Environmental and Genetic Contribution to Hypertension Prevalence: Data from an Epidemiological Survey on Sardinian Genetic Isolates

Ginevra Biino,Simona Vaccargiu,Mauro Adamo,Mario Pirastu,Gianfranco Parati,Maria Pina Concas,Andrea Angius,Robert Clarke

doi:10.1371/journal.pone.0059612

Abstract

Background and ObjectivesHypertension 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 ResultsAn 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.ConclusionGenetic 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.

Highlights

Human hypertension represents a major cause of cardiovascular morbidity and mortality affecting one in three adults worldwide [1,2]
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
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]

Summary

Introduction

Human hypertension represents a major cause of cardiovascular morbidity and mortality affecting one in three adults worldwide [1,2]. 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. Hypertension represents a major cause of cardiovascular morbidity and mortality worldwide but its prevalence has been shown to vary in different countries. We estimated the current prevalence, distribution and determinants of hypertension in isolated Sardinian populations and investigated the environmental and genetic contribution to hypertension prevalence taking advantage of the characteristics of such populations

Methods

Results

Discussion

Conclusion