Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Age-dependent increase in blood pressure in two different Native American communities in Brazil Diana Meyerfreund a , Christine P. Gonc ¸alves a , Roberto S. Cunha a , Alexandre C. Pereira b , Jose ´ E. Krieger b and Jose ´ G. Mill a Objective Cardiovascular risk factors were surveyed in two Indian populations (Guarani, n U 60; Tupinikin, n U 496) and in a non-Indian group (n U 114) living in the same reserve in southeast Brazilian coast. The relationship between an age- dependent blood pressure (BP) increase with salt consumption was also investigated. Methods Overnight (12 h) urine was collected to evaluate Na excretion. Fasting glucose and lipids, anthropometry, BP, ECG and carotid-femoral pulse wave velocity (PWV) were measured in a clinic visit. Participation (318 men/352 women, age 20–94 years; mean U 37.6 W 14.9 years) comprised 80% of the eligible population. Results The prevalence of hypertension, diabetes and high cholesterol was similar in Tupinikins and in non-Indians and higher than in Guaranis. The prevalence of smoking and obesity was higher in the latter group. Hypertension and diabetes were detected in only one individual of the Guarani group. Mean BP adjusted to age and BMI was significantly lower (P < 0.01) in Guaranis (82.8 W 1.6 mmHg) than in Tupinikins (92.3 W 0.5 mmHg) and non-Indians (91.6 W 1.1 mmHg). Urinary Na excretion (mEq/12h), however, was similar in the three groups (Guarani U 94 W 40; Tupinikin U 105 W 56; non- Indian U 109 W 55; P > 0.05). PWV (m/s) was lower (P < 0.01) in Guarani (7.5 W 1.4) than in Tupinikins (8.8 W 2.2) and non-Indians (8.4 W 2.0). Multiple regression analysis showed that age and waist-to-hip ratio (WHR) were independent predictors of SBP and DBP (r 2 U 0.44) in Tupinikins, whereas the WHR was the unique independent predictor of BP variability in Guaranis (r 2 U 0.22). Conclusion Lower BP levels in Guaranis cannot be explained by low salt intake observed in other primitive populations. J Hypertens 27:1753–1760 Q 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins. Journal of Hypertension 2009, 27:1753–1760 Keywords: arterial hypertension, blood pressure, ethnic groups, Indians Abbreviations: BP, blood Pressure; PWV, pulse wave velocity; WHR, waist- to-hip ratio a Department of Physiological Sciences, Federal University of Espı ´rito Santo, Vito ´ ria, Espı ´rito Santo and b Heart Institute (InCor), University of Sa ˜ o Paulo Medical School, Sa ˜ o Paulo, Brazil Correspondence to Jose ´ G. Mill, MD, PhD, Departamento de Cie ˆ ncias Fisiolo ´ gicas, Centro de Cie ˆ ncias da Sau ´ de, Universidade Federal do Espı ´rito Santo, Av. Marechal Campos 1468, Vito ´ ria, Espı ´rito Santo 29042-755, Brazil Tel: +55 27 3335 7335; fax: +55 27 3335 7330; e-mail: jgmill@npd.ufes.br Received 12 December 2008 Revised 18 April 2009 Accepted 7 May 2009 Introduction Essential hypertension in humans is a complex and multifactorial disease influenced by a great number of genetic and environmental factors [1]. Observational and experimental studies have shown that high dietary sodium intake, obesity and excessive stress are conditions associated with blood pressure increase and hypertension development, mainly in individuals with genetic predis- position to develop this disease [2–7]. Thus, studies in animal models, human twins and families suggest that inherited markers contribute to more than 50% of the blood pressure variability in human populations [1,8]. Amerindian populations demonstrated low blood pres- sure levels when living in their traditional lifestyle and the occurrence of hypertension and other cardiovascular diseases was sporadic [9,10]. Yanomami Indians, for example, when investigated in the Intersalt Study two decades ago, had an average arterial pressure of only 96/61 mmHg. Hypertension and obesity cases were not found in that study. More importantly, it was also observed that SBP did not increase with age, a finding attributed to the very low urinary sodium excretion (<1 mmol Na/24h) because salt was not used in food preparation process [3,10]. Similar results were found in other Amerindians groups living in the Brazilian Amazonia when an investigation was performed in individuals still living in their primitive life conditions [11,12]. Sub- sequent studies have shown that the age-dependent blood pressure increase in these primitive populations is timely related to the emergence of other chronic diseases, includ- ing dyslipidemias, type 2 diabetes and atherosclerosis [9,13–15]. Despite the good documentation of the epide- miological transition in some native communities, mainly in the North American Indians, the relative participation of genetic and environmental factors to the uprising of chronic degenerative diseases in primitive communities is not completely understood. Presumably, adoption of acculturated eating habits, such as the intake of foods rich in sodium and carbohydrates with elevated glicemic index, may trigger genetic markers that facilitate the expression of specific phenotypes favoring development Original article 1753 0263-6352 ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI:10.1097/HJH.0b013e32832e0b2b