title: Cigarette smoking adversely affects disease activity and disease-specific quality of life in patients with Crohn's disease at a tertiary referral center.
abstract: OBJECTIVE
  Smoking has a negative impact on disease activity in Crohn's disease (CD). Smoking may also affect the quality of life, but this has not been evaluated using validated measures over time. We assessed the relationship between smoking and disease-specific quality of life over time in a tertiary referral inflammatory bowel disease cohort.
  
  
  METHODS
  Retrospective cohort study from July 2004 to July 2009 in patients with CD identified from the University of Maryland, Baltimore, Institutional Review Board-approved University of Maryland School of Medicine Inflammatory Bowel Disease Program database. Smoking status was classified as current, former, and never. Age was categorized as <40 years, 40-59 years, and ≥60 years. Index visit disease activity and quality of life was measured with the Harvey-Bradshaw index, and the Short Inflammatory Bowel Disease Questionnaire (SIBDQ). Repeated measures linear regression was used to assess the association between smoking and quality of life over time after adjustment for confounding variables.
  
  
  RESULTS
  A total of 608 patients were included, of whom 42% were male; 80% were Caucasian; 22% were current smokers; 24% were former smokers; and 54% were never smokers. Over time, adjusted Harvey-Bradshaw index scores declined in all patients, but current smokers had consistently higher scores. After adjustment for sex, age, and disease duration, never smokers had higher mean SIBDQ scores at index visit compared to former and current smokers (P<0.0001); all increased over time but SIBDQ scores for never smokers remained consistently highest.
  
  
  CONCLUSIONS
  Smoking has a negative impact on disease activity and quality of life in patients with CD. Prospects of improved disease activity and quality of life should be proposed as an additional incentive to encourage smoking cessation in patients with CD.
authors.affiliation: Division of Gastroenterology and Hepatology.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Quezada
authors.affiliation: Division of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Langenberg
authors.affiliation: Division of Gastroenterology and Hepatology.
authors.forename: Raymond K
authors.initials: RK
authors.lastname: Cross
keywords: Harvey–Bradshaw index; SIBDQ; inflammatory bowel disease