—Dr Harding mentions an apparent discrepancy in the number of cataracts in our recent study of cigarette smoking and our earlier aspirin study.1 In the cigarette smoking study we analyzed eyes with cataract, whereas in the aspirin study we analyzed people with cataract. In addition, we were able to identify additional incident cases since the publication of the aspirin results.Dr Salchert questions whether the study medications may have affected the results. All analyses were adjusted for the potential confounding effects of treatment assignment so the relationship of cigarette smoking with cataract was independent of study treatment. Questions concerning cataract and macular degeneration were asked of study participants because of scientific evidence that study medications might lower the risk of these diseases.Finally, Drs Ravenholt, Roy, and Harding propose mechanisms that require further study.
Christen WG, Manson JE, Glynn RJ, Buring JE, Rosner B, Hennekens CH, Seddon JM. Cigarette Smoking and Risk of Cataracts-Reply. JAMA. 1993;269(6):748. doi:10.1001/jama.1993.03500060047028