Women smokers 4 times more likely to have bulge in brain's blood vessel, high BP increases risk 7-fold: Study
An estimated 6.5M people in the US alone are thought to have this condition known as brain aneurysm and if it bursts, the resulting bleed can be fatal
Women smokers are four times more likely than their non-smoking peers to have an unruptured aneurysm, which is a bulge or ballooning in a blood vessel in the brain. This risk is even greater, seven times as high, if they also have high blood pressure, say researchers from Harvard Medical School, Boston, and University at Buffalo School of Medicine and Biomedical Sciences, New York.
A brain aneurysm can leak or rupture, causing bleeding into the brain. A ruptured aneurysm requires treatment right away. According to the American Stroke Association, once an aneurysm bleeds, the chance of death is about 40% and the chance of some brain damage is about 66%, even if the aneurysm is treated. If the aneurysm is not treated quickly enough, another bleed may occur from the already ruptured aneurysm.
"An estimated 6.5 million people in the US alone are thought to harbor an unruptured brain aneurysm, a weakened bulging artery, in the brain. If an aneurysm bursts, the resulting bleed can be fatal. The known risk factors include a previous aneurysm, family history, multiple cysts on the kidneys (polycystic kidney disease), and connective tissue disorders," explains the research team in the study published in Journal of Neurology Neurosurgery & Psychiatry. The other US institutes involved in the research are Gates Vascular Institute, St Joseph’s Hospital and Medical Center, University of Calgary, University of Florida, and State University of New York.
The authors studied 545 women, aged 30 to 60, who were undergoing brain scans at five large teaching and research hospitals in the US and Canada between 2016 and 2018. "The decision to focus on patients within this age range (30 to 60 years) was based on the prevalence of cigarette smoking in the US, which has been reported to be the highest in patients aged between 30 and 60 years," they explain.
Imaging revealed that 152 of the 545 women had 185 unruptured brain aneurysms between them. Some 113 of these women were then matched with 113 others of the same age and ethnicity, but with normal scan results. The most common reason for a brain scan was a persistent headache, a symptom in nearly two-thirds of those with brain aneurysms (62.5%), and in nearly half of those without (44%), shows analysis. “Most of the aneurysms were located in the carotid artery, and on average, they measured 2-5 mm in diameter,” says the study.
Researchers found that high blood pressure was more common among women with abnormal brain scans (46% versus 31%) as was current or previous smoking (57.5% versus 37%). Women with brain aneurysms also tended to be heavier smokers than those with normal brain scans, averaging 20 cigarettes a day compared with 12. Women with brain aneurysms also smoked for longer: 29 years versus 20 years, on average.
When the two groups of women were directly compared, the authors found that smokers were four times as likely to have arterial abnormality as non-smokers, and they were seven times as likely to do so if they also had chronic high blood pressure. In two-thirds of cases (66%), no active treatment was given other than monitoring. But the remainder were treated with surgery and other invasive interventions. “From 545 eligible patients, 113 aneurysm patients were matched to 113 controls. Positive smoking history was encountered in 57.5% of cases and 37.2% of controls. Women aged between 30 and 60 years with a positive smoking history have a four-fold increased risk for having an unruptured intracranial aneurysm (UIA), and a seven-fold increased risk if they have underlying chronic hypertension," the findings state.
This is an observational study, and as such, cannot establish cause, say experts. The researchers also acknowledge that their study relied on patient recall and they did not have any information on rupture risk for those whose scans revealed an aneurysm. However, based on their findings, they suggest screening for unruptured brain aneurysms in women aged between 30 and 60 years who smoke cigarettes. "These findings indicate that women aged between 30 and 60 years with a positive smoking history could benefit from a screening recommendation," write authors.