Mette Aadahl

Validation of a new self-report instrument for measuring physical activity.

PURPOSE Development and validation of a physical activity scale for measuring physical activity in 24 h of sports, work, and leisure time on an average weekday. METHODS For development of the physical activity scale, 2500 randomly selected Danish men and women between the age of 20 and 60 were contacted by mail and asked to select frequent and relevant physical activities from a number of activities of known MET intensity. The activities were included in the physical activity scale, organized in nine different MET levels ranging from sleep/rest (0.9 METs) to high-intensity physical activities (>6 METs). Face validity of the physical activity scale was explored through interviews with 10 volunteer men and women. Concurrent validity was assessed against 4 d of accelerometry (CSA 7164) and physical activity diary in 40 volunteer men and women between 20 and 60 yr of age. RESULTS The correlation between the activity scale and the diary was high (r = 0.74, P = 0.000), whereas correlation between the activity scale and accelerometer measurements was poor (r = 0.20, NS). The physical activity scale MET-time was systematically higher than average MET-time estimated from the diary, and the difference increased with increasing total MET-time. CONCLUSION The physical activity scale appears to be a simple and valid alternative to measuring physical activity by diary in adult sedentary to moderately active Danes. The scale encompasses work, leisure time, and sports activity in one measure; it is easy to administer, and it provides detailed information on different activity levels as well as a single measure of the total amount of physical activity on an average weekday.

Effect of screening and lifestyle counselling on incidence of ischaemic heart disease in general population: Inter99 randomised trial

Objective To investigate the effect of systematic screening for risk factors for ischaemic heart disease followed by repeated lifestyle counselling on the 10 year development of ischaemic heart disease at a population level. Design Randomised controlled community based trial. Setting Suburbs of Copenhagen, Denmark Participants 59 616 people aged 30-60 years randomised with different age and sex randomisation ratios to an intervention group (n=11 629) and a control group (n=47 987). Intervention The intervention group was invited for screening, risk assessment, and lifestyle counselling up to four times over a five year period. All participants with an unhealthy lifestyle had individually tailored lifestyle counselling at all visits (at baseline and after one and three years); those at high risk of ischaemic heart disease, according to predefined criteria, were furthermore offered six sessions of group based lifestyle counselling on smoking cessation, diet, and physical activity. After five years all were invited for a final counselling session. Participants were referred to their general practitioner for medical treatment, if relevant. The control group was not invited for screening. Main outcome measures The primary outcome measure was incidence of ischaemic heart disease in the intervention group compared with the control group. Secondary outcome measures were stroke, combined events (ischaemic heart disease, stroke, or both), and mortality. Results 6091 (52.4%) people in the intervention group participated at baseline. Among 5978 people eligible at five year follow-up (59 died and 54 emigrated), 4028 (67.4%) attended. A total of 3163 people died in the 10 year follow-up period. Among 58 308 without a history of ischaemic heart disease at baseline, 2782 developed ischaemic heart disease. Among 58 940 without a history of stroke at baseline, 1726 developed stroke. No significant difference was seen between the intervention and control groups in the primary end point (hazard ratio for ischaemic heart disease 1.03, 95% confidence interval 0.94 to 1.13) or in the secondary endpoints (stroke 0.98, 0.87 to 1.11; combined endpoint 1.01, 0.93 to 1.09; total mortality 1.00, 0.91 to 1.09). Conclusion A community based, individually tailored intervention programme with screening for risk of ischaemic heart disease and repeated lifestyle intervention over five years had no effect on ischaemic heart disease, stroke, or mortality at the population level after 10 years. Trial registration Clinical trials NCT00289237.

Gene × Physical Activity Interactions in Obesity: Combined Analysis of 111,421 Individuals of European Ancestry

Numerous obesity loci have been identified using genome-wide association studies. A UK study indicated that physical activity may attenuate the cumulative effect of 12 of these loci, but replication studies are lacking. Therefore, we tested whether the aggregate effect of these loci is diminished in adults of European ancestry reporting high levels of physical activity. Twelve obesity-susceptibility loci were genotyped or imputed in 111,421 participants. A genetic risk score (GRS) was calculated by summing the BMI-associated alleles of each genetic variant. Physical activity was assessed using self-administered questionnaires. Multiplicative interactions between the GRS and physical activity on BMI were tested in linear and logistic regression models in each cohort, with adjustment for age, age2, sex, study center (for multicenter studies), and the marginal terms for physical activity and the GRS. These results were combined using meta-analysis weighted by cohort sample size. The meta-analysis yielded a statistically significant GRS × physical activity interaction effect estimate (Pinteraction = 0.015). However, a statistically significant interaction effect was only apparent in North American cohorts (n = 39,810, Pinteraction = 0.014 vs. n = 71,611, Pinteraction = 0.275 for Europeans). In secondary analyses, both the FTO rs1121980 (Pinteraction = 0.003) and the SEC16B rs10913469 (Pinteraction = 0.025) variants showed evidence of SNP × physical activity interactions. This meta-analysis of 111,421 individuals provides further support for an interaction between physical activity and a GRS in obesity disposition, although these findings hinge on the inclusion of cohorts from North America, indicating that these results are either population-specific or non-causal.

Self-reported physical activity compared with maximal oxygen uptake in adults

Background Physical activity level and cardiorespiratory fitness are both inversely associated with the risk of cardiovascular diseases and with all-cause mortality. Physical activity questionnaires are often validated against objectively measured maximal oxygen uptake (Vo 2max). Aim To validate a self-report physical activity questionnaire against Vo 2max and furthermore to establish whether a simple question on self-rated physical fitness could predict objectively measured Vo 2max. Methods A total of 102 men and women aged between 35 and 65 years were recruited from an ongoing population-based intervention study, the Inter99 Study. Participants reported their self-rated fitness and daily physical activity using a new questionnaire based on metabolic equivalents (MET). Vo 2max (ml/kg per min) was determined using a graded bicycle test with increasing workload until exhaustion and with simultaneous measurement of breath-to-breath oxygen uptake in 15-s periods. Statistical analyses were performed by linear regression analyses using the self-reported physical activity level as an independent variable and Vo 2max (l/min) as an dependent variable, and with covariates sex, age and bodyweight. Results Data from 53 men and 47 women were analysed. The amount of daily vigorous activity (>6 MET) was significantly positively associated with Vo 2max (P=0.0001, R 2 = 0.76), whereas the total amount of physical activity was not significantly associated with Vo 2max (P=0.098, R 2 = 0.69). A significant trend across three groups of self-rated fitness in relation to Vo 2max (ml/kg per min) was found (P for trend <0.0001). Conclusion The physical activity questionnaire has acceptable validity when compared with Vo 2max in adult men and women. Furthermore, a simple question on self-rated fitness seems to reflect measured Vo 2max objectively.

Cohort Profile: The Health2006 cohort, Research Centre for Prevention and Health

Research Centre for Prevention and Health, Copenhagen University Hospital Glostrup, The Capital Region of Denmark, Denmark, National Allergy Research Centre, Department of Dermato-Allergology, Copenhagen University Hospital Gentofte, Denmark, Danish Research Centre for Chemical Sensitivities, Gentofte University Hospital, University of Copenhagen, Copenhagen, Denmark, Hagedorn Research Institute and Steno Diabetes Centre, Gentofte, Denmark, The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark and Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark

Construct validity of a revised Physical Activity Scale and testing by cognitive interviewing.

Aim: To validate the construct validity of a new version of a Physical Activity Scale (PAS 2) for measuring average weekly physical activity of sleep, work, and leisure time to determine whether a further criterion validation is justified. Methods: The validity of responses to the questionnaire was evaluated by cognitive interviewing in 16 Danish men and women aged 21—70 years. Construct validity was validated in 342 men and women aged 35—66 years by assessing agreement between 24-h MET-scores obtained from average weekly physical activity measured by PAS 2 and a 24-h Physical Activity Scale (PAS 1), previously found to overestimate physical activity. Results: Cognitive interviewing revealed few problems in the questions on physical activity in different domains. No problems regarding the structure of the questionnaire were identified. The agreement between PAS 1 and PAS 2 MET-scores was high among participants with a PAS 1 24-h MET-score <45 MET-hours. Among participants with a PAS 1 24-h MET-score ≥45 MET-hours, the weekly-based scale, PAS 2, systematically estimated fewer MET-hours compared to the 24-h based scale, PAS 1. The difference increased proportionally with the average of the two MET-scores. Conclusions: Few, small, lexical revisions were implemented into the new scale to improve the validity. As hypothesized, PAS 2 produced lower estimates of energy expenditure compared to PAS 1, indicating that the new scale may provide more valid measurements and that further validation against an objective criterion is justified.

Influence of time spent on TV viewing and vigorous intensity physical activity on cardiovascular biomarkers. The Inter 99 study.

Introduction Sedentary behaviour, especially TV viewing, has been identified as a possible risk factor for cardiovascular disease, whereas physical activity seems to protect against major cardiovascular risk factors: obesity, dyslipidemia and hypertension. The aim of this study was to explore the association between both time spent on TV viewing and vigorous intensity physical activity in relation to body mass index, waist circumference, waist/hip ratio, serum lipids and blood pressure. Methods A total of 1693 men and women, 33-64 years of age, from the 3-year follow-up of a population-based intervention study, The Inter 99 study, were included in this cross-sectional design. Information on TV viewing, physical activity and other lifestyle habits was obtained by self-report questionnaire. Associations between TV viewing/physical activity and biological cardiovascular risk factors were explored by multiple linear regression analyses. Results Data from 835 (51%) men and 805 (49%) women were included. Mean age was 50.8 years (33.0-64.6). Men had a higher overall physical activity score than women (P < 0.0001). TV viewing was significantly, positively associated with waist/hip ratio (P = 0.005), body mass index (P = 0.03), triglycerides (P = 0.005), low density lipoprotein cholesterol (P = 0.03), total cholesterol (P = 0.01), systolic (P = 0.05) and diastolic blood pressure (P = 0.03), but not with waist circumference and high density lipoprotein cholesterol (HDL). Engaging in vigorous intensity physical activity was associated with higher HDL (P = 0.0006) and lower waist circumference (P < 0.0001). Conclusion TV viewing and physical activity should be regarded as separate types of behaviour that relate to different cardiovascular disease risk factors. Eur J Cardiovasc Prev Rehabil 14:660-665

Sleep duration and sleep quality are associated differently with alterations of glucose homeostasis.

Diabet. Med. 29, e354–e360 (2012)

The relationship between lifestyle and self-reported health in a general population: The Inter99 study

OBJECTIVES The aim of this paper is to describe the relationship between smoking status, dietary habits, physical activity and alcohol intake, and mental and physical self-reported health in a general population. MEASURES A large population-based study Inter99, Copenhagen, Denmark, 1999-2006. Self-reported health-related quality of life was measured by Short Form 12 (SF-12). Mental and physical health component scores were computed. RESULTS At baseline, SF-12 was completed by 6305 (92.3%) participants in the intervention groups, and 3017 (72.4%) persons in the control group. In cross-sectional analyses, persons with an unhealthy lifestyle reported significantly worse physical and mental health than persons with a healthier lifestyle. In longitudinal data, using adjusted multivariate analyses (N=3,084), we found an association between increased physical activity at five-year follow-up and improvement in physical health ( odds ratio=2.30 (95% confidence interval=1.7-3.2)) in the high-intensity intervention group. Improvement in mental health was associated with a much healthier diet at 5-year follow-up than at baseline ( odds ratio=1.68 (95% confidence interval=1.1-2.5)). CONCLUSIONS This study describes the negative relationship between unhealthy lifestyle and self-reported mental and physical health in a general population. Also, it shows the impact of improvements in lifestyle on self-reported health in a general population, which has not been investigated before.

High risk strategy in smoking cessation is feasible on a population-based level. The Inter99 study.

INTRODUCTION A high risk strategy is one of more strategies in public health. Smoking remains the most important contributor to the burden of disease in developed countries. METHODS A population-based multi-factorial intervention study, Inter99 (1999-2006), Copenhagen, Denmark, using a high risk strategy. All 2408 daily smokers were repeatedly offered individual face-to-face lifestyle counselling. Smokers in the high-intensity group were offered participation in smoking cessation groups. We measured point abstinence at 1, 3 and 5-year follow-up and compared with a control group, using adjusted intention-to treat analyses. RESULTS Compared with the control group it was twice as likely to be self-reported abstinent at 5-year follow-up in the high-intensity intervention group (OR: 2.19; 95%CI: 1.7-2.8; p<0.001). The effect of the intervention was significant, even when comparing validated abstinence in the intervention groups with self-reported abstinence in the control group (OR: 1.38; 95%CI: 1.1-1.8; p=0.014). Male gender, vocational training, higher age at onset of smoking, high knowledge of harm of smoking and lower tobacco consumption predicted abstinence. CONCLUSION A high risk strategy showed a significant effect on smoking in the long term. Proactive recruitment, face-to-face setting, repeated offer of assistance to quit and a multi-factorial approach may explain the success of the intervention.