Introduction
In recent decades, the accumulation of extensive anthropometric data has facilitated detailed studies of both spatial (geographical and cross-populational) and temporal (secular and intergenerational) variations in body size across global populations. Most countries have experienced significant increases in body size over the last 100–150 years (Danubio and Sanna, Reference Danubio and Sanna2008; NCD-RisC, 2016, 2017). Although the trend towards larger body sizes is consistent, variations in timing, intensity, and extent exist across different populations (Kryst et al., Reference Kryst, Kowal, Woronkowicz, Sobiecki and Cichocka2012; Bodzsar et al., Reference Bodzsar, Zsakai and Mascie-Taylor2016; Malina et al., Reference Malina, Little and Pena Reyes2018; Kirchengast et al., Reference Kirchengast, Juan, Waldhoer and Yang2022; Ikeda and Nishi, Reference Ikeda and Nishi2023; Liczbińska et al., Reference Liczbińska, Gautam, Bharati and Malina2023). For example, research on Russian populations shows significant differences in the patterns and rates of body size changes across various regions and time periods (Godina, Reference Godina2011; Kozlov and Vershubsky, Reference Kozlov and Vershubsky2015; Lebedeva et al., Reference Lebedeva, Kucherova and Godina2020; Negasheva et al., Reference Negasheva, Khafizova and Movsesian2023). These regional studies underscore the complexity and diversity of secular changes in anthropometric parameters over time.
Theoretical background
Spatiotemporal analysis of anthropometric characteristics, particularly height, is crucial for assessing population well-being from a historical perspective. Height serves as a cumulative indicator, reflecting both genetic factors and external environmental influences, including ecological, socio-economic, epidemiological, nutritional, and psycho-emotional factors (Cole, Reference Cole2003; Silventoinen, Reference Silventoinen2003; Perkins et al., Reference Perkins, Subramanian, Davey Smith and Özaltin2016; Bogin, Reference Bogin2021; Hermanussen et al., Reference Hermanussen, Erofeev and Scheffler2022; Conery and Grant, Reference Conery and Grant2023). It is suggested that the significant secular changes in human body sizes observed over the past 100–150 years are predominantly due to shifts in external environmental conditions rather than major genetic reorganisation (Cole, Reference Cole2003; Bozzoli et al., Reference Bozzoli, Deaton and Quintana-Domeque2009; Steckel, Reference Steckel2009, Reference Steckel, Cameron and Schell2012; Baten and Blum, Reference Baten and Blum2014; Hatton, Reference Hatton2014; Perkins et al., Reference Perkins, Subramanian, Davey Smith and Özaltin2016; Bogin, Reference Bogin2021). These changes include political and economic developments, agricultural and technological progress, urbanisation, enhancements in urban infrastructure and housing, improvements in sanitation and hygiene, modernisation of healthcare systems, and demographic shifts such as family size and structure.
The growth process and its outcomes, particularly in terms of body size, are influenced by epidemiological and sanitary-hygienic contexts, along with psychological factors, during key developmental stages. Research has shown that these factors significantly contribute to determining the definitive values of body size indicators (Bozzoli et al., Reference Bozzoli, Deaton and Quintana-Domeque2009; Komlos and Lauderdale, Reference Komlos and Lauderdale2007; Perkins et al., Reference Perkins, Subramanian, Davey Smith and Özaltin2016). Advances in medicine and healthcare reforms, especially in Europe and the USA, have markedly improved public health, as evidenced by increased life expectancy and reduced mortality rates from infectious diseases, including a decline in infant mortality. These developments have coincided with marked changes in body sizes (Crimmins and Finch, Reference Crimmins and Finch2005; Steckel, Reference Steckel, Cameron and Schell2012; Hatton, Reference Hatton2014).
Metrics such as life expectancy and mortality rates are often used to assess the impact of the epidemiological environment on intergenerational changes in body size. The postneonatal infant mortality rate is a particularly sensitive indicator (Bozzoli et al., Reference Bozzoli, Deaton and Quintana-Domeque2009; Hatton, Reference Hatton2014). Studies have demonstrated a close interconnection between secular trends in body size and infant mortality, often showing mirrored patterns (Schmidt et al., Reference Schmidt, Jørgensen and Michaelsen1995; Crimmins and Finch, Reference Crimmins and Finch2005; Bozzoli et al., Reference Bozzoli, Deaton and Quintana-Domeque2009; Quintana-Domeque et al., Reference Quintana-Domeque, Bozzoli and Bosch2011; Spijker et al., Reference Spijker, Cámara and Blanes2012; Akachi and Canning, Reference Akachi and Canning2015; Borrescio-Higa et al., Reference Borrescio-Higa, Bozzoli and Droller2019). An inverse relationship between infant mortality and final height has been documented across various demographic groups, based on anthropometric data for 31 demographic groups born between 1950 and 1980 in England, the USA, and 10 European countries (Bozzoli et al., Reference Bozzoli, Deaton and Quintana-Domeque2009).
Urbanisation’s impact on body size trends is multifaceted and somewhat ambiguous (Steckel, Reference Steckel, Cameron and Schell2012). In the 19th and 20th centuries, urbanisation suppressed the temporal dynamics of somatic features like height due to increased population density, disease proliferation, and poor sanitary conditions (Steckel, Reference Steckel, Cameron and Schell2012; Hatton, Reference Hatton2014; Carson, Reference Carson2020). However, in the last century, urbanisation has positively influenced the secular dynamics of anthropometric parameters through improvements in sanitary, hygienic, and living conditions, leading to more significant intergenerational changes in urban populations compared to rural ones (Luo et al., Reference Luo, Yang, Lei, Wang, Papasian and Deng2009; Godina, Reference Godina2011; Paciorek et al., Reference Paciorek, Stevens, Finucane and Ezzati2013; Kozlov and Vershubsky, Reference Kozlov and Vershubsky2015).
However, although urbanisation and economic growth have improved access to nutrition and healthcare, they have also led to lifestyle changes. These include decreased physical activity and an increase in the consumption of high-calorie, processed foods, which contribute to higher BMI values. The intergenerational dynamics of body mass and BMI among males and females across all age groups are characterised by a secular increase, with a gradual intensification during the second half of the 20th century (Danubio & Sanna, Reference Danubio and Sanna2008; NCD-RisC, 2017). Furthermore, in many countries, the prevalence of individuals with overweight and obesity has risen throughout the past century (NCD-RisC, 2017).
Among the factors contributing to population adiposity and the spread of overweight and obesity, one of the dominant causes is the development of specific conditions in urbanised environments, driven by socio-economic transformations such as increased economic prosperity in developed countries. These conditions encourage an increase in body fat mass, particularly through reduced levels of physical activity (due to changes in types of work and leisure activities, trends towards a sedentary lifestyle, and hypodynamia) and significant changes in population nutrition (such as shifts in the production, distribution, and consumption of food products, and the transition to a Western-style diet characterised by higher levels of animal proteins, high-calorie, and processed foods) (Atkinson et al., Reference Atkinson, Lowe and Moore2016; Hruby & Frank, Reference Hruby and Frank2015). However, recent studies indicate changes in the temporal somatic trend of BMI in the 21st century among the younger generation, with a reduction in the prevalence of overweight and obesity (Kryst et al., Reference Kryst, Żegleń, Woronkowicz and Kowal2022).
A reduction in BMI among children, adolescents, and young people in Russia and some Eastern European countries at the turn of the 20th and 21st centuries is usually attributed to the deterioration of socio-economic living conditions following the collapse of the USSR (Negasheva et al., Reference Negasheva, Khafizova and Movsesian2023). The observed decrease in BMI in some countries during the 21st century is most often linked to changes in lifestyle, particularly dietary, and exercise habits (Kryst et al., Reference Kryst, Żegleń, Woronkowicz and Kowal2022).
Historical background
The process of urbanisation in Russia during the 20th century was intense, intersecting with significant socio-political and economic upheavals. Initially, urban populations surged by 55% from 1897 to 1913, but World War I, the Revolutions, and the Civil War caused severe declines due to famine, epidemics, and migration away from cities (Nefedova and Treivish, Reference Nefedova and Treivish2003; Makhrova et al., Reference Makhrova, Nefedova and Treivish2013). From 1914 to 1926, populations in Moscow and St Petersburg nearly halved.
The period from 1926 to 1939 marked a resurgence in urbanisation, driven by Soviet policies of forced industrialisation and collectivisation, which significantly increased the urban population (Nefedova and Treivish, Reference Nefedova and Treivish2003; Makhrova et al., Reference Makhrova, Nefedova and Treivish2013; Wiśniewski, Reference Wiśniewski2017). Post-World War II, urbanisation regained momentum, particularly from the 1950s to the mid-1980s, with the rate of urban growth stabilising from the 1960s through the 1980s (Nefedova and Treivish, Reference Nefedova and Treivish2003).
The 1990s saw a decline in urban population growth due to economic and social crises, but the 2000s experienced a revival, particularly in major cities (Nefedova and Treivish, Reference Nefedova and Treivish2003; Makhrova et al., Reference Makhrova, Nefedova and Treivish2013). Despite crises at the century’s start and in the 1990s, Moscow’s population consistently grew, reinforcing its dominance as a centre of urbanisation into the current era (Denisenko and Stepanova, Reference Denisenko and Stepanova2013; Makhrova et al., Reference Makhrova, Nefedova and Treivish2013; Kolosov and Nefedova, Reference Kolosov and Nefedova2014; Wiśniewski, Reference Wiśniewski2017).
Concurrently, changes in the epidemiological environment significantly impacted health metrics. The 20th century’s mortality rates and life expectancy showed overall positive trends, largely due to healthcare advancements (Reshetnikov et al., Reference Reshetnikov, Arsentyev, Boljevic, Timofeyev and Jakovljević2019a, Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b). However, several health crises occurred throughout the century (Minagawa, Reference Minagawa2018; Reshetnikov et al., Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b). Fertility patterns also shifted, reflecting smaller family sizes and changing societal preferences (Billingsley and Duntava, Reference Billingsley and Duntava2017; Vishnevsky et al., Reference Vishnevsky, Denisov and Sakevich2017).
In Moscow, notable increases in height and weight were observed from the late 19th to the early 20th century. Despite periods of gains followed by declines or stagnation, this trend of variability in body sizes underscores the need to consider the broader historical context to understand these fluctuations. While there are relatively few studies empirically assessing the relationship between these secular body size trends and socio-economic factors in Russian populations, previous research has begun to explore this, particularly focusing on Moscow’s youth (Negasheva et al., Reference Negasheva, Zimina, Khafizova, Sirazetdinov and Sineva2020; Negasheva et al., Reference Negasheva, Khafizova and Movsesian2023).
During the first two decades of the 21st century, Russia maintained a relatively stable political climate, experienced economic growth, and implemented national projects in the social sector, such as healthcare and education. These developments led to an improved standard of living and favourable changes in the population’s biological status.
By 2021, Russia’s socio-economic landscape included growth in the energy, technology, and services sectors, sustaining employment despite global fluctuations and the COVID-19 pandemic. Improvements in healthcare access and quality enhanced public health, while government initiatives in urban infrastructure, education, and public health contributed to higher living standards.
The aim of this study is to assess the impact of urbanisation, changes in the epidemiological environment, and demographic processes (such as shifts in birth rates) on intergenerational somatic trends among young adults aged 17–22 years in Moscow. Spanning a significant historical scope of 100–150 years, this research provides a comprehensive analysis of these long-term trends and their socio-demographic correlates. It is hypothesised that changes in body sizes among Moscow’s youth and across Russia are closely linked to socio-demographic factors, including urbanisation, healthcare improvements, and economic shifts. Periods of urban and economic growth are expected to correlate with increases in body size, while eras marked by socio-economic challenges may exhibit stagnation or declines in these trends.
Data and methods
The meta-analysis was based on retrospective anthropometric and demographic data from literary sources and open statistical databases.
Anthropometric data
The time series of anthropometric indicators were constructed using published average values from screening surveys of Moscow’s youth across the 20th and early 21st centuries. Datasets were comparable in terms of age, nationality, and residency, focusing on 17–20-year-old Russian males and females born and residing in Moscow. Birth cohorts ranged from 1860 to 1870 for males and 1907–1908 for females, extending to 2003–2004. Height data are available since the 1880s for males and from 1926 for females, extending to the present, and body weight data from the early 20th century for both sexes. The secular trend in the body mass index (BMI) has been traceable from the early 1970s onwards. The analysed anthropometric parameters encompassed body height (measured with a Martin anthropometer (GPM, Switzerland), accurate to 1 mm) and body weight (measured using a medical scale (Mаssа-K VEМ-150 А3, Russia), accurate to 0.05 kg). BMI was calculated from individual data as the ratio of body weight (kg) to the square of body height (m): individual BMI = kg/m2. In total, anthropometric data from over 10,775 individuals (4,823 young males and 5,952 young females) were analysed, with methodologies and measurement techniques following Martin and Saller (Reference Martin and Saller1957). The average values of the anthropometric parameters used in this study are publicly accessible in the sources cited in Table 1, which also provides details on the years of examination and sample sizes.
Table 1. Anthropometric indicator values for young males and females in Moscow across various years of examination
Note. N/D – no data.
Socio-demographic data
The study’s demographic data were sourced from the Federal State Statistics Service (Rosstat, 2023) databases, with additional sources cited separately (Table 2). All the data used are publicly available. Nine demographic indicators were utilised, organised into three categories (Table 2). The first category included urbanisation metrics (Russia’s urban population size, proportion of the permanent urban population in Russia, and population size of Moscow). The second category covered population growth indicators (birth rate and fertility rate). The third category combined epidemiological indicators (life expectancy at birth, total mortality rate, infant mortality rate, and healthcare expenditures).
Table 2. Information on the socio-demographic indicators used and data sources
Primarily, socio-demographic parameters for Moscow’s population were used. For some indicators, due to the short duration of time series (from the 1990s to present), analogous data for Russia’s urban population were utilised (Table S1). It was presumed that these time series might reflect a similar or closely related temporal trend of the socio-demographic indicator for Moscow’s population.
Statistical analysis
To investigate the direction and strength of the relationships between the time series of anthropometric features and demographic indicators, Spearman’s rank correlation coefficients were calculated. For a more in-depth analysis of the identified associations and to assess the relative impact of demographic factors on the temporal variation of somatic traits, multiple linear regression models were created using the least squares method. The selection of predictors for the regression equation was performed through a stepwise inclusion method, selecting only those parameters contributing significantly to the overall correlation. The total variation in the outcome variable, explained by the collective effect of all predictors included in the model, was assessed using the coefficient of multiple determination (R 2).
Statistical processing was conducted using the STATISTICA 10 software package and Microsoft Excel from the Microsoft 365 suite, with the latter also being utilised for data visualisation.
Results
Correlations between anthropometric measures and socio-demographic indicators
The outcomes of the correlation analysis revealed the presence of stable relationships of moderate to high strength between the time series of anthropometric values (such as height and weight, BMI) and various demographic indicators.
For the data series spanning a substantial historical range (from the end of the 19th – beginning of the 20th century to the 2020s), the Spearman correlation coefficients were statistically significant, with absolute values exceeding 0.47, and displayed a positive correlation. The strongest correlational links were identified between long-term body size changes and urbanisation indicators, notably the population size of Moscow (Fig. 1), and the expected lifespan of the population (Fig. 2), for which data have been available since the 1880s.
Figure 1. Secular trend in height among young males and females in Moscow, and changes in Moscow’s population size from the late 19th to the early 21st century.
Note: Abbreviations: SEM, standard error of the mean; rs, Spearman’s rank correlation coefficient.
Figure 2. Secular trend in weight among young males in Moscow, and changes in life expectancy at birth in Russia’s urban population from the early 20th to the early 21st century.
Note: Abbreviations: SEM, standard error of the mean; rs, Spearman’s rank correlation coefficient.
The correlation coefficients between the time series of anthropometric characteristics and demographic indicators, spanning from the second half of the 20th century to the present, are presented in Table 3. The graphical representations of their combined temporal dynamics are displayed in Figs. 3–4 and in Supplementary materials (Figures S1–3).
Table 3. Spearman’s correlation coefficients between anthropometric and demographic variables for Moscow population during the time interval from the second half of the 20th century to the present
Note. Statistically significant correlation coefficients are highlighted in bold; the minimum significance level is assumed to be 0.05
Abbreviation: BMI, body mass index.
Figure 3. Secular trend in BMI among young males and females in Moscow, and changes in the birth rate and mortality rate in Moscow’s population from the 1960s to 2021.
Note. Abbreviation: SEM, standard error of mean; rs, Spearman’s rank correlation coefficient.
Figure 4. Secular trend in height among young males in Moscow, and changes in the infant mortality rate in Russia’s urban population from the 1950s to 2021.
Note. SEM, standard error of mean; r s, Spearman’s rank correlation coefficient.
Positive correlations have been observed between the time series of somatic characteristics and population growth indicators, such as birth rates and natural population growth rates, with correlation coefficients ranging from 0.50 to 0.77 (Table 3, Fig. 3). Slight sex differences were observed in the absolute values of the correlation coefficients. In most of the socio-demographic indicators studied, higher correlation coefficients were found among the young males. Furthermore, there were positive associations detected for two demographic variables related to population health and healthcare. An increase in life expectancy in the population of Moscow and higher healthcare expenditures were associated with an increase in the average values of body size indicators (Table 3). Conversely, negative correlation links were identified between somatic feature series and mortality rates, particularly infant mortality, with correlation coefficients ranging from −0.47 to −0.72 (Table 3, Figs. 3–4).
Evaluation of the relative impact of different socio-demographic factors on the secular trend
In the subsequent stage of the study, multiple regression analysis was performed to evaluate the relative contribution of various demographic factors to the temporal variability of anthropometric indicators. Regression models were developed for the total body sizes (height and weight) using the most comprehensive sets of demographic data available for two periods: from the 1960s to 1970s to the present and from 1990 to 2021. The predictors from each demographic category were selected based on existing literature and the results of the correlation analysis.
The complete multiple regression models, incorporating all available predictors from the second half of the 20th century, reveal a statistically significant positive impact of Moscow’s population size (β = 1.899, p < 0.05) and infant mortality rate (β = 1.685, p < 0.05) on the temporal variability in height among young males. The stepwise variable inclusion procedure enhances the statistical parameters of the regression models and identifies Moscow’s population size and the infant mortality rate as significant predictors for the height of young males.
The results of the regression analysis show that demographic factors explain approximately 50–60% of the temporal variation in body weight for both young males and females. Models that consider all the demographic factors examined are statistically significant for both sexes (p < 0.01), but none of the individual factors exhibit a statistically significant impact. However, after conducting a stepwise variable inclusion procedure, it becomes evident that life expectancy is a significant predictor for males (β = 0.733, p < 0.001), and the population size of Moscow is a significant predictor for females (β = 0.592, p < 0.01.)
In the regression analysis using data available from the early 21st century to the present, the demographic predictors focused on variables representing Moscow’s population. The results presented in Table 4 are, in general, similar to those obtained in the previous series of analyses for a broader time interval.
Table 4. The results of multiple regression analyses of height to estimate the impact of demographic factors on temporal changes in anthropometric variables among young males and females in Moscow from the 1990s to 2021
Note. β – regression coefficients of independent variables; R – multiple regression coefficient; R 2 – coefficient of determination; Adj. R 2 – adjusted coefficient of determination; F – F-test; p – significance level; statistically significant regression coefficients are highlighted in bold (p < 0.05).
In the case of height, for both young males and females, the population size of Moscow’s permanent residents emerges as a significant predictor (Table 4). When it comes to the temporal variation in body weight, the multiple regression models, with variables included in a stepwise manner, reaffirmed the significant positive influence of Moscow’s population size and life expectancy.
Specifically, in the group of young males, the population size of Moscow was found to have a significant impact (β = 0.806, p < 0.001), while in the group of young females, life expectancy was a significant predictor (β = 0.741, p < 0.001).
The correlation analysis across all somatic feature groups indicated the highest number of statistically significant links with factors such as Moscow’s population size, life expectancy, and infant mortality rate. The multiple regression analysis also suggests that urbanisation (indicated by the population size of Moscow) contributes most significantly and reliably to the intergenerational variation of somatic features.
Discussion
The combined analysis of anthropometric and demographic retrospective data has identified significant associations between the secular changes in the body sizes of Moscow’s youth and the time dynamics of statistical indicators that characterise urbanisation, living standards of the population, and the epidemiological environment in Russia. To the best of current knowledge, this study is the first to examine the relationships between long-term time series of anthropometric and socio-demographic factors, assessing the impact of key social processes occurring in Russia in the 20th century on the secular trend of principal body size indicators.
Urbanisation in Russia and its impact on the secular trend
The intergenerational increase in height and weight among Moscow’s youth has coincided with the rapid growth of Moscow’s population, a result of the intense urbanisation process in Russia during the 20th century (see Fig. 1). The population growth in the capital is both a marker and a driver of Moscow’s socio-economic development. Regional centres like Moscow far exceed other localities in economic activity and financial resources. Characterised by higher income levels, a sophisticated social structure, and greater access to high-quality education and healthcare, these centres provide more favourable living conditions. This environment attracts migratory inflows, further fuelling population growth (Nefedova and Glezer, Reference Nefedova and Glezer2023). Enhanced economic prosperity in urban areas leads to better living standards, including improved nutrition and healthcare access. Thus, a specific set of conditions in highly urbanised environments promotes faster growth and development in children and adolescents, intensifying the secular trend in body size indicators.
Changes in Russia’s epidemiological environment and their impact on the secular trend
Throughout the 20th century, Russia’s epidemiological environment underwent significant changes driven by economic and social factors. These shifts, part of the epidemiological transition, reflect changes in health and disease patterns due to socio-economic, political, cultural, medical, and technological transformations (Omran, Reference Omran1998; Vishnevsky, Reference Vishnevsky2021). This transition is intertwined with factors affecting secular trends in body size, embedded in the historical and societal context. Political and economic crises and periods of stagnation can impede these trends, reflecting the country’s overall condition (Vishnevsky, Reference Vishnevsky2021).
Initial modest increases in the height of young males in Moscow at the turn of the 19th and 20th centuries were disrupted by the tumultuous events of the early 20th century, including World War I, the Civil War, political upheavals, a collapse in the healthcare system, and outbreaks of infectious diseases. These events severely worsened the epidemiological situation, leading to high mortality rates, reduced birth rates, and shorter mean heights in the cohorts born during this period (Reshetnikov et al., Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b).
In response, the Bolshevik government established a unified national healthcare system focused on universal, free medical services, with special emphasis on preventive care, social hygiene, and maternal and child health (Baranov et al., Reference Baranov, Namazova-Baranova, Albitskiy, Ustinova, Terletskaya and Komarova2016; Reshetnikov et al., Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b). This system benefited large cities such as Moscow and Leningrad, leading to significant health improvements in the 1920s, evidenced by decreased morbidity and mortality rates, increased life expectancy, and intergenerational growth in height (Baranov et al., Reference Baranov, Namazova-Baranova, Albitskiy, Ustinova, Terletskaya and Komarova2016; Reshetnikov et al., Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b).
The 1930s, marked by rapid industrialisation and collectivisation, the devastating 1932 famine, and wartime hardships, interrupted these positive trends, causing a decline in population health and increased disease rates (Reshetnikov et al., Reference Reshetnikov, Arsentyev, Boljevic, Timofeyev and Jakovljević2019a). Data on youth body size during this period are inconclusive, with some reports of modest increases and others noting decreases in height and weight (Brainerd, Reference Brainerd2010; Vlastovsky, Reference Vlastovsky1966).
In the post-war period, followed by the relatively stable phases of the USSR’s history, there was a marked improvement in the epidemiological situation. The era known as the ‘Thaw’, characterised by increased political openness, saw a rise in government healthcare spending (Reshetnikov et al., Reference Reshetnikov, Arsentyev, Boljevic, Timofeyev and Jakovljević2019a). From the mid-1950s to the late 1980s, public health indicators improved significantly, as evidenced by an increase in life expectancy (Shkolnikov et al., Reference Shkolnikov, McKee and Leon2001) and a reduction in infant mortality rates to below 100 per 1,000 live births. This decline in infant mortality marked the beginning of the epidemiological transition in Russia (Vishnevsky, Reference Vishnevsky2021). Correspondingly, this period also witnessed significant secular increases in the height and weight of young people in Moscow.
The mid-1980s brought political and economic transformations, leading to the Soviet Union’s dissolution. This era of socio-political crisis and economic decline destabilised the social sphere, slowing the epidemiological transition and causing a public health crisis (Stuckler et al., Reference Stuckler, King and McKee2009; Shkolnikov et al., Reference Shkolnikov, Andreev, McKee and Leon2013; Minagawa, Reference Minagawa2018; Reshetnikov et al., Reference Reshetnikov, Ekkert, Capasso, Arsentyev, Mikerova and Yakushina2019b). During Perestroika, declines in health were evident, with stagnation in height trends and decreases in body weight and BMI metrics (see Fig. 3). Life expectancy dropped dramatically in the mid-1990s, while mortality rates surged, influenced by declining living standards, psychological stress, and unhealthy behaviours (Balabanova et al., Reference Balabanova, McKee, Pomerleau, Rose and Haerpfer2004; Shkolnikov et al., Reference Shkolnikov, Andreev, McKee and Leon2013; Minagawa, Reference Minagawa2018).
In contrast, the early 21st century has seen improved socio-political and economic conditions in Russia. Investments in healthcare and education have led to better living standards, a consistent rise in life expectancy, and a decrease in mortality rates, along with increases in average weight and BMI among the youth (Shkolnikov et al., Reference Shkolnikov, Andreev, McKee and Leon2013; Minagawa, Reference Minagawa2018).
Changes in birth rate in Russia and their impact on secular trends
The concurrent increase in body sizes of Moscow’s youth and the decrease in birth rates may be linked. A reduction in the number of children per family allows for better resource allocation and care for each child, potentially contributing to improved physical development (Silventoinen, Reference Silventoinen2003; Hatton, Reference Hatton2014). This study did not find divergent trends in birth rates over time; instead, it identified significant positive correlations and parallel trends between changes in birth rates and body sizes (see Table 3 and Fig. 3). The fluctuations in birth rates reflect the socio-political and economic dynamics of the 20th century in Russia, impacting living standards and health outcomes (Sobotka, Reference Sobotka2011; Kreyenfeld et al., Reference Kreyenfeld, Andersson and Pailhé2012; Billingsley and Duntava, Reference Billingsley and Duntava2017). These fluctuations, marked by periods of increase and decline, were influenced by socio-economic transformations, social upheavals, and pro-natalist policies. Although these fluctuations often represent transient social changes, they also overshadow broader birth rate trends (Vishnevsky et al., Reference Vishnevsky, Denisov and Sakevich2017). Therefore, changes in birth rates can be seen as indicators of the general improvement or deterioration in the population’s well-being. The associations identified in this study are biologically significant, suggesting that the temporal trends in somatic indicators, such as body size, are influenced by similar environmental conditions.
The results overall indicate that somatic secular trends follow similar directions for both sexes, with comparable associations between body size time series and socio-economic characteristics. However, slight sex differences were observed in the strength of correlations, particularly between the time series of anthropometric traits and socio-demographic indicators related to changes in the epidemiological environment. One possible explanation is that males may be more sensitive to environmental factors, both negative and positive, and therefore exhibit greater reactivity, responding more quickly and strongly to these influences (Stinson, Reference Stinson1985).
It is important to note that demographic factors such as birth rate, mortality rate, and life expectancy are closely linked to broader socio-economic and environmental conditions. Thus, the secular trends in body size indicators among Moscow’s youth are the result of multifaceted socio-demographic transformations. These interconnected factors highlight the role of socio-economic development in shaping demographic trends and physical growth. Socio-economic improvements that reduce mortality rates and increase life expectancy also enhance children’s physical development by providing better living conditions, sanitation, and nutrition.
The findings of this study demonstrate that the temporal variability of the socio-demographic factors studied has a comparable influence on the secular variation of anthropometric indicators, such as height and weight (Table 4). It is well established that different somatic traits exhibit varying degrees of heritability (Conery and Grant, Reference Conery and Grant2023; Robinson et al., Reference Robinson, English, Moser, Lloyd-Jones and Triplett2017), meaning that the influence of endogenous (genetic) versus exogenous (environmental) factors on phenotypic variation differs across traits. Therefore, one might expect that traits more strongly determined by genetics would be less influenced by environmental changes, resulting in weaker correlations. However, the results of this study revealed that, over the examined period, environmental factors – rather than genetics – were the primary drivers and regulators of variation in anthropometric traits, regardless of the heritability of their variability.
Conclusion
This study demonstrates a significant relationship between demographic changes and the development of body size among Moscow’s youth, highlighting the profound influence of urbanisation, socio-economic advancements, and healthcare improvements. The progression of urban development and improved living standards has nurtured healthier, better-nourished generations. Throughout the 20th century – particularly in the latter half, except for the 1990s – socio-demographic shifts led to notable increases in key body size metrics across generations, reflecting the impact of societal transformations on physical development. Additionally, the trend towards smaller family sizes likely enhanced child welfare, contributing to the observed secular growth in height and weight.
The research also underscores the pivotal role of the epidemiological transition in the 20th century, characterised by public health advancements that extended life expectancy and reduced infant mortality despite economic and political challenges. The links between mortality rates, life expectancy, and body size emphasise how the epidemiological environment shapes public health outcomes.
These findings advocate for integrating historical epidemiological insights into contemporary public health policymaking to better understand and improve the well-being of future generations.
Limitations
This study sheds light on the anthropometric development of Moscow’s youth over the past century but has notable limitations. Its focus on Moscow, due to its distinct socio-economic and healthcare environment, may not allow for generalisation to the entire Russian Federation, which exhibits significant regional diversity. The reliance on historical data introduces potential variations in data quality and consistency. Moreover, internal migration to Moscow poses a risk of bias, as migrants’ health and socio-economic statuses may differ from those of the native population. Additionally, the rapid socio-economic and healthcare changes in recent years might not be fully captured, suggesting a need for continued investigation into these trends. Recognising these limitations paves the way for future research, encouraging broader geographic coverage and the adoption of longitudinal designs to further unravel these complex dynamics.
Supplementary materials
The supplementary material for this article can be found at https://doi.org/10.1017/S0021932024000385
Author contribution
MN and AK conceived the idea, designed the study, collected, and analysed the data. MN supervised the study. AK performed the statistical analysis and wrote the original draft of the manuscript. MN and AM revised and edited the manuscript. The final version of the manuscript has been reviewed and approved by all authors.
Funding statement
This work was supported by Russian Science Foundation [grant number: 23-18-00086].
Competing interests
The authors declare none.
Ethical approval
The study design and conduct of the research obtained approval from the Bioethics Commission at the Moscow State University (meeting № 152-d held on 18.05.2023). All procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on experiments involving humans and with the Helsinki Declaration of 1975, as revised in 2008.
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