Hypertensive female smokers are at an exceptionally high risk of fatal brain hemorrhage.
University researchers have found that hypertension is a major risk factor for subarachnoid haemorrhage (SAH) ― one of the most devastating cerebrovascular catastrophes causing death in 40 to 50 percent of cases.
In a press statement, published by international, online journal PLOS ONE, the researchers say that the most common cause of SAH is a rupture of an intracranial aneurysm. If found, it can be treated before rupture. However, some will never rupture and doctors don’t know which will and which won’t. Therefore, they don’t know which patients should be treated and who can safely be left untreated.
This is why it is important to identify SAH risk factors. To-date, prospective studies have been limited and little is known about the effect of risk factors on incidence rates. The new research is the largest SAH risk factor study ever and most long-term (nearly ten years).
The study has found that the risk of SAH depends strongly on a combination of certain risk factors, namely: increasing age, female sex, hypertension and smoking. Interestingly, high body mass index (BMI) may decrease the risk. In fact, “such an extreme risk factor-dependent variation in the incidence of any cardiovascular disease is exceptional, and may have significant clinical implications,” said one of the main study authors, Associate Professor Miikka Korja from the Helsinki University Central Hospital and Australian School of Advanced Medicine.
They also said that female smokers with high systolic blood pressure have 20 times higher rates of these brain bleeds than never-smoking men with low blood pressure. They said this may mean that these women diagnosed with unruptured intracranial aneurysms should be treated. Alternatively, never-smoking men with low blood pressure values and intracranial aneurysms may not need to be treated at all.
The study group also identified three new risk factors for SAH: previous myocardial infarction, history of stroke in mother, and elevated cholesterol levels in men. These results revise the understanding of the epidemiology of SAH and indicate that the risk factors are similar to those for other cardiovascular diseases.
“We have previously shown that lifestyle risk factors affect significantly the life expectancy of SAH survivors, and now we have shown that the same risk factors also affect dramatically the risk of SAH itself. Thus, it appears quite clear that especially smoking cessation and hypertension treatment are important in preventing SAH and increasing life expectancy after SAH,” concluded one of the study group members, Academy Professor Jaakko Kaprio, from the University of Helsinki and National Institute for Health and Welfare. The researchers say they hope their findings truly help doctors and patients.