Background: A large health survey was previously conducted in 1984—86, the Nord-Trøndelag Health Study (HUNT 1), and another was conducted in 1995—97 (HUNT 2). A third, HUNT 3, started in 2006. However, the physical activity (PA) questionnaires have not yet been validated. Aims: To assess the reliability and validity of the self-reported physical activity questionnaire in the Nord-Trøndelag Health Study (HUNT 1). Methods: The HUNT 1 questionnaire was administered to a random sample of 108 healthy men aged 20—39 years. Repeatability was assessed with a repeat questionnaire after one week, and validity by comparing results with direct measurement of VO₂ during maximal work on a treadmill, with ActiReg, an instrument that measures PA and energy expenditure (EE) and with the International Physical Activity Questionnaire (IPAQ). ActiReg records the main body positions (stand, sit, bent forward and lie) together with the motion of the trunk and/or one leg each second. Results: The results indicated strong, significant agreement on test—retest (weighted kappa frequency, r=0.80, intensity, r=0.82, and duration, r=0.69). We found a moderate, significant correlation, r=0.48 (p≤0.01), between the index based on questionnaire responses and VO_2max. Metabolic equivalent (MET) values of 6 or more from ActiReg and ``vigorous activity'' from the IPAQ most strongly correlated with the index (r=0.39, r=0.55, respectively). Associations of other measures obtained from ActiReg with questionnaire responses were weaker. Conclusions: Our results indicate that the PA questionnaire in HUNT 1 is reproducible and provides a useful measure of leisure-time PA for men. The questionnaire is very short, and compared favourably with much longer instruments for assessment of more vigorous PA. It should be an appropriate tool for use in further epidemiological studies, particularly when the interest is in aspects of PA reflected in fitness or METs greater than 6.

There is no standardized method for the assessment of physical activity (PA). Therefore it is important to investigate the validity and comparability of different measures. The International Physical Activity Questionnaire (IPAQ) has been developed as an instrument for cross-national assessment of PA and has been validated in 12 countries. These instruments have acceptable measurement properties for monitoring population levels of PA among 18–65 year-old adults in diverse settings. However, there are some concerns that IPAQ may over-report PA.

To create and find accurate and reliable instruments for the measurement of physical activity has been a challenge in epidemiological studies. We investigated the reliability and validity of two different physical activity questionnaires in 71 adolescents aged 13–18 years; the WHO, Health Behaviour in Schoolchildren (HBSC) questionnaire, and the International Physical Activity Questionnaire (IPAQ, short version).

Lifestyle risk behaviours are responsible for a large proportion of disease burden and premature mortality worldwide. Risk behaviours tend to cluster in populations. We developed a new lifestyle risk index by including emerging risk factors (sleep, sitting time, and social participation) and examine unique risk combinations and their associations with all-cause and cardio-metabolic mortality. Data are from a large population-based cohort study in a Norway, the Nord-Trøndelag Health Study (HUNT), with an average follow-up time of 14.1 years. Baseline data from 1995–97 were linked to the Norwegian Causes of Death Registry. The analytic sample comprised 36 911 adults aged 20–69 years. Cox regression models were first fitted for seven risk factors (poor diet, excessive alcohol consumption, current smoking, physical inactivity, excessive sitting, too much/too little sleep, and poor social participation) separately and then adjusted for socio-demographic covariates. Based on these results, a lifestyle risk index was developed. Finally, we explored common combinations of the risk factors in relation to all-cause and cardio-metabolic mortality outcomes. All single risk factors, except for diet, were significantly associated with both mortality outcomes, and were therefore selected to form a lifestyle risk index. Risk of mortality increased as the index score increased. The hazard ratio for all-cause mortality increased from 1.37 (1.15-1.62) to 6.15 (3.56-10.63) as the number of index risk factors increased from one to six respectively. Among the most common risk factor combinations the association with mortality was particularly strong when smoking and/or social participation were included. This study adds to previous research on multiple risk behaviours by incorporating emerging risk factors. Findings regarding social participation and prolonged sitting suggest new components of healthy lifestyles and potential new directions for population health interventions.

Pooling data from thigh-worn accelerometers across multiple studies has great potential to advance evidence on the health benefits of physical activity. This requires harmonization of information on body postures, physical activity types, volumes and time patterns across different brands of devices. The aim of this study is to compare the physical behavior estimates provided by three different brands of thigh-worn accelerometers. Twenty participants volunteered for a 7-day free-living measurement. Three accelerometers - ActiGraph GT3X+, Axivity AX3 and ActivPAL Micro4 - were randomly placed in a vertical line on the midsection of the right thigh. Raw data from each accelerometer was processed and classified into 8 physical activities and postures using the Acti4 software. Absolute differences between estimates and the respective coefficient of variation (CV) were calculated. We observed very minor differences between physical behavior estimates from three different accelerometer brands. When averaged over 24 h (1,440 min), the absolute difference (CV) between accelerometers were: 1.2 mins (0.001) for lying/sitting, 3.4 mins (0.02) for standing, 3.5 mins (0.06) for moving, 1.9 mins (0.03) for walking, 0.1 mins (0.19) for running, 1.2 mins (0.19) for stair climbing, 1.9 mins (0.07) for cycling. Moreover, there was an average absolute difference of 282 steps (0.03) per 24 h. Physical behaviors were classified with negligible difference between the accelerometer brands. These results support harmonization of data from different thigh-worn accelerometers across multiple cohorts when analyzed in an identical manner.