[Physical activity in the German National Cohort (NAKO): use of multiple assessment tools and initial results]. / Körperliche Aktivität in der NAKO Gesundheitsstudie: erste Ergebnisse des multimodalen Erhebungskonzepts.

BACKGROUND: Physical activity is a complex behavior that is difficult to measure validly and reliably in large, population-based studies. Data on physical activity are available for the initial 100,000 participants of the German National Cohort. OBJECTIVES: To describe the baseline physical activity assessment in the cohort and to present initial descriptive results. MATERIAL AND METHODS: Physical activity was assessed using a combination of tools, including two self-administered questionnaires, the Questionnaire on Annual Physical Activity Pattern (QUAP) and the Global Physical Activity Questionnaire (GPAQ); a computer-based 24­h physical activity recall (cpar24); and 7­day accelerometry (Actigraph GT3X/+; ActiGraph, Pensacola, FL, USA). RESULTS: The availability of data varied between assessment instruments (QUAP: n = 16,372; GPAQ: n = 90,900; cpar24: n = 23,989; accelerometry: n = 35,218). Analyses across measurement tools showed that on average, women spent 75 to 216 min/d, and men spent 73 to 224 min/d in moderate or higher intensity total physical activity. Persons aged 20-39 years spent 66 to 200 min/d, and persons aged 40-69 years spent 78 to 244 min/d in moderate or higher intensity total physical activity. CONCLUSIONS: Initial baseline analyses of physical activity in this cohort show the value of using a combination of questionnaires, 24­h recalls, and a movement sensor. The comprehensive data collection represents a valuable resource for future analyses and will improve our understanding of the association between physical activity and disease prevention.

[Measuring physical fitness in the German National Cohort-methods, quality assurance, and first descriptive results]. / Messung der körperlichen Fitness in der NAKO Gesundheitsstudie ­ Methoden, Qualitätssicherung und erste deskriptive Ergebnisse.

Physical fitness is defined as an individual's ability to be physically active. The main components are cardiorespiratory fitness (CRF), muscle strength, and flexibility. Regardless of physical activity level, physical fitness is an important determinant of morbidity and mortality.The aim of the current study was to describe the physical fitness assessment methodology in the German National Cohort (NAKO) and to present initial descriptive results in a subsample of the cohort.In the NAKO, hand grip strength (GS) and CRF as physical fitness components were assessed at baseline using a hand dynamometer and a submaximal bicycle ergometer test, respectively. Maximum oxygen uptake (VO2max) was estimated as a result of the bicycle ergometer test. The results of a total of 99,068 GS measurements and 3094 CRF measurements are based on a data set at halftime of the NAKO baseline survey (age 20-73 years, 47% men).Males showed higher values of physical fitness compared to women (males: GS = 47.8 kg, VO2max = 36.4 ml·min-1 · kg-1; females: GS = 29.9 kg, VO2max = 32.3 ml · min-1 · kg-1). GS declined from the age of 50 onwards, whereas VO2max levels decreased continuously between the age groups of 20-29 and ≥60 years. GS and VO2max showed a linear positive association after adjustment for body weight (males ß = 0.21; females ß = 0.35).These results indicate that the physical fitness measured in the NAKO are comparable to other population-based studies. Future analyses in this study will focus on examining the independent relations of GS and CRF with risk of morbidity and mortality.

Association between cardiorespiratory fitness and colorectal cancer in the UK Biobank.

Increased cardiorespiratory fitness is related to decreased risk of major chronic illnesses, including cardiovascular disease, type 2 diabetes, and cancer, but its association with colorectal cancer specifically has received very little attention. We examined the relation of cardiorespiratory fitness to colorectal cancer in 59,191 UK Biobank participants aged 39-70 years without prevalent cancer at baseline, followed from 2009 to 2014. Submaximal bicycle ergometry was conducted at study entry, and cardiorespiratory fitness was defined as physical work capacity at 75% of the maximum heart rate, standardised to body mass (PWC75%). Multivariable Cox proportional hazards regression was performed to obtain hazard ratios (HR) and corresponding 95% confidence intervals (CI). During a mean follow-up of 4.6 years, 232 participants developed colorectal cancer (151 colon cancers; 79 rectal cancers). When comparing the 75th to the 25th percentiles of PWC75%, the multivariable-adjusted HR of colorectal cancer was 0.78 (95% CI 0.62-0.97). That relation was largely driven by an inverse association with colon cancer (HR 0.74, 95% CI 0.56-0.97) and less so with rectal cancer (HR 0.88, 95% CI 0.62-1.26; p value for difference by colorectal cancer endpoint = 0.056). The inverse relation of cardiorespiratory fitness with colorectal cancer was more evident in men (HR 0.72, 95% CI 0.55-0.94) than women (HR 0.99, 95% CI 0.71-1.38), although the gender difference was not statistically significant (p value for interaction = 0.192). Increased cardiorespiratory fitness is associated with decreased risk of colorectal cancer. Potential heterogeneity by colorectal cancer anatomic subsite and gender requires further study.

Sedentary Behavior and Prostate Cancer: A Systematic Review and Meta-Analysis of Prospective Cohort Studies.

Prostate cancer is the second most common cancer in men worldwide, and sedentary behavior is widespread, yet reviews and meta-analyses summarizing the role of sedentary behavior as a potential risk factor for prostate cancer are scarce. We searched PubMed, Web of Science, and Cochrane databases for relevant articles up to January 2019. We pooled maximally adjusted risk estimates in a random effects model and performed meta-regression meta-analysis, assessed heterogeneity and publication bias using I², funnel plots, and Egger and Begg tests, and conducted sensitivity analyses and influence diagnostics. Data from 12 prospective cohort studies including a total of 30,810 prostate cancer cases were analyzed. We found no statistically significant association between high versus low sedentary behavior and prostate cancer incidence [RR = 1.07; 95% confidence interval (CI), 0.99-1.16; P = 0.10]. We noted that adjustment for body mass index (BMI) modified the relation of sedentary behavior to prostate cancer, particularly aggressive cancer. Sedentary behavior was related to a statistically significant increased risk of aggressive prostate cancer in analyses not adjusted for BMI (RR = 1.21; 95% CI, 1.03-1.43), whereas no association was apparent in BMI-adjusted analyses (RR = 0.98; 95% CI, 0.90-1.07), and the difference between those summary risk estimates was statistically significant (P difference = 0.02). Sedentary behavior is not independently associated with prostate cancer. However, prolonged sedentary behavior may be related to increased risk of aggressive prostate cancer through a mechanism involving obesity. This finding represents a potentially important step toward considering sedentary behavior as a modifiable behavioral risk factor for aggressive prostate cancer.

Use of previous-day recalls of physical activity and sedentary behavior in epidemiologic studies: results from four instruments.

BACKGROUND: The last few years have seen renewed interest in use-of-time recalls in epidemiological studies, driven by a focus on the 24-h day [including sleep, sitting, and light physical activity (LPA)] rather than just moderate-vigorous physical activity (MVPA). This paper describes four different computerised use-of-time instruments (ACT24, PAR, MARCA and cpar24) and presents population time-use data from a collective sample of 8286 adults from different population studies conducted in Australia/New Zealand, Germany and the United States. METHODS: The instruments were developed independently but showed a number of similarities: they were self-administered through the web or used computer-assisted telephone interviews; all captured energy expenditure using variants of the Ainsworth Compendium; each had been validated against criterion measures; and they used a domain structure whereby activities were aggregated under categories such as Personal Care and Work. RESULTS: Estimates of physical activity level (average daily rate of energy expenditure in METs) ranged from 1.53 to 1.78 in the four studies, strikingly similar to population estimates derived from doubly labelled water. There was broad agreement in the amount of time spent in sleep (7.2-8.6 h), MVPA (1.6-3.1 h), personal care (1.6-2.4 h), and transportation (1.1-1.8 h). There were consistent sex differences, with women spending 28-81% more time on chores, 8-40% more time in LPA, and 3-39% less time in MVPA than men. CONCLUSIONS: Although there were many similarities between instruments, differences in operationalizing definitions of sedentary behaviour and LPA resulted in substantive differences in the amounts of time reported in sedentary and physically active behaviours. Future research should focus on deriving a core set of basic activities and associated energy expenditure estimates, an agreed classificatory hierarchy for the major behavioural and activity domains, and systems to capture relevant social and environmental contexts.