Widening educational differences in cancer survival in Norway.

BACKGROUND: All-cause and cause-specific mortality have long been known to be associated with various indicators of socio-economic status, and social gradients have been shown also for cancer survival. In recent decades, several studies have reported increasing social differentials in mortality rates. This study aims to investigate the development with respect to cancer survival, which has not been done before.
METHODS: Discrete-time hazard regression models for cancer deaths among women and men diagnosed with cancer 1970-2007 at age 30-89 were estimated, using register data encompassing the entire Norwegian population. The analysis was based on >200,000 cancer deaths during over 2 million person-years of exposure among >440,000 individuals diagnosed with cancer.
RESULTS: There has been an increasing advantage for women of all educational categories when compared with those with only compulsory schooling. No such widening of the educational gap has appeared with respect to cancer survival among men.
CONCLUSIONS: Increasing educational differentials in health at the time of diagnosis, health behaviour and cancer treatment seem plausible, and would to some extent accord with the increasing social gaps in all-cause or cause-specific mortality rates that have been reported in other studies. Also, it is not impossible that such trends in the educational gradients in health and treatment are stronger for women than for men, though such sex differences have not been indicated in mortality studies. There is no obvious explanation for the complete absence of change in the education effects among men.