Mortality trends from oral cancer in Andalusia, Spain, 1975-1998

Morbidity and mortality rates from oral cancer appear to be on the rise amo ng developed countries throughout the world during tl e last decades. The o bject of the present study was to investigate the recent changes in the mor tality from oral cancer in the more than seven million inhabitants of Andal usia, Spain. Data on the number of deaths by oral cancer from 1975 to 1998 were obtained from annual publications by the Statistics Institute. Crude, age-standardi zed, truncated, cumulative and age-specific rates of mortality were calcula ted by gender as well as potential years of life lost rates. Poisson regres sion models were fitted in order to quantify the influence of age and year of death on the mortality rates by gender. Age-adjusted mortality rates increased from 2.79 in 1975-79 to 3.41 in 1995 -98 in males and from 0.39 to 0.45 in females during the same period. Incre ases were more marked when comparing the truncated age-adjusted rates. Rela tive risks increased with age from 2.35 to 23.12 in 55 to 64-y-old and 85-y -old males respectively, and from 2.91 to 21.50 in 55 to 64-y-old and 85-y- old females respectively, when comparing with the 35-54-y-old age group, Th ere was an interaction between age at death and year of death in males but not in females. Mortality from oral cancer increased in males in Andalusia over the study p eriod, simultaneous to an important change in the pattern of occurrence by age. There was a cohort effect in males and females across the studied time interval.