1. Smoking And Outcome From Traumatic Brain Injury Olli Tenovuo Department of Neurology University of Turku Finland

2. Introduction The cholinergic system is known to be frequently involved in the chronic sequels of TBI.The cholinergic system is known to be frequently involved in the chronic sequels of TBI. Nicotine is a strong modulator of the cholinergic system.Nicotine is a strong modulator of the cholinergic system.

3. Purpose of the study To study whether smoking history is connected with the outcome from TBI,whether smoking history is connected with the outcome from TBI, whether the response to cholinergic drugs depends on the smoking history in victims of TBI.whether the response to cholinergic drugs depends on the smoking history in victims of TBI.

4. Material and methods A questionnaire concerning the smoking and drinking history, the eventual response to cholinergic drugs and the subjective outcome from TBI was sent to all TBI patients included in a database of 1029 patients, treated at a neurological outpatient university clinic after 1.1.1993.

5. Material and methods, continued In total, 531 patients responded.In total, 531 patients responded. Data on injury severity (measured with Glasgow Coma Scale and duration of posttraumatic amnesia) and outcome (measured with the Glasgow Outcome Scale, extended version = GOS-E) were collected from the medical records.Data on injury severity (measured with Glasgow Coma Scale and duration of posttraumatic amnesia) and outcome (measured with the Glasgow Outcome Scale, extended version = GOS-E) were collected from the medical records.

6. Results Those who had smoked at the time of injury (n = 216) were significantly younger (p < 0.001).Those who had smoked at the time of injury (n = 216) were significantly younger (p < 0.001). The smokers showed a poorer outcome measured with the GOS-E, also after taking into account TBI severity and age (p = 0.03).The smokers showed a poorer outcome measured with the GOS-E, also after taking into account TBI severity and age (p = 0.03). The subjective recovery between the smokers and non-smokers did not differ (p = 0.11)The subjective recovery between the smokers and non-smokers did not differ (p = 0.11)

7. Results, continued One-fourth (24 %) of the smokers felt that the effect of smoking had changed due to the injury.One-fourth (24 %) of the smokers felt that the effect of smoking had changed due to the injury. In 83 % of these the effect had become more negative, and 25 % of those who had smoked at the time of injury had stopped smoking afterwards.In 83 % of these the effect had become more negative, and 25 % of those who had smoked at the time of injury had stopped smoking afterwards.

8. Results, continued The tolerance for alcohol had decreased in 52 % and increased in 5 % of those who had used alcohol after the injury (n = 424).The tolerance for alcohol had decreased in 52 % and increased in 5 % of those who had used alcohol after the injury (n = 424). After the injury, 11 % had stopped and 36 % had reduced their alcohol consumption, but in 16 % consumption had increased.After the injury, 11 % had stopped and 36 % had reduced their alcohol consumption, but in 16 % consumption had increased.

9. Results, continued Altogether 28 % of patients had tried cholinergic medication, but the treatment response was very similar in both smokers and non-smokers (p = 0.71).Altogether 28 % of patients had tried cholinergic medication, but the treatment response was very similar in both smokers and non-smokers (p = 0.71).

10. Discussion These results suggest that smoking at the time of injury may have a negative influence on the outcome of TBI.These results suggest that smoking at the time of injury may have a negative influence on the outcome of TBI. TBI frequently lowers the tolerance for tobacco, and especially for alcohol.TBI frequently lowers the tolerance for tobacco, and especially for alcohol. Many TBI patients stop smoking and drinking after the injury, and although altered financial status may have an effect, the lowered tolerance has an apparent influence.Many TBI patients stop smoking and drinking after the injury, and although altered financial status may have an effect, the lowered tolerance has an apparent influence. The treatment response to cholinergic stimulation does not seem to depend on smoking history.The treatment response to cholinergic stimulation does not seem to depend on smoking history.

11. Discussion, continued In theory, modulation of the cholinergic system by smoking could affect the brains ability to recoverIn theory, modulation of the cholinergic system by smoking could affect the brains ability to recover This study suggests that this may hold true in humans, but the eventual realtionship may also be indirect (e.g. smokers having more abuse problems or lower education and thus lower cognitive reserve)This study suggests that this may hold true in humans, but the eventual realtionship may also be indirect (e.g. smokers having more abuse problems or lower education and thus lower cognitive reserve)