Time trends and sex patterns in Hodgkin's disease incidence in Canada, 1970-1995

Purpose: To examine time trends and sex patterns in Hodgkin's disease incid ence in Canada, from 1970 through 1995. Method: In addition to analyses of the secular trends and sex ratio in inci dence rates, age-period-cohort models were fitted to estimate the effects o n the trends. Age-specific male/female incidence rate ratios were examined for the disease and for its two major histologic subtypes. Results: The overall age-adjusted incidence: rate of Hodgkin's disease decr eased significantly in males (3.5 per 100,000 in 1970-71 to 2.8 in 1994-95) bur only slightly in females (2.4 per 100,000 to 2.3). There was a signifi cant increase in the incidence among females aged 10-29 and among males age d 10-24, but a dramatic decrease among older ages. Age-period-cohort modell ing showed that birth cohort and period effects were responsible for the ob served trends in males and females, respectively. Conclusion: The risk factors responsible for Hodgkin's disease are differen t in females and males. Reproductive factors are likely to be associated wi th the occurrence of the disease in young women.