Background: Environmental factors are associated with acquiring multiple sclerosis (MS) particularly in adolescence. Objective: To test for association between MS and exposure to passive smoking at the age of 10–19. Methods: A total of 919 patients from the Danish MS Registry and Biobank and 3419 healthy blood donors who had not smoked before the age of 19 were targeted. We analyzed separately for each sex and for those never-smokers (cohort 1) and active smokers above the age of 19 (cohort 2). All participants completed standardized questionnaires about smoking and lifestyle. We matched cases and controls in the ratio of 1:2 by propensity scores discarding unmatchable individuals and used logistic regression adjusted for all covariates and interactions. Results: After matching, we included 110/213 male cases/controls and 232/377 female case/controls in cohort 1. In cohort 2, the numbers were 160/320 and 417/760, respectively. Among women in cohort 1, the odds ratio (OR) for MS by passive smoking at the age of 10–19 was 1.432 (p = 0.037) but in men it was 1.232 (p = 0.39). Among men in cohort 2, OR was 1.593 (p = 0.022) but among women it was only 1.102 (p = 0.44). Conclusion: Among never smokers, female MS cases were more often than female controls reported with passive smoking between the age of 10 and 19, and among smokers above the age of 19, male MS patients were more often than male controls reported with passive smoking.

中文翻译：

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青春期接触被动吸烟会增加患多发性硬化症的风险

背景：环境因素与获得多发性硬化症 (MS) 相关，尤其是在青春期。目的：测试 MS 与 10-19 岁接触被动吸烟之间的关联。方法：共有来自丹麦 MS Registry and Biobank 的 919 名患者和 3419 名 19 岁之前未吸烟的健康献血者为目标。我们分别分析了每个性别和从不吸烟者（队列 1）和 19 岁以上的活跃吸烟者（队列 2）。所有参与者都完成了关于吸烟和生活方式的标准化问卷。我们通过倾向评分以 1:2 的比例匹配病例和对照，丢弃无法匹配的个体，并使用对所有协变量和相互作用进行调整的逻辑回归。结果：匹配后，我们在队列 1 中包括 110/213 男性病例/对照和 232/377 女性病例/对照。在队列 2 中，数字分别为 160/320 和 417/760。在队列 1 的女性中，10-19 岁被动吸烟导致 MS 的优势比 (OR) 为 1.432 (p = 0.037)，但在男性中为 1.232 (p = 0.39)。在队列 2 的男性中，OR 为 1.593 (p = 0.022)，但在女性中仅为 1.102 (p = 0.44)。结论：在从不吸烟者中，10~19 岁之间被动吸烟的女性 MS 患者多于女性对照组，19 岁以上吸烟者中，男性 MS 患者被动吸烟的比例高于男性对照组。037) 但在男性中为 1.232 (p = 0.39)。在队列 2 的男性中，OR 为 1.593 (p = 0.022)，但在女性中仅为 1.102 (p = 0.44)。结论：在从不吸烟者中，10~19 岁之间被动吸烟的女性 MS 患者多于女性对照组，19 岁以上吸烟者中，男性 MS 患者被动吸烟的比例高于男性对照组。037) 但在男性中为 1.232 (p = 0.39)。在队列 2 的男性中，OR 为 1.593 (p = 0.022)，但在女性中仅为 1.102 (p = 0.44)。结论：在从不吸烟者中，10~19 岁之间被动吸烟的女性 MS 患者多于女性对照组，19 岁以上吸烟者中，男性 MS 患者被动吸烟的比例高于男性对照组。