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

Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993

Introduction

Human physical growth, biological maturation, and intelligence have been documented as increasing for over 100 years. Comparing the timing of secular trends in these characteristics could provide insight into what underlies them. However, they have not been examined in parallel in the same cohort during different developmental phases. Thus, the aim of this study was to examine secular trends in body height, weight, and head circumference, biological maturation, and intelligence by assessing these traits concurrently at four points during development: the ages of 4, 9, 14, and 18 years.

Methods

Data derived from growth measures, bone age as an indicator of biological maturation, and full-scale intelligence tests were drawn from 236 participants of the Zurich Longitudinal Studies born between 1978 and 1993. In addition, birth weight was analyzed as an indicator of prenatal conditions.

Results

Secular trends for height and weight at 4 years were positive (0.35 SD increase per decade for height and an insignificant 0.27 SD increase per decade for weight) and remained similar at 9 and 14 years (height: 0.46 SD and 0.38 SD increase per decade; weight: 0.51 SD and 0.51 SD increase per decade, respectively) as well as for weight at age 18 years (0.36 SD increase per decade). In contrast, the secular trend in height was no longer evident at age 18 years (0.09 SD increase per decade). Secular trends for biological maturation at 14 years were similar to those of height and weight (0.54 SD increase per decade). At 18 years, the trend was non-significant (0.38 SD increase per decade). For intelligence, a positive secular trend was found at 4 years (0.54 SD increase per decade). In contrast, negative secular trends were observed at 9 years (0.54 SD decrease per decade) and 14 years (0.60 SD decrease per decade). No secular trend was observed at any of the four ages for head circumference (0.01, 0.24, 0.17, and - 0.04 SD increase per decade, respectively) and birth weight (0.01 SD decrease per decade).

Discussion

The different patterns of changes in physical growth, biological maturation, and intelligence between 1978 and 1993 indicate that distinct mechanisms underlie these secular trends.

Update on the Obesity Epidemic: After the Sudden Rise, Is the Upward Trajectory Beginning to Flatten?

PURPOSE OF REVIEW

To provide an update on current obesity prevalence trends and summarize the available evidence suggesting a possible plateau or stabilization in obesity rates after the previous sudden global rise.

RECENT FINDINGS

The escalating global obesity epidemic represents one of the most serious public health challenges. There have been some indications that in high-income populations, the rate of obesity increase in adults has been stabilized after the decade 2000-2010, suggesting a possible plateau. Current evidence also suggests that obesity rates have been stabilized in children and adolescents of most economically advanced countries since 2000, which is possibly related to healthier dietary habits and increased levels of physical activity. On the other hand, there is a steady uninterrupted rise in low-income nations, and the universal trend is obesity escalation rather than slowdown, mainly driven by sharp increases in the obesity prevalence of low-income populations. Furthermore, an increasing number of high- and middle-income countries are currently experiencing an epidemic of severe obesity. In high-income populations, severe obesity is expected to double its prevalence from 10 to 20% between 2020 and 2035, posing an enormous threat for healthcare systems. Even if transiently stabilized, the obesity prevalence remains globally at unacceptably high levels, and there is no guarantee that the current stability (if any) will be maintained for long. In this review, we explore the underlying drivers of the global obesity epidemic; we provide possible explanations for the reported slowdown of the obesity rates in some countries; and we overall take a critical perspective on the obesity plateau hypothesis, emphasizing the urgent need for immediate effective actions at population and regional level in order to halt the alarming obesity escalation and its serious health risks.

Lifestyle effects on aging and CVD: A spotlight on the nutrient-sensing network

Aging is widespread worldwide and a significant risk factor for cardiovascular disease (CVD). Mechanisms underlying aging have attracted considerable attention in recent years. Remarkably, aging and CVD overlap in numerous ways, with deregulated nutrient sensing as a common mechanism and lifestyle as a communal modifier. Interestingly, lifestyle triggers or suppresses multiple nutrient-related signaling pathways. In this review, we first present the composition of the nutrient-sensing network (NSN) and its metabolic impact on aging and CVD. Secondly, we review how risk factors closely associated with CVD, including adverse life states such as sedentary behavior, sleep disorders, high-fat diet, and psychosocial stress, contribute to aging and CVD, with a focus on the bridging role of the NSN. Finally, we focus on the positive effects of beneficial dietary interventions, specifically dietary restriction and the Mediterranean diet, on the regulation of nutrient metabolism and the delayed effects of aging and CVD that depend on the balance of the NSN. In summary, we expound on the interaction between lifestyle, NSN, aging, and CVD.

Unsupervised machine learning method for indirect estimation of reference intervals for chronic kidney disease in the Puerto Rican population

Reference intervals (RIs) for clinical laboratory values are extremely important for diagnostics and treatment of patients. However, the determination of these ranges is costly and time-consuming. As a result, often different unverified RIs are used in practice for the same analyte and the same range is used for all patients despite evidence that the values are gender, age, and ethnicity dependent. Moreover, the abnormal flags are rudimentary, merely indicating if a value is within the RI. At the same time, clinical lab data generated in the everyday medical practice contains a wealth of information, that given the correct methodology, can help determine the RIs for each specific segment of the population, including populations that suffer from health disparities. In this work, we develop unsupervised machine learning methods, based on Gaussian mixtures, to determine RIs of analytes related to chronic kidney disease, using millions of routine lab results for the Puerto Rican population. We show that the measures are both gender and age dependent and we find evidence for normal age-related organ function deterioration and failure. We also show that the joint distribution of measures improves the diagnostic value of the lab results.

Intergenerational transmission of height in a historical population: From taller mothers to larger offspring at birth (and as adults)

Changes in growth and height reflect changes in nutritional status and health. The systematic surveillance of growth can suggest areas for interventions. Moreover, phenotypic variation has a strong intergenerational component. There is a lack of historical family data that can be used to track the transmission of height over subsequent generations. Maternal height is a proxy for conditions experienced by one generation that relates to the health/growth of future generations. Cross-sectional/cohort studies have shown that shorter maternal height is closely associated with lower birth weight of offspring. We analyzed the maternal height and offspring weight at birth in the maternity hospital in Basel, Switzerland, from 1896 to 1939 (N = ∼12,000) using generalized additive models (GAMs). We observed that average height of the mothers increased by ∼4 cm across 60 birth years and that average birth weight of their children shows a similarly shaped and upward trend 28 years later. Our final model (adjusted for year, parity, sex of the child, gestational age, and maternal birth year) revealed a significant and almost linear association between maternal height and birth weight. Maternal height was the second most important variable modeling birth weight, after gestational age. In addition, we found a significant association between maternal height and aggregated average height of males from the same birth years at time of conscription, 19 years later. Our results have implications for public health: When (female/maternal) height increases due to improved nutritional status, size at birth-and subsequently also the height in adulthood of the next generation-increases as well. However, the directions of development in this regard may currently differ depending on the world region.

Weight Status Prediction Using a Neuron Network Based on Individual and Behavioral Data

BACKGROUND

The worldwide epidemic of weight gain and obesity is increasing in response to the evolution of lifestyles. Our aim is to provide a new predictive method for current and future weight status estimation based on individual and behavioral characteristics.

METHODS

The data of 273 normal (NW), overweight (OW) and obese (OB) subjects were assigned either to the training or to the test sample. The multi-layer perceptron classifier (MLP) classified the data into one of the three weight statuses (NW, OW, OB), and the classification model accuracy was determined using the test dataset and the confusion matrix.

RESULTS

On the basis of age, height, light-intensity physical activity and the daily number of vegetable portions consumed, the multi-layer perceptron classifier achieved 75.8% accuracy with 90.3% for NW, 34.2% for OW and 66.7% for OB. The NW and OW subjects showed the highest and the lowest number of true positives, respectively. The OW subjects were very often confused with NW. The OB subjects were confused with OW or NW 16.6% of the time.

CONCLUSIONS

To increase the accuracy of the classification, a greater number of data and/or variables are needed.

Bergmann’s rule is a “just-so” story of human body size

Carl Bergmann was an astute naturalist and physiologist. His ideas about animal size and shape were important advances in the pre-Darwinian nineteenth century. Bergmann’s rule claims that that in cold climates, large body mass increases the ratio of volume-to-surface area and provides for maximum metabolic heat retention in mammals and birds. Conversely, in warmer temperatures, smaller body mass increases surface area relative to volume and allows for greater heat loss. For humans, we now know that body size and shape are regulated more by social-economic-political-emotional (SEPE) factors as well as nutrition-infection interactions. Temperature has virtually no effect. Bergmann’s rule is a “just-so” story and should be relegated to teaching and scholarship about the history of science. That “rule” is no longer acceptable science and has nothing to tell us about physiological anthropology.

A quantitative synthesis study on body mass index and associated factors among adult men and women in Switzerland

Excess weight is caused by multiple factors and has increased sharply in Switzerland since the 1990s. Its consequences represent a major challenge for Switzerland, both in terms of health and the economy. Until now, there has been no cross-dataset overview study on excess weight in adults in Switzerland. Therefore, our aim was to conduct the first synthesis on excess weight in Switzerland. We included all existing nationwide Swiss studies (eight total), which included information on body mass index (BMI). Mixed multinomial logistic regression analyses were performed to assess the associations between different socio-demographic, lifestyle cofactors and the World Health Organization (WHO) categories for BMI. Along with lifestyle factors, socio-demographic factors were among the strongest determinants of BMI. In addition, self-rated health status was significantly lower for underweight, pre-obese and obese men and women than for normal weight persons. The present study is the first to synthesise all nationwide evidence on the importance of several socio-demographic and lifestyle factors as risk factors for excess weight. In particular, the highlighted importance of lifestyle factors for excess weight opens up the opportunity for further public health interventions.

The role of body height as a co-factor of excess weight in Switzerland

Object

Excess weight (Body Mass Index [BMI] ≥25.0 kg/m²) is a major health issue worldwide, including in Switzerland. For high‐income countries, little attention has been paid to body height in context of excess weight. The aim of this study is to assess the importance of body height as a co‐factor for excess weight in multiple large nationwide data sets.

Data and methods

In this comparative study, we included the largest nationwide and population‐based studies in the fields of public health, nutrition and economics for Switzerland, as well as data of the medical examination during conscription for the Swiss Armed Forces, which contained information on BMI and, if possible, waist‐to‐height‐ratio (WHtR) and waist‐to‐hip‐ratio (WHR).

Results

The multinomial logistic regressions show that the probability of belonging to the excess weight category (BMI ≥25.0 kg/m²) decreased with increasing height in both sexes inall contemporary data sets. This negative association was shown to be constant, only among conscripts measured in the 1870s the association was positive, when increasing height was associated with a higher BMI. The negative association not only emerge in BMI, but also in WHtR and WHR.

Conclusion

Our results emphasize the importance of body height as a co‐factor of excess weight, suggesting a clear negative association between height and BMI, WHtR and WHR. Evidence indicates that both early‐life environmental exposures and alleles associated with height may contribute to these associations. This knowledge could serve as further starting points for prevention programs in the field of public health.

Diffusion of scientific concepts on obesity in the global context: a historical review

ABSTRACT This article aimed to carry out a historical analysis of the dissemination of the scientific concepts on obesity, overweight and excess weight in the field of nutritional epidemiology in the world. The methodological procedures comprised: (1) Systematic search in the PubMed® database using single keywords and without date filter; (2) Documentary analysis of normative instruments on the websites of the World Health Organization, the Centers for Disease Control and Prevention and the World Obesity Federation; and (3) Analysis of the scientific production of scientists participating in the obesity classification of the International Obesity Task Force. The historical analysis showed that, considering the volume of publications on obesity, it appears that in the 1940-1949 decade the problem of obesity emerged on the world scenario. From the number of publications issued in the last 20 years, which corresponds to 85% of the investigated period, we can deduct that scientists’ concern to investigate the subject as a phenomenon coincides with the World Health Organization declaration of obesity as a global epidemic issued in the year 2000. In accordance with normative procedures established by international organizations, there has been a hegemonic use of the concepts of obesity and overweight, in this order of priority, by scientists worldwide. The concept of excess weight has experienced a relative rise since the year 2000, but its use has been very restricted, expressing dissonance in face of the recommendations of international standardization organizations, a fact that suggests discussion and review of its use by the world scientific community.

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.

Multiple measures derived from 3D photonic body scans improve predictions of fat and muscle mass in young Swiss men

INTRODUCTION

Digital tools like 3D laser-based photonic scanners, which can assess external anthropometric measurements for population based studies, and predict body composition, are gaining in importance. Here we focus on a) systematic deviation between manually determined and scanned standard measurements, b) differences regarding the strength of association between these standard measurements and body composition, and c) improving these predictions of body composition by considering additional scan measurements.

METHODS

We analysed 104 men aged 19-23. Bioelectrical Impedance Analysis was used to estimate whole body fat mass, visceral fat mass and skeletal muscle mass (SMM). For the 3D body scans, an Anthroscan VITUSbodyscan was used to automatically obtain 90 body shape measurements. Manual anthropometric measurements (height, weight, waist circumference) were also taken.

RESULTS

Scanned and manually measured height, waist circumference, waist-to-height-ratio, and BMI were strongly correlated (Spearman Rho>0.96), however we also found systematic differences. When these variables were used to predict body fat or muscle mass, explained variation and prediction standard errors were similar between scanned and manual measurements. The univariable predictions performed well for both visceral fat (r2 up to 0.92) and absolute fat mass (AFM, r2 up to 0.87) but not for SMM (r2 up to 0.54). Of the 90 body scanner measures used in the multivariable prediction models, belly circumference and middle hip circumference were the most important predictors of body fat content. Stepwise forward model selection using the AIC criterion showed that the best predictive power (r2 up to 0.99) was achieved with models including 49 scanner measurements.

CONCLUSION

The use of a 3D full body scanner produced results that strongly correlate to manually measured anthropometric measures. Predictions were improved substantially by including multiple measurements, which can only be obtained with a 3D body scanner, in the models.

Secular evolution of femoral morphology from a clinical perspective

INTRODUCTION

Intramedullary nailing is the surgical method of choice for the treatment of proximal femur or femoral shaft fractures. Implant manufacturers aim to design implants fitting for the broadest possible population segment. As complete morphological data sets of long bones are not widely available, anatomical collections of historical dry bone specimens may represent abundant additional sources of morphological three-dimensional (3D) data for implant design, provided they are consistent with present populations. This study aims to investigate secular trends and age-related changes of femoral morphology of the Caucasian population over the past 800 years.

MATERIALS AND METHODS

Computer graphical measurements of 3D-datasets of right and left femora derived from computed tomography (CT) scans, representative of the present Caucasian population, were compared to computer graphical measurements of 3D-datasets of right and left femora derived from CT scans of specimens from a historical medieval European bone collection.

RESULTS

Clinically relevant parameters of historical medieval European femora were found mostly consistent with correlative data of the present Caucasian population. Additionally, for some of the evaluated parameters, particularly anteversion, morphological differences significantly correlated to individual age and sex could be identified, whereas other parameters such as caput-collum-diaphyseal angle or radius of anterior femoral bowing were not correlated to individual age or sex.

CONCLUSION

The findings suggest that more recent historical specimen collections may be a convenient and easily accessible source of new 3D morphological data, as well as to complement existing data, to be used by researchers and manufacturers for the development of intramedullary femoral nails.

Have Swiss adult males and females stopped growing taller? Evidence from the population-based nutrition survey menuCH, 2014/2015

Data from the National Nutrition Survey for adults (menuCH) allow for the assessment of recent trends in measured height by year of birth for adult men and women from a population-based sample. The aim of the present study was to test if - similarly to conscripts and schoolchildren - the Swiss adult population stopped growing taller in recent birth cohorts, and if so, when the change occurred. We found that - when self-reported - height was overestimated on average by about 1 cm in both men and women, with an increasing tendency with older age and with shorter height. Average measured height increased by 4.5-5.0 cm for adult men and women between the birth years 1937-1949 and 1990-1995. However, this increase was not linear, and starting with the 1970s birth years, average height plateaued on a level of about 178 cm for men and 166 cm for women. Being born outside of Switzerland or adjustment for potential shrinkage with increasing age did not change this temporal pattern. We also found shorter average height among participants from the Italian part of Switzerland and those with lower educational level. It remains unclear if the phenomenon of stabilisation affects all subgroups of the Swiss population. Future studies should combine a larger number of population-based surveys to enhance the sample size, for example, for people with a migration background or with different educational levels. Continuing growth monitoring needs to be performed to assess if environmental and demographic changes with an impact on body growth (adverse trends in nutrition, increasing social inequality in health, ethnic composition of the population) positively or negatively influence future trends in average height.

Spatial Association of Food Sales in Supermarkets with the Mean BMI of Young Men: An Ecological Study

Supermarket food sales data might serve as a simple indicator of population-level dietary habits that influence the prevalence of excess weight in local environments. To test this possibility, we investigated how variation in store-level food sales composition across Switzerland is associated with the mean Body Mass Index (BMI) of young men (Swiss Army conscripts) living near the stores. We obtained data on annual food sales (2011) for 553 stores from the largest supermarket chain in Switzerland, identified foods commonly regarded as “healthy” or “unhealthy” based on nutrient content, and determined their contribution to each store’s total sales (Swiss francs). We found that the sales percentages of both “healthy” and “unhealthy” food types varied by 2- to 3-fold among stores. Their balance ranged from −15.3% to 18.0% of total sales; it was positively associated with area-based socioeconomic position (r = 0.63) and negatively associated with the mean BMI of young men in the area (r = −0.42). Thus, even though we compared supermarkets from a single chain, different shopping behaviors of customers caused stores in privileged areas to sell relatively more healthy food. Knowledge about such patterns could help in designing in-store interventions for healthier nutrition and monitoring their effects over time.

Development of physical fitness performance in young Swiss men from 2006 to 2015

From 1980 to 2000, physical fitness decreased and body mass index (BMI) increased in the population of many industrialized countries. Little is known about these trends after the year 2000. This study aimed to investigate physical fitness performance, physical activity (PA) behavior, and BMI of young, male Swiss adults between 2006 and 2015. For this purpose, results from the Swiss Armed Forces mandatory recruitment were used. A total of 306 746 male conscripts provided complete fitness test data, mean ± SD (range from 5th to 95th percentile): 20 ± 1 (18‐21) years, 178 ± 7 (168‐189) cm; 74 ± 13 (58‐97) kg, predicted maximal oxygen consumption of 49.9 ± 4.6 (41.8‐56.9) mL/kg/min (Conconi test), 125 ± 58 (43‐232) seconds in trunk muscle strength test (prone bridge), 2.31 ± 0.24 (1.90‐2.66) m in standing long jump, 6.46 ± 0.73 (5.30‐7.70) m in seated shot put (2 kg medical‐ball shot) and 45.6 ± 12.2 (29.9‐66.7) seconds in one‐leg standing test (sum of both legs; eyes closed after 10 seconds and head tilted back after 20 seconds). In the investigated population, 73.8% fulfilled basic PA recommendations, 46.2% were classified as regularly vigorously active. Performances in aerobic endurance and muscle power did not show secular changes over time. However, core stability performance and PA behavior increased, while balance ability decreased over this 10‐year period. Average BMI increased by 2.0% between 2006 and 2010 and did not change thereafter. Male Swiss adults are at least as physically fit as they were a decade ago. The secular trends of decreasing physical performances and increasing BMI have stopped, and self‐reported sport participation and leisure time PA have been increased in the observed population over the last 10 years.

Sugar Addiction: From Evolution to Revolution

The obesity epidemic has been widely publicized in the media worldwide. Investigators at all levels have been looking for factors that have contributed to the development of this epidemic. Two major theories have been proposed: (1) sedentary lifestyle and (2) variety and ease of inexpensive palatable foods. In the present review, we analyze how nutrients like sugar that are often used to make foods more appealing could also lead to habituation and even in some cases addiction thereby uniquely contributing to the obesity epidemic. We review the evolutionary aspects of feeding and how they have shaped the human brain to function in "survival mode" signaling to "eat as much as you can while you can." This leads to our present understanding of how the dopaminergic system is involved in reward and its functions in hedonistic rewards, like eating of highly palatable foods, and drug addiction. We also review how other neurotransmitters, like acetylcholine, interact in the satiation processes to counteract the dopamine system. Lastly, we analyze the important question of whether there is sufficient empirical evidence of sugar addiction, discussed within the broader context of food addiction.

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.

Ladies first: Female and male adult height in Switzerland, 1770-1930

When investigating the well-being of a society, the living conditions of females are of special importance, not only due to the immediate impact for those directly involved, but also because of the potential intergenerational effects. Studying the dimorphism in the mean height helps to depict variation in the basic biological sex difference due to gender-related factors that potentially determine net nutrition. To expand knowledge of diachronic development in Swiss well-being conditions we investigate changes in the height of adult females born 1770-1930, and compare the series with data on contemporary males from the same sources: We employ a sample of N = 21'028 women and N = 21'329 men from passport-, convict-, maternity hospital-, and voluntary World War II army auxiliary records. The secular height trend is found both in males, from the 1870s/1880s, and in females starting with the 1840s/1850s birth cohorts. During the decades under study, mean height increased from 157 cm to 164 cm in female and 167 cm to 172 cm in male passport applicants, 154 cm to 159 cm in female and 167 cm to 169 cm in male convicts, 159 cm to 163 cm in female auxiliaries, and 155 cm to 159 cm in females giving birth in the maternity hospital of Basel. Because females seem to have started the secular trend in height earlier than their male contemporaries, the height dimorphism decreased during the second half of the 19th century. Differences between socio-economic status (SES) and data sources are found in both females and males: Women with low SES were significantly shorter than those of the other SES groups in all sources (on average 1.40 cm, p-values between 0.00 and 0.03). In men we found individuals of upper SES to be significantly taller (on average 1.96 cm, p-value = 0.00-0.10). Concerning differences between the sources, overall, passport applicants were the tallest for men as well as women; in females the individuals measured at the maternity hospital and in prison were the shortest. The variances across the datasets highlight the importance of considering different sources to depict average living conditions. Noteworthy is the finding that the diverse sources under study all show the same trajectory of increasing mean height over the course of the 19th century. In the long run, the improving net nutritional status of Swiss females may have been one of the contributors behind the general rise in well-being of the country's population from the later 19th century onwards.

Increasing variability of body mass and health correlates in Swiss conscripts, a possible role of relaxed natural selection?

BACKGROUND AND OBJECTIVES

The body mass index (BMI) is an established anthropometric index for the development of obesity-related conditions. However, little is known about the distribution of BMI within a population, especially about this distribution's temporal change. Here, we analysed changes in the distribution of height, weight and BMI over the past 140 years based on data of Swiss conscripts and tested for correlations between anthropometric data and standard blood parameters.

METHODS

Height and weight were measured in 59 504 young Swiss males aged 18-19 years during conscription in 1875-79, 1932-36, 1994 and 2010-12. For 65% of conscripts in 2010-12, results of standard blood analysis were available. We calculated descriptive statistics of the distribution of height, weight and BMI over the four time periods and tested for associations between BMI and metabolic parameters.

RESULTS

Average and median body height, body weight and BMI increased over time. Height did no longer increase between 1994 and 2010-12, while weight and BMI still increased over these two decades. Variability ranges of weight and BMI increased over time, while variation of body height remained constant. Elevated levels of metabolic and inflammatory blood parameters were found at both ends of BMI distribution.

CONCLUSIONS AND IMPLICATIONS

Both overweight and underweight subgroups showed similar changes in inflammation parameters, pointing toward related metabolic deficiencies in both conditions. In addition to environmental influences, our results indicate a potential role of relaxed natural selection on genes affecting metabolism and body composition.