Childhood Overweight and Obesity During and After the COVID-19 Pandemic.

This cohort study analyzes the prevalence of overweight and obesity among preschool children in Sweden before, during, and after the COVID-19 pandemic and longitudinal trends in body mass index.

Mapping robust multiscale communities in chromosome contact networks.

To better understand DNA's 3D folding in cell nuclei, researchers developed chromosome capture methods such as Hi-C that measure the contact frequencies between all DNA segment pairs across the genome. As Hi-C data sets often are massive, it is common to use bioinformatics methods to group DNA segments into 3D regions with correlated contact patterns, such as Topologically associated domains and A/B compartments. Recently, another research direction emerged that treats the Hi-C data as a network of 3D contacts. In this representation, one can use community detection algorithms from complex network theory that group nodes into tightly connected mesoscale communities. However, because Hi-C networks are so densely connected, several node partitions may represent feasible solutions to the community detection problem but are indistinguishable unless including other data. Because this limitation is a fundamental property of the network, this problem persists regardless of the community-finding or data-clustering method. To help remedy this problem, we developed a method that charts the solution landscape of network partitions in Hi-C data from human cells. Our approach allows us to scan seamlessly through the scales of the network and determine regimes where we can expect reliable community structures. We find that some scales are more robust than others and that strong clusters may differ significantly. Our work highlights that finding a robust community structure hinges on thoughtful algorithm design or method cross-evaluation.

Swedish Child Health Services Register: a quality register for child health services and children's well-being.

BACKGROUND: Swedish child health services (CHS) is a free-of-charge healthcare system that reaches almost all children under the age of 6. The aim for the CHS is to improve children's physical, psychological and social health by promoting health and development, preventing illness and detecting emerging problems early in the child's life. The services are defined in a national programme divided into three parts: universal interventions, targeted interventions and indicated interventions.The Swedish Child Health Services Register (BHVQ) is a national Quality Register developed in 2013. The register extracts data from the child's health record and automatically presents current data in real time. At present, the register includes 21 variables. AIM: We aim to describe data available in the BHVQ and the completeness of data in BHVQ across variables. METHODS: Child-specific data were exported from the register, and data for children born in the regions were retrieved from Statistics Sweden to calculate coverage. RESULTS: The register includes over 110 000 children born between 2011 and 2022 from 221 child healthcare centres in eight of Sweden's 21 regions. In seven of the eight regions, 100% of centres report data.The completeness of data differs between participating regions and birth cohorts. The average coverage for children born in 2021 is 71%. CONCLUSIONS: The BHVQ is a valuable resource for evaluating Child Health Services nationally, with high coverage for the youngest children. As a result of continuous improvement of the services, the possibility to follow the development of children's health in Sweden is possible through the register. When fully expanded, the register will be a natural and essential part of developing preventive services, improving healthcare for children below 6 years of age and a tool for developing evidence-based child health interventions.

Energy Trade-off and 4 Extreme Human Body Types.

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.

Increased incidence of overweight and obesity among preschool Swedish children during the COVID-19 pandemic.

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<0.001) during the COVID-19 pandemic. Obesity in 3-year-old girls increased from 2.8% to 3.9%. Four-year-olds increased in obesity, and overweight (girls) and the prevalence of underweight decreased in boys. No change in BMI was observed in 5-year-olds. Children in areas of low socioeconomic status had higher risk of obesity. 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.

Mapping nonlocal relationships between metadata and network structure with metadata-dependent encoding of random walks.

Integrating structural information and metadata, such as gender, social status, or interests, enriches networks and enables a better understanding of the large-scale structure of complex systems. However, existing approaches to augment networks with metadata for community detection only consider immediately adjacent nodes and cannot exploit the nonlocal relationships between metadata and large-scale network structure present in many spatial and social systems. Here, we develop a flow-based community detection framework based on the map equation that integrates network information and metadata of distant nodes and reveals more complex relationships. We analyze social and spatial networks and find that our methodology can detect functional metadata-informed communities distinct from those derived solely from network information or metadata. For example, in a mobility network of London, we identify communities that reflect the heterogeneity of income distribution, and in a European power grid network, we identify communities that capture relationships between geography and energy prices beyond country borders.

Novel type of references for BMI aligned for onset of puberty - using the QEPS growth model.

OBJECTIVES: Despite inter-individual variations in pubertal timing, growth references are conventionally constructed relative to chronological age (C-age). Thus, they are based on reference populations containing a mix of prepubertal and pubertal individuals, making them of limited use for detecting abnormal growth during adolescence. Recently we developed new types of height and weight references, with growth aligned to age at onset of the pubertal growth spurt (P-age). Here, we aim to develop a corresponding reference for pubertal BMI. METHODS: The QEPS-height and weight models were used to define a corresponding QEPS-BMI model. QEPS-BMI was modified by the same individual, constitutional weight-height-factor (WHF) as computed for QEPS-weight. QEPS-BMI functions were computed with QEPS weight and height functions fitted on longitudinal measurements from 1418 individuals (698 girls) from GrowUp1990Gothenburg cohort. These individual BMI functions were used to develop BMI references aligned for height at AgeP5; when 5% of specific puberty-related (P-function) height had been attained. Pubertal timing, stature at pubertal onset, and childhood BMI, were investigated in subgroups of children from the cohort GrowUp1974Gothenburg using the new references. RESULTS: References (median, standard deviation score (SDS)) were generated for total BMI (QEPS-functions), for ongoing prepubertal growth (QE-function) vs C-age, and for total BMI and separated into BMI specific to puberty (P-function) and BMI gain from ongoing basic growth (QES-functions), allowing individual growth to be aligned based on P-age. Growth in basic BMI was greater than average for children categorized as tall and/or with high-BMI at puberty-start. In children categorized as short at puberty-start, P-function-related-BMI was greater than average. CONCLUSIONS: Use of these new pubertal BMI references will make it possible for the first time to consider individual variations owing to pubertal timing when evaluating BMI. This will improve the detection of abnormal changes in body composition when used in combination with pubertal height and weight references also abnormal growth. Other benefits in the clinic will include improved growth monitoring during treatment for children who are overweight/obese or underweight. Furthermore, in research settings these new references represent a novel tool for exploring human growth.

Growth pattern evaluation of the Edinburgh and Gothenburg cohorts by QEPS height model.

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.

The Quadratic-Exponential-Pubertal-Stop model is valid for analysing human growth patterns and developing novel growth references.

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.

Novel type of references for weight aligned for onset of puberty - using the QEPS growth model.

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.

Swedish references for weight, weight-for-height and body mass index: The GrowUp 1990 Gothenburg study.

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 < years: -3SDS, +2.3SDS). References were constructed using the LMS method. RESULTS: The updated weight reference became similar to the GrowUp 1974 Gothenburg reference: BMI increased rapidly up to lower levels in the 1990 cohort during infancy/early childhood, similar in both groups in late childhood/adolescence, despite lower values at +2SDS. Compared with the WHO weight standard, median and -2SDS weight values were higher for the 1990 cohort, whereas +2SDS values were lower, resulting in narrower normal range. Median values were greater and ±2SDS narrower for the 1990 vs the WHO weight-for-height reference. International Obesity Task force (IOTF) BMI lines for definitions for over- and underweight were added. CONCLUSION: We present updated references for weight, weight-for-height and BMI, providing a healthy goal for weight development when monitoring growth within healthcare settings.

The pubertal growth spurt is diminished in children with severe obesity.

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.

A new type of pubertal height reference based on growth aligned for onset of pubertal growth.

Objectives Growth references of today traditionally describe growth in relation to chronological age. Despite the broad variation in age of pubertal maturation, references related to biological age are lacking. To fill this knowledge gap, we aimed to develop a new type of pubertal height reference for improved growth evaluation during puberty, considering individual variation in pubertal timing. Methods Longitudinal length/height measures were obtained from birth to adult height in 1,572 healthy Swedish children (763 girls) born at term ∼1990 to nonsmoking mothers and Nordic parents, a subgroup of GrowUp1990Gothenburg cohort. A total height reference was constructed from Quadratic-Exponential-Puberty-Stop (QEPS)-function-estimated heights from individual height curves that had been aligned for time/age at onset of pubertal growth (5% of P-function growth). References that separated growth into specific pubertal heightSDS (P-function growth) and basic heightSDS (QES-function growth) were also generated. Results References (cm and SDS) are presented for total height, and height subdivided into that specific to puberty and to basic growth arising independently of puberty. The usefulness of the new pubertal growth reference was explored by identifying differences in the underlying growth functions that translate into differences in pubertal height gain for children of varying body mass, height, and with different pubertal timings. Conclusions A new type of height reference allowing alignment of individual growth curves, based on the timing of the pubertal growth spurt was developed using QEPS-model functions. This represents a paradigm shift in pubertal growth research and growth monitoring during the adolescent period.

A new Swedish reference for total and prepubertal height.

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.

Nordic populations are still getting taller - secular changes in height from the 20th to 21st century.

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.

Estimating secular changes in longitudinal growth patterns underlying adult height with the QEPS model: the Grow Up Gothenburg cohorts.

BACKGROUND: 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. METHODS: Growth characteristics of the longitudinal 1974 and 1990-birth cohorts (n = 4181) were compared using the QEPS model together with adult heights. RESULTS: 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. CONCLUSION: 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.

Insight into human pubertal growth by applying the QEPS growth model.

BACKGROUND: Computerized mathematical models describing absolute and relative individual growth during puberty in both cm and standard deviation (SD)-scores are lacking. The present study aimed to fill this gap, by applying the QEPS-model that delineates mathematically the specific pubertal functions of the total growth curve. METHODS: Study population used was the individual growth curves of the longitudinally followed cohort GrowUp1974 Gothenburg (n = 2280). The QEPS-model describes total height as (T)otal-function: a combination of four shape-invariant growth functions, modified by time-scale and height-scale parameters: a (Q)uadratic-function for the continuous growth from fetal life to adulthood; a negative (E)xponential-function adds the rapid, declining fetal/infancy growth; a (P)ubertal-function the specific pubertal growth spurt; a (S)top-function the declining growth until adult height. A constructed variable, MathSelect, was developed for assessing data-quality. CIs and SD-scores for growth estimates were calculated for each individual. QEPS-model estimates used for pubertal growth; from the T-function: onset of puberty as minimal height velocity (AgeT ONSET ); mid-puberty as peak height velocity (AgeT PHV ); end of puberty as height velocity decreased to 1 cm/year (AgeT END ); duration of different intervals and gain (AgeT ONSET-END and Tpubgain); from the P-function: onset of puberty, estimated as growth at 1% or 5% (AgeP1 , AgeP5); mid-puberty as 50% (AgeP50) and PHV (AgeP PHV ); end of pubertal growth at 95 or 99% (AgeP95, AgeP99); duration of different intervals and pubertal gain (Ppubgain; P max ); from the QES-function: gain (QESpubgain) . RESULTS: Application of these mathematical estimates for onset, middle and end of puberty of P-function, QES-function, and T-function during puberty showed: the later the onset of puberty, the greater the adult height; pubertal gain due to the P-function growth was independent of age at onset of puberty; boys had higher total gain during puberty due to P-function growth than to QES-function growth; for girls it was reversed. CONCLUSIONS: QEPS is the first growth model to provide individualized estimates of both the specific pubertal growth function and the total growth during puberty, with accompanying SD-scores and Cis for each individual. These QEPS-derived estimates enable more in-depth analysis of different aspects of pubertal growth than previously possible.

Pubertal height gain is inversely related to peak BMI in childhood.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Modelling individual longitudinal human growth from fetal to adult life - QEPS I.

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. 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.