Filling the weight gap: Estimating body weight and BMI using height, chest and upper arm circumference of Swiss conscripts in the first half of the 20th century

We estimate weight and BMI values based on height, chest circumference, and mid upper arm circumference measures of Swiss conscripts in the city of Zurich for each year between 1904 and 1932. Height, chest circumference, and mid upper arm circumference were measured each year from 1904 to 1951. Body weight is available from 1933 to 1951. We used prediction equations from the literature, and also developed our own equations, which we tested and validated on the dataset from 1933 to 1951. We used a representative sample of usually 19-year-old Swiss males (N = 88,792, coverage > 88 %). There was an increase in average height and chest circumference between 1904 and 1951. During both world wars, chest circumference, mid upper arm circumference, weight, and BMI decreased, while height stagnated. Overall mean weight and BMI increased from 1904 to 1951, but decreased during the Great Depression. After World War II, weight quickly returned to the pre-war and pre-Great Depression level, while BMI had not reached the 1933 level by 1951. Average weights of the lower and middle socioeconomic groups were catching up with average weight of the upper socioeconomic group from 1904 to 1951. The convergence in height is less pronounced. Finally, we show that it is possible to accurately predict mean weight and BMI from other anthropometric measurements. We suggest that our estimation approach could be replicated for other historical populations to obtain more information on how nutritional status changed over time.

The BMI values of the lower classes likely declined during the Great Depression

The BMI values of inmates in the McNeil Island Penitentiary in Washington State declined between the 1860s and the 1910s birth cohorts by 1.44. Furthermore, those who were imprisoned in the 1930s had significantly lower BMI values (by between 0.72 and 1.01) than those who were incarcerated at the end of the 19th century. This corresponds to a decrease in weight of some 2.25kg (4.95lbs) for a man of average height of 173.86cm (68.5inches). The diminution in nutritional status among this lower-class sample is hardly surprising, given the high level of unemployment at the time but has not been verified until now. In marked contrast, the BMI values of Citadel cadets increased by 1.5 units in the 1930s. This divergence in BMI values is most likely due to the different social status, to the different regional origins of the two samples or to both.