This file was dowloaded from the institutional repository Brage NIH - brage.bibsys.no/nih Hallal, P. C., Andersen, L. B., Bull, F., Guthold, R., Haskell, W., Ekelund, U. (2012). Global physical activity levels: surveillance progress, pitfalls, and prospects. The Lancet, 380, 247-257. Dette er siste tekst-versjon av artikkelen, og den kan inneholde små forskjeller fra forlagets pdf-versjon. Forlagets pdf-versjon finner du på www.thelancet.com: http://dx.doi.org/10.1016/S0140-6736(12)60646-1 This is the final text version of the article, and it may contain minor differences from the journal's pdf version. The original publication is available at www.thelancet.com: http://dx.doi.org/10.1016/S0140-6736(12)60646-1 1 Physical Activity 1 Physical activity levels of the world’s population Surveillance progress, gaps and prospects Pedro C Hallal, Lars Bo Andersen, Fiona C Bull, Regina Guthold, William Haskell, Ulf Ekelund, for the Lancet Physical Activity Series Working Group* * Members listed at the end of the paper Universidade Federal de Pelotas, Brazil (Dr. Pedro C. Hallal), Department of Exercise Epidemiology, Center for Research in Childhood Health, University of Southern Denmark, Denmark (Dr. Lars Bo Andersen), School of Population Health, The University of Western Australia, Perth, Australia (Prof. Fiona Bull), Department of Chronic Diseases and Health Promotion, World Health Organization, Switzerland (Dr. Regina Guthold), Stanford Prevention Research Center, Stanford University School of Medicine, Unites States of America (Prof. William Haskell), Medical Research Council Epidemiology Unit, Cambridge, United Kingdom and Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway (Dr. Ulf Ekelund and Dr. Lars Bo Andersen) Correspondence to: Pedro C Hallal, Marechal Deodoro 1160 – 96020-220 - Pelotas, RS, Brazil – Phone (fax): +55 53 3284-1300 - Email: [email protected] Text: 4,663 words; Summary: 141 words; References: 148; Figures: 6; Tables: 1; Web Appendix: 1; Web Table: 1; Web Figure: 1; Panels: 2 2 SUMMARY To help policy makers implement effective non-communicable disease prevention programs, data on physical activity prevalence and trends are essential. We describe physical activity levels worldwide using adult data from 122 countries and adolescent data from 105 countries. The prevalence of physical inactivity in adults was 31.1% (95%CI being calculated), ranging from 17% (95%CI being calculated) in South-East Asia to approximately 43% in the Americas and the Eastern Mediterranean region. Inactivity increased with age and was higher in women and in wealthier countries. The proportion of 13-15 year-olds performing fewer than 60 minutes/day of moderate-to- vigorous intensity physical activity was 80.3% (95%CI 80.1; 80.5); boys were more active than girls. Continued improvement in monitoring population levels of physical activity can help guide the development of policies and programs to increase physical activity and reduce the burden of non-communicable diseases in the 21st century. 3 Key messages  Surveillance of physical activity levels of adult and adolescent populations has progressed substantially in the last decade. Available data collected using standardised self-report instruments now provide estimates of physical activity for 122 countries, or two thirds of the 194 World Health Organization Member States; these data should be used to inform policy and practice worldwide.  Available data show that globally one third of adults and four out of five adolescents do not reach public health guidelines on recommended levels of physical activity.  Notable disparities exist in the prevalence of physical inactivity; in most countries inactivity is higher in females compared with males and older adults are less active than younger adults. These consistent patterns should be used to help policy makers implement effective non-communicable disease prevention and treatment programs.  Trend data from high-income countries suggest that occupational physical activity is declining and there has been an increase in leisure-time physical activity among adults. There are insufficient data from low- and middle-income countries to explore patterns of activity over time and domain.  Gaps in surveillance of physical activity remain. No data are available from about 1/3 of the world's countries, mostly low- and middle-income nations in Africa and Central Asia. Data on trends in physical activity are scarce.  The World Health Organization’s STEPwise approach to risk factor surveillance provides a good framework and practical set of tools for initiating physical activity surveillance in low- and middle-income countries in particular.  Advances in new technologies and measurement methods, especially accelerometry, show promise for future surveillance of physical activity. These devices have potential widespread practical application if equipment costs continue to decline and sufficient efforts are directed towards increasing technical skills and workforce capacity in low- and middle-income countries. 4 PHYSICAL ACTIVITY IN A CHANGING WORLD Starting with the industrial revolution, the development of new technologies has enabled humans to reduce the amount of physical labour needed to accomplish numerous tasks throughout their daily lives. As the availability of new technologic devices has continued to increase, the impact on physical labour and consequences on human energy expenditure has expanded to more aspects of the lives of more and more people. The impact of some of these technologies on reducing physical activity is very obvious (e.g., steam, gas and electric engine; trains automobiles, trucks) while others are more subtle and complex (e.g., televisions, computers, electronic entertainment, the internet, and wireless communication devices). The use of many of these technologies has been driven by the goal of achieving greater individual worker productivity and to reduce physical hardships and disabilities caused by jobs requiring continuous heavy labour. However, the human body has evolved over the millennia in such a manner that most of its systems (e.g., skeletal, muscle, metabolic, cardiovascular) do not develop and function in an optimal manner unless activated by frequent physical activity.1 While this technology revolution has been of great benefit to many populations throughout the world, it has come at a major cost in terms of the contribution of physical inactivity to the worldwide epidemic of non- communicable diseases (NCDs).2 In 2009 physical inactivity was identified as the fourth leading risk factor of NCDs and accounted for over 3 million preventable deaths.3 5 Comparing patterns of participation in physical activity between countries and across world regions was an unachievable goal until a decade ago,4 largely due to the absence of standardised instruments suitable for international use. Both barriers reflected a collective ‘blind spot’, because the evidence on the health benefits of physical activity had grown stronger5 thus underpinning the importance of collecting surveillance data to guide national action.6 In the absence of a suitable instrument, earlier efforts to characterise patterns of physical activity frequently applied measures of occupational classification or estimations of leisure-time physical activity energy expenditure as the best available indicators. This was the case in early ground breaking epidemiological studies conducted by Morris et al.7 8 and later in the Harvard Alumni studies conducted by Paffenbarger and colleagues, respectively.9 It was only during the late 1990’s that an international group of academics developed a standardised instrument for assessing physical activity worldwide, and proceeded to test its validity and reliability in 12 countries.10 The development of the International Physical Activity Questionnaire (IPAQ) and later similar work leading to the development of the Global Physical Activity Questionnaire (GPAQ) provided the much needed measurement instruments to support national monitoring and the inclusion of physical inactivity in risk factor surveillance systems.11 As a result, comparable data collected through IPAQ and GPAQ in about two thirds of the countries globally now provide for the first time the opportunity for a comparative assessment of global patterns of physical activity. The aim of this first article of the Lancet Physical Activity Series is thus to present a picture of physical activity levels of the world’s population, showing the differences in participation between regions and populations as well as patterns in different types of physical activity, namely walking and vigorous-intensity activity. Due to the particular 6 and highly relevant synergies between health, physical activity and the environment, we also describe patterns of ‘active transportation’, which combines walking and cycling. We also highlight the gaps that remain in physical activity surveillance, in particular the lack of trend data in the majority of countries and the absence of data in many low- and middle-income countries. Because new technology may offer greater scope for surveillance in the future, we provide a snapshot of data collected through motion sensors in adults and young people. We also present data on the emerging science of sedentary behaviours, overview what is known about trends in physical activity and highlight the importance of using surveillance data to drive national and global action. HOW (IN)ACTIVE IS THE WORLD’S POPULATION? Self-reported physical activity (adults) We obtained comparable estimates on physical inactivity for adult populations from 122 countries using the World Health Organization (WHO) Global Health Observatory Data Repository.12 The combined population of these 122 countries represents 88.9% of the world’s total population. For the present analysis, physical inactivity was defined as not meeting any of the following criteria: a) 30 minutes of moderate-intensity physical activity on at least 5 days each week, b) 20 minutes of vigorous-intensity physical activity on at least 3 days each week, or (c) an equivalent combination achieving 600 metabolic equivalent (MET)-min per week.13-15 One MET is defined as the energy spent when sitting quietly. This resting metabolic rate was multiplied by 4 for moderate- intensity activity, and by 8 for vigorous-intensity activity. 13-15 Inclusion criteria for country data to be considered for the comparable estimates required, amongst others, 7 assessment of physical activity on all-domains (i.e. leisure-time, occupation, transportation and housework). Further details about the methods used to analyse these data are presented in Web Appendix 1. The overall prevalence of physical inactivity worldwide for adults was 31.1% (95%CI being calculated). This global prevalence represents the weighted average of the prevalence in the 122 countries studied, taking into account the population of each country. There were wide variations in the prevalence of inactivity across WHO regions: Africa (27.5%; 95%CI being calculated), Americas (43.3%; 95%CI being calculated), Eastern Mediterranean (43.2%; 95%CI being calculated), Europe (34.8%; 95%CI being calculated), South-East Asia (17.0%; 95%CI being calculated) and Western Pacific (33.7%; 95%CI being calculated) (Figure 1). Globally, women were more inactive (33.9%) than men (27.9%). Web Table 1 displays individual country results; there were wide differences across countries, for example the prevalence of inactivity for both sexes combined ranged from 4.7% (95%CI 4.3; 5.1) in Bangladesh to 71.9% (95%CI 31.0; 87.2%) in Malta. In Figure 2 we show that inactivity increases with age in all WHO regions, a pattern known to have a strong biological basis.16 In spite of the linear association being observed in all regions, heterogeneity was marked. For example, older adults (60+ years) from South-East Asia were much more active than older adults from all other regions, and actually more active than young adults (15-29 years) from the Americas, the Eastern Mediterranean, European and Western Pacific regions. 8 Figure 3 presents physical inactivity by World Bank income classification. The prevalence of physical inactivity was higher in wealthier countries. For years, surveys focusing solely on leisure-time physical activity suggested that within countries, physical inactivity was more frequent among the poor as compared to those of higher socioeconomic status.17 18 It was only in the last decade, when standardised instruments focused on total physical activity (i.e. leisure-time, occupational, housework and transport-related activity) that a different social patterning of inactivity became apparent.4 19 Whether or not this pattern will persist in the future is unknown, but evidence from a study in Brazil suggests that while the prevalence of physical inactivity increased sharply among the poor in a five-year period, no significant differences were observed among the better-off. 20 The hypothesis that the social patterning of physical inactivity might be shifting is reinforced by declining occupational physical activity levels (more frequent among the poor) and increases in leisure-time physical activity (more frequent among the rich) reported in a systematic review.21 Walking is a common, accessible, inexpensive form of physical activity and has been shown to be an important component of total physical activity among adult populations.22 Walking is an aerobic activity requiring use of large skeletal muscles that confers the multifarious benefits of physical activity for health with minimal adverse effects.23 Interventions aimed at increasing population levels of walking exist and have proven its efficacy.24 We estimated the proportion of adults reporting walking for at least 10 consecutive minutes on five or more days per week. Overall, global prevalence was 64.1% (95%CI being calculated), but interestingly, the variation across WHO regions was modest: Africa (57.0%; 95%CI being calculated), Americas (65.6%; 95%CI being calculated), Eastern Mediterranean (66.9%; 95%CI being calculated), 9 Europe (66.8%; 95%CI being calculated), South-East Asia (67.2%; 95%CI being calculated) and Western Pacific (65.0%; 95%CI being calculated). Moreover there was almost no difference in patterns of walking between men and women and across age groups (Figure 4). This is in part explained by the measurement of all types of walking, namely recreation, transport and occupational walking. Participation in vigorous-intensity physical activity is another key indicator of physical activity levels. There are well-established health benefits from undertaking activity at vigorous-intensity5 and this was recognised in the recent WHO Global Physical Activity Recommendations.14 Moreover, there is evidence that vigorous compared with moderate intensity activity has higher reliability and validity in standardised self-report instruments.10 We therefore estimated the proportion of adults reporting three or more days per week, of vigorous-intensity physical activity. The overall prevalence was 31.4% (95%CI being calculated), and marked differences across regions were detected: Africa (38.0%; 95%CI being calculated), Americas (24.6%; 95%CI being calculated), Eastern Mediterranean (43.2%; 95%CI being calculated), Europe (25.4%; 95%CI being calculated), South-East Asia (43.2%; 95%CI being calculated), Western Pacific (35.3%; 95%CI being calculated). Within each age category, men were more likely to participate in vigorous-intensity physical activity than women. Also, both in men and women, vigorous-intensity physical activity participation decreased with age (Figure 4). Self-reported physical activity (adolescents) There are substantial short- and long-term health benefits from regular physical activity for young people.25 However, measurement of physical activity in children is