Association between Smoking Status and Clostridium difficile Infection in Medicare Beneficiaries in the United States, 1991–2007.

Footnotes:aOdds ratio for C. difficile infection (yes/no).bIncidence rate ratio for number of C. difficile-related visits.cCovariates were year of birth (centered), sex, race, ethnicity, body mass index, alcohol use, marital status, education, total assets, region of residence, heart disease, chronic lung disease, diabetes mellitus, stroke, end-stage renal disease, depression, Crohn’s disease, ulcerative colitis, irritable bowel disease, celiac disease, number of medical visits, number of infection-related visits.