Beyond cold and class: drivers of anthropometric differences in modernising Finland

While anthropometric measurements are a recognised proxy for a population's living standards, socioeconomic status often explains only a portion of the observed variance. We study Finnish conscripts born 1910–1926 to elucidate key factors causing these differences. Our data include draft measurements of height and weight, as well as information on men’s social and regional backgrounds, which are linked to municipality-level climate and agricultural data. Modernising Finland provides an intriguing case with its significant height differences between social classes, linguistic groups and regions deriving from an interplay of class, urbanisation and climate. Our findings reveal a socioeconomic gradient in height that accounts for differences between linguistic groups. However, socioeconomic status (SES) is a weak predictor of the substantial regional height variations. Instead, these differences originated from varying levels of industrialisation and climatic conditions, which dictated the biological standard of living for the large agrarian population. In cold climates where agriculture was adverse, urban life had a height premium. Notably, while height and weight were generally linearly correlated, farmers presented an exception: they were short but heavy. Our analysis demonstrates that single factors like social class are insufficient to capture the complex environmental and economic determinants of human growth.