Smoking escalates the risk of developing Amyotrophic Lateral Sclerosis (ALS), which is also called as Lou Gehrig's disease, researchers said.

Lead researcher and neurologist Dr. Carmel Armon, from Baystate Medical Centre, has found compelling evidence linking smoking and ALS, and insists it can now be considered an 'established' risk factor.

ALS is a fatal neurodegenerative disease affecting the motor nerves and the voluntary muscles.

"Application of evidence-based methods, separates better-designed studies from studies with limitations that may not be relied on.

The better-designed studies show consistently that smoking increases the risk of developing ALS, with some findings suggesting that smoking may be implicated directly in causing the disease," said Armon.

He says that identifying smoking as an established risk factor for ALS has three implications.

"First and foremost the findings provide a link between the environment and the occurrence of ALS, where none had been previously identified with this level of certainty," said Armon.

"Additional implications are that since smoking has no redeeming features, avoidance of smoking may reduce the occurrence of ALS in the future, and since some of the mechanisms by which smoking causes other diseases in humans are understood fairly well, recognizing its role in the occurrence of ALS may help pinpoint the biological processes that initiate the disease," he added.