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Background The COVID-19 pandemic has had wide effects on child health globally. Increased prevalence of childhood obesity has been observed by a number of countries during the pandemic. The absence of a formal societal lockdown during the pandemic, made Sweden stand out compared to other countries. This study aims to examine changes in BMI among preschool children in Sweden before and during COVID-19 pandemic. Methods Retrospective population-based cross-sectional study, with longitudinal follow-up for a portion of the children. The study included 25 049 children from three Swedish regions, with growth measures at 3- (n = 16 237), 4- (n = 14 437) and 5-years of age (n = 11 711). Care Need Index was used as a socioeconomic parameter at health centre level. Results There was an increase in BMI in children aged three (P = 0.028) and four (P Conclusions Overweight and obesity increased among 3- and 4-year-old children in Sweden, findings that were accentuated in children attending child health centres in areas with lower socioeconomic status. The COVID-19 pandemic is likely to have affected health behaviours negatively in Swedish preschool children. Our results expose the need for extended efforts directed to prevent childhood obesity, especially targeting lower socioeconomic areas.

Background Resource trade-off theory suggests that increased performance on a given trait comes at the cost of decreased performance on other traits. Methods Growth data from 1889 subjects (996 girls) were used from the GrowUp1974 Gothenburg study. Energy Trade-Off (ETO) between height and weight for individuals with extreme body types was characterized using a novel ETO-Score (ETOS). Four extreme body types were defined based on height and ETOI at early adulthood: tall-slender, short-stout, short-slender, and tall-stout; their growth trajectories assessed from ages 0.5-17.5 years.A GWAS using UK BioBank data was conducted to identify gene variants associated with height, BMI, and for the first time with ETOS. Results Height and ETOS trajectories show a two-hit pattern with profound changes during early infancy and at puberty for tall-slender and short-stout body types. Several loci (including FTO, ADCY3, GDF5, ) and pathways were identified by GWAS as being highly associated with ETOS. The most strongly associated pathways were related to “extracellular matrix,” “signal transduction,” “chromatin organization,” and “energy metabolism.” Conclusions ETOS represents a novel anthropometric trait with utility in describing body types. We discovered the multiple genomic loci and pathways probably involved in energy trade-off.

Geohistorical records, either stratigraphic sections, boreholes, ice cores, or archaeological sites, are inherently complex. Despite their limitations, the high-dimensional and spatiotemporally resolved data retrieved from individual geohistorical records allow for evaluation of past biotic responses to natural and human-induced environmental changes. Network analysis is becoming an increasingly popular alternative for modelling the dynamics of geohistorical data. However, the complexity of geohistorical data raises questions about the limitations of standard network models widely used in paleobiology research. They risk obscuring large-scale patterns by washing out higher-order node interactions when assuming independent pairwise links. Recently introduced higher-order representations and models better suited for the complex relational structure of geohistorical data provide an opportunity to move paleobiology research beyond these challenges. Higher-order networks can represent the spatiotemporal constraints on the information paths underlying geohistorical data, capturing the high-dimensional patterns more accurately. Here we describe how to design higher-order network models of geohistorical data, address some practical decisions involved in modeling complex dependencies, and discuss critical methodological and conceptual issues that make it difficult to compare results across studies in the growing body of network paleobiology. We illustrate multilayer networks, hypergraphs, and varying Markov time models through case studies on the fossil record from continental shelf ecosystems and delineate future research directions for current challenges in the emerging field of network paleobiology.

BACKGROUND The QEPS-growth-model, developed and validated in GrowUp-Gothenburg cohorts, used for developing growth references and investigating healthy/pathological growth, lacks external validation from other longitudinal cohorts of healthy individuals. AIM To investigate if the QEPS-model can fit the longitudinal Edinburgh growth study of another design than GrowUp-Gothenburg cohorts, and to compare growth patterns in the individuals born in mid-1970s in North-Western Europe. METHODS Longitudinal growth data were obtained from the Edinburgh and the GrowUp1974Gothenburg cohorts. The QEPS-model was used to describe length/height from birth to adult height with confidence interval, and the multivariable regression model for estimating the contribution of the different QEPS-functions to adult height. RESULTS The QEPS-model fitted the Edinburgh cohort well, with high accuracy, and low confidence intervals indicating high precision. Despite 3 cm shorter stature (less QE-function growth) in Scottish children, the growth patterns of the cohorts were similar, especially for specific pubertal growth. The contribution to adult height from different QEPS functions was similar. CONCLUSION The QEPS-model is validated for the first time in a longitudinal study of healthy individuals of another design and found to fit with high accuracy and precision. The Scottish and Western-Swedish cohorts born in mid-1970s showed similar growth patterns for both sexes, especially pubertal growth. IMPACT For the first time, the QEPS height model was used and found to fit another longitudinal cohort of healthy individuals other than the Swedish longitudinal cohorts. With large numbers of individual measurements in each growth phase, the QEPS model calculates growth estimates with narrow confidence intervals (high precision) and high accuracy. The two different cohorts born in the mid-1970s from Scotland and Western Sweden have similar growth patterns, despite a 3 cm difference in adult height.

Paleobiologists often employ network-based methods to analyze the inherently complex data retrieved from geohistorical records. Because they lack a common framework for designing, performing, evaluating, and communicating network-based studies, reproducibility and interdisciplinary research are hampered. The high-dimensional and spatiotemporally resolved data also raise questions about the limitations of standard network models. They risk obscuring paleontological patterns by washing out higher-order node interactions when assuming independent pairwise links. Recently introduced higher-order representations and models better suited for the complex relational structure of geohistorical data provide an opportunity to move paleobiology research beyond these challenges. Higher-order models can represent the spatiotemporal constraints on the information paths underlying geohistorical data, capturing the high-dimensional patterns more accurately. Here we describe how to use the Map Equation framework for designing higher-order models of geohistorical data, address some practical decisions involved in modeling complex dependencies, and discuss critical methodological and conceptual issues that make it difficult to compare results across studies in the growing body of network paleobiology research. We illustrate multilayer networks, hypergraphs, and varying Markov time models for higher-order networks in case studies on gradient analysis, bioregionalization, and macroevolution, and delineate future research directions for current challenges in the emerging field of network paleobiology.

Resource trade-off theory suggests that increased performance on a given trait comes at the cost of decreased performance on other traits.Growth data from 1889 subjects (996 girls) were used from the GrowUp1974 Gothenburg study. Energy Trade-Off (ETO) between height and weight for individuals with extreme body types was characterized using a novel ETO-Score (ETOS). Four extreme body types were defined based on height and ETOI at early adulthood: tall-slender, short-stout, short-slender, and tall-stout; their growth trajectories assessed from ages 0.5-17.5 years.A GWAS using UK BioBank data was conducted to identify gene variants associated with height, BMI, and for the first time with ETOS.Height and ETOS trajectories show a two-hit pattern with profound changes during early infancy and at puberty for tall-slender and short-stout body types.Several loci (including FTO, ADCY3, GDF5, ) and pathways were identified by GWAS as being highly associated with ETOS. The most strongly associated pathways were related to 'extracellular matrix', 'signal transduction', 'chromatin organization', and 'energy metabolism'.ETOS represents a novel anthropometric trait with utility in describing body types. We discovered the multiple genomic loci and pathways probably involved in energy trade-off.

Background At the population level, there is a negative linear correlation between childhood body mass index (BMI) and pubertal height gain. However, in children with obesity, there are no studies showing whether the severity of obesity affects pubertal height gain. Moreover, how obesity in childhood affects pubertal timing is controversial, especially in boys. We aimed to investigate the impact of severe obesity in childhood on the pubertal growth spurt in both sexes. Methods The study group consisted of 68 patients (32 boys) with childhood onset obesity followed in a Spanish university hospital. The QEPS growth model was used to calculate pubertal growth function estimates for each individual. The highest individual prepubertal BMI SDS value was related to the age at onset of pubertal growth and pubertal height gain. Results were compared to analyses from individuals in a community-based setting (n = 1901) with different weight status. Results A higher peak BMI in childhood was associated with less specific pubertal height gain in children with moderate-to-extreme obesity. For boys, the higher the BMI, the earlier the onset of pubertal growth. For girls with obesity, this correlation was not linear. Conclusions Obesity in childhood impairs the pubertal growth spurt in a severity-related fashion. Impact The higher the BMI in childhood, the lower the pubertal height gain in children with moderate-to-extreme obesity. For boys with obesity, the higher the BMI, the earlier the onset of pubertal growth. The results contribute to the research field of how weight status in childhood is related to pubertal timing and pubertal growth. The results have implications for understanding how childhood obesity is related to further growth.

AIM To update the Swedish references for weight, weight-for-height and body mass index (BMI) considering the secular trend for height but not including that for weight. METHODS Longitudinal measures of height and weight were obtained (0-18 years) from 1418 (698 girls) healthy children from the GrowUp 1990 Gothenburg cohort born at term to non-smoking mothers and Nordic parents. A total of 145 individuals with extreme BMI value vs GrowUp 1974 BMI SDS reference were excluded (0-2 years: ±4SDS, 2

AIM: Human growth patterns are important, especially in paediatrics and public health, and the aim of this review was to provide an overview of human growth, especially secular changes of growth and pubertal growth. METHODS: This review of human growth was mainly based on studies published during the 20th and early 21st centuries. Special attention was paid to secular changes, pubertal growth, Nordic growth studies and the contribution of the Quadratic-Exponential-Pubertal-Stop (QEPS) growth model for analysing growth patterns. RESULTS: Human growth patterns showed wide variations between different individuals, sexes and populations and over time. There were ongoing positive secular change in height in four of the Nordic countries, Denmark, Finland, Norway and Sweden, over four decades. Childhood weight status had linear correlations with specific pubertal growth, in both healthy children and those with severe obesity. The QEPS model provided novel estimates of pubertal growth that made it possible to conduct more detailed analyses of pubertal growth than before. Growth references, adjusted for puberty, have been developed and future opportunities for using the QEPS model for growth studies are highlighted. CONCLUSION: The QEPS was a valid growth model for analysing human growth patterns and developing novel types of growth references.

Aim We aimed to develop up‐to‐date references with standard deviation scores (SDS) for prepubertal and total height. Methods Longitudinal length/height measures from 1572 healthy children (51.5% boys) born at term in 1989‐1991 to non‐smoking mothers and Nordic parents were obtained from the GrowUp 1990 Gothenburg cohort. A total height SDS reference from birth to adult height was constructed from Quadratic‐Exponential‐Pubertal‐Stop (QEPS) function estimated heights based on individual growth curves. A prepubertal height SDS reference, showing growth trajectory in the absence of puberty, was constructed using the QE functions. Results The total height reference showed taller prepubertal mean heights (for boys 1‐2 cm; for girls 0.5‐1.0 cm) with a narrower normal within ± 2SDS range vs the GrowUp 1974 Gothenburg reference. Adult height was increased by + 0.9 cm for women (168.6 cm) and by + 1.6 cm for men (182.0 cm). Height in children growing at −2SDS (the cut‐off used for referrals) differed up to 2 cm vs the GrowUp 1974 Gothenburg reference, 3 cm vs Swedish 1981 references and World Health Organisation (WHO) 0‐5 years standard, and 6‐8 cm vs the WHO 5‐19 years reference. Conclusion Up‐to‐date total and prepubertal height references offer promise of improved growth monitoring compared with the references used in Sweden today.

Background Growth references are traditionally constructed relative to chronological age, despite inter-individual variations in pubertal timing. A new type of height reference was recently developed allowing growth to be aligned based on onset of pubertal height growth. We here aim to develop a corresponding reference for pubertal weight. Methods To model QEPS-weight, 3595 subjects (1779 girls) from GrowUp1974Gothenburg and GrowUp1990Gothenburg were used. The QEPS-height-model was transformed to a corresponding QEPS-weight-model; thereafter, QEPS-weight was modified by an individual, constitutional weight-height-factor. Longitudinal weight and length/height measurements from 1418 individuals (698 girls) from GrowUp1990Gothenburg were then used to create weight references aligned for height at pubertal onset (the age at 5% of P-function growth, AgeP5). GrowUp1974Gothenburg subgroups based on pubertal timing, stature at pubertal onset, and childhood body composition were assessed using the references. Results References (median, SDS) for total weight (QEPS-functions), weight specific to puberty (P-function), and weight gain in the absence of specific pubertal growth (basic weight, QES-functions), allowing alignment of individual growth based on age at pubertal onset. For both sexes, basic weight was greater than average for late maturing, tall and high-BMI subgroups. The P-function-related weight was greater than average in short and lower than average in tall children, in those with high BMI, and in girls but not boys with low BMI. Conclusions New pubertal weight references allow individual variations in pubertal timing to be taken into consideration when evaluating growth. When used together with the comparable pubertal height reference, this will improve growth monitoring in clinical practice for identifying abnormal growth and serve as a valuable research tool providing insight into human growth.

Over the past 150 years, humans have become taller, and puberty has begun earlier. It is unclear if these changes are continuing in Sweden, and how longitudinal growth patterns are involved. We aimed to evaluate the underlying changes in growth patterns from birth to adulthood by QEPS estimates in two Swedish cohorts born in 1974 and 1990. Growth characteristics of the longitudinal 1974 and 1990-birth cohorts (n = 4181) were compared using the QEPS model together with adult heights. There was more rapid fetal/infancy growth in girls/boys born in 1990 compared to 1974, as shown by a faster Etimescale and they were heavier at birth. The laterborn were taller also in childhood as shown by a higher Q-function. Girls born in 1990 had earlier and more pronounced growth during puberty than girls born in 1974. Individuals in the 1990 cohort attained greater adult heights than those in the 1974 cohort; 6 mm taller for females and 10 mm for males. A positive change in adult height was attributed to more growth during childhood in both sexes and during puberty for girls. The QEPS model proved to be effective detecting small changes of growth patterns, between two longitudinal growth cohorts born only 16 years apart.

Childhood BMI may influence subsequent growth in height as well as the timing of puberty. The aim of the present study was to investigate associations between BMI in childhood and subsequent height gain/pubertal growth. Longitudinal growth data were used (GrowUp1990Gothenburg cohort, n = 1,901). The QEPS growth-model was used to characterize height gain in relation to the highest BMISDS value between 3.5 and 8 y of age. Children were defined as overweight/obese (OwOb) or normal weight/underweight (NwUw), using the 2012 International Obesity Task Force criteria. A negative association between childhood BMISDS and pubertal height gain was observed. Already at birth, OwOb children were heavier than NwUw children, and had a greater height velocity during childhood. Onset of puberty was 3.5/3.0 mo earlier in OwOb girls/boys, and they had 2.3/3.1 cm less pubertal height gain from the QEPS-models specific P-function than NwUw children. Adult height was not related to childhood BMI. We found that pubertal height gain was inversely related to peak BMI in childhood. Higher childhood BMISDS was associated with more growth before onset of puberty, earlier puberty, and less pubertal height gain, resulting in similar adult heights for OwOb and NwUw children.

Background Only one mathematical model to date describes human growth and its different phases from fetal life until adult height. Aim To develop a model describing growth from fetal life to adult height taking maturation/biological tempo into consideration. Methods Subjects: The model was developed based on longitudinal mean height values obtained from published growth references for a cohort of 3650 healthy Swedish children followed from birth circa 1974 until adult height combined with birth-length for circa 400 000 healthy infants born 1990-1995. Results The QEPS-model for individual growth was constructed with a combination of four basic shape-invariant growth functions: a quadratic Q-function and a negative exponential E-function, both started during fetal life, 8 months before birth; the E-function levelled off after birth, whereas the Q-function continued until end of growth. A specific nonlinear pubertal P-function started at onset of puberty, and a stop S-function ended growth according to both the Q-function continuing during puberty and the specific P-function. For each function, an individual height-scale parameter was defined, and for the E- and P-functions, a time-scale parameter; giving six modifying parameters in total. In addition standardized proportional scores were used for biological interpretations. The QEPS-model was used to fit and generate mathematical functions suitable to describe the growth of the healthy population of Swedish children; thereafter, the model was modified using four height-scale parameters to model individual height in cm, and two time-scale parameters to adjust for the individual tempo of growth. Individual confidence intervals were calculated for all parameters. Conclusions A new shape-invariant growth model, QEPS, was developed, that requires only four basic growth functions to describe the total pattern of growth in height from fetal life to adult height, with addition of height- and time-scale parameters describing individual growth. The model can describe a wide variety of growth curves. Moreover, it is the first model to provide confidence intervals which enable us to describe the precision/quality of individual parameters.

Aim The study aims to investigate secular changes in adult height among Nordic reference populations during the last four decades and in parents of Swedish study participants, and to study during which growth phase(s) infancy, childhood or puberty changes in height and tempo occurred. Methods Length and height data were obtained from publications on populations used as current and previous national height references in Denmark, Finland, Norway and Sweden. Measurements from birth until adult height and original parental heights of participants in Swedish reference populations born 1956, 1974, and 1990 were used. Results Adult height has increased progressively in Nordic populations born in 1950s-1990s; for females by 6 mm/decade Norway, 4 mm; Sweden, 6 mm; Finland and Denmark, 7 mm; for males by 9 mm/decade, in Sweden, 5 mm; Finland, 7 mm; Denmark 8 mm; Norway, 15 mm. This was due to more growth during childhood despite earlier timing of mid-puberty. Heights of Swedish parents born 1920s-1960s increased 11 mm/decade for mothers, 14 mm/decade for fathers. Conclusion The Nordic countries comprise some of the tallest populations in the world yet continue to show a positive secular change in adult height alongside a faster tempo of growth by earlier timing of puberty, highlighting the need to regularly update national height references.