Background: The Epstein-Barr virus (EBV) plays a role in the causation of Hodgkin lymphoma (HL) and multiple sclerosis (MS). A previous study showed that the time trends of mortality from Crohn's disease (CD) and MS shared striking similarities. It was hypothesized that such similarities would also involve the time trends of ulcerative colitis and HL.

Aims: To compare the time trends of CD and UC with those of HL and MS in 6 different countries.

Methods: Using the vital statistics of England, Canada, Netherlands, Scotland, Switzerland, and United States from 1951 to 2020, the time trends of mortality from these 4 diseases were compared. The time-dependent changes of death rates were subjected to a birth-cohort analysis.

Results: Similar trends were observed in all 6 countries. UC mortality rose among generations born during the nineteenth century and decreased among all generations born subsequently during the twentieth century. CD mortality was similarly characterized by a birth-cohort pattern with a rise and fall that were shifted by 20-30 years towards more recent generations when compared to UC. The birth-cohort pattern of UC was matched by a similar pattern of HL, whereas the birth-cohort pattern of CD was matched by a similar pattern of MS.

Conclusions: The similarities in the ubiquitous birth-cohort patterns of UC, CD, HL, and MS suggest that these 4 diseases share a common environmental risk factor. Such risk factor may be linked to EBV or its acquisition during an early period of a patient's lifetime.