REDUCED DURATION OF BREASTFEEDING IS ASSOCIATED WITH A HIGHER RISK OF MS IN BOTH ITALIAN AND NORWEGIAN ADULT MALES: THE ENVIMS STUDY

Background: Longer duration of breastfeeding is associated with a reduced risk of allergic and immune-mediated diseases including multiple sclerosis (MS). With a large multinational casecontrol study, we investigated the association between breastfeeding and MS risk in two distinct populations. Methods: A questionnaire (EnvIMS-Q) eliciting information on feeding practices during the first year of life was administered to individuals with MS and frequency age and sex-matched controls from Italy and Norway. Two exposure categories were created: breastfeeding for at least 4 months (reference), no breastfeeding/breastfeeding for 3 months or less (reduced exposure). Logistic regression with odds ratio (ORs) and 95% confidence intervals (95% CIs), adjusting for covariates was used to assess the association. Results: 547 cases and 1039 controls in Italy, and 737 cases and 1335 controls in Norway were included. A significant association of MS with ‘reduced exposure’ to breastfeeding was found in Italy (ORadj  = 1.37 (1.09, 1.73)), but not in Norway (ORadj  = 1.13 (0.91, 1.40)). For both countries significant associations were observed in men (ORItaly 2.33 (1.50, 3.65), ORNorway 2.11 (1.30, 3.44)). Conclusion: Shorter duration of breastfeed was associated with an increased risk of MS in men in Italy and in Norway. Acknowledgements: FISM (2007/R/14, 2008/R/19), Regione Autonoma Sardegna, Assessorato Igiene/Sanità, Italy.