Hypertension often has a strong genetic component. Indeed, studies have shown that certain ethnic groups - people of Latin American and African decent, for example - have higher incidences than other groups.
There are still many myths out there about it, such as if you're normal weight, don't smoke, eat well, don't have a lot of stress, exercise and eat a healthy diet, you cannot get hypertension.
That's not true.
What Kif says is sensible, however. Overweight is a factor in the development of hypertension, as is smoking, excessive drinking - moderate drinking can actually be helpful, and sedentary lifestyle.
My father's family has a very strong history of hypertension. He was 42 when he was first diagnosed, and still struggles to control it.
My sister, age 39, is on medication, however. I have borderline hyptertension myself, probably kept in check by doing lots of exercise and eating about 80% vegetarian. I do drink a glass or two of wine or watered down wine a day.
BUT, diagnosed early and carefully managed, it's not a given that all people w/hypertension will go on to develop heart disease.
It's also possible to treat it to get it under control and then manage it w/lifestyle changes entirely. But again, this requires checking it regularly.
Kif speaks sense! It can also be a secondary symptom. In my FIL's case, it was a secondary symptom of his Type II diabetes.
He is seeing a doctor, however, and hopefully they will get to the bottom of it!
If he smokes, he needs to get treatment to try to quit.
Smoking and hypertension are a very bad combination.