Materials and methods

A survey was designed and mailed to 2,000 members of the Rocky Mountain Chapter of the Crohn's Colitis Foundation (CCF) with mailing addresses in Colorado, Utah and Wyoming. The survey was also sent to 1,000 members of the Colorado Multiple Sclerosis Society (MSS), which was selected as a source of controls because of the organizational similarity to CCF. Members of the MSS include people with and without MS, which is a chronic, but non-enteric disease. Case respondents provided age of onset, basis of diagnosis, and family members affected. For each life stage, information collected included types and numbers of animals on premises, commercial livestock proximity, occupational history, dairy and meat consumption, and drinking water supply. Univariate analysis of binomial variables was performed with results considered significant at P<0.05.

Results

Response rate was 32.6% and 19.4% for the CCF and MS Society, respectively. A total of 395 cases and 455 controls were available for analysis. Age of cases was 48.7 years + 50.6 (SD) and 46.8 years +16.4 for controls. Age at diagnosis was 34.2+15.9 years. Univariate analysis identified several significant variables. Logistic regression analysis will be used to identify the factors that best explain the occurrence of CD. A cumulative risk model will also be developed.

Conclusions and limitations

Historical information obtained from this study will be the basis for a model describing exposure to risk factors and/or protective factors that are associated with CD. A key feature of this study was the assessment of potential risk factors for development of CD where early life exposures may be important.