New York, Nov 4 (IANS): Smokers are three times more likely than non-smokers to develop chronic back pain, warns a research.

"Smoking affects the brain. We found that it affects the way the brain responds to back pain and seems to make individuals less resilient to an episode of pain," said Bogdan Petre, technical scientist at the Northwestern University's Feinberg School of Medicine in the US.

The results came from an observational study of 160 adults, with new cases of back pain.

They were asked to rate the intensity of their back pain in a questionnaire that also asked about their smoking status.

Scientists analysed MRI activity between two brain areas, which are involved in addictive behaviour and motivated learning.

These two regions of the brain "talk" to one another and scientists discovered that the strength of that connection helps determine who will become a chronic pain patient.

This connection was very strong and active in the brain's of smokers.

"But we saw a dramatic drop in this circuit's activity in smokers who - of their own will - quit smoking during the study. When they stopped smoking, their vulnerably to chronic pain also decreased," Petre added.

Medication such as anti-inflammatory drugs did help participants manage pain but it did not change the activity of the brain circuit.

Kicking the butt is the only solution if smokers want to get rid of back pain, the authors concluded.

The study was published online in the journal Human Brain Mapping.