The continental "winners" of WW1 suffered more than the losers of the civil war.
Check out https://populationpyramid.net/france/1950/ and https://populationpyramid.net/germany/1950/ there are two features you can notice on these: one is a belt at the 30~34 level which is a birth deficit from the WW1 (combined with WW2 losses), the second is that the male side has a giant bite taken out above the 45-49 line, those are the deaths from WW1, 30% of the male cohorts of fighting ages were lost in the trenches, parts of the battlefields between Belgium and France are still completely unfit for any human activity, they remain "red zones" a century later[0] with poisonous compounds (e.g. arsenic) representing double-digit amounts of soil, and even in "rehabilitated" areas of farmers keep harvesting iron[1]
Also striking is this graph of life expectancy at birth for the population of France in each given year, in Figure 1 of this paper [0]. You can click on the figure to see it without needing to login.
