Alcohol Consumption and MS Risk: Less alcohol is not necessarily better for you
In a report issued earlier this year researchers from the Karolinska Institutet in Stockholm, Sweden concluded that based on their research, drinking low levels of alcohol has little to no effect on the risk of developing MS. They also said that higher levels of alcohol consumption may actually protect against the development of MS. The possible association of alcohol consumption and risk of MS has been previously studied as part of two case-control studies and one prospective study with inconsistent results. Using large population-based studies, authors of the Stockholm report investigated the possible association of alcohol consumption and MS and related that association to the effects of smoking—a known risk factor in developing MS.
A statistically significant inverse association was found between alcohol consumption and the risk of developing MS in both men and women (Hedström, 2014). This means that those who regularly drank higher levels of alcohol were less likely to develop MS. The report is based on two case-control studies in Sweden: Epidemiological Investigation of Multiple Sclerosis (EIMS), and Genes and Environment in Multiple Sclerosis (GEMS).
In the EIMS study, only participants with a disease onset within the previous five years (study period April 2005 to June 2011) who reported no change in alcohol habits before and after developing MS were included in the analysis (745 cases, 1761 controls). In the GEMS study, detailed information was obtained regarding alcohol consumption during different age periods up to the participants’ current age (5874 cases, 5246 controls). Participants were recruited from the Swedish national MS registry between November 2009 and November 2011.
In EIMS, women who reported high alcohol consumption had an odds ratio (OR) of 0.6 (95% CI, 0.4-1.0) of developing MS compared with non-drinking women, whereas men with high alcohol consumption had an OR of 0.5 (95% CI, 0.2-1.0) compared with non-drinking men. In GEMS, the OR was 0.7 (95% CI, 0.6-0.9) for women and 0.7 (95% CI, 0.2-0.9) for men.
Alcohol consumption was categorized based on the amount of intake (grams of alcohol) per week: high consumption (>112 grams/week for women and >168 g/wk for men), moderate consumption (50-112 g/wk for women and 100-168 g/wk for men), and low consumption (<50 g/wk for women and <100 g/wk for men). One standard drink contains approximately 10 grams of alcohol. Examples of a standard drink, according to the Alcohol Advisory Counsel of New Zealand, include 100 ml glass of wine, 330 ml can of beer at 4 percent alcohol, or 30 ml shot of spirits.
In both studies, the risk reduction associated with alcohol consumption was more pronounced among smokers than among never smokers. Smokers who did not drink had odds ratios (OR) of 1.8 and 1.9 of developing MS compared with non-smokers who drank in EIMS and GEMS, respectively. The risk for smokers who drank was lower with OR of 1.4 in both studies.
Hedström et al. suggest that selection bias or reverse causality could have influenced their results, however they determined that this is unlikely. In addition to concluding that alcohol consumption exhibits a dose-dependent inverse association with MS risk, the study’s authors indicate that their findings give no support for advising patients with MS to completely refrain from alcohol.
In fact, moderate-alcohol consumption has anti-inflammatory effects by increasing cytokine interleukin (IL)-10 levels and decreasing monocyte inflammatory responses (Mandrekar, 2006). In a 1999 study, patients with untreated MS had lower levels of IL-10-secreting cells in peripheral blood compared with patients with other neurological diseases and healthy subjects (Ozenci, 1999). Patients treated with interferon beta-1b have normal levels of IL-10 (Ozenci, 2000).
Hedström AK, Hillert J, Olsson T, Alfredsson L. Alcohol as a Modifiable Lifestyle Factor Affecting Multiple Sclerosis Risk. JAMA Neurol. Published online January 6, 2014. doi:10.1001/jamaneurol.2013.5858. Accessed at http://www.ncbi.nlm.nih.gov/pubmed/24395432.
Mandrekar P, Catalano D, White B, Szabo G. Moderate alcohol intake in humans attenuates monocyte inflammatory responses. Alcohol Clin Exp Res. 2006;30(1):135-139.
Ozenci V, Kouwenhoven M, Huang YM, Xiao B, Kivisäkk P, Fredrikson S. Multiple sclerosis: levels of interleukin-10-secreting blood mononuclear cells are low in untreated patients but augmented during interferon-beta-1b treatment. Scand J Immunol. 1999 May;49(5):554-61. Accessed at http://www.ncbi.nlm.nih.gov/pubmed/10320650
Ozenci V, Kouwenhoven M, Huang YM, Xiao B, Kivisäkk P, Link H. Multiple sclerosis is associated with an imbalance between tumour necrosis factor-alpha (TNF-a)- and IL-10-secreting blood cells that is corrected by interferon-beta (IFN-b) treatment. Clin Exp Immunol. 2000 Apr;120(1):147-53. Accessed at http://www.ncbi.nlm.nih.gov/pubmed/10759776