Smoking ‘increases the risk of early death from motor neurone disease’
Also known as ALS, the disease is a progressive degenerative illness affecting nerve cells that allow you to speak, swallow and breathe
Smokers diagnosed with motor neurone disease are more likely to die than those patients who don't smoke, new evidence has suggested.
Smokers are also likely to see the symptoms of the disease, also known as amyotrophic lateral sclerosis or ALS, appear at a younger age.
ALS, the focus of the worldwide Ice Bucket Challenge in 2014, which raised a staggering £88 million or $115 million, is a progressive degenerative disease affecting nerve cells in the brain and spinal cord (motor neurons).
These nerve cells control a range of muscle functions from speaking and swallowing to breathing.
Motor neurone disease affects around two in every 100,000 people in the UK every year.
There is currently no cure for the disease, but scientists have linked various factors to its development - including genes, age, gender, underlying conditions and lifestyle.
In a bid to find out if tobacco might play a role, a team of researchers gathered information on the smoking habits and evidence of respiratory disease (COPD) among 650 people diagnosed with ALS between 2007 and 2011 in one region of northern Italy.
Of the patients, 121 (18.6 per cent) were regular smokers at the time they were diagnosed with ALS.
Meanwhile, 182 (28 per cent) had stubbed out their habit before diagnosis, while 347 (53.4 per cent) were life-long non-smokers.
In total, 44 of the patients had COPD, which is known to shorten a person's lifespan; 22 of them were ex-smokers.
The average survival of patients with COPD was shorter than that of people without it.
But smoking seemed to be linked to faster disease progression and how long a patient lived after diagnosis, whether or not they had underlying COPD.
Current smokers had a significantly shorter lifespan than did either ex-smokers or lifelong non-smokers.
They survived an average of one year and nine months while former smokers survived an average of two years and three months, and non-smokers lived for an average of two years and seven months after diagnosis.
This difference held true irrespective of the age at which symptoms started, where they started, gender, or severity of COPD.
Smokers also tended to be younger when diagnosed, averaging just under 65, than either ex-smokers (67.5), or lifelong non-smokers (just over 66), and they tended to experience more rapid disease progression.
This is an observational study, so no firm conclusions can be drawn about cause and effect, and while the researchers describe their findings as “intriguing,” they point out that as yet it is unclear how smoking might affect the development and progression of ALS.
Several possible explanations have been mooted, including disruption of enzymes that curb free radical damage, and the potential for smoking to damage DNA, with the effects persisting even after a smoker has quit.
The findings are published online in the Journal of Neurology Neurosurgery and Psychiatry.