Thyroid, colon and kidney cancer rose fastest, by more than 2.5% a year. Rectal, prostate and liver cancers, skin melanoma and multiple myeloma each rose by more than 1% a year, though melanoma rates have fallen since 2013. Lung and ovarian cancer declined. For colon and breast cancer, the sharpest increases were in adults under 35.

The data are observational and contain no individual risk-factor information, so the reasons remain unclear. The researchers note that rising detection may partly explain the thyroid and kidney trends, and that obesity has been suggested as one contributing factor. Patterns were largely consistent across the region, which has high-quality cancer registration and nationally harmonized data in the NORDCAN database.

KI cancer epidemiologist Anna Johansson, the study’s lead author, said: “Although the cancer risk among young individuals is very low in comparison to the older population, these increases are a concern since the reasons behind these patterns remain poorly understood.”