An association between smoking and Amyotrophic Lateral Sclerosis (ALS), a rare, progressive neurodegenerative disorder characterized by the progressive degeneration of nerve cells in the brain, brainstem, and spinal cord.

You design a study to determine if there is an association between smoking and Amyotrophic Lateral Sclerosis (ALS), a rare, progressive neurodegenerative disorder characterized by the progressive degeneration of nerve cells in the brain, brainstem, and spinal cord. You recruit 50 individuals with ALS (ALS+) and 100 individuals who did not have ALS (ALS-). Participants then fill out a questionnaire about past and current cigarette smoking habits. Of your 50 cases, 15 report having ever smoked cigarettes. Of your 100 controls, 25 report having ever smoked cigarettes. Start by filling out the 2×2 table for the scenario. a. What is the study design? b. Provide a specific case-definition for ALS for your study. In other words, how would you recruit individuals with ALS into your study? c. What are the odds of ever smoking cigarettes among people with ALS (ALS+)? d. What are the odds of ever smoking cigarettes among people who did not have ALS (ALS-)? e. What is the odds ratio of smoking cigarettes comparing people who did have ALS (ALS+) and those who did not have ALS (ALS-)? Interpret your odds ratio in a sentence.