BACKGROUND AND PURPOSE: 

• Despite research efforts, amyotrophic lateral sclerosis (ALS) remains a fatal disease with no known etiology  
• There is some research implicating genetics but limited data on environmental factors 
• Men are more commonly affected and when women are diagnosed with ALS, they tend to be older  
  • Additional studies suggest that sex hormones may modulate ALS risk  
• Rooney et al. (Neurology, 2017) sought to determine if exogenous hormone exposure may be associated with risk for ALS in women 

METHODS: 

• Case-Control study  
• Euro-MOTOR Consortium   
  • Generation of data on potential environmental etiologic factors from ALS cases and controls across 3 different countries (Ireland, Italy, and the Netherlands) 
  • Incident cases and controls matched by age, sex, and location 
• A validated questionnaire was used to assess hormonal exposures, including reproductive history, breastfeeding, contraceptive use, hormonal replacement therapy, and gynecologic surgical history 
• Multivariate logistic regression models adjusted for biasing factors and applied to determine association between female hormones and ALS risk 

RESULTS: 

• Study included 653 patients and 1,217 controls  
• History of ever having used oral contraceptives (OCP) was significantly associated with reduced ALS risk 
  • Odds ratio (OR) 0.65, 95% CI 0.51-0.84 
  • Dose-response effect was observed between duration of OCP use and reduced ALS risk  
    • OR 0.98, 95% CI 0.96–0.99 per year of use 
• Hormone treatment (HT) was associated with a reduced risk of ALS, but only in the Netherlands  
  • OR 0.57, 95% CI 0.37-0.85 
  • Isolated finding to Netherland only may be related to lower prevalence of HT users or different formulations elsewhere 
• History of hysterectomy or oophorectomy was not associated with ALS 

CONCLUSION: 

• There appears to be an association between exogenous estrogens and progestogens and reduced ALS risk in women 
• Hormonal factors may be important etiological factors in ALS 
• While this study is currently the largest on this topic, some of the findings contradict previous studies and authors recommend further research to replicate their findings 

Learn More – Primary Sources:  

A case-control study of hormonal exposures as etiologic factors for ALS in women: Euro-MOTOR

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