing movement during programs outside school.

An observational study of physical activity in parks in Asian and Pacific Islander communities in urban Honolulu, Hawaii, 2009

INTRODUCTION

Research on park use among Asians and Pacific Islanders is limited. This study examined use and conditions of 6 urban parks, varying in size, location, and neighborhood income level, in predominantly Asian and Pacific Islander communities in Honolulu, Hawaii. Sociodemographic predictors of park use were also identified.

METHODS

Observations were conducted from June through October 2009. Raters used the System for Observing Play and Recreation in Communities to count the number of people in predesignated zones and to code their physical activity level as sedentary, moderate, or vigorous. Raters coded park conditions on the basis of accessibility and usability, whether equipment and supervision were provided, and whether organized activities were occurring. Differences associated with sex and age of park users and income level of the neighborhood were examined by using χ² and logistic regression.

RESULTS

Raters observed 6,477 park users, most of whom were men. Approximately 60% of users were sedentary, 26% were engaged in moderate activities, and 14% performed vigorous activities. Women and girls were less active than men and boys. More users were present in the evenings, but morning users were more active. Although park users in low-income neighborhoods were more active than users in high-income neighborhoods, fewer people used the low-income parks. Most parks were accessible and usable but few provided equipment and supervision. Organized activities were rarely observed.

CONCLUSION

More efforts should be made to promote parks as a physical activity resource in Asian and Pacific Islander communities, particularly for women, girls, and low-income residents. More research should be conducted to identify barriers and facilitators to park use, especially among underrepresented populations.

Awareness and use of the Heart Symbol by Finnish consumers

Objective

To study the awareness of the Heart Symbol in different age and educational groups, and changes in the awareness over a 9-year period. In addition, the reported use of products with the symbol was examined.

Design

A series of annual cross-sectional postal surveys on Health Behaviour and Health among the Finnish Adult Population.

Setting

A random sample (n 5000 per annum) from the Finnish population aged 15–64 years, drawn from the National Population Register, received a questionnaire.

Subjects

Men and women (n 29 378) participating in the surveys in 2000–2009.

Results

At the early 2000s, 48 % of men and 73 % of women reported to be familiar with the symbol. The corresponding rates were 66 % for men and 91 % for women in 2009. The reported use of products with the symbol increased from 29 % to 52 % in men and from 40 % to 72 % in women. In men, the awareness did not vary by age, whereas older women (45–64 years) were less likely to be aware of the symbol compared with younger women (25–34 years). Men and women with the highest education were best aware of the symbol and more likely to use the products in the early 2000s. The educational differences diminished or disappeared during the study period.

Conclusions

The majority of Finnish adults are familiar with the Heart Symbol, and the reported use of such products increased in all age and educational groups, especially among the less educated. The symbol may work as an effective measure to diminish nutrition-related health inequalities.

Performance of the international physical activity questionnaire (short form) in subgroups of the Hong Kong chinese population

BACKGROUND

The International Physical Activity Questionnaire (IPAQ-SF) has been validated and recommended as an efficient method to assess physical activity, but its validity has not been investigated in different population subgroups. We examined variations in IPAQ validity in the Hong Kong Chinese population by six factors: sex, age, job status, educational level, body mass index (BMI), and visceral fat level (VFL).

METHODS

A total of 1,270 adults (aged 42.9 ± SD 14.4 years, 46.1% male) completed the Chinese version of IPAQ (IPAQ-C) and wore an accelerometer (ActiGraph) for four days afterwards. The IPAQ-C and the ActiGraph were compared in terms of estimated Metabolic Equivalent Task minutes per week (MET-min/wk), minutes spent in activity of moderate or vigorous intensity (MVPA), and agreement in the classification of physical activity.

RESULTS

The overall Spearman correlation (ρ) of between the IPAQ-C and ActiGraph was low (0.11 ± 0.03; range in subgroups 0.06-0.24) and was the highest among high VFL participants (0.24 ± 0.05). Difference between self-reported and ActiGraph-derived MET-min/wk (overall 2966 ± 140) was the smallest among participants with tertiary education (1804 ± 208). When physical activity was categorized into over or under 150 min/wk, overall agreement between self-report and accelerometer was 81.3% (± 1.1%; subgroup range: 77.2%-91.4%); agreement was the highest among those who were employed full-time in physically demanding jobs (91.4% ± 2.7%).

CONCLUSIONS

Sex, age, job status, educational level, and obesity were found to influence the criterion validity of IPAQ-C, yet none of the subgroups showed good validity (ρ = 0.06 to 0.24). IPAQ-SF validity is questionable in our Chinese population.

Estimation of daily energy expenditure in pregnant and non-pregnant women using a wrist-worn tri-axial accelerometer

BACKGROUND

Few studies have compared the validity of objective measures of physical activity energy expenditure (PAEE) in pregnant and non-pregnant women. PAEE is commonly estimated with accelerometers attached to the hip or waist, but little is known about the validity and participant acceptability of wrist attachment. The objectives of the current study were to assess the validity of a simple summary measure derived from a wrist-worn accelerometer (GENEA, Unilever Discover, UK) to estimate PAEE in pregnant and non-pregnant women, and to evaluate participant acceptability.

METHODS

Non-pregnant (N = 73) and pregnant (N = 35) Swedish women (aged 20-35 yrs) wore the accelerometer on their wrist for 10 days during which total energy expenditure (TEE) was assessed using doubly-labelled water. PAEE was calculated as 0.9×TEE-REE. British participants (N = 99; aged 22-65 yrs) wore accelerometers on their non-dominant wrist and hip for seven days and were asked to score the acceptability of monitor placement (scored 1 [least] through 10 [most] acceptable).

RESULTS

There was no significant correlation between body weight and PAEE. In non-pregnant women, acceleration explained 24% of the variation in PAEE, which decreased to 19% in leave-one-out cross-validation. In pregnant women, acceleration explained 11% of the variation in PAEE, which was not significant in leave-one-out cross-validation. Median (IQR) acceptability of wrist and hip placement was 9(8-10) and 9(7-10), respectively; there was a within-individual difference of 0.47 (p<.001).

CONCLUSIONS

A simple summary measure derived from a wrist-worn tri-axial accelerometer adds significantly to the prediction of energy expenditure in non-pregnant women and is scored acceptable by participants.

Acculturation, physical activity and television viewing in Hispanic women: findings from the 2005 California Women's Health Survey

OBJECTIVE

To assess the relationship of acculturation with physical activity and sedentary behaviours among Hispanic women in California.

DESIGN

Data from the 2005 California Women's Health Survey (CWHS) - a cross-sectional telephonic survey of health indicators and health-related behaviours and attitudes - were used.

SETTING

Using a random-digit dialling process, data were collected monthly from January to December 2005.

SUBJECTS

A total of 1298 women aged ≥18 years in California who self-identified as Hispanic.

RESULTS

Of the participants included in the analysis, 49 % were adherent to physical activity recommendations (with 150 min of weekly activity signifying adherence). There was no significant association between language acculturation and moderate or vigorous physical activity after controlling for potential confounders such as smoking, age and employment status. There was also no association between duration of residence in the USA and moderate or vigorous physical activity. Language acculturation was positively associated with television (TV) viewing, with highly acculturated women reporting more hours of TV viewing compared with women with an intermediate acculturation score (P = 0·0001), and those with an intermediate score reporting more hours of TV viewing compared with those with a low score (P = 0·003). This relationship persisted after inclusion of smoking, employment status, age and education in the model.

CONCLUSIONS

Higher levels of language acculturation may be associated with increased sedentary behaviours because of the influence of US culture on those women who have assimilated to the culture. Acculturation is an important factor to be taken into account when designing health education interventions for the Hispanic female population.

Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time

BACKGROUND

How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women.

METHODS

At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours) and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κweighted) and absolute percentage agreement.

RESULTS

The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P < 0.003), although the associations for housework were by far the weakest (Spearman correlations, 0.01 and -0.03 respectively for housework, and 0.11-0.37 for all other activities). Repeatability of responses to physical activity questions on the baseline questionnaire declined significantly over time. For strenuous activity, absolute agreement was 64% (κweighted = 0.71) for questionnaires administered less than 6 months apart, and 52% (κweighted = 0.51) for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κweighted = 0.67) and 47% (κweighted = 0.58).

CONCLUSIONS

In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET-hours expended, reported 3 years later. The weakest associations were with housework. Agreement for identical questions asked on two occasions about the frequency of physical activity decreased over time.

Prospectively assessed posttraumatic stress disorder and associated physical activity

OBJECTIVES

We examined the association of physical activity with prospectively assessed posttraumatic stress disorder (PTSD) symptoms in a military cohort.

METHODS

Using baseline and follow-up questionnaire data from a large prospective study of U.S. service members, we applied multivariable logistic regression to examine the adjusted odds of new-onset and persistent PTSD symptoms associated with light/moderate physical activity, vigorous physical activity, and strength training at follow-up.

RESULTS

Of the 38,883 participants, 89.4% reported engaging in at least 30 minutes of physical activity per week. At follow-up, those who reported proportionately less physical activity were more likely to screen positive for PTSD. Vigorous physical activity had the most consistent relationship with PTSD. Those who reported at least 20 minutes of vigorous physical activity twice weekly had significantly decreased odds for new-onset (odds ratio [OR] = 0.58, 95% confidence interval [CI] 0.49, 0.70) and persistent (OR = 0.59, 95% CI 0.42, 0.83) PTSD symptoms.

CONCLUSIONS

Engagement in physical activity, especially vigorous activity, is significantly associated with decreased odds of PTSD symptoms among U.S. service members. While further longitudinal research is necessary, a physical activity component may be valuable to PTSD treatment and prevention programs.

Correlates of pedometer-measured and self-reported physical activity among young Australian adults

Accurately quantifying physical activity is important for investigating relations with potential correlates, but past studies have mostly relied on self-report measures, which may be susceptible to error and biases, limiting interpretability. This study aimed to examine correlates of pedometer-determined physical activity and compare them with correlates of self-reported physical activity. Cross-sectional data were taken from 2017 Australian adults (aged 26-36 years) who were involved in the Childhood Determinants of Adult Health follow-up study during 2004-2006. Daily steps were recorded for seven days using Yamax pedometers and physical activity (total min/week) was reported via the long International Physical Activity Questionnaire. Demographic, biological, behavioral, psychological, social and environmental factors were assessed. Lower education, blue collar occupation and higher mental health score (men) and low-moderate alcohol intake (women) were positively associated with self-report and pedometer-measured activity. Among men, body mass index (BMI) was inversely and physical health score was positively associated with pedometer-measured activity while smoking, low to moderate alcohol intake, higher general health and urban area of residence were positively associated with self-reported activity. Among women, age and general health status were positively associated and number of live births inversely associated with pedometer-measured activity, while lower education, blue collar occupation, part time employment, smoking, diet, higher physical health score and higher mental health score were positively associated and white collar occupation inversely associated with self-reported activity. Many physical activity correlates differed depending on the measure employed; researchers should be mindful of these differences when selecting measures of physical activity.

Assessing physical activity and its relationship to cardiovascular risk factors: NHANES 2003-2006

BACKGROUND

Levels of physical activity (PA) in the general population are difficult to characterize. Historically measurement has been based on self-report, which can be subject to bias. PA monitor use has created opportunities to improve surveillance and analytic research on activity and health. The aims of the current study were to investigate the associations between objectively measured PA and cardiovascular disease risk factors and obesity.

METHODS

Data on PA from accelerometers, demographics, blood pressure, plasma glucose and lipids, self-reported hypertension and diabetes were obtained for adults, ages 20-65, in the NHANES surveys, 2003-2006. Outcomes were assessed as levels of moderate and vigorous activity, percentage of participants meeting recommended guidelines, and the correlations between activity and cardiovascular risk factors. Accelerometry data were available on 3,370 adults. Based on standard algorithms, activity levels were extremely low in all age-gender-race/ethnic groups, with an average of only 1 bout of vigorous activity lasting longer than 1 minute/day.

RESULTS

Men spent 35 minutes in moderate activity/day, women 21 minutes; >75% of this activity was accumulated in 1-minute bouts. Levels of activity declined sharply after age 50 in all groups. Negative associations were observed between minutes of combined moderate and vigorous activity and systolic blood pressure, blood glucose, diabetes, hypertension, body mass index and obesity, and a positive association was seen with HDL-cholesterol (all P ≤ 0.03), suggesting valid rank ordering of participants by activity level.

CONCLUSION

The magnitude of the gap between self-report and accelerometry activity must be a result of either a vast social acceptability bias in reporting or inaccurate measurement with accelerometry. Therefore, due to the low validity of self reported PA data for epidemiologic research, it is pertinent to encourage the use of valid, objective methods to assess PA.

Revision of the Dutch clinical algorithm for assessing patient needs in cardiac rehabilitation based on identified implementation problems

BACKGROUND

Despite all available evidence of its effectiveness, cardiac rehabilitation and secondary prevention (CRSP) is still insufficiently implemented in current clinical practice. Based on an analysis of implementation problems, recently the Dutch clinical algorithm for the assessment of patient's CRSP needs was revised. The purpose of this paper is to describe the revision process and its results to improve CRSP guideline implementation.

METHODS

The National Institute for Health and Clinical Excellence (NICE) guidelines manual for conducting guideline revisions was followed. Information on the use of the algorithm in practice was collected from electronic medical records and by conducting semi-structured interviews. Next, an expert advisory group identified the problems for use in daily practice and defined the scope for the revision. A multidisciplinary guideline development group subsequently wrote the revised algorithm.

RESULTS

A large variation in assessed patient needs was observed between CRSP clinics. Assessment based on clinical judgement was found to be a source of practice variation and is therefore avoided in the revised algorithm. It was decided to add assessment instruments for anxiety and depression, cardiovascular risk factors, stress, attitude of partner and lifestyle parameters.

CONCLUSION

The Dutch clinical algorithm for assessing patient needs for CRSP was revised using a combination of patient data from routine practice, knowledge from academic experts and experience from field experts. The revised algorithm is a practical tool consisting of assessment instruments to improve CRSP guideline adherence in the Netherlands. This algorithm may also be useful for other Western countries to organize their CRSP needs assessment procedure.

Depressive symptoms, physical inactivity and risk of cardiovascular mortality in older adults: the Cardiovascular Health Study

Background

Depressed older individuals have a higher mortality than older persons without depression. Depression is associated with physical inactivity, and low levels of physical activity have been shown in some cohorts to be a partial mediator of the relationship between depression and cardiovascular events and mortality.

Methods

A cohort of 5888 individuals (mean 72.8±5.6 years, 58% female, 16% African-American) from four US communities was followed for an average of 10.3 years. Self-reported depressive symptoms (10-item Center for Epidemiological Studies Depression Scale) were assessed annually and self-reported physical activity was assessed at baseline and at 3 and 7 years. To estimate how much of the increased risk of cardiovascular mortality associated with depressive symptoms was due to physical inactivity, Cox regression with time-varying covariates was used to determine the percentage change in the log HR of depressive symptoms for cardiovascular mortality after adding physical activity variables.

Results

At baseline, 20% of participants scored above the cut-off for depressive symptoms. There were 2915 deaths (49.8%), of which 1176 (20.1%) were from cardiovascular causes. Depressive symptoms and physical inactivity each independently increased the risk of cardiovascular mortality and were strongly associated with each other (all p<0.001). Individuals with both depressive symptoms and physical inactivity had greater cardiovascular mortality than those with either individually (p<0.001, log rank test). Physical inactivity reduced the log HR of depressive symptoms for cardiovascular mortality by 26% after adjustment. This was similar for persons with (25%) and without (23%) established coronary heart disease.

Conclusions

Physical inactivity accounted for a significant proportion of the risk of cardiovascular mortality due to depressive symptoms in older adults, regardless of coronary heart disease status.

Predictors of measurement error in energy intake during pregnancy

Nutrition plays a critical role in maternal and fetal health; however, research on error in the measurement of energy intake during pregnancy is limited. The authors analyzed data on 998 women living in central North Carolina with singleton pregnancies during 2001-2005. Second-trimester diet was assessed by food frequency questionnaire. Estimated energy requirements were calculated using Institute of Medicine prediction equations, with adjustment for energy costs during the second trimester. Implausible values for daily energy intake were determined using confidence limits of agreement for energy intake/estimated energy requirements. Prevalences of low energy reporting (LER) and high energy reporting (HER) were 32.8% and 12.9%, respectively. In a multivariable analysis, pregravid body mass index was related to both LER and HER; LER was higher in both overweight (odds ratio = 1.96, 95% confidence interval: 1.26, 3.02; P = 0.031) and obese (odds ratio = 3.29, 95% confidence interval: 2.33, 4.65; P < 0.001) women than in normal-weight counterparts. Other predictors of LER included marriage and higher levels of physical activity. HER was higher among subjects who were underweight, African-American, and less educated and subjects who had higher depressive symptom scores. LER and HER are prevalent during pregnancy. Identifying their predictors may improve data collection and analytic methods for reducing systematic bias in the study of diet and reproductive outcomes.

Physical activity, television viewing time, and retinal microvascular caliber: the multi-ethnic study of atherosclerosis

Physical activities and sedentary behaviors are 2 broad classes of behavior that may be clearly distinguished from each other and have different patterns of determinants. The authors examined the associations of physical activity and television viewing time with retinal vascular caliber among US adults (n = 5,893) from 4 racial/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (2002-2004) that included non-Hispanic whites, blacks, Hispanics, and Chinese. Physical activity and television viewing time were assessed by using a questionnaire, and vascular calibers (arteriolar and venular) were measured from digital retinal photographs. Those in the lowest quartile of physical activity had wider retinal venular caliber compared with those in the highest quartile in multivariate models adjusted for demographic, cardiovascular, behavioral, and inflammatory risk factors. This was noted in non-Hispanic whites and Hispanics but not in blacks or Chinese. For television viewing time, non-Hispanic whites (but not the other racial/ethnic groups) who were in the highest quartile of television viewing time had wider retinal venular caliber compared with those in the lowest quartile. No associations were noted with arteriolar caliber. Lower levels of physical activity (among non-Hispanic whites and Hispanics) and higher levels of television viewing time (among whites) are associated with wider retinal venules.

Validity of self-reported leisure-time sedentary behavior in adolescents

BACKGROUND

To evaluate the concordance between leisure-time sedentary behavior in adolescents assessed by an activity-based questionnaire and accelerometry. A convenience sample of 128 girls and 73 boys, 11-15 years of age (12.6 ± 1.1 years) from six states across the United States examined as part of the feasibility studies for the Trial of Activity in Adolescent Girls (TAAG). Three days of self-reported time spent watching TV/videos, using computers, playing video/computer games, and talking on the phone was assessed using a modified version of the Self-Administered Physical Activity Checklist (SAPAC). Criterion measure of sedentary behavior was via accelerometry over three days using a cut point of < 50 counts · 30 sec⁻¹ epoch. Comparisons between sedentary behavior by the two instruments were made.

RESULTS

Adolescents generally underestimated minutes of sedentary behavior compared to accelerometry-measured minutes. The overall correlation between minutes of sedentary behavior by self-report and accelerometry was weak (Spearman r = 0.14; 95% CI 0.05, 0.23). Adjustment of sedentary minutes of behavior for total minutes assessed using either percentages or the residuals method tended to increase correlations slightly. However, regression analyses showed no significant association between self-reported sedentary behavior and minutes of sedentary behavior captured via accelerometry.

DISCUSSION

These findings suggest that the modified 3-day Self-Administered Physical Activity Checklist is not a reliable method for assessing sedentary behavior. It is recommended that until validation studies for self-report instruments of sedentary behavior demonstrate validity, objective measures should be used.

Activity monitoring in chronic obstructive pulmonary disease

The measurement of daily physical activity (PA) has become a significant outcome in patients with chronic obstructive pulmonary disease (COPD). Recent data have shown the independent association between PA markers, hospitalizations, and mortality. Daily PA can be quantified by direct observation, assessment of energy expenditure, questionnaires, and activity monitors (motion sensors). This review aims to describe the methods used to quantify daily PA in COPD on the basis of the published literature and to suggest potential applications of activity monitoring methods in clinical research and daily care of COPD patients.

Relation of Children's Dietary reporting accuracy to cognitive ability

A validation study of children's dietary reporting provided an opportunity to investigate whether cognitive ability is a source of systematic error in dietary recalls. From the fall of 2004 through the spring of 2007, fourth-grade children (n = 374) in Columbia, South Carolina, were observed eating school meals and interviewed to obtain 24-hour dietary recalls; subsequently, measures of dietary reporting error were calculated. The common factor extracted from 4 subject-area achievement tests (scores on which were provided by the school district for 362 children) was used as a measure of cognitive ability. For the 325 children who reported school meals that met the criteria to be reports about school meals, as cognitive ability increased, dietary reporting error decreased; the relation between cognitive ability and dietary reporting performance was stronger among girls than among boys. The mean cognitive ability for 37 children who reported no meals that satisfied the criteria for being reports about school meals was significantly lower than that for the 325 children who reported meals that satisfied these criteria. These findings indicate that cognitive ability is a source of systematic error in children's dietary recalls. More generally, the quality of epidemiologic survey data may depend systematically on the cognitive ability of respondents.

The geography of recreational physical activity in England

Levels of physical activity have declined considerably over recent decades in England, and there is evidence that activity patterns vary across areas. Previous studies of the geography of physical activity have frequently relied on model based synthetic estimates. Using data from a large population survey this study develops a direct measure of recreational physical activity and investigates variations in activity patterns across English Local Authorities. For both sexes the results show a distinct geography of recreational physical activity associated with north/south variations and urban/rural status. The environmental and behavioural factors driving those patterns are still poorly understood. We conclude that the variations observed might reflect recreational opportunities and the socio-cultural context of areas.

National School Lunch Program participation and sex differences in body mass index trajectories of children from low-income families

OBJECTIVES

To investigate participation patterns in the National School Lunch Program (NSLP) among low-income children from kindergarten to fifth grade and to examine the ways in which participation influences sex differences in the trajectories of body mass index (BMI) through the eighth grade.

DESIGN

Longitudinal, secondary data analysis.

SETTING

Sample of low-income US children who entered kindergarten in 1998.

PARTICIPANTS

Girls (n = 574) and boys (n = 566) from low-income families who participated in the Early Childhood Longitudinal Study, Kindergarten Cohort.

MAIN EXPOSURE

Participation in the NSLP.

MAIN OUTCOME MEASURES

Temporary and persistent patterns of NSLP participation, and age-specific and sex-specific BMI raw scores calculated at 5 data points.

RESULTS

Among the low-income children who attended schools that participated in the NSLP, both the children who persistently participated in the program and those who temporarily participated in the program displayed similar socioeconomically disadvantaged factors. Nonlinear mixed models indicated a larger rate of change in BMI (ie, an increase) among low-income, participating girls than among low-income, nonparticipating girls; however, mean BMIs did not significantly differ between low-income girls who participated and those who did not participate. No significant differences were observed among low-income boys.

CONCLUSIONS

Results suggest that participation in the NSLP is associated with rapid weight gain for low-income girls but not for low-income boys.

An emergency department intervention to improve knowledge of child passenger safety

OBJECTIVES

The objective of the study was to test the impact of an educational video in improving child passenger safety knowledge.

METHODS

This was a prospective randomized study performed in the emergency department of an urban children's hospital involving parents of non-critically ill children younger than 9 years. Parents were randomized to observe a video on child passenger safety or comparison group. All completed a survey, 8-question pretest at enrollment, and posttest after 1 month and received written safety materials at discharge. The outcome measure to test knowledge was the difference in mean pretest-posttest scores on a questionnaire.

RESULTS

We enrolled 274 parents (137 intervention, 137 comparison). Thirty subjects were found ineligible for analysis after enrollment because their children were outside the age range for inclusion. Analysis was restricted to 131 parents in the intervention group and 113 in the comparison group. No significant differences existed between groups when comparing demographics and child passenger safety characteristics except for the number of children in the household. After excluding those lost to follow-up (91 parents) and who dropped out (14 parents), analysis was restricted to 74 subjects in the intervention group and 65 in the comparison group. Mean pretest scores were as follows: intervention, 4.95 (SD, 1.49); comparison, 5.12 (SD, 1.32). Mean posttest scores were as follows: intervention, 5.24 (SD,1.60); comparison, 4.77 (SD, 1.39). Difference in mean pretest-posttest scores showed a significant improvement in the intervention group compared with the comparison group: 0.65 (95% confidence interval, 0.14-1.16) on independent-samples t test (P = 0.012).

CONCLUSIONS

Child passenger safety education can be effectively imparted to parents in the emergency department.

Associations between sitting time and weight in young adult Australian women

OBJECTIVE

Sedentary behaviour may be a contributor to weight gain in today's young adult women, who are gaining weight faster than women in their mothers' generation. The aim was to examine the relationships between sitting time and weight in young women.

METHOD

Data were from women born in 1973-1978 who completed surveys in 2000, 2003 and 2006 for the Australian Longitudinal Study on Women's Health. Associations between concurrent changes in sitting-time and weight, and prospective associations between these variables, were examined using ANOVA and linear regressions, stratified by BMI-category in 2000 (n=5562).

RESULTS

Among overweight and obese women, percentage weight change from 2000 to 2006 was higher in those whose sitting time increased (>20%) than in those whose sitting time decreased (>20%) over the same period (p<0.05). Conversely, percentage change in sitting time was significantly higher in those who gained weight (>5%) than in those who lost weight (>5%) (p<0.05). There were no prospective associations between (change in) sitting time and weight change, or between (change in) weight and change in sitting time.

CONCLUSION

The results confirm associations between concurrent changes in weight and changes in sitting time in overweight and obese women, but no prospective relationships were found.

A lifestyle assessment and intervention tool for pediatric weight management: the HABITS questionnaire

BACKGROUND

Lifestyle assessment and intervention tools are useful in promoting pediatric weight management. The present study aimed to establish convergent validity and reliability for a quick simple measure of food intake and physical activity/sedentary behaviour. The HABITS questionnaire can be used to identify and monitor behavioural intervention targets.

METHODS

Thirty-five youths (ages 7-16 years) were recruited from the waiting area of the Jacobi Medical Center Child and Teen Health Services. To establish convergent validity for the HABITS questionnaire, study participants completed the HABITS questionnaire, a 24-h recall and a modified version of the Modifiable Activity Questionnaire for Adolescents (MAQ). Participants completed a second HABITS questionnaire within 1 month to assess test-retest reliability. Internal consistency for dietary and physical activity/sedentary behaviour subscales was assessed using Cronbach's alpha, and test-retest reliability was assessed using Cohen's Kappa coefficient. Spearman's rank correlation coefficients were calculated for individual items using the 24-h recall and the MAQ as reference standards.

RESULTS

The HABITS questionnaire subscales showed moderate internal consistency (Cronbach's alpha of 0.61 and 0.59 for the dietary and physical activity/sedentary behaviour subscale, respectively). The test-retest reliability was 0.94 for the dietary subscale and 0.87 for the physical activity/sedentary behaviour subscale. Several items on the HABITS questionnaire were moderately correlated with information reported in the MAQ and the 24-h recall (r = 0.38-0.59, P < 0.05).

CONCLUSIONS

The HABITS questionnaire can reliably be used in a paediatric setting to quickly assess key dietary and physical activity/sedentary behaviours and to promote behaviour change for weight management.

Detection of gait and postures using a miniaturized triaxial accelerometer-based system: accuracy in patients with mild to moderate Parkinson's disease

OBJECTIVE

To examine whether gait and postures can accurately be detected with a single small body-fixed device in patients with mild to moderate Parkinson's disease (PD).

DESIGN

Results of a triaxial accelerometer-based method were evaluated against video observation scores (criterion measure). Study 1: Subjects performed basic mobility-related activities (walking, lying, sitting, standing) in a fixed and free sequence. Study 2: Subjects were monitored while doing similar activities as in study 1 and while doing usual domestic activities.

SETTING

Study 1: Standardized set-up in a movement laboratory. Study 2: Home environment.

PARTICIPANTS

(N=37) Study 1: Patients with PD (n=32; mean age +/- SD, 67.3+/-6.6y; mean disease duration +/- SD, 6.1+/-3.4y). Study 2: Patients with PD (n=5; mean age +/- SD, 76.0+/-7.3y; mean disease duration +/- SD, 3.8+/-4.7y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The degree of correspondence between the monitor and the video observation for the duration of each activity. Overall agreement, sensitivity, specificity, and positive predictive values were calculated.

RESULTS

Study 1: Overall agreement ranged between 69.8% and 90.8% (fixed sequence) and 57.5% and 96.9% (free sequence). Study 2: Overall agreement ranged between 60.0% and 89.2%. Lying, sitting (home), and walking were detected most accurately with mean sensitivity varying from 81.7% to 99.9%. Lower values were found for sitting (laboratory), standing, and shuffling.

CONCLUSIONS

This triaxial monitor system is a practical and valuable tool for objective, continuous evaluation of walking and postures in patients with mild to moderate PD. Detection of sitting and standing requires further fine-tuning.

Reducing socially desirable responses in epidemiologic surveys: an extension of the randomized-response technique

BACKGROUND

Even though the validity of self-reports of sensitive behaviors is threatened by social desirability bias, interviews and questionnaires are widely used in epidemiologic surveys on these topics.

METHODS

In the randomized-response technique, a randomization device is used to determine whether participants are asked to respond truthfully or whether they are prompted to provide a prespecified response. In this study, the randomized-response technique was extended by using a cheating-detection modification to obtain more valid data. The survey was on the dental hygiene habits of Chinese college students.

RESULTS

Whereas only 35% of men and 10% of women admitted to insufficient dental hygiene when questioned directly, 51% of men and 20% of women attested to this socially undesirable behavior in a randomized-response survey.

CONCLUSIONS

Given the considerable discrepancy between the results obtained by direct questioning and by using the randomized-response technique, we propose that this technique be considered for use in epidemiologic studies of sensitive behaviors.

The impact of combined health factors on cardiovascular disease mortality

BACKGROUND

The combined effect of modifiable health factors on the risk of cardiovascular disease (CVD) mortality has not been well established. The objective of this study was to determine the association between 5 modifiable health factors in combination on the risk of CVD mortality in a sample of adult men.

METHODS

A cohort of 38,110 men (aged 20-84 years and of middle and upper socioeconomic strata) was followed over time until their date of death or December 31, 2003. A health profile score (unweighted and weighted) was developed based on cardiorespiratory fitness (CRF; moderate or high vs low), self-reported physical activity (active vs inactive), smoking status (not current vs current), alcohol consumption (1-14 drinks per week vs 0 or >14 drinks per week), and body mass index (BMI; 18.5-24.9 vs >or=25.0 kg/m(2)).

RESULTS

During 16.1 +/- 8.4 years of follow-up and 613,571 man-years of exposure, there were 949 deaths from CVD. High CRF, normal BMI, being physically active, and not currently smoking were individually associated with reduced risk of CVD mortality after adjusting for confounders. When considered in combination, a minimum of 2 of 5 positive health factors reduced the risk of CVD mortality (hazard ratio = 0.67, 95% CI 0.49-0.91). The weighted score indicated that a combination of high CRF, not currently smoking, and normal BMI is of most clinical importance to CVD mortality (hazard ratio = 0.31, 95% CI 0.24-0.39).

CONCLUSIONS

Exposure to increasing numbers of beneficial health factors in adulthood reduced the risk of CVD mortality in men, and multibehavioral prevention efforts in adulthood should be encouraged.

Eight self-administered 24-hour dietary recalls using the Internet are feasible in African Americans and Whites: the energetics study

OBJECTIVE

To support research and to provide food and nutrition practitioners with a strong foundation for nutrient-based counseling, there is a need for affordable automated 24-hour dietary recalls. Multiple days of intake, along with repeated reports over time, are needed to achieve stable indicators of individual intakes and to support evaluation of success in meeting dietary goals because of intraindividual intake variability. Little information has been published on subject responses, participation rates, and the perceived subject burden of repeated 24-hour recalls. Our aim was to determine the willingness of subjects to conduct eight 24-hour recalls via the Internet.

DESIGN

A study to validate a Web-based, automated, self-administered 24-hour recall (DietDay, Centrax Corporation, Chicago, IL).

SUBJECTS/SETTING

Two-hundred and sixty-one white and African-American subjects within 50 miles of the University of California-Los Angeles participated in the study. Subjects completed 3 DietDays at the study visits and another 5 days on their own. The last 2 DietDays were completed 1 and 2 months after the final clinic visit. Subjects were notified by automatic e-mail of the need for DietDay completion, and nonresponders were followed up with personalized e-mails and phone calls.

RESULTS

The perceived subject burden was minimal and, even after completing six recalls, 92% were willing to continue reporting their daily diets 1 and 2 months later. White subjects had a slightly higher rate of return, with 94% completing all eight recalls, compared to 91% of African-American subjects. Participants were able to access the Internet in their homes, offices, library, or homes of friends or family. It is also of interest that 82% of subjects believed the 24-hour recall was superior to a diet history in reflecting their normal diet.

CONCLUSION

These results open up new opportunities for food and nutrition practitioners to strengthen their nutritional counseling in an efficient and affordable manner without additional time investment.

Television viewing is not predictive of BMI in Black and Hispanic young adult females

Previous studies have observed that television (TV) viewing is predictive of obesity and weight gain. We examined whether the cross-sectional association between TV viewing and BMI varied by racial/ethnic subgroups among young women in Wave III (collected in 2001-2002) of the National Longitudinal Study of Adolescent Health. We used multivariate linear regression to examine the relationship between TV viewing and BMI among 6,049 females while controlling for sociodemographic and health attributes. We stratified the sample by race/ethnicity to better understand the association between TV viewing and BMI across different groups. Black and Hispanic females had higher BMIs (black: 28.5 kg/m(2), Hispanic: 27.3 kg/m(2), white: 26.0 kg/m(2)) than white females, while black females reported higher numbers of hours spent watching TV (black: 14.7 h/week, Hispanic: 10.6 h/week, white: 11.2 h/week) when compared to their white and Hispanic peers. TV viewing was positively associated with BMI (beta = 0.79, P = 0.003 for 8-14 vs. < or =7 h/week; beta = 1.18, P = 0.01 for >14 vs. < or =7 h/week) independent of race/ethnicity, age, maternal education, history of pregnancy, parental obesity, and household income. However, in models stratified by race/ethnicity, increased TV viewing was associated with increased BMI only among white females; TV viewing was not predictive of higher BMI in black or Hispanic young adult females. Among black and Hispanic females, counseling to decrease TV viewing may be important but insufficient for promoting weight loss.

Low physical activity is associated with proinflammatory high-density lipoprotein and increased subclinical atherosclerosis in women with systemic lupus erythematosus

OBJECTIVE

To investigate the association between physical activity, functional activity of high-density lipoprotein (HDL), and subclinical cardiovascular disease in patients with systemic lupus erythematosus (SLE).

METHODS

A total of 242 SLE patients (all women) participated in this cross-sectional study from February 2004 to February 2008. Carotid plaque and intima-media thickness (IMT), antioxidant function of HDL, and traditional cardiac risk factors were measured. Physical activity was assessed from self-reports by calculating the metabolic equivalents (METS) per week and by the physical function domain of the Medical Outcomes Study Short Form 36 (SF-36). Data were analyzed using bivariate and multivariate regression analyses.

RESULTS

Number of METS per week spent performing strenuous exercise was negatively correlated with IMT (r = -0.4, P = 0.002) and number of plaques (r = -0.30, P = 0.0001). Physical function as assessed by the SF-36 was also negatively correlated with IMT (r = -0.14, P = 0.03) and number of plaques (r = -0.14, P = 0.04). In multivariate analyses, number of strenuous exercise METS was significantly associated with IMT (t = -2.2, P = 0.028) and number of plaques (t = -2.5, P = 0.014) when controlling for markers of SLE disease activity and damage, but not after controlling for traditional cardiac risk factors. Low physical activity, defined as <225 total METS per week, was associated with the presence of proinflammatory HDL (P = 0.03).

CONCLUSION

Low physical activity is associated with increased subclinical atherosclerosis and proinflammatory HDL in patients with SLE. Increased strenuous exercise may reduce the risk of atherosclerosis in SLE.

Physical activity and mortality risk in the Japanese elderly: a cohort study

BACKGROUND

Physical activity recommendations for older adults with poor health needs to be understood.

PURPOSE

This study aims to examine the association between the frequency of physical activity and mortality among a sample of elderly subjects, most of whom were under treatment for pre-existing disease.

METHODS

Data on the frequency of leisure-time physical activity, walking for transportation, and non-exercise physical activity were obtained from a population-based cohort study in Shizuoka, Japan. Of the randomly selected 22,200 residents aged 65-84 years, 10,385 subjects were followed from 1999 to 2006 and analyzed. Hazard ratios (HRs) and 95% CIs were obtained for all-cause; cardiovascular disease (CVD); and cancer mortality, after adjusting for covariates such as pre-existing disease(s). A subgroup analysis that was restricted to subjects under treatment for pre-existing disease(s) at baseline was further conducted. Data were collected between 1999 and 2006, and all analyses were conducted in 2008 and 2009.

RESULTS

Every physical activity was associated with a reduced risk of all-cause and CVD mortality, among not only the total sample but even those under treatment. The HRs for CVD mortality among participants with 5 or more days of non-exercise physical activity per week for the total sample and those with pre-existing disease(s) were 0.38 (95% CI=0.22, 0.55) and 0.35 (95% CI=0.24, 0.52), respectively, compared with no non-exercise physical activity. The association between physical activity and cancer mortality was not clear.

CONCLUSIONS

This study suggests a protective effect of physical activity on all-cause and CVD mortality among Japanese elderly people with pre-existing disease.

Knowledge, attitudes and practices regarding dengue infection in Westmoreland, Jamaica

BACKGROUND

Dengue virus infection causes significant morbidity and mortality in most tropical and sub-tropical countries of the world. Dengue fever is endemic in Jamaica and continues to be a public health concern. There is a paucity of information on knowledge, attitudes and practices (KAP) of Jamaicans regarding dengue infection.

OBJECTIVE

To describe dengue-related knowledge, attitudes and practices (KAP) of residents of Westmoreland, Jamaica.

METHODS

A cross-sectional questionnaire survey of 192 parents attending child health clinics in the Parish of Westmoreland was conducted.

RESULTS

More than half of the parents (54%) had good knowledge about signs, symptoms and mode of transmission of dengue. Approximately 47% considered dengue to be a serious but preventable disease to which they are vulnerable. Nevertheless, a majority (77%) did not use effective dengue preventive methods such as screening of homes and 51% did not use bed nets. Educational attainment (OR, 2.98; CI, 1.23, 7.23) was positively associated with knowledge of dengue. There was no correlation between knowledge about dengue and preventive practices (p = 0.34). Radio and TV were the predominant sources of information about dengue fever.

CONCLUSION

Findings suggest that the good knowledge about dengue fever among residents of Westmoreland did not translate to adoption of preventive measures. Health programme planners and practitioners need to identify and facilitate removal of barriers to behaviour change related to control of dengue fever among the population. Future campaigns should focus on educating and encouraging individuals and families to adopt simple, preventive actions, such as, use of insecticide treated bed nets and screening of homes.

Factors predicting glycemic control in middle-aged and older adults with type 2 diabetes

INTRODUCTION

Few studies have prospectively assessed the explanatory effects of demographics, clinical conditions, treatment modality, and general lifestyle behaviors on glycemic control in large heterogeneous samples of middle-aged and older adults with type 2 diabetes. We hierarchically examined these factors, focused especially on the effects of modifiable factors (ie, general lifestyle behaviors), and compared predictive patterns between middle-aged and older adults.

METHODS

We used nationally representative data from the 1998 and 2000 Health and Retirement Study (HRS) and the HRS 2003 Diabetes Study. We analyzed data from 379 middle-aged adults (aged 51-64 y) and 430 older adults (aged >or=65 y) who self-reported having type 2 diabetes at baseline.

RESULTS

Among middle-aged adults, demographic factors and clinical conditions were the strongest predictors of hemoglobin A1c (HbA1c) levels. However, among older adults, treatment modality (diet only, oral medication, or insulin only or in combination with other regimens) significantly affected HbA1c levels. Lifestyle (physical activity, smoking, drinking, and body weight control), independent of the effects of demographics, clinical conditions, and treatment modality, significantly affected HbA1c levels. An increase of 1 healthy behavior was associated with a decrease in HbA1c levels of more than 1 percentage point.

CONCLUSION

Our findings provide support for current diabetes guidelines that recommend a lifestyle regimen across the entire span of diabetes care and highlight the need to help both sociodemographically and clinically disadvantaged middle-aged adults with type 2 diabetes as well as older adults who exhibit poor adherence to medication recommendations to achieve better glycemic control.

Cardiometabolic risk in younger and older adults across an index of ambulatory activity

BACKGROUND

Pedometers are increasingly being used to assess population levels of physical activity and as motivational tools for individuals to increase their physical activity. To maximize their utility, a framework for classifying pedometer-determined activity into meaningful health-related categories is needed.

PURPOSE

This study investigated whether a pedometer step index proposed by Tudor-Locke and Bassett can effectively group younger and older adults according to cardiometabolic health status.

METHODS

Analyses (conducted in 2008) used cross-sectional data from the Childhood Determinants of Adult Health study (1793 adults aged 26-36 years; collected 2004-2006) and from the Tasmanian Older Adult Cohort study (1014 adults aged 50-80 years; collected 2002-2006). Participants wore a pedometer for 7 days and the prevalence of cardiometabolic health indicators, including the metabolic syndrome, elevated Pathobiological Determinants of Atherosclerosis in Youth risk scores, and elevated Framingham risk scores, was examined across the following step categories: sedentary (< 5000); low-active (5000-7499); somewhat active (7500-9999); active (10,000-12,499); and high-active (> or = 12,500).

RESULTS

With the exception of younger men, individuals achieving > or = 5000 steps had a substantially lower prevalence of adverse cardiometabolic health indicators than those obtaining fewer steps. Differences in the prevalence of adverse indicators were generally modest across higher steps-per-day categories. However, younger men and women in the high-active category had a substantially lower prevalence of some adverse health indicators.

CONCLUSIONS

In general, the proposed index for classifying pedometer activity effectively distinguishes cardiometabolic health risk. Pedometers may be a useful tool for objectively identifying inactive individuals at greatest risk for poor cardiometabolic health.

Spinal segmental stabilisation exercises for chronic low back pain: programme adherence and its influence on clinical outcome

Exercise rehabilitation is one of the few evidence-based treatments for chronic non-specific low back pain (cLBP), but individual success is notoriously variable and may depend on the patient's adherence to the prescribed exercise regime. This prospective study examined factors associated with adherence and the relationship between adherence and outcome after a programme of physiotherapeutic spine stabilisation exercises. A total of 32/37 patients with cLBP completed the study (mean age, 44.0 (SD = 12.3) years; 11/32 (34%) male). Adherence to the 9-week programme was documented as: percent attendance at therapy, percent adherence to daily home exercises (patient diary) and percent commitment to rehabilitation (Sports Injury Rehabilitation Adherence Scale (SIRAS)). The average of these three measures formed a multidimensional adherence index (MAI). Psychological disturbance, fear-avoidance beliefs, catastrophising, exercise self-efficacy and health locus of control were measured by questionnaire; disability in everyday activities was scored with the Roland-Morris disability scale and back pain intensity with a 0-10 graphic rating scale. Overall, adherence to therapy was very good (average MAI score, 85%; median (IQR), 89 (15)%). The only psychological/beliefs variable showing a unique significant association with MAI was exercise self-efficacy (Rho = 0.36, P = 0.045). Pain intensity and self-rated disability decreased significantly after therapy (each P < 0.01). Adherence to home exercises showed a moderate, positive correlation with the reduction in average pain (Rho = 0.54, P = 0.003) and disability (Rho = 0.38, P = 0.036); higher MAI scores were associated with greater reductions in average pain (Rho = 0.48, P = 0.008) and a (n.s.) tendency for greater reductions in disability (Rho = 0.32, P = 0.07) Neither attendance at therapy nor SIRAS were significantly related to any of the outcomes. The benefits of rehabilitation depended to a large extent on the patient's exercise behaviour outside of the formal physiotherapy sessions. Hence, more effort should be invested in finding ways to improve patients' motivation to take responsibility for the success of their own therapy, perhaps by increasing exercise self-efficacy. Whether the "adherence-outcome" interaction was mediated by improvements in function related to the specific exercises, or by a more "global" effect of the programme, remains to be examined.

Neighborhood social cohesion and disorder in relation to walking in community-dwelling older adults: a multilevel analysis

Objectives. To examine the role of neighborhood social conditions and walking in community-dwelling older adults. Methods. A multi-level analysis of data from 4,317 older adults (mean age = 74.5; 73% black) from a geographically-defined urban community. Participants completed structured interviews including 14 questions on neighborhood conditions and self-reported walking. The neighborhood questions were summarized into individual-level measures of perceived neighborhood social cohesion and disorder. These measures were aggregated by neighborhood to construct neighborhood-level measures of social cohesion and disorder. Results. Neighborhood-level disorder, but not social cohesion, was significantly associated with walking, independent individual-level neighborhood perceptions and other correlates of walking. Further adjustment for race weakened this association to a marginally significant level. Discussion. Neighborhood conditions may shape walking behavior in older adults, especially conditions that reflect physical neglect or social threat. Promotion of walking behavior in older adults may require improvement of the safety and upkeep of the neighborhood environment.

Observational epidemiologic studies of nutrition and cancer: the next generation (with better observation)

It would be of enormous public health importance if diet and physical activity, both modifiable behavioral factors, were causally related to cancer. Nevertheless, the nutritional epidemiology of cancer remains problematic, in part because of persistent concerns that standard questionnaires measure diet and physical activity with too much error. We present a new strategy for addressing this measurement error problem. First, as background, we note that food frequency and physical activity questionnaires require respondents to report "typical" diet or activity over the previous year or longer. Multiple 24-hour recalls (24HR), based on reporting only the previous day's behavior, offer potential cognitive advantages over the questionnaires, and biomarker evidence suggests the 24-hour dietary recall is more accurate than the food frequency questionnaire. The expense involved in administering multiple 24 HRs in large epidemiologic studies, however, has up to now been prohibitive. In that context, we suggest that Internet-based 24 HRs, for both diet and physical activity, represent a practical and cost-effective approach for incorporating multiple recalls in large epidemiologic studies. We discuss (1) recent efforts to develop such Internet-based instruments and their accompanying software support systems; (2) ongoing studies to evaluate the feasibility of using these new instruments in cohort studies; (3) additional investigations to gauge the accuracy of the Internet-based recalls vis-à-vis standard instruments and biomarkers; and (4) new statistical approaches for combining the new instruments with standard assessment tools and biomarkers The incorporation of Internet-based 24 HRs into large epidemiologic studies may help advance our understanding of the nutritional determinants of cancer.

Disagreement in physical activity assessed by accelerometer and self-report in subgroups of age, gender, education and weight status

BACKGROUND

The purpose of this study is to compare self-reported time (by questionnaire) and objectively measured time (by accelerometer) spent on physical activity at moderate (MPA) and vigorous intensity (VPA) in subgroups of age, gender, education and weight status.

METHODS

In total, 236 adolescents (aged 12-18) and 301 adults (aged 22-40), completed the questionnaire and wore an accelerometer for two weeks.

RESULTS

Adolescents reported exceptionally more time spent on MPA (mean difference 596 +/- 704 min/wk) and VPA (mean difference 178 +/- 315 min/wk) than was assessed objectively by the accelerometer. Based on the questionnaire, high educated adolescents spent more time on MPA (205 min/wk, p = 0.002) and VPA (120 min/wk, p = 0.01) than low educated adolescents, but according to the accelerometer they spent less time on MPA (149 min/wk, p = 0.001) and VPA (47 min/wk, p = 0.001). Among adults there was moderate agreement between self-reported time and objectively measured time spent on MPA, but in general the reported time spent on MPA (mean difference 107 +/- 334 min/wk) and VPA (mean difference 169 +/- 250 min/wk) exceeded the time measured with the accelerometer. Overweight adults reported significantly more VPA (57 min/wk, p = 0.04) than normal weight adults, but this was not confirmed by the accelerometer data.

CONCLUSION

We observed large differences in time spent on MPA and VPA measured by questionnaire and accelerometer in adolescents but reasonably good agreement in adults. Differences between methods varied by gender, education and weight status. This finding raises serious questions about the use of questionnaires to quantify MPA and VPA in adolescents. There is a clear need in advanced valid assessments of PA in adolescents.

TRIAL NUMBER

ISRCTN93896459.

The effect of a physical activity intervention on bias in self-reported activity

PURPOSE

A positive outcome in self-reported behavior could be detected erroneously if an intervention caused over-reporting of the targeted behavior. Data collected from a multi-site randomized trial were examined to determine if adolescent girls who received a physical activity intervention over-reported their activity more than girls who received no intervention.

METHODS

Activity was measured using accelerometers and self-reports (3-Day Physical Activity Recall, 3DPAR) in cross-sectional samples preintervention (6th grade, n = 1,464) and post-intervention (8th grade, n = 3,114). Log-transformed accelerometer minutes were regressed on 3DPAR blocks, treatment group, and their interaction, while adjusting for race, body mass index, and timing of data collection.

RESULTS

Preintervention, the association between measures did not differ between groups, but post-intervention 3DPAR blocks were associated with fewer log-accelerometer minutes of moderate-vigorous physical activity (MVPA) in intervention girls than in control girls (p = 0.002). The group difference was primarily in the upper 15% of the 3DPAR distribution, where control girls had >1.7 more accelerometer minutes of MVPA than intervention girls who reported identical activity levels. Group differences in this subsample were 8.5%-16.2% of the mean activity levels; the intervention was powered to detect a difference of 10%.

CONCLUSION

Self-report measures should be interpreted with caution when used to evaluate a physical activity intervention.