Normative data for insulin-like growth factor-1 (IGF-1) in healthy children and adolescents from India.

BACKGROUND: Serum IGF-1 is an important biochemical tool to diagnose and monitor GH-related disorders. However, ethnic-specific Indian data following consensus criteria for the establishment of normative data, are not available. Our objective was to generate chronological age (CA)-, bone age (BA)- and Tanner stage-specific normative data for IGF-1 in healthy Indian children and adolescents. METHODS: A cross-sectional epidemiological study was conducted in schools and the community, which enrolled apparently healthy children and adolescents with robust exclusion criteria. The outcome measure was serum IGF-1 assessed using an electro-chemiluminescence immunoassay (ECLIA). The 2.5th, 5th, 10th, 25th, 50th (median), 75th, 90th, 95th, and 97.5th centiles for IGF-1 were estimated using generalized additive models. RESULTS: We recruited 2226 apparently healthy participants and following exclusion, 1948 (1006 boys, 942 girls) were included in the final analysis. Girls had median IGF-1 peak at CA of 13 years (321.7 ng/mL), BA of 14 years (350.2 ng/mL) and Tanner stage IV (345 ng/mL), while boys had median IGF-1 peak at CA of 15 years (318.9 ng/mL) BA of 15 years (340.6 ng/mL) and Tanner stage III (304.8 ng/mL). Girls had earlier rise, peak and higher IGF-1 values. The reference interval (2.5th-97.5th percentile) was broader during peri-pubertal ages, indicating a higher physiological variability. CONCLUSION: This study provides ethnicity-specific normative data on serum IGF-1 and will improve the diagnostic utility of IGF-1 in the evaluation and management of growth disorders in Indian children and adolescents.

Creatine kinase serum levels in children revisited: New reference intervals from a large cohort of healthy children and adolescents.

BACKGROUND: Creatine Kinase (CK) has become increasingly important in pediatrics as a commonly used laboratory screening parameter for neuromuscular diseases. Recent research suggests that hyperCKemia in children is not always associated with pathology and can occur due to several reasons. Little is known of various clinical factors that may influence CK throughout child development. OBJECTIVE: This study aimed to establish reliable age- and sex-specific reference ranges for serum CK levels in healthy infants, children, and adolescents. In addition, the effect of puberty, oral contraceptive (OC) use as well as steroid hormones on CK was examined. MATERIALS AND METHODS: The data was collected from subjects of the longitudinal population-based "LIFE Child"-cohort between 2011 and 2016 in Leipzig, Germany. 5238 blood samples of 2707 healthy children, aged between 0.14 months and 18 years, were analyzed. RESULTS: Serum CK levels raised during the first year of life, peaking shortly after age one (P50girls = 2.7 µkat/L, P50boys = 2.90 µkat/L). There was a pronounced difference in the 97.5th percentile between boys and girls during adolescence with its maximum at age 18 (P97.5girls = 5.74 µkat/L, P97.5boys= 14.48 µkat/L). Also, mean CK serum levels were significantly higher in boys (bboys = 0.29, pboys < 0.001). Intake of oral contraceptives (OC), extreme underweight, underweight and obesity revealed a significant inverse correlation with CK serum levels. CONCLUSION: Age, sex, OC intake and weight status affect serum CK levels, particularly during infancy and puberty. We recommend the use of age- and sex-specific reference values for CK serum levels to assess the clinical relevance of measurements.

Associations between gestational weight gain and weight development of the offspring: Differences depending on maternal pre-pregnancy BMI.

PURPOSE: Obesity rates are rising, and the gestational weight gain (GWG) of most women does not comply with current guidelines. This study assesses the association of pre-pregnancy BMI (ppBMI) and GWG with the child's weight development and investigates whether associations with GWG differ depending on ppBMI. METHODS: Data were obtained from the cohort study LIFE Child (Germany), comprising 691 mother-child pairs. Children's weight was followed until age five. Associations between maternal ppBMI, GWG, and children's weight were evaluated using regression analyses. RESULTS: The association between GWG and birth weight (BW) was significantly positive in normal and underweight (n/u) women (ßGWG = 0.05, p < 0.01, 95% confidence interval (CI) 0.03-0.07), but not in women with overweight or obesity (o/o) (ßGWG = 0.0002, p = 0.99, 95% CI -0.03 to 0.03). The risk of giving birth to an infant who was large for gestational age (LGA) increased with rising GWG in n/u women (OR = 1.6, p < 0.01, 95% CI 1.23-2.25). Women with o/o were at increased risk for a LGA baby regardless of GWG (OR = 3, p < 0.01, 95% CI 1.34-6.97). This trend persisted in the child's weight development during the first 5 years of life. CONCLUSION: Women with o/o might increase their offspring's risk for higher weight at birth and in early childhood. In n/u women, GWG might be the more influential factor. Women should strive for normal weight before conception and should be more attentive to GWG.

Pediatric reference intervals for serum folate and cobalamin based on a European population without exposure to folic acid fortification.

The aim of the present study was to define pediatric reference intervals for serum cobalamin and folate utilizing data generated from a population not exposed to food fortified with folic acid. Folate and cobalamin results analyzed by electrochemiluminescence immunoassay (Roche Cobas) were obtained from 2375 children (2 months to 17.99 years of age). The serum samples were collected between 2011 and 2015 as part of the LIFE (Leipzig Research Centre for Civilization Diseases) Child cohort study in Germany, where folic acid fortification of food is not mandated. These results were used to generate age- and gender-specific reference intervals presented as non-parametric 2.5 and 97.5 percentiles. Because of a subsequent restandardisation of the Roche folate assay in 2016, folate values were recalculated accordingly for adaptation to results obtained using the present calibration. In both genders, folate concentrations decreased continuously with age, whereas cobalamin concentrations peaked at five years of age and then declined. Teenage females had higher concentrations of cobalamin in the age group 12-17.99 years.

Parent-perceived recurrent pain in children: associations with maternal pain, depressiveness, socioeconomic status, and children's behavioural difficulties.

Objectives: The current study aimed to examine the potential transgenerational associations between maternal pain and depressiveness and childhood pain, and to explore the associations between the children's difficulties and recurrent pain (defined as pain occurring at least once a month in the previous 6 month) in healthy children aged 3-13 years. Methods: We collected Data between 2015 and 2019 as part of the LIFE Child study in Germany and investigated associations of maternal pain and depressiveness, child age, sex, pubertal stage, emotional difficulties, conduct difficulties, hyperactivity/inattention, peer group difficulties, and prosocial skills, and family socioeconomic status with the frequency of parent-perceived headache, backache, and stomachache in a sample of 1,850 children (4,819 documented visits) using logistic and ordinal regression analyses. Results: Overall, 10.4%, 24.4%, and 45.2% of parents reported their children had recurrent backache, headache, and stomachache, respectively, with 5.5% of children were reported to experience all three types of pain simultaneously. Higher age, female sex, puberty, emotional difficulties, low family socioeconomic status, as well as higher maternal impairment due to pain and maternal depressiveness were significantly associated with more frequent pain. Conclusions: Our study suggests that maternal pain, maternal depressiveness, and lower family socioeconomic status as well as child's emotional difficulties are significantly associated with a higher frequency of recurrent pain in children perceived by their parents.

Lipoprotein(a) serum concentrations in children in relation to body mass index, age and sex.

BACKGROUND: Lipoprotein(a) (Lp(a)) is an inherited risk factor for atherosclerotic cardiovascular disease (ASCVD). Limited data exist on Lp(a) values in children. We aimed to evaluate whether Lp(a) concentrations in youth are influenced by BMI. METHODS: 756 blood samples of 248 children with obesity and 264 matched healthy children aged 5 and 18 years, enrolled in the population-based LIFE Child (German civilization diseases cohort) study, were analyzed. Repeat measurements were available in 154 children (1-4 follow ups, ~1 year apart). RESULTS: The median Lp(a) concentration in the total cohort (n = 512) at first visit was 9.7 mg/dL (IQR 4.0-28.3). Lp(a) concentrations between 30-50 mg/dL were observed in 11.5%, while 12.5% exhibited Lp(a) ≧50 mg/dL. There was no association of Lp(a) with body mass index (BMI) (ß = 0.004, P = 0.49). Lp(a) levels did not correlate with age or sex, while Lp(a) was associated positively with low-density lipoprotein cholesterol (ß = 0.05, P < 0.0001). The Lp(a) risk category remained stable in 94% of all children in repeated measurements. CONCLUSIONS: The data showed no association of Lp(a) levels in children with BMI, age or sex. Measurement of Lp(a) in youth may be useful to identify children at increased lifetime risk for ASCVD. IMPACT: In youth, Lp(a) levels are not affected by age, sex and BMI. Lp(a) risk categories remain stable over time in repeated measurements in children. Measurement of Lp(a) in children may be useful as an additional factor to identify children at increased lifetime risk for ASCVD and for reverse family screening.

Associations between sleep problems and emotional/behavioural difficulties in healthy children and adolescents.

OBJECTIVE: This study aimed to (1) characterise sleep disturbances and emotional/behavioural difficulties among healthy German children and adolescents aged 3 to 13 years, (2) examine the association between parent-reported sleep problems and emotional/behavioural difficulties, (3) point out possible relations between specific kinds of sleep disturbances and different behavioural difficulties. METHODS: Data were collected between 2011 and 2015 within the LIFE Child study in Germany. The sample included 1101 3- to 13-year-old children and adolescents. Information on sleep disturbances-assessed via the Children's Sleep Habits Questionnaire (CSHQ), emotional/behavioural difficulties-assessed via the Strengths and Difficulties Questionnaire (SDQ), and socioeconomic status was provided by participants' parents. Multiple regressions were applied to analyse the associations between general and specific sleep disturbances (independent variables) and emotional/behavioural difficulties (dependent variables). RESULTS: The total CSHQ score was positively associated with the total SDQ score and all SDQ subscales (emotional problems, conduct problems, hyperactivity/inattention, peer relationship problems). Most of the CSHQ subscales were related to SDQ subscale scores, except for a few non-significant relations with hyperactivity/inattention and conduct problems. The CSHQ total score, daytime sleepiness, sleep duration and parasomnias showed the strongest associations with the SDQ total score. CONCLUSION: This study confirms an association between children's and adolescents' sleep habits and psychological health. We were able to demonstrate the association between sleep problems and emotional/behavioural difficulties in a large sample of healthy participants. In particular, we observed a significant relation between parasomnias and hyperactive/inattentive behaviour as well as a significant association between emotional problems and sleep problems, especially daytime sleepiness, sleep anxiety and parasomnias.

Relation between socioeconomic status and maternal serum lipids to infant lipid concentrations and anthropometry in the first year of life.

PURPOSE: The physical health and development of an individual are influenced by multiple parameters and shaped by internal and external factors during pregnancy. However, it is unclear whether there is an association between maternal lipid concentrations in the third trimester of pregnancy and infant serum lipids as well as anthropometric growth, and whether these factors are influenced by the socioeconomic status (SES) of the mothers. METHODS: Between 2011 and 2021, 982 mother-child pairs were recruited in the LIFE-Child study. To investigate the influence of prenatal factors, pregnant women at the 24th and 36th week of gestation as well as children at the age of 3, 6 and 12 months were examined and serum lipids determined. Socioeconomic status (SES) was assessed using the validated Winkler Index. RESULTS: A higher maternal BMI was associated with a significantly lower Winkler score and a higher infant weight, height, head circumference and BMI from birth up to the 4th-5th week of life. In addition, the Winkler Index correlates with maternal HDL cholesterol and ApoA1 levels. There was no relation between the delivery mode and the maternal BMI or SES. For the maternal HDL cholesterol concentration in the third trimester, an inverse relation to children's height, weight, head circumference and BMI up to the first year of life as well as the chest and abdominal circumference to an age of 3 months was found. Children born to mothers with dyslipidemia in pregnancy tended to have a worse lipid profile than those born to normolipidemic mothers. CONCLUSION: Serum lipid concentrations and anthropometric parameters of children in the first year of life are affected by multiple factors like maternal BMI, lipid levels and SES.

Family structure, socioeconomic status, and mental health in childhood.

The changing landscape of family structures over the last decades has led to a growing need to investigate its impact on children's well-being. This study examined differences in mental health among children from different family compositions and how these differences may be affected by familial socioeconomic status (SES). Data were collected within the LIFE Child study. Participants included 2828 children aged 3-17 years raised in traditional families, stepfamilies, or single-parent families. Mental health was measured using the Strengths and Difficulties Questionnaire (SDQ (behavioral strengths and difficulties)) and the KIDSCREEN-27 questionnaire (quality of life). Linear regression analyses were applied to examine associations between family structure, SES, and mental health outcomes. Children from single-parent families exhibited worse mental health outcomes than those from traditional families across all domains of the SDQ and the KIDSCREEN-27. Children from stepfamilies showed significantly higher Total Difficulties scores (B = 1.29 and 1.42), with 3- to 10-year-olds displaying higher scores in the Hyperactivity & Inattention (B = 0.61) and Peer Relationship Problems (B = 0.36) subscales, and 11- to 17-year-olds showing higher Conduct Problems (B = 0.31), Emotional Symptoms (B = 0.58), and a worse Parent Relationship scores (B = - 1.82) than children from traditional families (all p < 0.05). After controlling for SES, several associations between family structure and mental health lost significance, while others persisted, particularly among older children. To promote mental health in non-traditional families, interventions should address socioeconomic disparities while also investigating factors contributing to the direct impact of family structure on mental well-being.Trial registration The LIFE Child study is registered on clinicaltrials.gov (No. NCT02550236).

Body image and behavioural and emotional difficulties in German children and adolescents.

BACKGROUND: Behavioural and emotional difficulties might play an important role in the development of body image disturbances, which represent serious risk factors for eating disorders or depression. The present study provides a detailed overview on body image disturbances and several behavioural and emotional difficulties (differences between gender, age, and weight status) and their inter-relations in German children and adolescents. METHODS: Data on body image disturbances, assessed through a Figure Rating Scale, and on behavioural and emotional difficulties, assessed through Goodman's Strengths and Difficulties Questionnaire (SDQ), were available for 5255 observations of 1982 German children and adolescents aged 8 to 18 years from the LIFE Child study, based in Leipzig, Germany. Associations were investigated using multiple logistic regression. Each association was checked for interaction with gender, age, and weight status. RESULTS: Boys reported more behavioural difficulties than girls, while girls reported more emotional difficulties. Gender, age and weight status were related to behavioural and emotional difficulties as well as body image disturbances. Individuals with fewer difficulties were more satisfied with their own body. Children and adolescents who desired to be larger showed more prosocial behaviour problems, conduct and emotional problems and more signs of hyperactivity. Those, who desired to be thinner showed more problems in all SDQ-subscales. A more accurate body size perception was associated with fewer behavioural and emotional difficulties. Children and adolescents who overestimated their body size showed more prosocial behaviour and emotional problems. Underestimation one's body size was associated with more signs of hyperactivity. CONCLUSION: The current findings highlight the importance of raising the awareness about the association between behavioural and emotional difficulties and body image disturbances in children and adolescents to prevent negative outcomes.

Children's satisfaction with a comprehensive study program-Results from the LIFE Child cohort study.

BACKGROUND: Research participants' satisfaction is a topic of great interest, especially in the context of longitudinal studies. Evaluation also represents an important component of quality management in the health care system. Adult studies found that personal characteristics, e.g., age, sex, ethnicity, and SES, can influence satisfaction with health care or study participation. Studies on paediatric participants are sparse. OBJECTIVES: To examine how children rated the study day of a cohort study and how these ratings were associated with sociodemographic and socioeconomic characteristics and retention in the context of a large cohort study. METHODS: Analyses were performed on 4- to 17-year-old participants of the German longitudinal cohort study LIFE Child (n = 2033). To assess the associations between overall satisfaction (high versus low/middle) and age, sex, body-mass index, socioecomonic status, and participation in a follow-up visit, we applied logistic mixed-effects models. RESULTS: Participants' overall satisfaction with the LIFE Child study day was high ("very good": 67.8%). Overall satisfaction was higher in 7-9 years olds (odds ratio [OR] 2.00, 95% confidence interval [CI 1.51, 2.66) and 10-12 years olds (OR 1.51, 95% CI 1.16, 1.98) than in 4-6 years olds and 13-17 years olds. Children with obesity were less likely to participate in a follow-up visit (OR 0.56, 95% CI 0.39, 0.78). Children reporting high overall satisfaction at the first study visit completed a follow-up visit more frequently (OR 1.32, 95% CI 1.05,1.67). CONCLUSIONS: A high level of satisfaction increased participants' attendance at a follow-up visit. Our results might be helpful for adapting the study program to the participants' needs in order to maximise retention and minimise attrition rates.

Bone turnover in lactating and nonlactating women.

PURPOSE: During lactation, bone turnover increases, reflecting the mobilization of Calcium from maternal skeletal stores and resulting in bone loss. However, mechanisms are not yet fully understood, and previous studies have been comparatively small. We aim to assess bone metabolism during lactation by comparing bone-metabolism-related-parameters between large cohorts of lactating and nonlactating women. METHODS: In a retrospective cohort study, we recruited 779 postpartum women and 742 healthy, nonpregnant, nonlactating controls. Postpartum women were examined 3 and 6 months after delivery and retrospectively assigned to either the exclusively breastfeeding (exc-bf) group if they had exclusively breastfed or the nonexclusively breastfeeding (nonexc-bf) group if they had not exclusively breastfed up to the respective visit. Serum levels of PTH, Estradiol, total Calcium, Phosphate, and bone turnover markers (ßCTX, P1NP, Osteocalcin) were compared between the groups. RESULTS: Bone turnover markers were significantly increased in exc-bf and nonexc-bf women compared with the controls (all ps < .001). ßCTX was approximately twice as high in exc-bf women than in the controls. PTH levels were marginally higher in exc-bf (p < .001) and nonexc-bf women (p = .003) compared with the controls (6 months). Estradiol was suppressed in exc-bf women compared with the controls (p < .001, 3 months). CONCLUSION: Exc-bf and even nonexc-bf states are characterized by an increase in bone formation and resorption markers. The PTH data distribution of exc-bf, nonexc-bf, and control groups in the underpart of the reference range suggest that lactational bone loss is relatively independent of PTH.

Association between TGFß1 Levels in Cord Blood and Weight Progress in the First Year of Life.

Transforming growth factor beta-1 (TGFß1) is an adipokine secreted from adipose tissue, placental tissue and immune cells with a role in cell proliferation, cell apoptosis and angiogenic proliferation. The role of TGFß1 in pregnancy and child growth and the source of cord TGFß1 are yet unknown. In this study, we sought to clarify the correlation of TGFß1 levels with parameters of intrauterine growth and child growth during the first year of life, and to determine whether their source is primarily of fetal or maternal origin. Serum samples and anthropometric measurements were obtained from the LIFE Child cohort of 79 healthy mother-child pairs. Measurements were conducted using enzyme-linked immunosorbent assays. Statistical analyses including Mann-Whitney U-test, correlation analyses and linear regression analyses were performed using GraphPad Prism and R. TGFß1 levels were significantly higher in cord than in maternal serum, suggesting a fetal origin. Multivariate regression analyses revealed strong positive associations between cord TGFß1 levels at birth and child weight at U6. Furthermore, cord TGFß1 was significantly correlated with child weight at approximately one year of age. An increase of 10,000 pg/mL in cord TGFß1 concentrations at birth was associated with a higher body weight of 201 g at roughly one year of age when adjusted for sex.

Tracking of serum lipids in healthy children on a year-to-year basis.

OBJECTIVES: To assess the stability of lipid profiles throughout childhood and evaluate their onset and dynamic. MATERIALS AND METHODS: Lipid markers were longitudinally measured in more than 1300 healthy children from the LIFE Child study (Germany) and categorized into normal, at-risk, or adverse. Year-to-year intra-person persistence of the categories during follow-ups was examined and Pearson's correlation coefficient was calculated. RESULTS: We found strong positive correlations for TC, LDL-C and ApoB (r > 0.75, p < 0.001) from the age of four years. Correlations were lowest during the first two years of life. Most children with normal levels also had normal levels the following year. Children with at-risk levels showed a tendency towards normal levels at the follow-up visit. Adverse levels of TC, LDL-C, ApoB (all ages), and HDL-C (from age 15) persisted in more than half of the affected children. Age-dependent patterns of stability were most pronounced and similar for TC, LDL-C, and ApoB. CONCLUSIONS: Normal levels of serum lipids show high stability and adverse levels stabilized in early childhood for TC, LDL, and ApoB. At-risk and adverse levels of TC, LDL-C or ApoB may warrant further or repeated diagnostic measurements with regards to preventing CVD in the long run.

Influence of growth and metabolic markers on hs-troponin T and NT-proBNP levels in healthy children.

Background and objectives: As part of the LIFE Child study, we previously described the associations between N-terminal-pro-hormone brain natriuretic peptide (NT-proBNP) and hs-troponin T (hs-TnT) levels and an individual's sex, age and pubertal status, as well as with body mass index (BMI) and serum lipid levels. For NT-proBNP, we found inverse associations with advancing puberty, increasing BMI and serum lipid levels. These findings led us to further question the putative influences of the developing individual's metabolic and growth status as represented by levels of insulin-like growth factor-1 (IGF-1) and IGF-1-binding protein-3 (IGF-BP3) as well as hemoglobin A1c (HbA1c) and Cystatin C (CysC). Material and methods: Serum values, medical history and anthropometric data provided by 2522 children aged 0.25-18 years were collected and analyzed as per study protocol. Results: A strong negative association between NT-proBNP values and IGF-1, IGF-BP3 and HbA1c levels was identified. For IGF-BP3, this interaction was modulated by sex and age, for HbA1c only by age. For hs-TnT, a positive association was found with IGF-BP3, IGF-1 and CysC. The association between hs-TnT and IGF-1 was sex dependent. The association between CysC and hs-TnT was stronger in girls, but the interaction with age was only seen in boys. Between hs-TnT and HbA1c, the association was significantly negative and modulated by age. Conclusion: Based on our large pediatric cohort, we could identify age- and sex-dependent interactions between the metabolic status represented by IGF-1, IGF-BP3, CysC and HbA1c levels and the cardiac markers NT-proBNP and hs-TnT.

Fasting indices of glucose-insulin-metabolism across life span and prediction of glycemic deterioration in children with obesity from new diagnostic cut-offs.

Background: Fasting indices of glucose-insulin-metabolism are an easy and affordable tool to assess insulin resistance. We aimed to establish reference ranges for fasting insulin indices that reflect age-dependent variation over the entire life span and subsequently test their clinical application regarding the prediction of glycemic deterioration in children. Methods: We calculated age- and puberty-dependent reference values for HOMA-IR, HOMA2-IR, HOMA-ß, McAuley index, fasting insulin, and fasting glucose from 6994 observations of 5512 non-obese healthy subjects aged 5-80 years. Applying those references, we determined the prevalence of insulin resistance among 2538 subjects with obesity. Furthermore, we investigated the intraindividual stability and the predictive values for future dysglycemia of these fasting indices in 516 children and adolescents with obesity up to 19 years of follow-up. We validated the results in three independent cohorts. Findings: There was a strong age-dependent variation of all indices throughout the life span, including prolonged recovery of pubertal insulin resistance and a subsequent continuous increase throughout adulthood. Already from age 5 years onwards, >40% of children with obesity presented with elevated parameters of insulin resistance. Applying newly developed reference ranges, insulin resistance among children with obesity doubled the risk for future glycemic deterioration (HOMA-IR HR 1.88 (95% CI 1.1-3.21)), fasting insulin HR 1.89 (95% CI 1.11-3.23). In contrast, fasting glucose alone was not predictive for emerging dysglycemia in children with obesity (HR 1.03 (95% CI 0.62-1.71)). The new insulin-based thresholds were superior to fasting glucose and HbA1c in detecting children eventually manifesting with dysglycemia in prospective analyses. Interpretation: The variation of fasting glucose-insulin-metabolism across the life span necessitates age-specific reference ranges. The improved prediction of future glycemic deterioration by indices based on fasting insulin beyond simple glucose measures alone could help to stratify risk characteristics of children with obesity in order to guide patient-tailored prevention and intervention approaches. Funding: German Research Foundation (DFG)-through SFB 1052, project number 209933838, subproject C5; Federal Ministry of Education and Research, Germany; European Union-European Regional Development Fund; Free State of Saxony. The German Diabetes Association, the CarbHealth consortium (01EA1908B). EU-IMI2-Consortium SOPHIA (grant agreement No 875534), German Center for Diabetes Research (DZD), grant number 82DZD14E03.

Pediatric reference values of alkaline phosphatase: Analysis from a German population-based cohort and influence of anthropometric and blood parameters.

BACKGROUND: Due to different growth and metabolic processes, reference values of alkaline phosphatase (AP) for children aged 3 month to 18 years are dependent on age and sex. They are not constant and differ from those of adults due to the growth processes taking place. Accordingly, reference levels of AP continuous across these ages were generated for boys and girls based on of a large German health- and population-based study, LIFE Child. We considered AP at different growth and Tanner stages and additionally its association with other anthropometric parameters. The association between AP and BMI was of particulary great interest due to controversial literature on this topic. The role of AP in liver metabolism was investigated by examining ALAT, ASAT, and GGT. METHODS: 3976 healthy children (12,093 visits) were included from the LIFE Child study from 2011 to 2020. The subjects´ age ranged from 3 months to 18 years. Serum samples from 3704 subjects (10,272 cases, 1952 boys and 1753 girls) were analysed for AP after applying specific exclusion criteria. After calculating of reference percentiles, associations between AP and height-SDS, growth velocity, BMI-SDS, Tanner stage and the liver enzymes ALAT, ASAT and GGT were examined via linear regression models. RESULTS: In the continuous reference levels, AP showed a first peak during the first year of life, followed by a plateau at a lower level until the start of puberty. In girls, AP increased beginning at the age 8, with a peak around 11 years, in boys beginning at the age 9, with a peak around age 13. Afterwards, AP values decreased continuously until age 18. In Tanner stages 1 and 2, AP levels did not differ between the two sexes. We found a strong positive association between AP-SDS and BMI-SDS. We also observed a significantly positive association between AP-SDS and height-SDS, which was stronger in boys than in girls. We found different intensities in the associations of AP with growth velocity depending on age group and sex. Furthermore, we found a significantly positive association between ALAT and AP in girls but not in boys, whereas ASAT-SDS and GGT-SDS were significantly positively associated with AP-SDS in both sexes. CONCLUSION: Sex and age, but also BMI may act as confounding factors for AP reference ranges. Our data confirm the remarkable association between AP and growth velocity (or height-SDS, respectively) during infancy and puberty. In addition, we were able to specify the associations between AP and ALAT, ASAT, and GGT and their differences in both sexes. These relations should be considered when evaluating liver and bone metabolism markers, especially in infancy.

Active school transport in an urban environment:prevalence and perceived barriers.

BACKGROUND: Active school transport (AST) can increase children's and adolescents' physical activity. The proportion of children and adolescents who engage in AST has declined internationally in recent decades. This study examines the prevalence, correlates, and perceived barriers to AST in the city of Leipzig, Germany. METHODS: The study sample includes 1070 participants, 364 children and 706 adolescents, aged between 6 and 18 years, as well as their parents. The parents as well as adolescents age 10 and above completed questionnaires concerning sociodemographic variables, means of transport/AST and perceived barriers to AST. The distance between home and school was calculated as the network distance from the home to school address using the Dijkstra algorithm. Based on these data, logistic models were fitted in a two-step variable selection process, using AST as the dependent variable. RESULTS: Approximately half of the children (59%) and adolescents (51%) engaged in AST. The prevalence of AST exhibited a negative correlation with age (Odds Ratio (OR) = 0.94, 95% confidence interval (CI) = 0.9-0.99, p = 0.015) and did not significantly differ by gender (children: ORgirls = 1.5, CI = 0.95-2.25, p = 0.075, adolescents: ORgirls = 1.01, CI = 0.75-1.37, p = 0.924). A high socioeconomic status was positively correlated to AST on the morning trip (OR = 1.7, CI 1.3-2.21, p < 0.01) but negatively on the afternoon trip (OR = 0.7, CI = 0.53-0.9, p < 0.01) in the summer. Common barriers for children (from their parents' perspective) and for adolescents (from their own and their parents' perspective) were distance and a heavy load to carry. The parents of adolescents did not perceive any other specific barriers as a serious impediment. Further significant barriers perceived by the younger children's parents were adults giving a lift on the way to other errands, no other children to walk or cycle with, and too much traffic. Too much traffic was also a significant barrier for adolescents, as were taking too much time and bad weather conditions. CONCLUSIONS: Future interventions promoting AST in an urban environment should be guided by the identified perceived barriers. TRIAL REGISTRATION: LIFE Child has been retrospectively registered with ClinicalTrials.gov (NCT02550236).

Media regulation strategies in parents of 4- to 16-year-old children and adolescents: a cross-sectional study.

BACKGROUND: Since children can only control and limit their own media use to a limited extent, it is often the parents who regulate their children's media use. However, there is insufficient research on which strategies they use and on how these strategies are related to socio-demographic and behavioral parameters. METHODS: The parental media regulation strategies co-use, active mediation, restrictive mediation, monitoring, and technical mediation were assessed in a sample of 563 four- to 16-year-old children and adolescents from middle to high social strata participating in the German cohort study LIFE Child. We investigated cross-sectional associations with socio-demographic characteristics (age and sex of child, age of parent, and socio-economic status (SES)) and other behavioral parameters of children (media use, ownership of media devices, engagement in extracurricular activities) and their parents (media use). RESULTS: All media regulation strategies were applied frequently, with restrictive mediation occurring most frequently. Overall, parents of younger children and of boys mediated media use more frequently, while we observed no differences depending on SES. Regarding child behavior, the ownership of a smartphone and a tablet/personal computer/laptop was associated with more frequent technical restriction, while screen time and engagement in extracurricular activities was not associated with parental media regulation. In contrast, parental screen time was related to more frequent co-use and less frequent use of restrictive and technical mediation. CONCLUSION: Parental regulation of child media use is influenced by parental attitudes and a perceived need for mediation (e.g., in younger children or children owning internet-enabled devices) rather than child behavior.