The appearance of new social class of wealthy commoners in the 19th and the early 20th century and its biological consequences

Abstract

Introduction. Political and economic changes that occurred on the territory of Poland during the second half of the 19th century contributed to change in social structures of rural and urban populations. Urban populations underwent a profound change due to industrialisation that caused appearance of new social classes, especially the class of wealthy commoners - the middle class. Influence of social stratification on human morphological characters and on growth at adolescence is well documented for recent populations, however, it is much less studied in the past population due to scarcity of appropriate data. Objective. To characterise: 1. body height and body mass of adults and 2. the adolescent growth spurt in various strata/class of Polish people during the second half of the 19th century and at the beginning of the 20th century. Material and Methods. Data on body height and body mass of adults (20+ years) and youths (7-20) of privileged and poor social strata living in the Kingdom of Poland and in its capital, Warsaw were derived from published historical sources. Means, and where possible standard deviations, of body height, weight and Body Mass Index (BMI) were calculated for various groups. Prevalence of obesity (BMI > = 30kg/m²) and overweight (BMI > = 25kg/m²) was assessed separately for nobility, middle class, working class and peasantry. LOESS curves were fitted to annual cross-sectional increments in body height and body weight of youths of different social classes in order to evaluate the presence and magnitude of growth spurts. Results. The largest average values of body height and body mass of males and females were found for nobility, somewhat lower were values for the middle class. In both groups average BMI exceeded 25 kg/m². Peasant males and females were shorter and lighter than those of upper class. Males and females of the urban working class were even shorter and lighter than peasants. BMI averages of peasants and working class were below 25 kg/m². About 30-40% of nobility and rich middle class people were overweight and 12-21% obese. Among lower class 5-20% were overweight. Obesity occurred in 4-9% of peasants, but no working class males were obese at all. Children of privileged classes were taller and heavier than children of the working class. Boys of noble and middle class families experienced adolescent growth spurts at 14-15 years with peak height velocity of 7cm/year and weight velocity of 5 kg/year. Among privileged girls adolescent growth spurts at 11-12 years with peak velocities of 6cm/year and weight velocity of 5 kg/year. Among poor working class boys and girls there were no adolescent growth spurt, Conclusions. Upward social mobility providing better living conditions and nutrition resulted in increases in body height and body mass of children and adults contributing to the occurrence of overweight and obesity. Adolescent growth spurt was not a universal phenomenon. It did not occur among children of poor social strata. Improved living conditions of privileged classes produced accelerated growth in adolescence.