Actividad física y factores asociados en adultos de área rural en Minas Gerais, Sureste de Brasil
Paula Gonçalves BicalhoI; Pedro Curi HallalII; Andréa GazzinelliI; Alan Goularte KnuthIII; Gustavo Velásquez-MeléndezI
IDepartamento de Enfermagem Materno Infantil e Saúde Pública. Escola de Enfermagem. Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil
IIDepartamento de Ginástica e Saúde. Escola Superior de Educação Física. Universidade Federal de Pelotas (UFPel). Pelotas, RS, Brasil
IIIPrograma de Pós-Graduação em Epidemiologia. Faculdade de Medicina. UFPel. Pelotas, RS, Brasil
OBJECTIVE: To estimate the physical activity level and its association with sociodemographic factors in adults living in rural areas.
METHODS: Cross-sectional population study including 567 adults in two rural communities from the Jequitinhonha Valley, Southeastern Brazil, during the years of 2008 and 2009. Physical activity levels were assessed with the adapted long version of the International Physical Activity Questionnaire. A cut-off point of 150 minutes per week was used in the analyses for the domains: occupational, household, leisure and commuting. The sociodemographic factors studied were sex, skin color, age, marital status, education and self-reported health. Bivariate analysis (chi-square test, p 0.05) and multiple logistic regression analysis were performed.
RESULTS: The prevalence of subjects practicing 150 min/wk or more of work related physical activity was 82.9% (95% CI: 77.8;88.0) of those currently working. The equivalent proportions for the other domains were: household 63.5% (95% CI: 59.6; 67.4); leisure time 10.1% (95% CI: 7.6;12.6) and commuting 32.0% (95% CI: 28.2;35.8%). Men were more active than women in leisure time, commuting and occupational domains, while women were more active in the household domain. Leisure time physical activity was more prevalent in younger subjects, those with higher levels of education and among those of black or mixed skin color. Commuting physical activity was more frequent among younger women and among men and women in excellent/good health. Men with higher level of schooling were less active in the commuting domain.
CONCLUSIONS: The prevalence of physically active adults in this rural area was high, but the levels of leisure time physical activity were low and followed patterns similar to those observed in urban areas, in relation to age, sex and educational status.
Descriptors: Adult. Motor Activity. Leisure Activities. Activities of Daily Living. Walking. Rural Population. Socioeconomic Factors. Cross-Sectional Studies.
OBJETIVO: Estimar los niveles de actividad física y su asociación con factores sociodemográficos en moradores de áreas rurales.
MÉTODOS: Estudio transversal, de base poblacional, incluyendo 567 adultos de dos comunidades rurales del Vale do Jequitinhonha, Sureste de Brasil, entre los años de 2008 y 2009. Los niveles de actividad física fueron colectados por medio de Cuestionario Internacional de Actividad Física, versión larga adaptada. Se utilizó el punto de corte de 150 minutos de actividad física semanal entre los dominios: trabajo, domicilio, ocio y traslados. Los factores sociodemográficos investigados fueron sexo, color de la piel, edad, estado marital, escolaridad y autopercepción de salud. Se realizaron análisis bivariado (Chi-cuadrado, p£0,05) y análisis múltiple de regresión logística.
RESULTADOS: La prevalencia de individuos que practicaron 150 minutos o más de actividad física en el trabajo fue de 82,9% (IC 95%: 77,8;88,0) entre los que trabajan actualmente. Esa proporción para los otros dominios fueron: 63,5% (IC 95%: 59,6;6;67,4) en el domicilio. 10,1% (IC 95%: 7,6;12,6) en el ocio y 32,0% (IC 95%: 28,2;35,8) en traslados. Los hombres fueron más activos que las mujeres en el ocio, traslados y trabajo, mientras que las mujeres fueron más activas en el ambiente doméstico. La actividad física de ocio fue más prevalente en individuos de mayor escolaridad, más jóvenes y entre los de color negro y pardo. En el traslado, mujeres más jóvenes y hombres y mujeres con estado de salud excelente/ bueno fueron más activos. Los hombres con mayor escolaridad fueron los menos activos en este dominio.
CONCLUSIONES: La prevalencia de adultos físicamente activos en área rural es alta, pero los niveles de actividad física en el ocio son bajos y siguen patrones similares a los de áreas urbanas según edad, sexo y escolaridad.
Descriptores: Adulto. Actividad Motora. Actividades Recreativas. Actividades Cotidianas. Caminata. Población Rural. Factores Socioeconómicos. Estudios Transversales.
The overall increase in non-communicable diseases and conditions constitutes a global public health problem. In this context, the practice of physical activity stands out as a form of health promotion and a way to prevent these diseases.ª Worldwide estimates from the World Health Organization (WHO), in 2002, indicated inactivity was responsible for almost two million annual deaths, for 22% of ischemic heart disease and for 10% to 16% of the cases of diabetes mellitus and breast, colon and rectal cancers. This data was mainly obtained from urban populations.b
Few population-level studies were performed in rural areas. Studies show that these communities also have a high prevalence of non-communicable diseases and conditions, despite their more active lifestyle.1,15,25
Knowing the physical activity levels of different populations allows for promoting physical activity by developing public policies adapted to the social, environmental and cultural contexts of each population. Measuring physical activity levels has proved challenging in population studies, including in regards to the comparability of studies.12 Also, it is hard to measure the activities performed in the different physical activity domains leisure, commuting, occupational and household with equal precision.13
Studies about physical activity levels in rural communities present additional challenges related to cultural differences, low education, poverty and difficult access to health services. In two published studies of adults, only physical activity in the leisure time domain was evaluated. In the Northeast and Southeast regions of Brazil, close to 1% of adults living in rural areas engaged in 30 minutes of daily exercise or sport.18 Another study, with perimenopausal women in Rio Grande do Norte, northern region, found that 37% engaged in 40 minutes of physical activity at least three days per week.24
The objective of this study was to estimate the physical activity levels of a rural population and evaluate the associated sociodemographic factors.
The cross-sectional population study was performed in the communities of Virgem das Graças and Caju in Jequitinhonha Valley, state of Minas Gerais, Southeastern Brazil. The population lives from mostly mixed subsistence farming and cattle raising, with corn and manioc as staples foods. The main sources of income are remittances from migrant workers and sales of small quantities of milk and manioc, in addition to the receipt of retirement pay, pensions and assistance from the government.8 The population has participated in several studies since 2001. One of these was about schistosomiasis and other parasitic infections8 and, starting in 2004, about non-communicable chronic diseases and their risk factors.25
The data were collected from May of 2008 until May of 2009, by rigorously trained undergraduate and graduate students. Interviews were performed face-to-face with a questionnaire.
All 612 individuals met the eligibility requirements of 18 or more years of age and living at least one year in the communities. These people were invited to visit a health clinic to participate in the study. The more distant households of the rural villages were visited by the researchers. There were 45 individuals (7.4%) categorized as losses, who during the data collection period were traveling, had physical or mental problems that made data collection difficult, were pregnant or refused.
The response variable was the practice of physical activity, measured with the long version of the International Physical Activity Questionnaire (IPAQ).c The IPAQ is an international tool for obtaining estimates of physical activity that are comparable across different populations. The questionnaire was developed by specialists in the field with the help of the World Health Organization and the Centers for Disease Control and Prevention (CDC). The long version of the IPAQ evaluates physical activity in the four domains occupational, household, leisure time and commuting according to the frequency and the duration of the physical activity performed in each domain during a usual week. The activities are separated according to their intensity, which is defined as the distinction between walking, other moderate physical activities and vigorous physical activities. Moderate activities are those that cause a small increase in respiratory frequency and require moderate physical exertion, and vigorous activities cause more rapid breathing than normal, with considerable physical exertion.5 Individuals that practiced 150 minutes or more of weekly physical activity were considered active.14,21 This duration was calculated by multiplying the number of days of moderately intense physical activity or walking by the number of minutes per day spent in each activity. The minutes of vigorous physical activity were multiplied by two, in addition to the aforementioned formula.
The long IPAQ was adapted to the rural area as recommended by its authors.c The adaptation consisted of small changes in the physical activities of each domain, without changing the structure of the questionnaire. For example, the activity of attending to a gym, utilized in the original questionnaire, was substituted by the activities of swimming in the river, weeding and hoeing. In the communities studied the predominant occupation involves physical exertion in agriculture, and a large part of the population lives from subsistence agriculture. Therefore, these activities in the occupational and household domains can overlap. In this case, agricultural work is related to daily household tasks, and therefore, some physical activities performed outside the home were considered as part of household activities, including activities in the backyard/porch in urban areas, and the yard/farmland in rural areas. The adapted questionnaire was tested in a pilot study in a rural area of the Paraopeba river valley, in the Belo Horizonte metropolitan area, Southeastern Brazil.
The independent variables were sex, skin color (white, mixed, black), age (18-30, 31-45, 46-59, > 60 years), marital status (married/in a union, single, separated/divorced/widowed), education (0, 1-4, 5-8, > 9 years of study) and self-reported health (excellent/good and regular/poor). Sex and skin color were provided by the interviewers. Age was confirmed through birth date and verified with an identity document or birth certificate. The other variables were provided by the participants.
The data were inserted with double entry in Epi Info 2000. The statistical analyses were performed using Stata 9.0. For the bivariate analysis, a chi-square test was used to verify differences in the proportion of active people, according to the independent variables. Results were considered statistically significant when p 0.05. Multiple logistic regression analysis was also performed with an estimated odds ration (OR) and 95% confidence interval (95% CI), and the results did not differ from the observations of the bivariate analysis. It was decided to present the findings of the bivariate analysis.
The study was approved by the Research Ethics Committee of the Universidade Federal de Minas Gerais (UFMG), appearance nº ETIC 604/07 of February 18, 2008. All participants signed an informed voluntary consent form, after agreeing to participate in the study.
There were 567 people interviewed in the two communities. Table 1 presents the characteristics of the study population. The age group of 45 to 59 years percentage was the smallest among men and women. More than half the population was classified as mixed skin, reported to be married or living with a partner and described their health as excellent/good. About 40% of the population reported having one to four years of schooling. The number of non-responses for the variables used was low. The greatest number of non-responses (15) occurred for the variable of self-reported health.
The prevalence of participants reporting at least 150 minutes of weekly physical activity were: 30.8% (95% CI: 27.0;34.6) in the occupational domain, when using total population as the denominator, and 82.9% (CI 95%: 77.8;88.0), when using only those currently working at the time of the interview as the denominator; 63.5% (CI 95%: 59.6;67.4) in the household domain; 10.1% (95% CI: 7.6;12.6) in the leisure domain; and 32.0% (95% CI: 28.2;35.8) in the commuting domain. When combining all the physical activity domains, 86.5% (95% CI: 83.7;89.4) of participants reported practicing 150 minutes or more of weekly physical activity.
In regards to sex, the percentage of individuals that attained 150 minutes of activity in leisure and commuting was three times greater among men compared to women. In the occupational domain, the prevalence was 29% greater for men. In the household domain, women were 42% more active (Figure).
In relation to occupational physical activity (Table 2), a greater percentage of participants in the 46 to 59 year age group performed at least 150 minutes, without differences in regards to sex. Participants with mixed or black skin had a greater chance of reaching 150 minutes of occupational physical activity. There was an inverse relationship between education and the percentage of participants performing 150 minutes at work, except when women were evaluated separately. A higher percentage of women, performing 150 minutes of occupational physical activity, classified their health as regular or poor. Marital status was not significantly associated with occupational physical activity.
Household physical activity was more frequent in older men and in younger women (Table 3). Mixed/black skin color was associated with a higher level of household physical activity only among women. Education had an inverted U shaped association with the practice of household physical activity, in the total population and in women. People, who are married or in stable unions, showed higher levels of household physical activity in the total population and among women. Self-reported health was not associated with greater physical activity levels in the household domain.
Leisure time physical activity was more frequent in individuals with greater education, lower age and among those of black or mixed color (Table 4). Single men and women with excellent/good health had higher levels of physical activity in this domain.
In the commuting domain, younger women were more active. Men and women that described health status as excellent/good showed more active commuting. Men with higher education were the least active in this domain. Marital status and skin color were not associated with commuting physical activity (Table 5).
The majority of associations observed through bivariate analysis were also found in the logistic regression analysis, except for those with positive confounding effects. There was a lack of association between education and household physical activity, between age and leisure time among women and between marital status and leisure time physical activity. The multiple regression analysis showed a direct association between commuting physical activity and age of men, which was not observed in the bivariate analysis.
The results of this study showed that 10.1% of participants reported performing at least 150 minutes/week of walking or other moderate to intense physical activities as leisure activities. Leisure time physical activity is recognized and recommended for its health benefits,14,21 and their low prevalence in this population, together with the high prevalence of overweight, obesity, hypertension and dyslipidemia present in these communities,23 can harm the health of people in rural areas in the future.
In the Living Standards Survey18 that included urban and rural population in the Northeast and Southeast Brazilian regions, the prevalence of leisure time physical activity was low (0.9%) among adults living in rural areas, even though it was estimated with another tool. When urban and rural areas were compared, men in rural areas were less likely to reach the recommended 30 minutes of physical activity on at least five days per week.18 Comparisons of urban and rural areas in other populations showed that residents of urban areas were more active than those in rural areas. Only in the Southern region of the United States was there no difference between rural and urban areas.16 On the other hand, a Chinese study with individuals aged 35-74 years showed that 78.1% of rural residents were active in the leisure and occupational domains, in contrast to 66.3% in the urban area.20 These differences can be explained through two main factors. In first place, the characteristics of rural communities are very different between countries and, in the case of Brazil, between regions. Rural activities in the occupational domain can differ greatly in the extent of mechanization and in the type of activity performed (e.g. extensive, family or subsistence agriculture; cattle raising; aquaculture; beekeeping; plant extraction and mineral extraction, among others). In addition, studies that only evaluate leisure time physical activity tend to produce discrepant results from studies that investigate other domains of physical activity. As observed in the present study, a large percentage of residents of rural areas concentrate their physical activity in other domains, such as occupational and household.
The associations, in this study between physical activity and sex, generally replicate the pattern observed in urban areas, where men are more active than women in the leisure time domain.19,d Two Brazilian studies analyzed the prevalence of physical activity in the four domains. In one of the studies, the pattern of physical activity, in relation to the sex of elderly people in Santa Catarina state, southern region, was similar to the present study's pattern for adults in the different domains. Women were more active than men only in household physical activities.3 In the other study, performed with adults (18 years of age or greater) and utilizing the System of Chronic Disease Surveillance by Telephone Interview (VIGITEL), there were no physical activity differences in the commuting domain between the sexes, and the frequency of people active in this domain was less than 10%.6 When evaluating the prevalence of total physical activity, some Brazilian studies did not find differences between the sexes in urban areas.2,10
The frequency of people active in the leisure domain decreased with age in this study. A study in a rural area of China showed the same trend.20 Nonetheless, in a study of rural communities in Missouri, United States, the elderly more frequently performed walks than younger individuals.4 Other studies gathered information on the different domains of physical activity but did not separate the domains and the associations with variables such as sex and age.9,17
In agreement with studies of urban areas in Brazil, individuals with greater education in the rural areas of Minas Gerais were also more active in the leisure domain.2,22,d In a study in China, though, an association was not identified between education and leisure time physical activity in urban or rural areas.20 In the occupational domain, there was an inverse relationship between education and physical activity: in the rural area of Minas Gerais, people with greater education were less active at work. These findings also occurred in urban and rural areas of China and agree with Brazilian data from studies in urban areas.7 People with more schooling are more active in leisure time. This may be related to a different relationship with work, which may allow for greater time availability and access to leisure activities. On the other hand, this study found a higher percentage of individuals with low education, who performed at least 150 minutes of physical activity in the occupational domain. This result can be attributed to the fact that labor activities involving greater physical force do not generally require greater education level.
Despite increased epidemiological studies over the past decades on physical activity in Brazil among urban populations, such as adults, children, adolescents and university students, studies did not exist with the specific goal of measuring physical activity in the different domains among rural populations. Since work is predominantly performed with physical exertion in subsistence agriculture, the activities in the occupational and household domains can be merged. The modifications to the questionnaire do not fundamentally alter it, but comparisons between studies in urban areas and those in rural areas should be interpreted with care.
The study limitations should be considered. The cross-sectional design does not allow for studying the relationship of time upon the variables; therefore, a phenomenon can occur through reverse causality. In regards to the external validity, the population studied may not represent other rural areas of Brazil and the world. In conclusion, the prevalence of individuals active in the leisure domain was low, with women three times less active than men. This demonstrates that interventions and public policies to encourage leisure time physical activity should be established for these populations. Interventions such as walking groups, collective games and gyms modeled on the "The City's Gym" program could include men and women of various age groups and education levels. The City's Gym program was established by the Recife Department of Health, Northeastern, Brazil, in 2002 as a health promotion policy and emphasized physical activity leisure time and healthy food. It is currently being implemented in various Brazilian municipalities, including Belo Horizonte.
Studies are needed to identify personal, environmental and sociocultural factors that interfere with the practice of physical activity by these populations. With this information, necessary and appropriate interventions to the reality of rural communities can be implemented.
1. Anselmi M, Avanzini F, Moreira JM, Montalvo G, Armani D, Prandi R, et al. Treatment and control of arterial hypertension in a rural community in Ecuador. Lancet. 2003;361(9364):1186-7. DOI:10.1016/S0140-6736(03)12918-2
2. Baretta E, Baretta M, Peres KG. Nível de atividade física e fatores associados em adultos no Município de Joaçaba, Santa Catarina, Brasil. Cad Saude Publica. 2007;23(7):1595-602. DOI:10.1590/S0102-311X2007000700010
3. Benedetti TR, Borges LJ, Petroski EL, Goncalves LHT. Atividade física e estado de saúde mental de idosos. Rev Saude Publica. 2008;42(2):302-7. DOI:10.1590/S0034-89102008005000007
4. Brownson RC, Housemann RA, Brown DR, Jackson-Thompson J, King AC, Malone BR, et al. Promoting physical activity in rural communities: walking trail access, use, and effects. Am J Prev Med. 2000:18(3):235-41. DOI:10.1016/S0749-3797(99)00165-8
5. Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, et al. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sports Exerc. 2003:35(8):1381-95. DOI:10.1249/01.MSS.0000078924.61453.FB
6. Cunha IC, Peixoto MRG, Jardim PCBV, Alexandre VP. Fatores associados à prática de atividade física na população adulta de Goiânia: Monitoramento por meio de entrevistas telefônicas. Rev Bras Epidemiol. 2008;11(3):495-504. DOI:10.1590/S1415-790X2008000300016
7. Florindo AA, Guimarães VV, Cesar CL, Barros MB, Alves MC, Goldbaum M. Epidemiology of leisure, transportation, occupational, and household physical activity: prevalence and associated factors. J Phys Act Health. 2009;6(5):625-32.
8. Gazzinelli A, Velásquez-Meléndez G, Crawford SB, LoVerde PT, Correa-Oliveira R, Kloos H. Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil. Acta Trop. 2006;99(2-3):260-71. DOI:10.1016/j.actatropica.2006.09.001
9. Gregory CO, Dai J, Ramirez-Zea M, Stein AD. Occupation is more important than rural or urban residence in explaining the prevalence of metabolic and cardiovascular disease risk in Guatemalan adults. J Nutr. 2007;137(5):1314-9.
10. Hallal PC, Victora CG, Wells JC, Lima RC. Physical inactivity: prevalence and associated variables in Brazilian adults. Med Sci Sports Exerc. 2003;35(11):1894-900. DOI:10.1249/01.MSS.0000093615.33774.0E
11. Hallal PC, Victora CG, Wells JC, Lima RC, Valle NJ. Comparison of short and full-lenght International Physical Activity Questionnaires. J Phys Act Health. 2004;1:227-34.
12. Hallal PC, Dumith SC, Bastos JP, Reichert FF, Siqueira FV, Azevedo MR. Evolução da pesquisa epidemiológica em atividade física no Brasil: uma revisão sistemática. Rev Saude Publica. 2007;41(3):453-60. DOI:10.1590/S0034-89102007000300018
13. Hallal PC, Anjos LA. Epidemiologia da atividade física. In: Kac G, Gigante C, Sichieri R, organizadores. Epidemiologia nutricional. Rio de Janeiro: Fiocruz; 2007. p. 461-72.
14. Haskell WL, Lee IM, Pate RR, Powell KE, Blair SN, Franklin BA, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc. 2007;39(8):1423-34. DOI:10.1249/mss.0b013e3180616b27
15. Matos AC, Ladeia AM. Assessment of cardiovascular risk factors in a rural community in the Brazilian state of Bahia. Arq Bras Cardiol. 2003;81(3):297-302. DOI:10.1590/S0066-782X2003001100009
16. Martin SL, Kirkner GJ, Mayo K, Matthews CE, Durstine JL, Hebert JR. Urban, rural, and regional variations in physical activity. J Rural Health. 2005;21(3):239-44. DOI:10.1111/j.1748-0361.2005.tb00089.x
17. Mohan V, Mathur P, Deepa R, Deepa M, Shukla DK, Menon GR, et al. Urban rural differences in prevalence of self-reported diabetes in India: the WHO-ICMR Indian NCD risk factor surveillance. Diabetes Res Clin Pract. 2008;80(1):159-68. DOI:10.1016/j.diabres.2007.11.018
18. Monteiro CA, Conde WL, Matsudo SM, Matsudo VR, Bonsenor IM, Lotufo PA. A descriptive epidemiology of leisure-time physical activity in Brazil, 1996-1997. Rev Panam Salud Publica. 2003;14(4):246-54.
19. Monteiro CA, Moura EC, Jaime PC, Lucca A, Florindo AA, Figueiredo IC, et al. Monitoramento de fatores de risco para doenças crônicas por entrevistas telefônicas. Rev Saude Publica. 2005;39(1):47-57. DOI:10.1590/S0034-89102005000100007
20. Muntner P, Gu D, Wildman RP, Chen J, Qan W, Whelton PK, et al. Prevalence of physical activity among Chinese adults: results from the International Collaborative Study of Cardiovascular Disease in Asia. Am J Public Health. 2005;95(9):1631-6. DOI:10.2105/AJPH.2004.044743
21. Pate RR, Pratt M, Blair SN, Haskell WL, Macera CA, Bouchard C, et al. Physical activity and public health. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. Jama. 1995;273(5):402-7. DOI:10.1001/jama.273.5.402
22. Salles-Costa R, Werneck GL, Lopes CS, Faerstein E. Associação entre fatores sócio-demográficos e prática de atividade física de lazer no Estudo Pró-Saúde. Cad Saude Publica. 2003;19(4):1095-105. DOI:10.1590/S0102-311X2003000400031
23. Silva DA, Felisbino-Mendes MS, Pimenta AM, Gazzinelli A, Kac G, Velásquez-Meléndez G. Distúrbios metabólicos e adiposidade em uma população rural. Arq Bras Endocrinol Metab. 2008;52(3):489-98. DOI:10.1590/S0004-27302008000300009
24. Silveira IL, Petronilo PA, Souza MO, Silva TDNC, Duarte JMBP, Maranhão TMO, et al. Prevalência de sintomas do climatério em mulheres dos meios rural e urbano no Rio Grande do Norte, Brasil. Rev Bras Ginecol Obstet. 2007;29(8):420-7. DOI:10.1590/S0100-72032007000800006
25. Velásquez-Meléndez G, Gazzinelli A, Côrrea-Oliveira R, Pimenta AM, Kac G. Prevalence of metabolic syndrome in a rural area of Brazil. Sao Paulo Med J. 2007;125(3):155-62. Correspondence: Received: 11/24/2009 The authors declare that there are no conflicts of interest.
Paula Gonçalves Bicalho
Av. Professor Alfredo Balena, 190
Escola Enfermagem sala 412
30130-100 Belo Horizonte, MG, Brasil
a Ministério da Saúde. Instituto Nacional do Câncer. Inquérito domiciliar sobre comportamento de risco e morbidade referida de doenças e agravos não transmissíveis [internet]. [cited 23 Aug 2007]. Available from: http://www.inca.gov.br/inquérito
b World Health Organization. Reducing risks, promoting healthy life. Geneva; 2002. (World health report 2002).
c International Physical Activity Questionnaire. Available from: http://www.ipaq.ki.se/ipaq.htm
d Ministério da Saúde. Secretaria de Vigilância à Saúde. Secretaria de Gestão Estratégica e Participativa. Vigitel Brasil 2008: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília, DF; 2009.
The authors declare that there are no conflicts of interest.