Brigid M. Lynch, Andrea Ramirez Varela and Terry Boyle
Brigid M. Lynch, Suzanne C. Dixon-Suen, Andrea Ramirez Varela, Yi Yang, Dallas R. English, Ding Ding, Paul A. Gardiner and Terry Boyle
Background: It is not always clear whether physical activity is causally related to health outcomes, or whether the associations are induced through confounding or other biases. Randomized controlled trials of physical activity are not feasible when outcomes of interest are rare or develop over many years. Thus, we need methods to improve causal inference in observational physical activity studies. Methods: We outline a range of approaches that can improve causal inference in observational physical activity research, and also discuss the impact of measurement error on results and methods to minimize this. Results: Key concepts and methods described include directed acyclic graphs, quantitative bias analysis, Mendelian randomization, and potential outcomes approaches which include propensity scores, g methods, and causal mediation. Conclusions: We provide a brief overview of some contemporary epidemiological methods that are beginning to be used in physical activity research. Adoption of these methods will help build a stronger body of evidence for the health benefits of physical activity.
Inacio C. M. da Silva, Valerie L. C. Payne, Adriano Akira Hino, Andrea Ramirez Varela, Rodrigo S. Reis, Ulf Ekelund and Pedro C. Hallal
The aim of this study was to review the evidence to date on the association between physical activity and safety from crime.
Articles with adult populations of 500+ participants investigating the association between physical activity and safety from crime were included. A methodological quality assessment was conducted using an adapted version of the Downs and Black checklist.
The literature search identified 15,864 articles. After assessment of titles, abstracts and full-texts, 89 articles were included. Most articles (84.3%) were derived from high-income countries and only 3 prospective articles were identified. Articles presented high methodological quality. In 38 articles (42.7%), at least one statistically significant association in the expected direction was reported (ie, safety from crime was positively associated with physical activity). Nine articles (10.1%) found an association in the unexpected direction and 42 (47.2%) did not find statistically significant associations. The results did not change when we analyzed articles separately by sex, age, type of measurement, or domains of physical activity evaluated.
The current evidence, mostly based on cross-sectional studies, suggests a lack of association between physical activity and safety from crime. Prospective studies and natural experiments are needed, particularly in areas with wide crime variability.
Andrea Ramirez Varela, Michael Pratt, Kenneth Powell, I-Min Lee, Adrian Bauman, Gregory Heath, Rafaela Costa Martins, Harold Kohl and Pedro C. Hallal
The Global Observatory for Physical Activity (GoPA!) was launched in response to the physical inactivity pandemic. The aim of this article is to present current information about surveillance, policy, and research on physical activity (PA) and health worldwide.
Information was collected for 217 countries. For 139 of these nations we identified a contact who confirmed information’s accuracy and completeness. Associations were calculated among surveillance, policy and research categories.
Of the 139 countries, 90.6% reported having completed 1 or more PA survey, but less than one-third had 3 or more. 106 included PA on a national plan, but only one-quarter of these were PA-specific. At least 1 peer reviewed publication was identified for 63.3% of the countries. Positive associations (P < .001) were found between research and policy (ρ = 0.35), research and surveillance (ρ = 0.41), and surveillance and policy (ρ = 0.31). Countries with a standalone plan were more likely to have surveillance. Countries with more research were more likely to have a standalone plan and surveillance.
Surveillance, policy, and research indicators were positively correlated, suggesting that action at multiple levels tends to stimulate progress in other areas. Efforts to expand PA-related surveillance, policy, and research in lower income countries are needed.