Environmental and Genetic Contribution to Hypertension Prevalence: Data from an Epidemiological Survey on Sardinian Genetic Isolates Ginevra Biino 1,2 *, Gianfranco Parati 3 , Maria Pina Concas 2 , Mauro Adamo 4 , Andrea Angius 1,5 , Simona Vaccargiu 1 , Mario Pirastu 1,4 1 Institute of Population Genetics, National Research Council of Italy, Sassari, Italy, 2 Institute of Molecular Genetics, National Research Council of Italy, Pavia, Italy, 3 Department of Cardiology, S.Luca Hospital, Istituto Auxologico Italiano, Milan; Chair of Cardiology & Department of Clinical Medicine and Prevention, University of Milano-Bicocca, Milan, Italy, 4 Shardna Life Sciences, Pula, Italy, 5 Institute of Genetic and Biomedical Research, National Research Council of Italy, Monserrato, Italy Abstract Background and Objectives: Hypertension represents a major cause of cardiovascular morbidity and mortality worldwide but its prevalence has been shown to vary in different countries. The reasons for such differences are still matter of debate, the relative contributions given by environmental and genetic factors being still poorly defined. We estimated the current prevalence, distribution and determinants of hypertension in isolated Sardinian populations and also investigated the environmental and genetic contribution to hypertension prevalence taking advantage of the characteristics of such populations. Methods and Results: An epidemiological survey with cross-sectional design was carried out measuring blood pressure in 9845 inhabitants of 10 villages of Ogliastra region between 2002 and 2008. Regression analysis for assessing blood pressure determinants and variance component models for estimating heritability were performed. Overall 38.8% of this population had hypertension, its prevalence varying significantly by age, sex and among villages taking into account age and sex structure of their population. About 50% of hypertensives had prior cardiovascular disease. High blood pressure was independently associated with age, obesity related factors, heart rate, total cholesterol, alcohol consumption, low education and smoking status, all these factors contributing more in women than in men. Heritability was 27% for diastolic and 36% for systolic blood pressure, its contribution being significantly higher in men (57%) than in women (46%). Finally, the genetic correlation between systolic and diastolic blood pressure was 0.74, indicating incomplete pleiotropy. Conclusion: Genetic factors involved in the expression of blood pressure traits account for about 30% of the phenotypic variance, but seem to play a larger role in men; comorbidities and environmental factors remain of predominant importance, but seem to contribute much more in women. Citation: Biino G, Parati G, Concas MP, Adamo M, Angius A, et al. (2013) Environmental and Genetic Contribution to Hypertension Prevalence: Data from an Epidemiological Survey on Sardinian Genetic Isolates. PLoS ONE 8(3): e59612. doi:10.1371/journal.pone.0059612 Editor: Robert Clarke, University of Oxford, United Kingdom Received October 4, 2012; Accepted February 15, 2013; Published March 20, 2013 Copyright: ß 2013 Biino et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was supported by a grant from the Italian Ministry of Education, University and Research (MERIT RBNE08NKH7_007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: Author Mario Pirastu, had an assignment in the commercial company Shardna Life Sciences, but this does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials. * E-mail: biino@igm.cnr.it Introduction Human hypertension represents a major cause of cardiovascular morbidity and mortality affecting one in three adults worldwide [1,2]. Recent large scale cohort studies have confirmed that high- quality epidemiological surveys are useful for the detection and prevention of such an important clinical condition [3,4], given that periodic surveys are central to provide the information necessary for planning hypertension prevention and control programs [5 8]. Moreover, because of the impact of uncontrolled hypertension on risk of cardiovascular mortality and morbidity worldwide, it is crucial to assess the prevalence of hypertension amongst different ethnic groups [9 12], and to determine the corresponding differences in the rate of blood pressure (BP) control by anti- hypertensive treatment [13,14]. In fact, prevalence of hypertension has been shown to differ in different countries or geographical regions. The reasons for such differences are still matter of debate, the relative contributions given by environmental and genetic factors being still poorly defined. Indeed, evidence from family studies suggests that hypertension has a complex origin, genetic factors being suggested to account for 30% of the phenotypic variability, the remainder being explained by environmental influences [15 17]. In order to perform a more in depth investigation of the respective role of environmental and genetic factors, we assessed the prevalence of hypertension and of some of its determinants in a peculiar geographically isolated area within Sardinia (Italy), called Ogliastra, characterized by a great deal of homogeneity in life style and eating habits [18]. Ogliastra villages are characterized by a PLOS ONE | www.plosone.org 1 March 2013 | Volume 8 | Issue 3 | e59612