Trends in cervical cancer in New Zealand.

Analysis of mortality and incidence rates over a 30-year period discloses differing trends in the risk of cervical cancer in older and younger women. Age-specific rates have been declining in older women, but there has been a marked rise in incidence among women under 40. Birth-cohort analyses show declining risks in successive cohorts of women born from late in the last century until the 1930's, except that risks were slightly elevated in the generation who were young adults during the Second World War. The risk of cervical cancer has increased very rapidly in cohorts born since the 1930s. A mathematical model suggests that women born around 1957 may have over three times the risk experienced by women born around 1932. The numbers of New Zealand women developing, and dying from, cervical cancer will increase strikingly over the next few decades unless effective control measures are introduced.