Physical activity research in the first 15 years of the "45 and Up" cohort study: a narrative review and citation analysis.

Background: The 45 and Up Study (the Study) is the largest study of healthy ageing in Australia and one of the biggest in the world. This review considered papers on physical activity in the first 15 years since the cohort was launched. Methods: This narrative review extracted papers in the Study inventory of publications and supplemented by searches in Scopus and Medline databases. Results: A total of 114 papers were identified, but after dual assessor extraction, 92 published articles were included that used physical activity as an exposure or outcome measure or reported physical activity prevalence in the sample studied. Results indicated that half of these physical activity studies used a cross sectional design. The 45 and Up survey responders were a highly active group, with three quarters meeting WHO recommended levels of physical activity. Optimal use of the longitudinal nature of this cohort linked physical activity exposures to a range of new health, environmental and wellbeing outcomes, and these papers were the most cited among 45 and Up physical activity papers. Nineteen of these 92 papers have been cited 50+ times, indicating good usage of 45 and Up physical activity data by the field. Discussion & Conclusion: Physical activity-related research has been an important part of the overall output of the 45 and Up Study, but recommendations for future research include greater use of the longitudinal nature of the cohort, more standardisation in the way physical activity estimates are described, and using waves of the 45 and Up Study physical activity data to explore patterns of activity over time as the exposure variable in relation to health outcomes. [ABSTRACT FROM AUTHOR]