Accuracy and inequalities in physical activity research
Authors: Jelle Van Cauwenberg, Bart De Clercq, Benedicte Deforche, Greet Cardon, Sebastien F M Chastin
Journal: The Lancet Global Health (2019)

Regina Guthold and colleagues1Guthold R Stevens GA Riley LM Bull FC Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1·9 million participants.Lancet Glob Health. 2018; 6: e933-e1044Summary Full Text Full Text PDF PubMed Scopus (1899) Google Scholar should be congratulated on their rigorous efforts to harmonise and analyse physical activity data from 358 surveys across 168 countries. The Article highlights global patterns of physical inactivity. We agree with the authors' call to prioritise and scale up policy to increase population levels of physical activity, but we feel that their analysis overlooks important social inequalities in physical activity that need to be taken into account by policy and research. The findings clearly highlight the need for increased policy investment in the promotion of physical activity to meet the WHO 2025 global physical activity target;2WHOGlobal Action Plan for the prevention and control of noncommunicable diseases 2013–2020. World Health Organization, Geneva2013Google Scholar a 10% reduction in prevalence of insufficient physical activity compared with 2010. The authors showed that 27·5% (95% uncertainty interval [UI] 25·0–32·2) of the world population was insufficiently physically active in 2016, with prevalence ranging from 16·3% (95% UI 14·3–20·7) in Oceania to 39·1% (37·8–40·6) in Latin America and the Caribbean. Additionally, the prevalence of physical inactivity in 2016 was more than twice as high in high-income countries than low-income countries (36·8% [95% UI 35·0–38·0] vs 16·2% [14·2–17·9]) and insufficient physical activity was higher among women than men (31·7% [28·6–39·0] vs 23·4% [21·1–30·7]). Worldwide, no change in prevalence of physical inactivity was observed between 2001 and 2016. However, increases in prevalence of physical inactivity were observed in high-income countries whereas the prevalence in low-income countries remained stable. The assessment of prevalence by sex, country income groups, and world regions is important to prioritise and target interventions. Furthermore, countries experiencing rapid urbanisation and economic development can learn from countries in which these societal changes have already occurred. However, we would argue that basing policy solely on global trend data might be misleading. Such data might mask important social inequalities in physical activity within countries. In high-income countries, where the majority of physical activity research has been done, subgroups with lower socioeconomic status typically have a higher risk of physical inactivity and associated non-communicable diseases.3Sommer I Griebler U Mahlknecht P et al.Socioeconomic inequalities in non-communicable diseases and their risk factors: an overview of systematic reviews.BMC Public Health. 2015; 15: 914Crossref PubMed Scopus (192) Google Scholar The direction of inequality in physical activity might be different in middle-income and low-income countries. Such differences have important implications for targeting policy initiatives aiming to promote physical activity in the least physically active subgroups. Additionally, the time trends reported by Guthold and colleagues might mask diverging trends in physical activity across socioeconomic subgroups. For example, the joint programming initiative Determinants of Diet and Physical Activity analysed surveillance data from 51 820 participants in 24 European countries.4Van Cauwenberg J Loyen A Lakerveld J et al.Differential influences of population densification and economic growth on Europeans' physical activity and sitting time.Cities. 2018; 82: 141-149Crossref Scopus (14) Google Scholar The study showed that increases in regional-level gross domestic product per capita (as a measure of economic development) were associated with increases in physical activity among highly educated European adults, but not among those with lower levels of education. Thus, in European countries, social inequalities in physical activity are increased by economic growth that only benefits the most wealthy individuals. Policies that do not consider this social inequality might actually exacerbate it. The trend of increasing inactivity in high-income countries reported by Guthold and colleagues might be associated with growing social inequalities in physical activity in these countries. As discussed by Guthold and colleagues, several lower-middle-income countries are currently experiencing rapid industrialisation and economic development, which might have considerable effects not only on the prevalence of physical inactivity within those countries, but also on social inequalities in physical activity. A comparison of physical inactivity prevalence stratified by socioeconomic status was beyond the scope of Guthold and colleagues' analysis. Additionally, the physical activity surveys included will not have incorporated a measure of socioeconomic status that is applicable to multicountry comparisons. However, studies using different measures of socioeconomic status could be combined to examine differences and trends in physical inactivity across relative levels of socioeconomic status. Future national physical activity surveys should include an absolute measure of inequality in terms of purchasing power to examine social inequalities in physical activity between and within countries and to monitor inequality trends over time. More research about social inequalities in physical activity and how societal changes (eg, urbanisation, globalisation, and economic development) influence these inequalities globally is warranted. We fully support the authors' call for policy makers to take action and for multisectoral collaboration to increase levels of physical activity. Furthermore, we hypothesise that the suggested policies, such as improved provision of cycling and walking infrastructure, improving road safety, and creating more opportunities in local community settings, would stimulate physical activity across the socioeconomic spectrum. However, in practice, access to physical activity resources might not be equally distributed.5Rigolon A A complex landscape of inequity in access to urban parks: a literature review.Landsc Urban Plan. 2016; 153: 160-169Crossref Scopus (325) Google Scholar Social inequalities should be considered in future physical activity research and policy. JVC was supported by a postdoctoral fellowship of the Research Foundation-Flanders (FWO; 12I1117N). We declare no competing interests. Accuracy and inequalities in physical activity researchI agree with Regina Guthold and colleagues1 and Ding Ding in the accompanying Comment2 that large-scale interventions are needed to increase physical activity. Colombia has been labelled the least active country in the world3 and Latin America and the Caribbean had some of the highest levels of insufficient physical activity in the analysis by Guthold and colleagues.1 However, far from being inactive, Colombia and Latin America are pioneers in large-scale physical activity interventions.4 Full-Text PDF Open AccessAccuracy and inequalities in physical activity researchIn their Article on global estimates and trends of insufficient physical activity in adults, Regina Guthold and colleagues (October, 2018)1 included data from nearly 2 million participants who were representative of 96% of the global population. A key finding was that about a quarter (27·5%) of adults worldwide do not get enough physical activity to meet current public health guidelines. However, this estimate was based on self-reported questionnaires and probably misrepresents the true burden of physical inactivity around the world. Full-Text PDF Open AccessAccuracy and inequalities in physical activity research – Authors' replyWe thank Jelle Van Cauwenberg and colleagues, Jean-Philippe Chaput, and Gary O'Donovan for their comments on our recent study, in which we analysed the prevalence of insufficient physical activity in 168 countries, and estimated regional and global trends. Full-Text PDF Open AccessWorldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1·9 million participantsIf current trends continue, the 2025 global physical activity target (a 10% relative reduction in insufficient physical activity) will not be met. Policies to increase population levels of physical activity need to be prioritised and scaled up urgently. Full-Text PDF Open Access