Nav: Home

Incidence of most fatal type of stroke decreasing -- thanks to a decrease in smoking?

August 12, 2016

A new study indicates that Finland's national tobacco policies seem to be radically reducing the incidence of subarachnoid haemorrhage, the most fatal form of stroke.

Previously it was thought that in Finland approximately a thousand people suffer subarachnoid haemorrhage (SAH) every year - most of them adults of working age. Up to half of those afflicted die within a year. Subarachnoid haemorrhage is typically caused by a ruptured cerebral aneurysm, which leads to a sudden increase in the intracranial pressure. Smoking is a key risk factor for SAH.

A Finnish study published in the journal Neurology looked at changes in the incidence of subarachnoid haemorrhage over a period of 15 years (1998-2012), and these were contrasted with changes in the prevalence of smoking. The results indicated that the number of people afflicted with SAH was nearly half of the previously assumed figure and that the number was in rapid decline, a trend which was particularly apparent in younger generations.

Within fifteen years, the prevalence of SAH had decreased by 45% among women, and 38% among men, under 50. During the same period, the prevalence of SAH decreased by 16% among women, and 26% among men, over 50. Smoking among Finns aged 15-64 decreased by 30% during the monitoring period.

"It is extraordinary for the incidence of any cardiovascular disease to decrease so rapidly at the population level in such a short time," says Professor Jaakko Kaprio from the University of Helsinki, one of the primary authors of the study and director of the Institute for Molecular Medicine Finland. "Even though we cannot demonstrate a direct causation in nation-wide studies, it is highly likely that the national tobacco policies in Finland have contributed to the decline in the incidence of this type of severe brain haemorrhage."

Cerebral aneurysms are fairly common - they are present in up to more than 10% of people over the age of 70 - but most of them never rupture. For decades, researchers have been searching for factors which could be used to identify persons at high risk of aneurysm ruptures and who should consequently be treated.

"Previous studies have indicated that smoking is one of the most important susceptibility factors for rupturing aneurysms, so in that sense the now established connection between a decrease in smoking and a decrease in SAH is not surprising," says the other primary author of the new study, Miikka Korja, a neurosurgeon at Helsinki University Hospital.

UNRELIABLE INCIDENCE STATISTICS FOR SAH

Dr. Miikka Korja points out that in most countries the incidence of SAH is unknown, as patients who immediately die of a haemorrhage outside of hospital are often erroneously classified as having succumbed to heart failure. In Finland, autopsies are conducted in most cases where a death occurs outside of hospital, confirming the cause of death.

"According to the research, approximately one fourth of people with subarachnoid haemorrhages have died outside of hospital or in the emergency room. All Nordic countries include deaths outside of hospitals in their incidence statistics for SAH, and have reached largely similar estimates. Nevertheless, assumptions of an extraordinarily high prevalence of SAH in Finland have been repeatedly stated, even in top medical journals, leading to Finnish SAH and aneurysm studies being disregarded in general surveys and recommendations. However, research does not back this assumption," Korja states.
-end-


University of Helsinki

Related Smoking Articles:

Smoking rates falling in adults, but stroke survivors' smoking rates remain steady
While the rate of Americans who smoke tobacco has fallen steadily over the last two decades, the rate of stroke survivors who smoke has not changed significantly.
What is your risk from smoking? Your network knows!
A new study from researchers at Penn's Annenberg School for Communication found that most people, smokers and non-smokers alike, were nowhere near accurate in their answers to questions about smoking's health effects.
Want to quit smoking? Partner up
Kicking the habit works best in pairs. That's the main message of a study presented today at EuroPrevent 2019, a scientific congress of the European Society of Cardiology (ESC).
Smoking and mortality in Asia
In this analysis of data from 20 studies conducted in China, Japan, South Korea, Singapore, Taiwan and India with more than 1 million participants, deaths associated with smoking continued to increase among men in Asia grouped by the years in which they were born.
Predictors of successfully quitting smoking among smokers registered at the quit smoking clinic at a public hospital in northeastern Malaysia
In the current issue of Family Medicine and Community Health, Nur Izzati Mohammad et al. consider how cigarette smoking is one of the risk factors leading to noncommunicable diseases such as cardiovascular and respiratory system diseases and cancer.
Restaurant and bar smoking bans do reduce smoking, especially among the highly educated
Smoking risk drops significantly in college graduates when they live near areas that have completely banned smoking in bars and restaurants, according to a new study in the American Journal of Epidemiology.
How the UK smoking ban increased wellbeing
Married women with children reported the largest increase in well-being following the smoking bans in the UK in 2006 and 2007 but there was no comparable increase for married men with children.
Smoking study personalizes treatment
A simple blood test is allowing Vanderbilt University Medical Center (VUMC) researchers to determine which patients should be prescribed varenicline (Chantix) to stop smoking and which patients could do just as well, and avoid side effects, by using a nicotine patch.
A biophysical smoking gun
While much about Alzheimer's disease remains a mystery, scientists do know that part of the disease's progression involves a normal protein called tau, aggregating to form ropelike inclusions within brain cells that eventually strangle the neurons.
A case where smoking helped
A mutation in the hemoglobin of a young woman in Germany was found to cause her mild anemia.
More Smoking News and Smoking Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.