Understanding the role of genetics in hypertension

Extract

This editorial refers to ‘Risk for hypertension crosses generations in the community: a multi-generational cohort study’^†, by T.J. Niiranen et al., on page 2300.

Hypertension is a major modifiable risk factor for renal, cardiovascular, and cerebrovascular disease, and a leading underlying cause of global mortality and morbidity.¹ Incremental advances in our understanding of blood pressure have highlighted its complex pathophysiology, whereby genetic and environmental factors combine with a plethora of physiological pathways and mechanisms ultimately to yield the phenotype. While epidemiological studies have improved our understanding of environmental factors in relation to blood pressure, especially with regards to diet and exercise, the exact role of genetics in this setting has been challenging to tease apart from the shared environment often found in families and communities.²

In this issue of the journal, Niiranen et al. provide an intriguing insight into this topic.³ Using blood pressure data systematically acquired across three generations of the Framingham Heart Study, the authors showed that higher blood pressure, not only in parents, but also in grandparents, is associated with risk of the same condition in the third-generation individuals. Specifically, a family history of hypertension developed before 55 years of age represents the strongest risk factor for high blood pressure in the offspring, independently of several measured environmental factors known to influence the risk of hypertension, including levels of physical activity, dietary sodium, and alcohol intake. Importantly, the fact that grandparental hypertension confers risk in grandchildren and that only 10% of the grandchildren had last reported living in Framingham, suggests that the impact of shared environment here is likely to be low, making the genetic effect perhaps more apparent. There are of course limitations in the approach which the authors describe, but overall these data support the concept of genetic predisposition to hypertension.