Device-measured physical activity, sedentary time, and risk of all-cause mortality: an individual participant data analysis of four prospective cohort studies

Reliability and Validity of Self-Reported Questionnaires Assessing Physical Activity and Sedentary Behavior in Finland

Reliable and valid data on physical activity (PA) and sedentary behavior (SB) are needed for implementing evidence-based interventions and policies. Monitoring of these behaviors is based on PA questionnaires (PAQs) and device-based measurements, but their comparability is challenging. The present study aimed to investigate the test-retest reliability and concurrent validity of Finnish versions of the widely used PAQs (IPAQ-SF, EHIS-PAQ, GPAQ, Eurobarometer) and to compare their data with accelerometer data. This study is based on the Finnish data of the European Union Physical Activity and Sport Monitoring project (EUPASMOS). Participants (n = 62 adults, 62% women) answered the PAQs twice, one week apart, and wore an accelerometer for these seven consecutive days. Intraclass correlations, Spearman's rank correlations, t-tests, and Cohen's kappa with bootstrap confidence intervals were used to analyze the data. The PAQs had typically moderate-to-good test-retest reliability (ICC 0.22-0.78), GPAQ, EHIS-PAQ, and Eurobarometer showing the highest reliability. The PAQs correlated with each other when assessing sitting and vigorous PA (R = 0.70-0.97) and had a fair-to-substantial agreement when analyzing adherence to the PA recommendations (74-97%, Cohen's kappa 0.25-0.73). All the PAQs had a poor criterion validity against the accelerometry data. The Finnish versions of the PAQs are moderately reliable and valid for assessing PA, adherence to PA recommendations and sitting among adult participants. However, the poor criterion validity against accelerometer data indicates that PAQs assess different aspects of PA constructs compared to accelerometry.

Measurement of Sedentary Behavior-The Outcomes of the Angle for Posture Estimation (APE) Method

Hip-worn accelerometers are commonly used to assess habitual physical activity, but their accuracy in precisely measuring sedentary behavior (SB) is generally considered low. The angle for postural estimation (APE) method has shown promising accuracy in SB measurement. This method relies on the constant nature of Earth's gravity and the assumption that walking posture is typically upright. This study investigated how cardiorespiratory fitness (CRF) and body mass index (BMI) are related to APE output. A total of 3475 participants with adequate accelerometer wear time were categorized into three groups according to CRF or BMI. Participants in low CRF and high BMI groups spent more time in reclining and lying postures (APE ≥ 30°) and less time in sitting and standing postures (APE < 30°) than the other groups. Furthermore, the strongest partial Spearman correlation with CRF (r = 0.284) and BMI (r = -0.320) was observed for APE values typical for standing. The findings underscore the utility of the APE method in studying associations between SB and health outcomes. Importantly, this study emphasizes the necessity of reserving the term "sedentary behavior" for studies wherein the classification of SB is based on both intensity and posture.

Long-term physical activity time-in-target range in young adults with cardiovascular events in later life

AIMS

Achieving at least 150 min per week of moderate-to-vigorous physical activity (PA) is a 'Class I, A level' recommendation for the primary prevention of cardiovascular disease. However, long-term PA is a complex behaviour and varied by lifetime, which was insufficiently reflected by the current studies. This study used time-in-target range (TTR) to measure the long-term PA level during young adulthood and investigated its relationship with cardiovascular events in later life.

METHODS AND RESULTS

Participants in the Coronary Artery Risk Development in Young Adults study were recruited (n = 2902) and allocated into four groups by PA TTR: <25% (n = 1028), 25 to <50% (n = 444), 50 to <75% (n = 424), 75 to 100% (n = 1006). TTR was estimated with linear interpolation across the first 15 years. The primary outcome was a composite of cardiovascular events. The mean (SD) age after the exposure period was 40.3 (3.6) years. After a median follow-up for an additional 18.9 years, the participants with a TTR of at least 75% had a 40% lower risk of the primary outcome (HR: 0.60; 95%CI: 0.38 to 0.95) compared with the lowest TTR group. Each 1-SD increase in TTR was also significantly associated with a 21% decreased risk of the primary outcome (HR: 0.79; 95%CI: 0.65-0.97).

CONCLUSION

Increasing PA is essential in young adulthood. In young adults, maintaining long-term guidelines-recommended PA levels may help to lower the risk of cardiovascular events in later life. Maintaining the guidelines-recommended PA level for at least 75% of time across young adulthood may be preferable.