> hypertension is not contagious

Common causes of hypertension are "contagious". Summary:

  spousal concordance: one partner’s chronic disease raises the odds the other has it too. If one spouse has hypertension, multiple studies suggest the other spouse’s risk is about 1.3 to 1.5 times higher than their cohort.

  Genetic causes can easily double risk over baseline cohort for children.

  However there is a strong environmental/lifestyle effect in children. Studies in Scandinavia show that children adopted into hypertensive households carry an elevated risk compared to the general population. A hypertensive parent with an adopted child nudges the child’s later-life risk by about 20–30% higher than baseline.