High blood pressure is divided into primary and secondary
hypertension,
secondary hypertension occurs in 10 % of patients and is due to other underlying diseases " kidney diseases, hormonal
disorders ... " or medications , and is treated by treating the cause.
primary hypertension is said to be
idiopathic which means that it has no known cause , but many factors play a role in it including
genetics,
obesity , diabetes ....
if you want more detailed information i advice you to have a look at the Health Information Center :
http://google.com/coop/cse?cx=007185308018807068018%3Ax2z07lqx3mg
which can give you more detailed explanation with scientific terms and so on .