Hervé Besson

Assessment of physical activity - a review of methodologies with reference to epidemiological research: a report of the exercise physiology section of the European Association of Cardiovascular Prevention and Rehabilitation

Physical activity has a fundamental role in the prevention and treatment of chronic disease. The precise measurement of physical activity is key to many surveillance and epidemiological studies investigating trends and associations with disease. Public health initiatives aimed at increasing physical activity rely on the measurement of physical activity to monitor their effectiveness. Physical activity is multidimensional, and a complex behaviour to measure; its various domains are often misunderstood. Inappropriate or crude measures of physical activity have serious implications, and are likely to lead to misleading results and underestimate effect size. In this review, key definitions and theoretical aspects, which underpin the measurement of physical activity, are briefly discussed. Methodologies particularly suited for use in epidemiological research are reviewed, with particular reference to their validity, primary outcome measure and considerations when using each in the field. It is acknowledged that the choice of method may be a compromise between accuracy level and feasibility, but the ultimate choice of tool must suit the stated aim of the research. A framework is presented to guide researchers on the selection of the most suitable tool for use in a specific study.

A systematic review of reliability and objective criterion-related validity of physical activity questionnaires

Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs.A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible.In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62–0.71 for existing, and 0.74–0.76 for new PAQs. Median validity coefficients ranged from 0.30–0.39 for existing, and from 0.25–0.41 for new PAQs.Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument.

Television viewing time independently predicts all-cause and cardiovascular mortality: the EPIC Norfolk Study

BACKGROUND Television viewing (TV), a highly prevalent behaviour, is associated with higher cardiovascular risk independently of physical activity. The relationship with mortality, however, is relatively unknown. METHODS We examined the prospective relationship between TV time and all-cause, cardiovascular and cancer mortality in a population-based cohort [The European Prospective Investigation into Cancer and Nutrition (EPIC), Norfolk] of 13 197 men and women {age [SD (standard deviation)]: 61.5 ± 9.0 years}. Participants were free from stroke, myocardial infarction and cancer at baseline in 1998-2000 and were followed up for death ascertainment until 2009 (9.5 ± 1.6 years). TV time, total physical activity energy expenditure (PAEE), education level, smoking status, alcohol consumption, anti-hypertensive and lipid-lowering medication use, participant and family history of disease and total energy intake were self-reported; height and weight were measured by standardized procedures. Hazard ratios (HRs) [95% confidence interval (CI)] for mortality were estimated per 1-h/day increase in TV. RESULTS Each 1-h/day increase in TV time was associated with increased hazard of all-cause (HR = 1.04, 95% CI = 1.01-1.09; 1270 deaths) and cardiovascular (HR = 1.07, 95% CI = 1.01-1.15; 373 deaths), but not cancer mortality (HR = 1.04, 95% CI = 0.98-1.10; 570 deaths). This was independent of gender, age, education, smoking, alcohol, medication, diabetes history, family history of cardiovascular disease and cancer, body mass index (BMI) and PAEE. They were similar when stratified by gender, age, education, BMI and PAEE. The population-attributable fraction for all-cause mortality comparing the highest TV tertile (>3.6 h/day) with the lowest (<2.5 h/day) was 5.4%. CONCLUSIONS These findings suggest that public health recommendations should consider advising a reduction in TV time, a predominant leisure activity in modern society, in addition to advocating physical activity.

Estimating physical activity energy expenditure, sedentary time, and physical activity intensity by self-report in adults

BACKGROUND Few questionnaires that assess usual physical activity have been reported to be valid for all different subdimensions of physical activity. OBJECTIVE The objective was to assess the validity and reliability of the Recent Physical Activity Questionnaire (RPAQ), which assesses usual physical activity (PA) in 4 domains (work, travel, recreation, and domestic life). DESIGN Total energy expenditure (TEE) was measured for 14 d by using the doubly labeled water technique combined with a measure of resting metabolic rate to yield PA energy expenditure (PAEE) in 25 men and 25 women. Simultaneously, intensity of activity was measured by using combined heart rate and movement sensing for 11 d. Repeatability of the RPAQ was assessed in an independent sample of 71 women and 60 men aged 31-57 y. RESULTS Estimated TEE and PAEE were significantly associated with criterion measures (TEE: r = 0.67; PAEE: r = 0.39) with mean (+/-SD) biases of -3452 +/- 2025 kJ/d and -13 +/- 24 kJ d(-1) kg(-1). The correlation between self-reported and measured time spent was significant for vigorous PA (r = 0.70) and marginally insignificant for sedentary time (r = 0.27, P = 0.06). The mean biases were relatively small for sedentary time and vigorous PA: 0.7 +/- 2.8 h/d and -12 +/- 24 min/d, respectively. The intraclass correlation coefficient for repeatability of total PAEE (kJ/d) was 0.76 (P < 0.0001). CONCLUSION The RPAQ is the first questionnaire with demonstrated validity for ranking individuals according to their time spent at vigorous-intensity activity and overall energy expenditure.

Adherence to the Mediterranean Diet Is Associated with Lower Abdominal Adiposity in European Men and Women

Given the lack of consistent evidence of the relationship between Mediterranean dietary patterns and body fat, we assessed the cross-sectional association between adherence to a modified Mediterranean diet, BMI, and waist circumference (WC). A total of 497,308 individuals (70.7% women) aged 25-70 y from 10 European countries participated in this study. Diet was assessed at baseline using detailed validated country-specific questionnaires, and anthropometrical measurements were collected using standardized procedures. The association between the degree of adherence to the modified-Mediterranean Diet Score (mMDS) (including high consumption of vegetables, legumes, fruits and nuts, cereals, fish and seafood, and unsaturated:saturated fatty acids ratio; moderate alcohol intake; and low consumption of meat and meat products and dairy products) and BMI (kg.m(-2)) or WC (cm) was modeled through mixed-effects linear regression, controlling for potential confounders. Overall, the mMDS was not significantly associated with BMI. Higher adherence to the Mediterranean diet was significantly associated with lower WC, for a given BMI, in both men (-0.09; 95% CI -0.14 to -0.04) and women (-0.06; 95% CI -0.10 to -0.01). The association was stronger in men (-0.20; 95% CI -0.23 to -0.17) and women (-0.17; 95% CI -0.21 to -0.13) from Northern European countries. Despite the observed heterogeneity among regions, results of this study suggest that adherence to a modified Mediterranean diet, high in foods of vegetable origin and unsaturated fatty acids, is associated with lower abdominal adiposity measured by WC in European men and women.

Correlates of objectively measured physical activity and sedentary behaviour in English children

BACKGROUND Evidence on the correlates of objectively measured physical activity and sedentary behaviour in childhood is limited. This study aimed to identify correlates of physical activity and sedentary behaviour among 7-year-old children in England. METHODS Physical activity was measured using Actigraph accelerometry in 480 participants as part of the Gateshead Millennium Study during 2006-07. Twenty-two potential correlates across five domains (demographic and biological; psychological, cognitive and emotional; behavioural; social and cultural; physical environmental) were tested for associations with total volume of habitual physical activity, moderate-vigorous intensity physical activity (MVPA) and sedentary behaviour. Multiple linear regression analysis was used. RESULTS Seven correlates, including four that are potentially modifiable, were significantly associated with total physical activity, MVPA and sedentary behaviour in final models: gender, child weight status, maternal age, child interest in active play, active commuting to school, parenting practice and season. Four of these variables were significantly associated with all three constructs in final models. The final models explained 18, 18 and 24% of variance in total volume of physical activity, MVPA and sedentary behaviour, respectively. CONCLUSION A number of potentially modifiable factors are associated with increased physical activity and/or reduced sedentary behaviour in English children. These could be valuable targets of future interventions.

Physical activity and gain in abdominal adiposity and body weight: prospective cohort study in 288,498 men and women

BACKGROUND The protective effect of physical activity (PA) on abdominal adiposity is unclear. OBJECTIVE We examined whether PA independently predicted gains in body weight and abdominal adiposity. DESIGN In a prospective cohort study [the EPIC (European Prospective Investigation into Cancer and Nutrition)], we followed 84,511 men and 203,987 women for 5.1 y. PA was assessed by a validated questionnaire, and individuals were categorized into 4 groups (inactive, moderately inactive, moderately active, and active). Body weight and waist circumference were measured at baseline and self-reported at follow-up. We used multilevel mixed-effects linear regression models and stratified our analyses by sex with adjustments for age, smoking status, alcohol consumption, educational level, total energy intake, duration of follow-up, baseline body weight, change in body weight, and waist circumference (when applicable). RESULTS PA significantly predicted a lower waist circumference (in cm) in men (β = -0.045; 95% CI: -0.057, -0.034) and in women (β = -0.035; 95% CI: -0.056, -0.015) independent of baseline body weight, baseline waist circumference, and other confounding factors. The magnitude of associations was materially unchanged after adjustment for change in body weight. PA was not significantly associated with annual weight gain (in kg) in men (β = -0.008; 95% CI: -0.02, 0.003) and women (β = -0.01; 95% CI: -0.02, 0.0006). The odds of becoming obese were reduced by 7% (P < 0.001) and 10% (P < 0.001) for a one-category difference in baseline PA in men and women, respectively. CONCLUSION Our results suggest that a higher level of PA reduces abdominal adiposity independent of baseline and changes in body weight and is thus a useful strategy for preventing chronic diseases and premature deaths.

Television Viewing and Incident Cardiovascular Disease: Prospective Associations and Mediation Analysis in the EPIC Norfolk Study

Background Although television viewing time is detrimentally associated with intermediate cardiovascular risk factors, the relationship with incident total (i.e. combined fatal and non-fatal) cardiovascular disease (CVD), non-fatal CVD and coronary heart disease is largely unknown. This study examined whether television viewing time is associated with these three outcomes, independently of physical activity energy expenditure and other confounding variables. Methodology/Principal Findings A population-based cohort of 12,608 men and women (aged 61.4±9.0), free from stroke, myocardial infarction and cancer at baseline in 1998–2000 were followed up until 2007 (6.9±1.9 years). Participants self-reported education, smoking, alcohol use, antihypertensive, lipid lowering and antidepressant medication, disease history, total energy intake, sleep duration, physical activity and television viewing. BMI, waist circumference, blood pressure, triglycerides, HDL cholesterol and glycated haemoglobin (HbA1c) were measured by standardized procedures; a clustered metabolic risk score was constructed. Every one hour/day increase in television viewing was associated with an increased hazard for total (HR = 1.06, 95%CI = 1.03–1.08; 2,620 cases), non-fatal CVD (HR = 1.06, 95%CI = 1.03–1.09; 2,134 cases), and coronary heart disease (HR = 1.08, 95%CI = 1.03–1.13; 940 cases), independent of gender, age, education, smoking, alcohol, medication, diabetes status, CVD family history, sleep duration and physical activity energy expenditure. Energy intake, BMI, waist circumference, blood pressure, triglycerides, HDL cholesterol, HbA1c and the clustered metabolic risk score only partially mediated these associations. Conclusions These results indicate that the most prevalent leisure time (sedentary) behaviour, television viewing, independently contributes to increased CVD risk. Recommendations on reducing television viewing time should be considered.

Relationship between Subdomains of Total Physical Activity and Mortality

PURPOSE The purpose of this study was to describe the association of the overall and domain-specific physical activity on all-cause and cardiovascular mortality. A large body of epidemiological evidence suggests a strong and consistent inverse association between physical activity and mortality risk. However, it is unclear how this association varies according to the domain of life in which the activity takes place. METHODS In an English population-based cohort of 14,903 participants (mean age = 63 yr), total and domain-specific physical activity was assessed using a validated questionnaire (EPAQ2). After a median follow-up of 7 yr, there were 1128 deaths, with 370 from cardiovascular disease. RESULTS The relative risks (95% confidence interval) for all-cause mortality due to physical activity undertaken at home, during exercise, at work, for transport, and in total were 0.81 (0.66-0.99), 0.66 (0.54-0.80), 0.84 (0.55-1.30), 0.82 (0.67-1.00), and 0.77 (0.61-0.98), respectively, after adjustment for baseline age, sex, social class, alcohol consumption, smoking status, history of diabetes, history of cancer, and history of cardiovascular disease and stroke. Cardiovascular mortality was inversely associated with physical activity undertaken at home (P for trend = 0.03), during exercise (P for trend = 0.001), and in total (P for trend = 0.007). The results were unchanged after excluding individuals with a history of heart disease, stroke, and cancer at baseline and those who died within the first 2 yr of follow-up. CONCLUSIONS In this study, physical activities at home and during exercise are associated with lower risk of mortality, whereas occupational and transportation-related activities are not. Promoting the potential benefits of physical activity undertaken at home and during exercise may be an important public health message for aging populations.

A cross-sectional analysis of physical activity and obesity indicators in European participants of the EPIC-PANACEA study

Objectives:Cross-sectional data suggest a strong association between low levels of physical activity and obesity. The EPIC-PANACEA (European Prospective Investigation into Cancer-Physical Activity, Nutrition, Alcohol, Cessation of Smoking, Eating out of home And obesity) project was designed to investigate the associations between physical activity and body mass index (BMI) and waist circumference based on individual data collected across nine European countries.Methods:In the European Prospective Investigation into Cancer and Nutrition (EPIC), 519 931 volunteers were recruited between 1992 and 2000, of whom 405 819 had data on main variables of interest. Height, body weight and waist circumference were measured using standardized procedures. Physical activity was assessed using a validated four-category index reflecting a self-reported usual activity during work and leisure time. The associations between physical activity and BMI and waist circumference were estimated using multilevel mixed effects linear regression models, adjusted for age, total energy intake, smoking status, alcohol consumption and educational level.Results:A total of 125 629 men and 280 190 women with a mean age of 52.9 (s.d. 9.7) and 51.5 (s.d. 10.0) years, respectively were included. The mean BMI was 26.6 kg/m2 (s.d. 3.6) in men and 25.0 kg/m2 (s.d. 4.5) in women. Fifty percent of men and 30% of women were categorized as being active or moderately active. A one-category difference in the physical activity index was inversely associated with a difference of 0.18 kg/m2 in the mean BMI (95% confidence interval, CI, 0.11, 0.24) and 1.04-cm (95% CI 0.82, 1.26) difference in waist circumference in men. The equivalent figures for women were 0.31 kg/m2 (95% CI 0.23, 0.38) and 0.90 cm (95% CI 0.71, 1.08), respectively.Conclusions:Physical activity is inversely associated with both BMI and waist circumference across nine European countries. Although we cannot interpret the association causally, our results were observed in a large and diverse cohort independently from many potential confounders.