ABC | Volume 110, Nº3, March 2018

Original Article Armstrong et al Urbanization and CV mortality among indigenous populations Arq Bras Cardiol. 2018; 110(3):240-245 Figure 3 – Mortality (≥ 30 y/o) in indigenous populations in the Sao Francisco Valley (Northeast Brazil), according to the degree of urbanization. Group 1 - less urbanized tribes; Group 2 - more urbanized tribes according to anthropological criteria. 40 30 20 10 0 2007 2008 2009 2010 2011 Year CV Death Mortality (%) Respiratory causes Cancer Unknown Violent death Other non-violent Diabetes 28.9 32.6 9.1 7.0 7.4 14.9 29.0 34.0 7.6 8.4 14.1 6.9 31.2 35.0 32.6 6.5 7.6 11.8 8.0 8.8 5.5 6.6 18.3 8.5 6.1 6.5 14.3 28.2 33.1 31.4 in Brazil, but surveys suggest that indigenous people have a less favorable CV risk profile than the general population. 17,18 Importantly, lifestyle differences related to CV risk are found in closely related traditional communities. 19 In fact, rapid changes in lifestyle affect indigenous populations differently from people in urban areas. 20 Not only risk factors appear to be increasing among indigenous people; the complications related to health care quality are also alarming. In fact, there is evidence that urbanization directly affects the health care quality of a given area. 21 Additionally, socioeconomic disadvantages do not seem to completely explain the increasing CV risk trends in indigenous populations. Regions majorly populated by indigenous people show increased CV risk beyond the effects of socioeconomic disadvantage. 3,22 This may be related to difficulties for indigenous populations when interacting with other ethnicities regarding their traditional medicine. 23 The classic expected dynamics of epidemiology for indigenous people in Brazil was based on two initial steps more closely related to infectious diseases, and a third step of epidemiologic transition and cultural losses. This third period would be characterized by an increase in chronic conditions such as CV disease and the emergence of an epidemiological profile similar to that of non-indigenous communities. 24 Our findings suggest that an epidemiological fourth step may be underway, in which the occurrence of CV diseases among indigenous people is not similar to that of the general population, but higher. These findings may be explained by rapid lifestyle and environmental modifications, added to a lower health care quality. Our study had several limitations and should be interpreted in the context of an exploratory investigation. Furthermore, we were limited to assessing the increases in the profile of CV risk factors as we assessed secondary data for mortality. Thus, concerns regarding potential misclassification bias certainly apply. Although large infrastructural changes have historically affected indigenous lifestyles, the magnitude of the deleterious impact of urbanization on the CV risk profile of these groups is not totally clear. Increases in blood pressure, obesity, and glycemic abnormalities are examples of known CV risk factors that may lead to subclinical cardiac abnormalities over time, before a CV event is established. 25-27 Further studies in the context of the PAI project are planned to address early subclinical abnormalities in these populations. Conclusions In conclusion, we show increasing trends in CV mortality over time among indigenous populations in the Sao Francisco Valley (Northeast Brazil), which appear to be negatively affected by a higher degree of urbanization. Lifestyle and environmental changes due to urbanization added to suboptimal health care may be implicated in the increase in CV risk among indigenous people. 243