| 1. |
- Dahlgren, Jovanna, 1964, et al.
(författare)
-
Models predicting the growth response to growth hormone treatment in short children independent of GH status, birth size and gestational age
- 2007
-
Ingår i: BMC Med Inform Decis Mak. - : Springer Science and Business Media LLC. - 1472-6947. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Mathematical models can be used to predict individual growth responses to growth hormone (GH) therapy. The aim of this study was to construct and validate high-precision models to predict the growth response to GH treatment of short children, independent of their GH status, birth size and gestational age. As the GH doses are included, these models can be used to individualize treatment. METHODS: Growth data from 415 short prepubertal children were used to construct models for predicting the growth response during the first years of GH therapy. The performance of the models was validated with data from a separate cohort of 112 children using the same inclusion criteria. RESULTS: Using only auxological data, the model had a standard error of the residuals (SDres), of 0.23 SDS. The model was improved when endocrine data (GHmax profile, IGF-I and leptin) collected before starting GH treatment were included. Inclusion of these data resulted in a decrease of the SDres to 0.15 SDS (corresponding to 1.1 cm in a 3-year-old child and 1.6 cm in a 7-year old). Validation of these models with a separate cohort, showed similar SDres for both types of models. Preterm children were not included in the Model group, but predictions for this group were within the expected range. CONCLUSION: These prediction models can with high accuracy be used to identify short children who will benefit from GH treatment. They are clinically useful as they are constructed using data from short children with a broad range of GH secretory status, birth size and gestational age.
|
|
| 2. |
- Nierop, Andreas FM, 1954, et al.
(författare)
-
Modelling individual longitudinal human growth from fetal to adult life - QEPS I
- 2016
-
Ingår i: Journal of Theoretical Biology. - : Elsevier BV. - 0022-5193. ; 406, s. 143-165
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 3. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
A new Swedish reference for total and prepubertal height.
- 2020
-
Ingår i: Acta paediatrica (Oslo, Norway : 1992). - : Wiley. - 1651-2227 .- 0803-5253. ; 109:4, s. 754-763
-
Tidskriftsartikel (refereegranskat)abstract
- We aimed to develop up-to-date references with standard deviation scores (SDS) for prepubertal and total height.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.The total height reference showed taller prepubertal mean heights (for boys 1-2cm; for girls 0.5-1.0cm) with a narrower normal within ±2SDS range versus the GrowUp 1974 Gothenburg reference. Adult height was increased by +0.9cm for females (168.6cm) and by +1.6cm for males (182.0cm). Height in children growing at -2SDS (the cutoff used for referrals) differed up to 2cm versus the GrowUp 1974 Gothenburg reference, 3cm versus Swedish 1981 references and World Health Organization (WHO) 0-5 years standard, and 6-8cm versus the WHO 5-19 years reference.Up-to-date total and prepubertal height references offer promise of improved growth monitoring compared with the references used in Sweden today.
|
|
| 4. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
A new type of pubertal height reference based on growth aligned for onset of pubertal growth
- 2020
-
Ingår i: Journal of Pediatric Endocrinology & Metabolism. - : Walter de Gruyter GmbH. - 0334-018X .- 2191-0251. ; 33:9, s. 1173-1182
-
Tidskriftsartikel (refereegranskat)abstract
- 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 similar to 1990 to nonsmoking mothers and Nordic parents, a subgroup of GrowUp(1990) Gothenburg 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 height(SDS ) P-function growth) and basic height(SDS) (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.
|
|
| 5. |
|
|
| 6. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
Mortality is not increased in rhGH-treated patients when adjusting for birth characteristics.
- 2016
-
Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 101:5, s. 2149-2159
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: This study aimed to investigate whether reported high mortality in childhood recombinant human GH (rhGH)-treated patients was related to birth-characteristics and/or rhGH treatment. Design and Setting: We sought to develop a mortality model of the Swedish general population born between 1973 and 2010, using continuous-hazard functions adjusting for birth characteristics, sex, age intervals, and calendar year to estimate standardized mortality ratio (SMR) and to apply this model to assess expected deaths in Swedish rhGH-treated patients with idiopathic isolated GH deficiency (IGHD), idiopathic short stature (155) or born small for gestational age (SGA). Participants:The general population: Swedish Medical Birth Register (1973-2010: 1 880 668 males; 1 781 131 females) and Cause of Death Register (1985-2010). Intervention Population: Three thousand eight hundred forty-seven patients starting rhGH treatment between 1985 and 2010 and followed in the National GH Register and/or in rhGH trials diagnosed with IGHD (n = 1890), ISS (n = 975), or SGA (n=982). Main Outcome Measures: Death. Results: Using conventional models adjusting for age, sex, and calendar-year, the SMR was 1.43 (95% confidence interval, 0.89-2.19), P = .14, observed/expected deaths 21/14.68. The rhGH population differed (P < .001) from the general population regarding birth weight, birth length, and congenital malformations. Application of an Advanced Model: When applying the developed mortality model of the general population, the ratio of observed/expected deaths in rhGH-treated patients was 21/21.99; SMR = 0.955 (0.591-1.456)P = .95. Model Comparison: Expected number of deaths were 14.68 (14.35-14.96) using the conventional model, and 21.99 (21.24-22.81) using the advanced model, P < .001, which had at all ages a higher gradient of risk per SD of the model, 24% (range, 18-42%; P < .001). Conclusions: Compared with the general Swedish population, the ratio of observed/expected deaths (21/21.99) was not increased in childhood rhGH-treated IGHD, ISS, and SGA patients when applying an advanced sex-specific mortality model adjusting for birth characteristics.
|
|
| 7. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
New Reference for Height in Swedish Boys and Girls
- 2014
-
Ingår i: Hormone Research in Paediatrics. 82 (suppl 1), s. 256. 53rd Annual Meeting of the European Society for Paediatric Endocrinology (ESPE). Dublin, Ireland, September 18-20, 2014. Hormone Research in Paediatrics.. - : S. Karger AG. - 1663-2818 .- 1663-2826.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: The actual Swedish growth references are based on a cohort born 1974. Objective and hypotheses: Due to secular changes there is need for new height references. Method: Material: Height measurements from birth to adult height (AH) in a cohort of healthy, Nordic and born full term 1990, 20.796 from 1647 boys, 19.202 from 1501 girls were used (ALL) and compared to both a subgroup with puberty close to mean (PHV G0.25 years) of 3.726 heights from 259 boys; 3.759 from 271 girls, and a subgroup (AM) with O10 height measurements evenly distributed (15.324 in 989 boys; 14.381 in 919 girls), and of high data quality. The 1974 cohort, with similar subgrouping, were used for comparison. Methods: For construction of height curves the LMS method was applied with LMS parameters based directly on the data: the power in the Box-Cox transformation (L), the median (M), and the generalized coefficient of variation (S). The GAMLSS R-package with a special LMS program was used, giving L, M, S and optional kurtosis as functions of age. Results: Height reference curves, with mean, G1, G2 SDS were obtained for 1990 of the ALL vs the AM material with similar results whereas the close puberty material showed the same mean but more narrow G1, G2 SDS during adolescence. When the different 1990 references were compared to 1974 references, the corresponding 1974 differences were found. The new references takes into account that the 1990 cohort had a more rapid infancy growth, increased prepubertal growth, especially in boys, increased pubertal gain, only in girls, and increased AH in both genders.
|
|
| 8. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
Novel type of references for BMI aligned for onset of puberty - using the QEPS growth model
- 2022
-
Ingår i: Bmc Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 22:1
-
Tidskriftsartikel (refereegranskat)abstract
- 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 GrowUp(1990)Gothenburg 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 GrowUp(1974)Gothenburg 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.
|
|
| 9. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
Novel type of references for weight aligned for onset of puberty - using the QEPS growth model
- 2021
-
Ingår i: Bmc Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 21:1
-
Tidskriftsartikel (refereegranskat)abstract
- 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 GrowUp(1974)Gothenburg and GrowUp(1990)Gothenburg 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 GrowUp(1990)Gothenburg were then used to create weight references aligned for height at pubertal onset (the age at 5% of P-function growth, AgeP5). GrowUp(1974)Gothenburg 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.
|
|
| 10. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
-
Swedish references for weight, weight-for-height and body mass index: The GrowUp 1990 Gothenburg study
- 2021
-
Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 110, s. 537-548
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
