Joël Floris

From left-skewness to symmetry: how body-height distribution among Swiss conscripts has changed shape since the late 19th century.

Abstract Background: It is generally accepted that height distribution in modern populations is nearly symmetrical. However, it may deviate from symmetry when nutritional status is inadequate. Aim and subjects: This study provides an analysis of changes in the shape of the height distributions among Swiss conscripts (n = 267 829) over the past 130 years based on a highly representative, standardized and unchanged data source. Results: The analysed distributions from the 1870s–1890s conscription years are markedly left-skewed (−0.76 to −0.82), with short and very short men significantly over-represented. Standard deviation is 7.7 cm. In particular, the left tails of the late-19th- and early-20th-century distributions are very heavy. In the first half of the 20th century the first signs of a diminution of the heavy left tail are observable, by the 1970s the phenomenon disappears and height distribution becomes symmetrical; standard deviation is now 6.5 cm. Conclusion: The relatively strong left-skewness during the late 19th and early 20th centuries may have been due to the interaction of a number of causes, chiefly malnutrition, a wider range in physical development at age 19 and widespread iodine deficiency.

From Undernutrition to Overnutrition: The Evolution of Overweight and Obesity among Young Men in Switzerland since the 19th Century

Objective: The global obesity epidemic continues, new approaches are needed to understand the causes. We analyzed data from an evolutionary perspective, stressing developmental plasticity. Methods: We present diachronical height, weight, and BMI data for 702,902 Swiss male conscripts aged 18-20 years, a representative, standardized and unchanged data source. Results: From 1875 to 1879, the height distribution was slightly left-skewed; 12.1% of the conscripts were underweight, overweight and obesity were rare. The BMI-to-height relationship was positive but not linear, and very short conscripts were particularly slim. Since the 1870s, Swiss conscripts became taller, a trend that markedly slowed in the 1990s. In contrast, weight increased in two distinct steps at the end of the 1980s and again after 2002. Since 2010, BMI did not increase but stabilized at a high level. Conclusions: The body of young men adapted differently to varying living conditions over time: First, less investment in height and weight under conditions of undernutrition and food uncertainty; second, more investment in height under more stable nutritional conditions; third, development of obesity during conditions of plateaued height growth, overnutrition, and decreasing physical activity. This example contributes to the evaluation of hypotheses on human developmental plasticity.

Temporal trends, regional variation and socio-economic differences in height, BMI and body proportions among German conscripts, 1956-2010

OBJECTIVE We analyse temporal trends and regional variation among the most recent available anthropometric data from German conscription in the years 2008-2010 and their historical contextualization since 1956. Design/setting/subjects The overall sample included German conscripts (N 13 857 313) from 1956 to 2010. RESULTS German conscripts changed from growing in height to growing in breadth. Over the analysed 54 years, average height of 19-year-old conscripts increased by 6·5 cm from 173·5 cm in 1956 (birth year 1937) to 180·0 cm in 2010 (birth year 1991). This increase plateaued since the 1990s (1970s birth years). The increase in average weight, however, did not lessen during the last two decades but increased in two steps: at the end of the 1980s and after 1999. The weight and BMI distributions became increasingly right-skewed, the prevalence of overweight and obesity increased from 11·6 % and 2·1 % in 1984 to 19·9 % and 8·5 % in 2010, respectively. The north-south gradient in height (north = taller) persisted during our observations. Height and weight of conscripts from East Germany matched the German average between the early 1990s and 2009. Between the 1980s and the early 1990s, the average chest circumference increased, the average difference between chest circumference when inhaling and exhaling decreased, as did leg length relative to trunk length. CONCLUSIONS Measuring anthropometric data for military conscripts yielded year-by-year monitoring of the health status of young men at a proscribed age. Such findings contribute to a more precise identification of groups at risk and thus help with further studies and to target interventions.

Associations between anthropometric indices, blood pressure and physical fitness performance in young Swiss men: a cross-sectional study

Objectives To assess the benefit of waist circumference (WC) measurements during routine conscription medical examination in two military conscription centres in Switzerland. We compared the prevalence of overweight and obesity assessed by body mass index (BMI) with the prevalence of elevated disease risks assessed by WC and waist-to-height ratio (WHtR). We investigated how these measures were associated with systolic blood pressure, physical fitness performance and socioeconomic determinants. Design Cross-sectional survey. Setting Two Swiss conscription centres in 2016. Participants 1548 Swiss male conscripts, 18–22 years old. Main outcome Prevalences of elevated WC, WHtR and BMI values according to WHO categories. Secondary outcomes include systolic blood pressure, physical fitness performance and endurance performance. Results Using BMI cut-points, 25.0% of all conscripts were overweight or obese. When applying WC cut-points, 9.2% had an increased disease risk, while 14.8% of the conscripts were at risk using WHtR cut-points. In the BMI range of 25.0–27.4 kg/m2, 3.6% showed an increased disease risk when using WC and 24.6% when using WHtR cut-points. Of the conscripts with a BMI of 27.5–29.9 kg/m2, 72.4% had an increased disease risk using WHtR, and 42.5% when using WC cut-points. Determinants of elevated BMI, WC and WHtR were low occupational status, rural residential area, older age and location in central and Northwest Switzerland. Systolic blood pressure increased with increasing BMI, WC and WHtR. Physical fitness and endurance test performances decreased with increasing BMI, WC and WHtR. Conclusion In addition to BMI, WC and WHtR add relevant information to the health assessment of young men. However, the prevalence of overweight/increased health risk differed when using BMI, WC or WHtR. Further studies should include measures of body composition to test whether these differences arise from muscular young men within the overweight BMI range, who had a normal WC.

Income Inequality amongst Swiss Primary School Teachers in the Late 19th Century

Abstract We examine the distribution of income across Swiss primary school teachers at the end of the 19th century. To assess income differences we use a detailed data set on the income of 14,000 Swiss primary school teachers in 1881 and 1894/95. In addition, we use annually aggregated test scores from pedagogical examinations at recruitment, to test for the impact of inequality on conscripts’ performance. Our results show that between-group inequality amounts to about 35 per cent of total income inequality, and that teachers’ income inequality does not play a role in explaining differences in the performance of conscripts in the pedagogical examinations.