Global Public Health, 2014 Vol. 9, No. 4, 369–381, http://dx.doi.org/10.1080/17441692.2014.894548

Review of the epidemiological evidence for physical activity and health from low- and middle-income countries Karen Miltona*, Rona Macnivenb and Adrian Baumanb a

School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UK; Prevention Research Collaboration, School of Public Health, University of Sydney, Sydney, Australia b

(Received 3 September 2013; accepted 15 January 2014) Almost 80% of deaths from non-communicable diseases (NCDs) occur in low- and middle-income countries. Physical inactivity is a key risk factor for NCDs. Enhancing understanding of the scientific evidence linking physical activity and health in lowand middle-income countries is important for supporting national efforts to promote physical activity and reduce NCDs in these countries. A systematic review of three electronic databases was conducted in July 2013, including large population-based epidemiological studies with adult participants, conducted in low- and middle-income countries, and published in the past 30 years. Physical activity was consistently associated with a reduced risk of all-cause mortality, cardiovascular disease (CVD), diabetes and several types of cancer. Positive associations were also found between physical activity and body composition (including overweight and obesity), blood pressure, cholesterol, metabolic indices and bone mineral density. Overall, the results confirm that the epidemiological research into the health benefits of physical activity in low- and middle-income countries is consistent with previous research conducted in high-income countries. This summary of the available research can be used as an advocacy tool in low- and middle-income countries to support greater prominence of physical activity in NCD policies. Keywords: epidemiology; physical activity; non-communicable disease; low- and middle-income countries

Introduction Non-communicable diseases (NCDs) are now the leading cause of global mortality, accounting for over 60% of deaths worldwide (World Health Organization, 2011). Of the 36 million deaths from NCDs in 2008, nearly 80% (29 million deaths) occurred in lowand middle-income countries (World Health Organization, 2011). This reflects both the size of the populations in low- and middle-income countries and the epidemiologic transition from infectious to chronic diseases (Miranda, Kinra, Casas, Davey Smith, & Ebrahim, 2008). In 2000, the World Health Organization (WHO) published a global strategy for the prevention and control of NCDs (World Health Organization, 2000). Within this document, physical inactivity was identified as one of the four key behavioural risk factors for NCDs, along with tobacco use, unhealthy diet and the harmful use of alcohol.

*Corresponding author. Email: [email protected] © 2014 Taylor & Francis

370

K. Milton et al.

Epidemiological research demonstrates that adults who are physically active have a reduced risk of developing many NCDs including coronary heart disease (CHD), stroke, hypertension and type II diabetes (Physical Activity Guidelines Advisory Committee, 2008). Despite the health benefits of physical activity, however, recent estimates suggest that approximately 30% of adults worldwide are not meeting the minimum recommendations for physical activity (Hallal et al., 2012). Population prevalence of physical inactivity varies considerably between countries, ranging from 4.7% in Bangladesh to 71.9% in Malta (Hallal et al., 2012). Physical inactivity is more prevalent in countries of high income than in those of low income (Hallal et al., 2012). However, with rapid urbanisation and economic growth, opportunities for physical activity in low- and middle-income countries are likely to decline, resulting in major negative health consequences. Reductions in overall physical activity (Aspray et al., 2000; Ng, Norton, & Popkin, 2009), occupational physical activity (Monda, Gordon-Larsen, Stevens, & Popkin, 2007) and active transport (Sobngwi et al., 2002) have all been linked with urbanisation and economic development in low- and middle-income countries and as a result, it is anticipated that the prevalence of NCDs in low- and middle-income countries is likely to increase for years to come (Kohl III et al., 2012). In September 2011, a United Nations (UN) high-level Summit was convened around NCDs. This Summit put NCDs on the global agenda and called for an international response to address the burden of these diseases throughout all parts of the world, and particularly in low- and middle-income countries. Following the UN Summit, the WHO developed a Global Monitoring Framework to enable global tracking of progress in preventing and controlling NCDs (World Health Organization, 2013). The framework outlined nine targets to be achieved by the year 2025, one of which was a 10% reduction in physical inactivity. This provided a clear mandate for action to address global levels of physical inactivity. A recent systematic review of NCD policy in low- and middle-income countries concluded that most low- and middle-income countries are poorly prepared to tackle the NCD epidemic (Lachat et al., 2013). Only a few low- and middle-income countries have developed national policies aimed at reducing NCDs, and even among those with national NCD policies, physical activity is rarely included (Lachat et al., 2013). In low- and middle-income countries, physical activity is often only considered by policy-makers in relation to obesity prevention (Bull & Bauman, 2011). This fails to recognise the broader benefits of physical activity for both physical and mental health. As a result, physical activity has been described as the ‘Cinderella’ risk factor for NCD prevention, which is defined as ‘poverty of policy attention and resourcing proportionate to its importance’ (Bull & Bauman, 2011, p. 14). Scaling up national policy efforts to promote physical activity is critical to reducing the prevalence of NCDs in low- and middle-income countries and achieving the targets set out in the Global Monitoring Framework (World Health Organization, 2013). One possible barrier to the inclusion of physical activity in NCD prevention is the lack of research evidence on physical activity and health from low- and middle-income countries. The available research evidence on the relationship between physical activity and health has primarily come from the USA and Europe, with relatively little research from other parts of the world, and particularly low- and middle-income countries. Although the benefits of physical activity are likely to be similar across populations, context-specific research is necessary to confirm this supposition. The lack of epidemiological research on the relationship between physical activity and health from

Global Public Health

371

low- and middle-income countries may reduce political support and policy development for physical activity and health in these countries. Therefore, enhancing understanding of the scientific evidence linking physical activity with a reduced risk of NCDs in low- and middle-income countries is an important step in supporting national efforts to promote physical activity in these countries. The aim of this review was to identify and summarise the epidemiological evidence for physical activity and health from developing countries. The review is presented in two parts. Part A focuses on the epidemiological evidence for physical activity and specific health outcomes such as all-cause mortality, cardiovascular disease (CVD), diabetes and cancer. Part B focuses on the associations between physical activity and other risk factors for NCDs, including overweight and obesity, high blood pressure and elevated blood cholesterol. Methods Literature searches were conducted using three electronic databases: Pub Med; Scopus; and Web of Science. The initial search focused on titles only and was based on the inclusion of three key elements: (1) physical activity; (2) health outcome or risk factor; and (3) low- or middle-income country. The included physical activity search terms were: ‘physical activity’, ‘motor activity’, ‘lifestyle activity’, ‘occupation* activity’, ‘exercise’, ‘fitness’, ‘energy expenditure’, ‘active travel’, ‘active transport*’, ‘active commuting’, ‘walk*’, ‘cycling’, ‘bicycling’, ‘sport’, ‘physical inactivity’, ‘sedentar*’ and ‘sitting’. The health outcome and risk factor search terms were: ‘health’, ‘chronic disease’, ‘mortality’, ‘death*’, a range of disease-specific terms (‘coronary heart disease’, ‘heart disease’, ‘ischemic heart disease’, ‘myocardial infarction’, ‘CHD’, ‘cardiovascular disease’, ‘CVD’, ‘stroke’, ‘cardio-respiratory’, ‘diabetes’, ‘cancer’, ‘mental health’, ‘depression’, ‘anxiety’, ‘dementia’, ‘Alzheimer’s’, ‘cognitive function’, ‘osteoporosis’, ‘hip fracture’, ‘fall*’, ‘musculoskeletal disorder’, ‘functional health’, ‘functional status’) and several risk factors (‘high blood pressure’, ‘hypertension’, ‘high cholesterol’, ‘hypercholesterolaemia’, ‘hyperlipidaemia’, ‘dyslipidemia’, ‘metabolic syndrome’, ‘insulin resistance’, ‘glucose sensitivity’, ‘overweight’, ‘obesity’, ‘body mass index’, ‘BMI’, ‘body composition’, ‘bone mineral density’, ‘bone density’, ‘bone health’). The low- and middle-income country search terms were: ‘upper middle income’, ‘lower middle income’, ‘middle income’, ‘low income’, ‘low and middle income’, ‘developing country*’, ‘developing population’ as well as the names of all countries and associated population groups classified as low-, lower middle-, or upper middle-income according to the World Bank in July of 2013.1 The search strategy was limited to papers in the English language and published from 1983 onwards, reflecting a 30-year period. Additional criteria for inclusion in the review were that the studies were population-based epidemiological studies, conducted with the adult population, and with a minimum sample size of n = 100. The initial search identified 1431 papers. After removing duplicates, the remaining 738 titles (and abstracts, if available) were screened for relevance by a member of the research team (KM). If the author was in any doubt over the inclusion or exclusion of a paper, it was included at this stage. This process led to the exclusion of 533 papers. The most common reason for exclusion was that the studies were conducted in adolescents or children rather than adults. A random subsample (20%) of these papers was checked by a second member of the research team (RM) to confirm their exclusion from the review.

372

K. Milton et al.

No inconsistencies in opinion were found. Abstracts could not be found for 12 of the remaining papers and these were excluded on this basis. All other abstracts (n = 193) were screened for inclusion by two members of the research team (KM and RM). Differences in opinion were resolved through discussion between all three members of the research team, until agreement was reached. This process led to the exclusion of 72 papers. The remaining 121 papers were included in the review. Studies were grouped according to whether they reported on specific health outcomes such as all-cause mortality, CVD, diabetes and cancer (Part A), or whether they focused on the associations between physical activity and other risk factors for NCDs such as overweight and obesity, high blood pressure and elevated blood cholesterol (Part B). These groupings were considered separately in the review. Forty-nine papers focused on health outcomes and were included in Part A of the review, while 64 papers focused on other risk factors for NCDs and were included in Part B of the review. The remaining eight papers reported on both health outcomes and risk factors and were included in both Part A and Part B. A summary of this process is shown in Figure 1. Each study was classified based on the reported associations with physical activity. Studies reporting a positive association between physical activity and the lower prevalence of a health outcome (for Part A) or risk factor (for Part B) were classified as +. Studies which reported no association or a negative association were classified as 0. Frequencies were calculated to show the number of studies classified as + and 0 for each health outcome and risk factor (a list of all papers which were included in the review is available as a supplementary file).

Results Physical activity was assessed using a variety of approaches; however, the most common approach was self-report, either using a self-administered questionnaire or collected via an interview. Many studies reported the use of ‘validated’ questionnaires but did not provide details of the specific tools that were used. Of the tools that were specified, the most commonly used were the Baecke Physical Activity Questionnaire (Baecke, Burema, & Frijters, 1982), the International Physical Activity Questionnaire (Craig et al., 2003) and the Global Physical Activity Questionnaire (Armstrong & Bull, 2006). Only five studies reported the use of objective measures including pedometers, accelerometers and/ or measures of fitness (dos Santos et al., 2012; Hui, Thomas, & Tomlinson, 2003; Lam, Lee, Wong, & Wong, 2012; Ma et al., 2010; Sternfeld & Janga, 2002). Part A – health outcomes A total of 57 papers reported on the links between physical activity and at least one health outcome and were included in Part A of the review. Table 1 shows the numbers of studies which reported on each health outcome and indicates the frequency of associations in terms of + (positive association) or 0 (no association or negative association). Some papers included more than one health outcome. For these papers, the association with each health outcome was considered separately. For example, if a study explored the effects of physical activity on heart disease and diabetes, the study is included within the frequency results for each of these conditions.

Global Public Health Pub Med Scopus Web of Science Total

373

n = 203 n = 497 n = 731 n = 1431 Duplicates n = 693

Unique papers n = 738

Titles screened by one member of the research team and 20% sample verified

Excluded papers n = 533

Unobtainable abstracts n = 12 Abstracts reviewed by two members of the research team n = 193

Excluded papers n = 72

Papers included in the review n = 121

Papers including health outcomes and risk factors n = 8

Health outcome papers n = 49

Papers included in health outcome review (Part A) n = 57

Figure 1.

Risk factor papers n = 64

Papers included in risk factor review (Part B) n = 72

Summary of the screening process for inclusion in the review.

All-cause mortality All seven studies which focused on all-cause mortality reported a positive association between physical activity and the reduced risk or mortality: three studies were conducted in China (Feng, Zhen, Duncan, Zeng, & Purser, 2010; Matthews et al., 2007; Schooling et al., 2006), and one study each was conducted in Taiwan (Hu et al., 2013), India (Kutty, Safraj, Vijayakumar, Anish, & Ajayan, 2011), Iran (Etemadi et al., 2013) and Cuba (Franco et al., 2007). Although all studies reported positive associations between physical activity and all-cause mortality, in some studies, the strength of the association differed between men and women (Kutty et al., 2011; Hu et al., 2013). In addition, although Hu et al. (2013) reported that leisure-time activity was associated with a reduced risk of

374

K. Milton et al.

Table 1. Frequency of included papers for each health outcome, grouped by reported association with physical activity [positive (+)/none or negative (0)]. Health outcome

+

0

Total

All-cause mortality Cardiovascular disease Type II diabetes Breast cancer Colon/colorectal cancer Prostate cancer Ovarian cancer Other cancer Osteoporosis Osteoarthritis Hip fracture Depression Cognitive function Total

7 9 15 6 5 4 3 2 2 0 2 1 2 58

0 0 1 1 2 1 0 0 1 1 0 0 0 7

7 9 16 7 7 5 3 2 3 1 2 1 2 65

mortality, occupational activity was associated with a greater risk of mortality, particularly in men. Cardiovascular disease Nine studies examined the associations between physical activity and CVD. Five studies reported on the links between physical activity and heart disease, all of which reported a positive association: two studies were conducted in China (Cheng et al., 2013; Du et al., 2011), one in Thailand (Jindawong, Kuhiranyaratn, Paileeklee, Ratanasiri, & SeeUbpalad, 2008), one in India (Rastogi et al., 2004) and one in Cuba (Franco et al., 2007). Three studies reported on the relationship between physical activity and stroke: two studies were conducted in China (Lee & Liang, 2010; Liang et al., 2009) and one study was conducted in Cuba (Franco et al., 2007). All three studies reported an inverse association between physical activity and ischemic stroke risk. Two other studies reported an inverse relationship between physical activity and CVD: one study was conducted in Taiwan (Hu et al., 2013) and the other was conducted in India (Kutty et al., 2011). However, consistent with the finding for all-cause mortality, Hu et al. (2013) suggested that although leisure-time activity was associated with a reduced risk of CVD, occupational activity may be associated with a greater risk. Type II diabetes Diabetes was the health outcome with the greatest number of research papers from lowand middle-income countries. Sixteen papers were found in total; 15 of which reported that physical activity was inversely related to diabetes. However, only three studies used a prospective cohort design, while the other studies involved only cross-sectional associations. Many studies were conducted in China but studies were also from a range of other countries including Brazil, Cameroon, Fiji and Sri Lanka. One study reported that active transport (i.e. walking or bicycling for transport) was associated with a higher risk of diabetes (Lu, Su, Xiang, Zhang, & Wu, 2013).

Global Public Health

375

Breast cancer Seven studies reported on the links between physical activity and breast cancer in women. Two studies were conducted in China (Gao et al., 2009; Pronk et al., 2011) and India (Datta & Biswas, 2009; Mathew et al., 2009) and the other three studies were conducted in Malaysia (Shahar, Salleh, Ghazali, Koon, & Wan Mohamud, 2010), Mexico (OrtizRodriguez et al., 2008) and Tunisia (Awatef et al., 2011). Six studies reported that physical activity was associated with a significant reduction in the risk of breast cancer. The other study reported that higher levels of physical activity were associated with higher risk of breast cancer (Datta & Biswas 2009). However, physical activity was reported to decrease following breast cancer diagnosis, which is when the physical activity assessment was conducted. Therefore, this study design did not allow the authors to make clear inferences about the relationship between physical activity and breast cancer. Colon/colorectal cancer Seven studies reported on the links between physical activity and colon or colorectal cancer: three studies were conducted in China (Chow et al., 1993; Hou et al., 2004; Wittemore et al., 1990), two in Turkey (Vetter et al., 1992; Dosemeci et al., 1993), one in Singapore (Peterson et al., 2008) and one in Jordan (Waly, Arafa, Jriesat, Sallam, & Al-Kafajei, 2010). Five studies reported positive associations. Low occupational physical activity (Chow et al., 1993), sedentary job (Dosemeci et al., 1993) and time spent sitting (Whittemore et al., 1990) were associated with an increased risk of colorectal cancer, while commuting physical activity (Hou et al., 2004) and the overall participation in physical activity and sports (Peterson et al., 2008) were associated with a lower risk of colorectal cancer. Two studies reported non-significant associations between physical activity and colorectal cancer (Vetter et al., 1992; Waly et al., 2010). Prostate cancer Five studies explored the links between physical activity and prostate cancer: three studies were conducted in China (Hsing, McLaughlin, Zheng, Gao, & Blot, 1994; Jian, Shen, Lee, & Binns, 2005; Lacey et al., 2001), one in Malaysia (Shahar et al., 2011) and one in Turkey (Dosemeci et al., 1993). Four studies reported that physical activity was associated with a reduced risk of developing prostate cancer. However, one study found that physical activity did not have a protective role (Lacey et al., 2001). Ovarian cancer All three studies which reported on the links between physical activity and ovarian cancer reported a positive association: two studies were conducted in China (Lee, Su, Pasalich, Wong & Binns, 2012; Zhang, Lee, & Binns, 2003) and one was conducted in Turkey (Dosemeci et al., 1993). Other cancer In addition to exploring the links between physical activity and colorectal cancer, prostate cancer and ovarian cancer, Dosemeci et al. (1993) also reported that physical activity was associated with a reduced risk of cancer of the larynx and melanoma. However, decreasing levels of physical activity were associated with decreasing risk of cancer of the

376

K. Milton et al.

cervix and the uterus. In addition, Salazar-Martinez et al. (2000) found that physical activity was associated with reduced risk of endometrial cancer. Osteoporosis, osteoarthritis and hip fracture Three studies explored the relationship between physical activity and osteoporosis, and all were conducted in postmenopausal women: two studies reported that physical activity was a protective factor for osteoporosis (Keramat, Larijani, Patwardhan, & Chopra, 2009; Motlagh et al., 2012), while the other study reported no association (Bhanji, Iqbal, Jabbar, Uzzaman, & Janjua, 2012). Only one study explored the links between physical activity and osteoarthritis (Lau et al., 2000). The study was conducted in Hong Kong, and stair climbing and lifting heavy weights were associated with increased risk of osteoarthritis of the hip and the knee. Two studies focused on the links between physical activity and hip fracture. Both studies were conducted in Thailand: one study was conducted with men (Suriyawongpaisal, Rajatanavin, Takkinstien, Wanvarie, & Apiyasawat, 2001) and the other was conducted with women (Boonyaratavej et al., 2001). Both studies reported that physical activity was associated with a reduced risk of hip fracture. Depression Only one study was found which reported on the links between physical activity and depression (Gallegos-Carrillo et al., 2013). The study was conducted in Mexico and found that physical activity had a protective effect against depression. Cognitive function Two studies reported on the links between physical activity and cognitive function. Both studies focused on older adults: one was conducted in Hong Kong (Lam et al., 2009) and the other was conducted in Nigeria (Ojofeitimi et al., 2002). Both studies reported that regular physical activity was associated with improved cognitive performance. Part B – risk factors A total of 72 papers reported on the associations between physical activity and other risk factors for NCDs. Table 2 shows the number of studies which reported on each risk factor and indicates the frequency of papers classified as + and 0. For papers that included more than one risk factor, the association with each risk factor was considered separately. Body composition Body composition, including waist circumference, overweight and obesity, was the risk factor with the greatest number of research papers from low- and middle-income countries. Thirty-eight papers were found in total. Over half of these papers came from China (n = 20). The other papers came from a range of countries including Iran, Nepal, Samoa, South Africa and Thailand. Thirty-five papers reported a positive relationship between physical activity and body composition. Higher levels of physical activity were associated with greater lean body mass and a reduced risk of overweight and obesity; however, several studies observed this relationship in men but not women (Gómez, Hernández-Prado, Morales, & Shamah-Levy, 2009; Joswiak et al., 1994; Komal, Jaipanesh, & Seemal, 2010). Three studies were classified as ‘0’. Sternfeld and Janga (2002) reported that higher levels of physical activity were generally associated with decreased percent body fat and smaller waist circumference; however, these findings were

Global Public Health

377

Table 2. Frequency of included papers for each risk factor, grouped by reported association with physical activity [positive (+)/none or negative (0)]. Risk factor

+

0

Total

Body composition/overweight/obesity High blood pressure/hypertension Elevated blood cholesterol/lipids Glucose metabolism Metabolic syndrome Bone mineral density Other risk factor Total

35 13 12 6 18 8 3 95

3 3 1 1 4 0 0 12

38 16 13 7 22 8 3 107

not statistically significant in Chinese women. Zimmet et al. (1991) reported little difference in body mass index and waist circumference between active and inactive groups, while Lu et al. (2013) reported that those who undertook less active travel had a lower risk of obesity. From the 38 studies reporting the association between physical activity and body composition, only two studies were longitudinal, while the others studies were all cross-sectional. High blood pressure/hypertension In total, 16 papers were identified which looked at the association between physical activity and blood pressure. Four studies were from China and two studies each were from India, Iran, and South Africa. The remaining studies were from Brazil, Bulgaria, Cameroon, Democratic Republic of Congo, Mauritius and Sri Lanka. Thirteen papers reported that physical activity was inversely related to blood pressure and/or was associated with a reduced risk of hypertension. Three studies found no association between physical activity and high blood pressure/hypertension (Charlton, Lambert, & Kreft, 1997; Reichert, Azevedo, Breier, & Gerage, 2009; Zimmet at al., 1991). Elevated blood cholesterol/lipids Thirteen studies explored the relationship between physical activity and cholesterol/lipids. Twelve studies reported that physical activity was associated with a more positive lipid profile. Five of these studies were conducted in China, two in Iran and one in India, Mexico, Mauritius, South Africa and Thailand. One paper reported that active travel was associated with a higher prevalence of cholesterol disorder in China (Lu et al., 2013). Glucose metabolism Seven studies were found which reported on the links between physical activity and glucose metabolism, six of which reported positive associations. Half of these studies were conducted with Chinese populations (n = 3). The others were conducted with Iranians, Mauritians and Pima Indians. One study, which was conducted in Samoa, reported that physical activity was not consistently associated with glucose levels (Joswiak et al., 1994).

378

K. Milton et al.

Metabolic syndrome Twenty-two studies reported on the association between physical activity and the metabolic syndrome. All studies used a cross-sectional design. Approximately half of the studies were conducted in China (n = 10), three were from Brazil, two from India and Iran, and one from Ethiopia, Malaysia, Mexico, Peru and Sri Lanka. Eighteen studies found that physical activity was associated with a reduced risk of the metabolic syndrome; however, four studies reported no association (Dalacorte, Reichert, & Vieira, 2008; Delavar, Sann, Syed Hassan, Lin, & Hanachi, 2008; Doro et al., 2006; Zuo, Yao, Hu, & Kong, 2011). Bone mineral density Bone mineral density was the only risk factor with unequivocal findings. Eight studies reported a positive association between physical activity and bone mineral density. The studies were conducted in the following countries: Brazil (Florindo et al., 2002), China (Ho et al., 1987; Zou, Lv, Guan, & Nie, 2010), India (Kumar, Mittal, Orito, Ishitani, & Ohta, 2010), Mexico (ParraCabrera, HernandezAvila, TamayoyOrozco, LopezCarrillo, & MenesesGonzalez, 1996), South Africa (Kolbe-Alexander, Charlton, & Lambert, 2004; Micklesfield et al., 2001) and Thailand (Pongchaiyakul et al., 2004). Other risk factors Three studies were found which looked at other risk factors. Ma, Liu and Ling (2003) reported that physical activity was associated with serum apolipoprotein B and total antioxidant capacity; Esteghamati et al. (2010) reported that higher physical activity was associated with lower serum leptin levels; and Esteghamati et al. (2012) found that physical activity was associated with C-reactive protein.

Discussion Recent global developments have emphasised the need to scale-up efforts to prevent and control NCDs throughout all regions of the world. Given that the majority of deaths from NCDs occur in low- and middle-income countries, these countries should be a priority for action. Physical inactivity has been identified as the fourth leading risk factor for NCDs (World Health Organization, 2009) and therefore increasing population levels of physical activity has huge potential to reduce the burden of these diseases. One ‘crucial approach’ to supporting increases in physical activity at the population level is the development and implementation of national policies (Kohl III et al., 2012, p. 296). However, few low- and middle-income countries have policies and actions targeting physical activity (Lachat et al., 2013). Context-specific evidence on the links between physical activity and health may be necessary to support the development of physical activity policies in these countries. Thus, the aim of this review was to identify and summarise the available epidemiological evidence for physical activity and health from low- and middle-income countries. Overall, the results confirm that the epidemiological research into the health benefits of physical activity in low- and middle-income countries is consistent with the established evidence base, which mostly comes from high-income countries. Specifically, this review found that physical activity was consistently associated with a reduced risk of all-cause mortality and CVD, including heart disease and stroke. These findings support the established evidence which shows a very strong inverse

Global Public Health

379

association between physical activity and all-cause mortality, and a strong inverse relationship between physical activity and CVD (Physical Activity Guidelines Advisory Committee, 2008). This review found evidence for the benefits of leisure-time physical activity in reducing the risk of diabetes in low- and middle-income countries, although one study reported that occupational activity may not have the same benefits. This is consistent with previous research which shows that people who are physically active have a decreased risk of developing type II diabetes (Physical Activity Guidelines Advisory Committee, 2008). The majority of studies addressing type II diabetes prevention have focused on vigorous-intensity physical activity, although moderate-intensity activity has been shown to be effective in some studies (Physical Activity Guidelines Advisory Committee, 2008). Further research into the impact of occupational physical activity on diabetes risk in lowand middle-income, as well as high-income, countries is warranted. In this review, physical activity was commonly associated with a reduced risk of several types of cancer including breast cancer, colorectal cancer, prostate cancer and ovarian cancer. Although the evidence was not always unanimous, the balance of evidence leans towards positive associations. From the established evidence base, which mostly comes from high-income countries, the clearest evidence for physical activity and a reduced risk of cancer has been found for colon and breast cancer and, overall, the evidence shows a moderate inverse relationship (Physical Activity Guidelines Advisory Committee, 2008). There is also some evidence linking physical activity with a reduced risk of lung, endometrial and ovarian cancers (Physical Activity Guidelines Advisory Committee, 2008). However, few studies were found which focused on these cancers in low- and middle-income countries. Physical activity was associated with a reduced risk of hip fracture; however, the associations between physical activity and osteoporosis and osteoarthritis were mixed. In terms of mental health, the research showed that physical activity was associated with lower risk of depression and improved cognitive function. However, only a small number of studies were available for each of these health outcomes. The links between physical activity and other risk factors for NCDs in low- and middle-income countries were also similar to what has been found previously. Many studies were found which reported positive associations between physical activity and body composition (including overweight and obesity), blood pressure, cholesterol, metabolic indices and bone mineral density. Although there were several studies that did not find convincing evidence for these associations, overall it appears that physical activity is associated with lower likelihood of developing many key risk factors for NCDs. The number of studies linking physical activity to specific health outcomes in lowand middle-income countries was small. For the major health outcomes of all-cause mortality and CVD, the number of studies was seven and nine, respectively. Although the results are consistent with the established evidence base, more studies are needed to understand whether the nature of the relationship between physical activity and health outcomes is consistent across diverse populations. More studies reported on the links between physical activity and other risk factors for NCDs, particularly body composition and metabolic syndrome. However, across both the health outcome studies and the risk factor studies, the majority used a cross-sectional study design. Observational studies and randomised controlled trials would provide stronger evidence for the associations between physical activity and health in low- and middle-income countries. However, there may be several barriers to the conduct of epidemiological studies on physical

380

K. Milton et al.

activity and NCDs in low- and middle-income countries, including a lack of funding for this type of research and a relatively small number of professionals with the relevant expertise to design and implement these types of studies. A limitation of this review is that the quality of the studies was not taken into consideration, and there are two main reasons for this. First, due to the small number of studies available from low- and middle-income countries, the review sought to be as inclusive as possible. Second, the main aim was to determine whether the patterns of evidence are similar for low- and middle-income countries in comparison to high-income countries, rather than to produce a quantitative estimate of the pooled risk. The pattern of risk was found to be similar in this narrative review to the meta-analytic estimates from developed countries and this provides sufficient evidence for action.

Conclusion The findings of this research confirm that the benefits of physical activity in reducing many disease outcomes and risk factors for NCDs are similar in low- and middle-income countries to that reported from high-income countries. This evidence, combined with the high prevalence of NCDs in low- and middle-income countries, makes a compelling case for the need to develop policies and actions to increase physical activity levels in these countries. It should be acknowledged that governments in low- and middle-income countries are making increasing effort to tackle the NCD epidemic; however, physical activity is rarely given sufficient focus. This summary of the available research linking physical activity and health in low- and middle-income countries can be used as an advocacy tool in these countries to ensure that physical activity is given sufficient prominence alongside the other risk factors for NCDs in future policies and actions.

Supplemental data Supplemental data for this article can be accessed here.

Note 1. Afghanistan, Albania, Algeria, American Samoa, Angola, Argentina, Armenia, Azerbaijan, Bangladesh, Belarus, Belize, Benin, Bhutan, Bolivia, Bosnia and Herzegovina, Botswana, Brazil, Bulgaria, Burkina Faso, Burundi, Cambodia, Cameroon, Cape Verde, Central African Republic, Chad, China, Comoros, Congo, Costa Rica, Côte d’Ivoire, Cuba, Djibouti, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Eritrea, Ethiopia, Fiji, Gabon, Gambia, Georgia, Ghana, Grenada, Guatemala, Guinea, Guinea-Bissau, Guyana, Haiti, Honduras, Hungary, India, Indonesia, Iran, Islamic Republic, Iraq, Jamaica, Jordan, Kazakhstan, Kenya, Kiribati, Korea Democratic Republic, Kosovo, Kyrgyz Republic, Lao, Lebanon, Lesotho, Liberia, Libya, Macedonia, Madagascar, Malawi, Malaysia, Maldives, Mali, Marshall Islands, Mauritania, Mauritius, Mexico, Micronesia, Moldova, Mongolia, Montenegro, Morocco, Mozambique, Myanmar, Namibia, Nepal, Nicaragua, Niger, Nigeria, Pakistan, Palau, Panama, Papua New Guinea, Paraguay, Peru, Philippines, Romania, Rwanda, Samoa, São Tomé and Principe, Senegal, Serbia, Seychelles, Sierra Leone, Solomon Islands, Somalia, South Africa, South Sudan, Sri Lanka, St. Lucia, St. Vincent and the Grenadines, Sudan, Suriname, Swaziland, Syrian Arab Republic, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Tonga, Tunisia, Turkey, Turkmenistan, Tuvalu, Uganda, Ukraine, Uzbekistan, Vanuatu, Venezuela, Vietnam, West Bank and Gaza, Yemen, Zambia, Zimbabwe.

Global Public Health

381

References Armstrong, T., & Bull, F. (2006). Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ). Journal of Public Health, 14, 66–70. doi:10.1007/s10389-0060024-x Aspray, T., Mugusi, F., Rashid, S., Whiting, D., Edwards, R., Alberti, K., & Unwin, N. (2000). Rural and urban differences in diabetes prevalence in Tanzania: The role of obesity, physical inactivity and urban living. Transactions of the Royal Society of Tropical Medicine and Hygiene, 94, 637–644. doi:10.1016/S0035-9203(00)90216-5 Baecke, J., Burema, J., & Frijters, J. (1982). A short questionnaire for the measurement of habitual physical activity in epidemiological studies. The American Journal of Clinical Nutrition, 36, 936–942. Bull, F., & Bauman, A. (2011). Physical inactivity: The ‘Cinderella’ risk factor for noncommunicable disease prevention. Journal of health Communication, 16(2), 13–26. doi:10.1080/10810730.2011. 601226 Craig, C., Marshall, A., Sjöström, M., Bauman, A., Booth, M., Ainsworth, B., … Oja, P. (2003). International physical activity questionnaire: 12-country reliability and validity. Medicine and Science in Sports and Exercise, 35, 1381–1395. doi:10.1249/01.MSS.0000078924.61453.FB Hallal, P., Andersen, L., Bull, F., Guthold, R., Haskell, W., & Ekelund, U. (2012). Global physical activity levels: Surveillance progress, pitfalls, and prospects. The Lancet, 380, 247–257. doi:10.1016/S0140-6736(12)60646-1 Kohl III, H., Craig, C., Lambert, E., Inoue, S., Alkandari, J., Leetongin, G., & Kahlmeier, S. (2012). The pandemic of physical inactivity: Global action for public health. The Lancet, 380, 294–305. doi:10.1016/S0140-6736(12)60898-8 Lachat, C., Otchere, S., Roberfroid, D., Abdulai, A., Seret, F., Milesevic, J., … Kolsteren, P. (2013). Diet and physical activity for the prevention of non-communicable diseases in low and middle income countries: A systematic policy review. PLoS Med, 10(6), 11. doi:10.1371/journal. pmed.1001465 Miranda, J., Kinra, S., Casas, J., Davey Smith, G., & Ebrahim, S. (2008). Non-communicable diseases in low- and middle-income countries: Context, determinants and health policy. Tropical Medicine and International Health, 13, 1225–1234. doi:10.1111/j.1365-3156.2008.02116.x Monda, K., Gordon-Larsen, P., Stevens, J., & Popkin, B. (2007). China’s transition: The effect of rapid urbanization on adult occupational physical activity. Social Science and Medicine, 64, 858– 870. doi:10.1016/j.socscimed.2006.10.019 Ng, S., Norton, E., & Popkin, B. (2009). Why have physical activity levels declined among Chinese adults? Findings from the 1991–2006 China health and nutrition surveys. Social Science and Medicine, 68, 1305–1314. doi:10.1016/j.socscimed.2009.01.035 Physical Activity Guidelines Advisory Committee. (2008). Physical activity guidelines advisory committee report 2008. Washington, DC: U.S. Department of Health and Human Services. Sobngwi, E., Mbanya, J., Unwin, N., Kengne, A., Fezeu, L., Minkoulou, E., … Alberti, K. (2002). Physical activity and its relationship with obesity, hypertension and diabetes in urban and rural Cameroon. International Journal of Obesity, 26, 1009–1016. doi:10.1038/sj.ijo.0802008 World Bank. (2013). World Bank list of economies (July 2013). Retrieved from http://data. worldbank.org World Health Organization. (2000). Global strategy for the prevention and control of noncommunicable diseases. Geneva: Author. World Health Organization. (2009). Global health risks: Mortality and burden of disease attributable to selected major risks. Geneva: Author. World Health Organization. (2011). Global status report on noncommunicable disease 2010. Geneva: Author. World Health Organization. (2013). Global monitoring framework on noncommunicable diseases. Geneva: Author.

Review of the epidemiological evidence for physical activity and health from low- and middle-income countries.

Almost 80% of deaths from non-communicable diseases (NCDs) occur in low- and middle-income countries. Physical inactivity is a key risk factor for NCD...
202KB Sizes 0 Downloads 3 Views