Time trends of mortality from Crohn's disease and ulcerative colitis.

AIMS

The present study served to test whether Crohn's disease and ulcerative colitis showed similarities in the temporal variation of their mortality rates among different countries.

METHODS

Mortality data from 21 different countries between 1951 and 2005 were analysed, including Argentina, Australia, Austria, Belgium, Canada, Chile, Denmark, England, Finland, France, Germany, Italy, Japan, Mexico, Netherlands, Scotland, Spain, Sweden, Switzerland, Taiwan and USA. The age-specific death rates of each individual country, as well as the average age-specific rates of all countries, were plotted against the period of death.

RESULTS

Death rates from ulcerative colitis were initially 6-fold higher than those of Crohn's disease. Mortality from ulcerative colitis decreased continuously during the past 50 years. Mortality from Crohn's disease increased from 1951 to 1975 until reaching a similar level as mortality from ulcerative colitis. Since then the death rates of both diseases have followed a parallel time course. A same type of behaviour was found in the time trends of each individual age-group. The data from most countries revealed similar temporal patterns.

CONCLUSIONS

The relationships between the temporal changes of mortality from Crohn's disease and ulcerative colitis might suggest the presence of one primary risk factor responsible for the occurrence of both diseases, and at the existence of one additional secondary risk factor, responsible for the expression of Crohn's disease alone.