Gender and Age Differences in Lifestyle Factors and Risk of Amyotrophic Lateral Sclerosis; A Case-Control Study in Japan

Background: We examined associations between lifestyle factors and the risk of ALS by combination of gender and age group (<65 year vs. ≥65 years), using a population-based case-control study in Japan. Methods: The study comprised 183 ALS patients diagnosed by El Escorial World Federation of Neurology criteria, and 306 gendersand age-matched controls randomly selected from the general population using the basic register of residents. Detailed information on lifestyle factors was obtained through a mailed self-administered questionnaire. The strength of association between ALS and a potential risk factor was assessed by calculating Odds Ratios (ORs) and 95% Confidence Intervals (CIs). Results: Type A behavior pattern was significantly associated with an increased ALS risk in all combination of gender and age group, and frequent intake of green-yellow vegetable was associated with an increased ALS risk in combination of gender and age group other than men ≥65 years. Moreover, vigorous exercise was associated with an increased ALS risk among men aged <65 years, and self-reported stress in both men and women aged ≥65 years. Conclusion: The present study found that Type A behavior pattern was associated with an increased ALS risk in all combination of gender and age group (<65 year vs. ≥65 years), the lifestyle factors were observed significant association only specific in combination of gender and age group. These findings suggest that Type A behavior as patient-specific endogenous oxidative stress may increase the risk of ALS common in all combination of gender and age group.