Evolution of birth-cohort patterns in lifestyle-associated cancer mortality across high-income countries.

BACKGROUND

Cancer mortality levels have declined across high-income countries, but progress has been uneven by cancer type. Examining birth-cohort patterns of lifestyle-related cancer mortality in an international context can shed light on how shared and differential global lifestyle transitions manifest differently across national contexts.

METHODS

We used harmonized cause-of-death data from the Human Cause of Death series of the Human Mortality Database for Canada, Czechia, England & Wales, France, Germany, Japan, Spain, and the USA from 2000 to 2020. We examined mortality from lung and larynx, colorectal, stomach, and liver cancer for ages 30-84 years by using rates of mortality improvement displayed on Lexis surfaces. Single-age death rates were estimated from grouped data by using penalized composite link models. Two-factor Poisson models and sex-stratified surfaces served as sensitivity analyses.

RESULTS

All eight countries showed declining age-standardized cancer mortality, but with diverging trends by cause and birth cohorts. Lung and larynx cancer declined broadly, with mortality patterns reflecting cohort cigarette-smoking histories. Colorectal cancer mortality increased among cohorts born after 1960 in the USA, Canada, and England & Wales, with a similar but delayed pattern in France and Germany. Liver cancer mortality was higher for cohorts born in 1945-55 than for earlier and later cohorts in several countries, with a re-emerging adverse pattern among cohorts born in around 1970-80.

CONCLUSION

Birth-cohort patterns in lifestyle-associated cancer mortality differ across national contexts. Worsening colorectal and liver cancer trends among younger cohorts call for increased prevention and screening strategies.