What I always think of if I hear this is the tallness paradox between Europe and USA. When controlling for ethnicity, the modern white person from the US is on

What I always think of if I hear this is the tallness paradox between Europe and USA. When controlling for ethnicity, the modern white person from the US is on average about 1.5 inches (4 cm) shorter than the average person from the EU. As far as I know its uncertain why exactly this is (american used to be taller until mid of the last century) but the usual suspect is class inequality the lets to poorer sanitation for poorer people which in turn are also more likely to infect richer people which leads to less growth in adolescents. But ultimately, the cause of this phenomenon in not known.