Crohn's Disease More Prevalent in States with High Smoking Rates

Although many studies have found Crohn’s disease (CD) patients are more likely to smoke than the general population, only a few have examined CD prevalence as it relates to regional smoking rates.

Compared to non-smokers, Crohn’s disease patients who smoke have a 2.5-fold increased risk of surgical recurrence, as well as twice the risk of relapsing disease. In light of the theory that smoking aggravates CD, researchers from the Price Institute of Surgical Research in Louisville, KY, hypothesized that states with high smoking rates also have high CD rates. To test their assumption, the investigators designed a population-based study and published their work as a letter in the online version of the Journal of Clinical Gastroenterology.

To acquire discharge data on CD, ulcerative colitis (UC), and lung cancer, the study authors turned to the Healthcare Cost and Utilization Project (HCUP), which collects patient discharge information from 30 US states. They also utilized International Classification of Diseases, 9th revision (ICD-9) codes to identify discharges associated with these disease states, as well as data from the US Centers for Disease Control and Prevention (CDC) to estimate smoking prevalence rates among adults residing in the 30 states included in the study.

According to the researchers, West Virginia, Kentucky, Missouri, Oklahoma, and Tennessee had the highest smoking rates — with approximately one-quarter of their populations identifying as smokers — while Utah, California, New Jersey, Maryland, and Arizona had the lowest rates.

After performing linear regression analysis on their data, the researchers verified a clear, significant correlation between smoking and high rates of hospital discharges for lung cancer and CD, though there was no relationship between smoking and hospital discharges for UC. In response to their findings, the authors urged clinicians to counsel and reiterate “stop smoking” messages to patients who have CD.