[1] Överkalix has a subarctic climate with significant temperature differences between the warm short summers and the long and cold winters.

This results in July days being warmer on average than other European cities as far south as Manchester and Dublin in the British Isles.

However, temperatures fall quickly once daylight diminishes, but winters are still less severe than other parts of the world at similar parallels due to mild North Atlantic air somewhat tempering cold extremes.

The study was conducted utilizing historical records, including harvests and food prices, in Överkalix, a small isolated municipality in northeast Sweden.

Mortality risk ratios (RR) on children and grandchildren were determined based on available food supply, as indicated by historical data.