Which of the following is a risk factor for ALS?

• A. Veterans
• B. NFL players
• C. Caucasian ethnicity
• D. All of the above

Answer: (D)

Risk factors for ALS include groups and exposures that studies have repeatedly linked to higher incidence. Military veterans have shown a higher risk in multiple analyses, which may reflect exposure to environmental toxins (like pesticides or solvents), physical stress, and injuries encountered during service. Among professional athletes in contact sports, increased ALS rates have been observed, potentially related to repetitive head trauma and the ensuing neuroinflammatory and axonal stress responses, though findings are not uniform across all studies. Caucasian ethnicity also shows a higher reported incidence of ALS compared with some other ethnic groups, suggesting a genetic predisposition and differing environmental exposures.

Because each of these factors has been associated with greater ALS risk, the most accurate choice is that all of the above are risk factors. Keep in mind that these are associations and do not guarantee disease development in any individual.