Heritability and risks associated with early onset hypertension: multigenerational, prospective analysis in the Framingham Heart Study

Dear Editor,

I read the paper by T J Niiranen1 et al with great interest. New data about theconnection between early onset versus late onset Hypertension as a risk factor for Hypertension in offspring and cardiovascular death were presented. The use of the cohort of the Framingham Heart Study and logical statistical analysis in the research protocol make the results clear and the conclusions credible.

But, I would like to pay special attention to the method of using blood pressure (BP) normal data at different ages presented in this study. Authors used the definition of Hypertension as blood pressure more then 140/90 mm. Hg. They took this approach for patients in different age groups (45, 55, 65 years). The results of statistical analysis were different for different groups. For example, for age >65 (Fig. 2) data showed a lower magnitude odd ratios of cardiovascular death versus non-cardiovascular death by age at onset of Hypertension than for age <65 (1.08 and 1, 52 – 2, 31 for Unadjusted model).

This data can have an additional explanation. Using data from Lancet 2 about middle SBP/DBP for high income countries and ZhGS formulas 3 for optimal BP determination we can get such results: for age 45 (124, 3/81, 4 and 124,7/77,3 mm. Hg), for age 65 (139,2/81,6 and 137,8/85 mm. Hg). These BP numbers are close to JNC8 recommendation 4. Both approaches 2,3 showed rise of BP with age. On the other hand, data from this paper showed negative correlation between age BP / hazard ratios.

We can conclude that the results of this research may be important not only to distinguish between early versus late onset of Hypertension in parents and offspring, cardiovascular outcomes, but also as confirmation of JNC84 recommendation about target BP for age >60

1. BMJ 2017;357:j1949
2. Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19·1 million participants. Lancet 2016; published online Nov 15.
3. www.researchgate.net/publication/281277846_Statistical_and_theoretical_a...
4. 2014 Evidence-Based Guideline for the Management of High Blood Pressure in AdultsReport From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507-520