Objective: The use of moist snuff is common in Sweden and leads to exposure to high doses of nicotine. Recent studies indicate that exposure to nicotine could modulate immune responses. The aim of this study was to investigate the influence of snuff use on the risk of developing multiple sclerosis (MS), taking smoking habits into consideration.
Methods: In two Swedish population-based, case-control studies (7883 cases, 9437 controls), subjects with different snuff use habits were compared regarding MS risk, by calculating odds ratios (ORs) with 95% confidence intervals (CIs).
Results: Snuff-takers have a decreased risk of developing MS compared with those who have never used moist snuff (OR 0.83, 95% CI 0.75-0.92), and we found clear evidence of an inverse dose-response correlation between cumulative dose of snuff use and the risk of developing the disease. We further observed that subjects who combined smoking and snuff use had a significantly lower risk for MS than smokers who had never used moist snuff, also after adjustment for amount of smoking.
Conclusions: Our results add evidence to the hypothesis that nicotine exerts anti-inflammatory and immune-modulating effects in a way that might decrease the risk of developing MS.
Swedish Snuff is not snorted like British Snuff, but it (Snug) is placed around the Gum
This study provides somewhat surprising results! It has been well-established that smoking is associated with an increased risk of MS, and this group have previously shown that this increased risk is not present in those who use snuff/chewing tobacco. We don't yet know why smoking appears to increase MS risk, and this study hints that it might be the route of delivery (i.e. tobacco smoke in the lungs) that is important. There is clearly more work to be done here to better understand this.
However, this is not a reason to start chewing tobacco - this has been associated with an increased risk of cancer in the same way that smoking is: http://www.cancer.gov/cancertopics/factsheet/Tobacco/smokeless