Contributions
Abstract: P357
Type: Poster Sessions
Abstract Category: Clinical aspects of MS - Epidemiology
Background: Several studies have previously indicated an increased risk of multiple sclerosis (MS) after exposure to organic solvents. Scientific results, however, have been contradictory and there has been debate on this issue. We sought to examine the association between exposure to organic solvents and MS risk adjusted for other known risk factors.
Method: Reports on prior occupational organic solvent exposure were provided by 1197 MS cases and 2361 population-based frequency matched controls from Norway and Sweden within the multinational case-control study on Environmental Risk Factors in Multiple Sclerosis (EnvIMS).
Results: Exposure to organic solvents was associated with an increased risk for MS with an OR of 1.46 (CI 95%: 1.16-1.83). The association remained similar in multivariable analyses adjusted for other established risk factors including smoking, having had infectious mononucleosis or low outdoor activity during adolescence as indication of low vitamin D status. In subgroup analyses, we found that the risk associated with organic solvents was only seen among persons who had smoked (OR=1.53 vs 1.11 for non-smokers; test for interaction p=0.06) and among those who had indication of low vitamin D status during adolescence (OR=2.28 vs 1.08 for higher vitamin D-status; test of interaction p=0.002).
Conclusion: In this study, we found that prior exposure to organic solvents was associated with an increased risk of MS. Interestingly, the increased risk seems to be present only in individuals at increased risk by smoking and low vitamin D-status. Potential mechanisms include increased permeability of the blood brain barrier through solvent exposure, which enables access to the CNS for immune competent blood cells triggered in the lungs due to tobacco smoking.
Acknowledgements: FISM grants 2007/R/14, 2008/R/19
Disclosure: The auther(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this abstract
Abstract: P357
Type: Poster Sessions
Abstract Category: Clinical aspects of MS - Epidemiology
Background: Several studies have previously indicated an increased risk of multiple sclerosis (MS) after exposure to organic solvents. Scientific results, however, have been contradictory and there has been debate on this issue. We sought to examine the association between exposure to organic solvents and MS risk adjusted for other known risk factors.
Method: Reports on prior occupational organic solvent exposure were provided by 1197 MS cases and 2361 population-based frequency matched controls from Norway and Sweden within the multinational case-control study on Environmental Risk Factors in Multiple Sclerosis (EnvIMS).
Results: Exposure to organic solvents was associated with an increased risk for MS with an OR of 1.46 (CI 95%: 1.16-1.83). The association remained similar in multivariable analyses adjusted for other established risk factors including smoking, having had infectious mononucleosis or low outdoor activity during adolescence as indication of low vitamin D status. In subgroup analyses, we found that the risk associated with organic solvents was only seen among persons who had smoked (OR=1.53 vs 1.11 for non-smokers; test for interaction p=0.06) and among those who had indication of low vitamin D status during adolescence (OR=2.28 vs 1.08 for higher vitamin D-status; test of interaction p=0.002).
Conclusion: In this study, we found that prior exposure to organic solvents was associated with an increased risk of MS. Interestingly, the increased risk seems to be present only in individuals at increased risk by smoking and low vitamin D-status. Potential mechanisms include increased permeability of the blood brain barrier through solvent exposure, which enables access to the CNS for immune competent blood cells triggered in the lungs due to tobacco smoking.
Acknowledgements: FISM grants 2007/R/14, 2008/R/19
Disclosure: The auther(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this abstract