Effect of hypoxia on the proliferation of porcine bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells in 2- and 3-dimensional culture.

OBJECTIVE: Bone marrow-derived mesenchymal stem cells (MSCs) and adipose-derived mesenchymal stem cells (ASCs) currently represent a promising tool for the regeneration of large bony defects. Therefore, it is pivotal to find the best cell source within the body and the best conditions for in vitro cellular expansion. This study compared cellular response of MSCs and ASCs from a porcine animal in normoxic (21% O2) and hypoxic (2% O2) cell culture conditions via 2D and 3D experimental settings. MATERIALS AND METHODS: The effect of constant exposure to hypoxia on primary pig stem cells was evaluated by two methods. First, a cumulative population doublings (cumPD) over a period of 40 days, a metabolic activity assay in both 2D and 3D beta-TCP-PHB scaffolds, followed by analysis of osteogenic differentiation potential in cell monolayers. RESULTS: Our results displayed enhanced cell culture proliferation in 2% O2 for both MSCs and ASCs, with impaired osteogenic differentiation of MSCs. The impact of constant hypoxia on porcine MSCs and ASCs exhibited a statistically significant decrease in osteogenic differentiation under hypoxic conditions with the MSCs. CONCLUSIONS: Our data suggest that MSCs and ASCs expanded in hypoxic culture conditions, might be more suitable for use in the clinical setting where large cell numbers are required. When differentiated in normoxic conditions, MSCs showed the highest osteogenic differentiation potential and might be the best choice of cells with consideration to bone repair.

Differential effects of low birthweight and intrauterine growth restriction on umbilical cord blood insulin-like growth factor concentrations.

OBJECTIVE: Alterations in the growth hormone-insulin-like growth factor (IGF) axis have been considered as a causal factor for intrauterine growth restriction (IUGR) and for the increased risk of metabolic disease in later life. We compared members of the IGF axis in umbilical cord blood between IUGR neonates, small for gestational age without foetal restriction (SGA) and appropriate for gestational age (AGA) neonates. DESIGN: Prospective controlled multicenter study. PATIENTS: Sixteen ultrasound-proven IUGR, 8 SGA and 40 AGA neonates. MEASUREMENTS: Concentrations of total IGF-I and total IGF-II by immunoassays, bioactive IGF by cell-based bioassay and IGFBP-I in mixed venous and arterial umbilical cord blood samples at birth. Auxological parameters at birth. RESULTS: IGF-I concentrations in IUGR [17·7 µg/l (CI 13·8;21·6)] were clearly below those in AGA [48·3 µg/l (CI 43·7;52·9)] and SGA neonates [36·0 µg/l (CI 26·6;45·4)]. IGF-II levels were significantly reduced in IUGR [201·4 µg/l (CI 190·2;212·6)] compared to AGA neonates [231·2 µg/l (CI 220·6;241·9)]. A trend for lower IGF-II concentrations was observed in IUGR when compared to SGA neonates [232·0 µg/l (CI 207·2;256·8)]. These differences could not be explained by confounding. For IGFBP-1, a trend towards higher values in IUGR was observed. CONCLUSIONS: Low IGF-I cord blood concentrations in hypotrophic neonates after IUGR might not only result from low birthweight per se, but also reflect prenatal placental environment. Alterations of the IGF axis could be in the causal pathway of IUGR and thus constitute a potential surrogate marker for IUGR in the assessment of foetal programming.

GDM Alters Expression of Placental Estrogen Receptor α in a Cell Type and Gender-Specific Manner.

OBJECTIVE: The nuclear receptor estrogen receptor α (ERα) is one of the key players in energy balance, insulin resistance, and trophoblast differentiation. We tested the hypothesis that gestational diabetes mellitus (GDM) alters expression of placental ERα in a cell type-specific manner and that this regulation may involve epigenetic changes. STUDY DESIGN: Expression of ERα was analyzed by immunohistochemistry using the semiquantitative immunoreactive score in 80 placentas (40 GDM/40 controls). Quantitative real-time polymerase chain reaction (PCR) measured ERα messenger RNA (mRNA) in decidual tissue. Methylation-specific PCR was performed to analyze cytosine-phosphatidyl-guanine-island methylation of the ERα promoter. RESULTS: Expression of ERα protein is upregulated (P = .011) in GDM in extravillous trophoblasts but not in syncytiotrophoblast. Gestational diabetes mellitus downregulated ERα in decidual vessels only in pregnancies with male but not female fetuses. Furthermore, mRNA of the ERα encoding gene estrogen receptor gene 1 (ESR1) was increased (+1.77 fold) in GDM decidua when compared to controls (P = .024). In parallel, the promoter of ESR1 was methylated only in decidua of healthy control individuals but not in GDM. CONCLUSION: Gestational diabetes mellitus affects expression of placental ERα in a cell type-dependent way, on epigenetic level. These data link GDM with epigenetic deregulations of ERα expression and open new insights into the intrauterine programming hypothesis of GDM.

Cervical conisation and the risk of preterm delivery: a retrospective matched pair analysis of a German cohort.

PURPOSE: Since the routine screening program for cervical dysplasia by Pap smear was established in the early 1970s, the rate of cervical cancer has continually dropped. Even if a high percentage of cervical dysplasia shows spontaneous restitution, the only effective therapy for persisting cervical dysplasia is local ablation or excision which might be associated with an increased risk of preterm delivery in subsequent pregnancies. However, data from German patients are missing, so the aim of this study was to evaluate the risk of preterm delivery and associated risks in a cohort of patients who had undergone cervical conisation previous to their pregnancies. METHODS: A total of 144 patients with conisation and subsequent pregnancy were identified. They were compared regarding week of delivery and preterm birth, fetal birth weight, fetal outcome and birth procedure (spontaneous delivery, vacuum extraction, primary and secondary cesarean section) with their matched partners. RESULTS: 135 patients with singleton pregnancies and their matched partners were evaluated in the final analysis. The mean age was 33.5 years. Comparing the case and control group we reached significant different results for week of delivery, but not preterm birth defined as birth prior to 37 weeks of gestation. CONCLUSIONS: Within this German cohort cervical conisation did not increase the risk for preterm birth, cesarean section or poor fetal outcome. We therefore conclude that cervical conisation is an appropriate method to treat women with cervical dysplasia also at childbearing age when prevention of cervical cancer is needed.

Gestational diabetes mellitus upregulates vitamin D receptor in extravillous trophoblasts and fetoplacental endothelial cells.

OBJECTIVE: Gestational diabetes mellitus (GDM) is often accompanied by low maternal vitamin D, that is, calcitriol (1,25[OH]2 vitamin D3), levels. Here, we tested the hypothesis that the placental vitamin D receptor (VDR) is regulated by calcitriol and altered in GDM with distinct changes in different placental cell types. Specifically, we aimed to localize VDR in human term placentas from normal and GDM pregnancies, to quantify its cellular expression and to study in vitro its regulation by its physiological agonist calcitriol. STUDY DESIGN: Placental tissue slides of 80 patients (40 with GDM/40 controls) were double stained for VDR and human leukocyte antigen G to identify extravillous trophoblasts (EVTs). Staining intensity was semiquantified. Quantitative real time-polymerase chain reaction and Western blotting measured VDR messenger RNA (mRNA) and protein in decidual tissue. The trophoblast cell line BeWo was used to study in vitro VDR regulation by calcitriol (0.01, 0.1, and 1 nmol/mL). RESULTS: Vitamin D receptor protein and mRNA levels are upregulated (P < .05) in EVT (1.8-fold) as well as in placental endothelium (5.8-fold) of patients with GDM. Expression of VDR is regulated by calcitriol in a bimodal manner: high doses (0.1 and 1 nmol/mL) caused downregulation, whereas the low dose (0.01 nmol/mL) resulted in VDR upregulation. CONCLUSION: Vitamin D receptor is upregulated in EVT and endothelium of GDM placentas. This could be due to low maternal vitamin D levels in patients with GDM because in vitro low calcitriol doses upregulate VDR in trophoblast cells.

Parental smoking and childhood obesity: higher effect estimates for maternal smoking in pregnancy compared with paternal smoking--a meta-analysis.

BACKGROUND: Some studies reported similar effect estimates for the impact of maternal smoking in pregnancy and paternal smoking on childhood obesity, whereas others suggested higher effects for maternal smoking. We performed a meta-analysis to compare the effect of in utero exposure to maternal smoking and that of paternal or household smoking exposure in utero or after birth with mutual adjustment. METHODS: Meta-analysis of observational studies identified in MEDLINE, EMBASE and Web of Knowledge published in 1900-2013. Study inclusion criterion was assessment of the association of maternal smoking during pregnancy and paternal or household smoking (anyone living in the household who smokes) at any time with childhood overweight and obesity. The analyses were based on all studies with mutually adjusted effect estimates for maternal and paternal/household smoking applying a random-effects model. RESULTS: Data for 109,838 mother/child pairs were reported in 12 studies. The pooled odds ratios (ORs) for overweight 1.33 [95% confidence interval (CI) 1.23;1.44] (n=6, I2=0.00%) and obesity 1.60 (95% CI 1.37;1.88) (n=4, I2=32.47%) for maternal smoking during pregnancy were higher than for paternal smoking: 1.07 (95% CI 1.00;1.16) (n=6, I2=41.34%) and 1.23 (95% CI 1.10;1.38) (n=4, I2=14.61%), respectively. Similar estimates with widely overlapping confidence limits were found for maternal smoking during pregnancy and childhood overweight and obesity: 1.35 (95% CI 1.20;1.51) (n=3, I2=0.00%) and 1.28 (95% CI 1.07;1.54) (n=3, I2=0.00%) compared with household smoking 1.22 (95% CI 1.06;1.39) (n=3, I2=72.14%) and 1.31 (95% CI 1.15;1.50)] (n=3, I2=0.00%). CONCLUSIONS: Higher effect estimates for maternal smoking in pregnancy compared with paternal smoking in mutually adjusted models may suggest a direct intrauterine effect.

Patient-specific determinants of responsiveness to robot-enhanced treadmill therapy in children and adolescents with cerebral palsy.

AIM: The aim of the study was to evaluate patient-specific determinants of responsiveness to robot-enhanced repetitive treadmill therapy (ROBERT) in patients with early-developed movement disorders. METHOD: Patients were treated over 12 sessions during a 3-week period. Gross Motor Function Measure-66 (GMFM-66) scores 1 day before ROBERT were compared with scores recorded 1 day after ROBERT. The association of GMFM-66 baseline score, age, sex, aetiology, and add-on botulinum toxin therapy to response to treatment was assessed. RESULTS: Eighty-three patients aged between 4 and 18 years (48 males, 35 females; mean age 10y 8mo, SD 6y 1mo; Gross Motor Function Classification System level I [n=12], II [n=21], III [n=35], IV [n=10], and V [n=1]) were each treated for a total of 7.2 (SD 1.9) treadmill walking hours. Aetiology was bilateral spastic cerebral palsy (BS-CP; n=69), unilateral CP (n=3), ataxic CP (n=3), hereditary spastic paraparesis (n=6), and genetic syndrome including spasticity (n=2). Meaningful improvements were observed in GMFM-66 (+2.5; 95% CI 2.0-3.0), GMFM-D (+5.2; 95% CI 3.6-6.8), and GMFM-E (+4.0; 95% CI 2.8-5.3). There was a high inter-individual variability in treatment response. After multivariable adjustment, the improvements in GMFM-66 and GMFM-E scores were positively associated with the GMFM-66 baseline score. The effect on GMFM-D improvement was inversely associated with age. INTERPRETATION: Gross motor abilities at baseline and age were identified as relevant determinants for the high degree of interpersonal variability in response to ROBERT.

Differences in BMI z-scores between offspring of smoking and nonsmoking mothers: a longitudinal study of German children from birth through 14 years of age.

BACKGROUND: Children of mothers who smoked during pregnancy have a lower birth weight but have a higher chance to become overweight during childhood. OBJECTIVES: We followed children longitudinally to assess the age when higher body mass index (BMI) z-scores became evident in the children of mothers who smoked during pregnancy, and to evaluate the trajectory of changes until adolescence. METHODS: We pooled data from two German cohort studies that included repeated anthropometric measurements until 14 years of age and information on smoking during pregnancy and other risk factors for overweight. We used longitudinal quantile regression to estimate age- and sex-specific associations between maternal smoking and the 10th, 25th, 50th, 75th, and 90th quantiles of the BMI z-score distribution in study participants from birth through 14 years of age, adjusted for potential confounders. We used additive mixed models to estimate associations with mean BMI z-scores. RESULTS: Mean and median (50th quantile) BMI z-scores at birth were smaller in the children of mothers who smoked during pregnancy compared with children of nonsmoking mothers, but BMI z-scores were significantly associated with maternal smoking beginning at the age of 4-5 years, and differences increased over time. For example, the difference in the median BMI z-score between the daughters of smokers versus nonsmokers was 0.12 (95% CI: 0.01, 0.21) at 5 years, and 0.30 (95% CI: 0.08, 0.39) at 14 years of age. For lower BMI z-score quantiles, the association with smoking was more pronounced in girls, whereas in boys the association was more pronounced for higher BMI z-score quantiles. CONCLUSIONS: A clear difference in BMI z-score (mean and median) between children of smoking and nonsmoking mothers emerged at 4-5 years of age. The shape and size of age-specific effect estimates for maternal smoking during pregnancy varied by age and sex across the BMI z-score distribution.

Overweight in adolescence can be predicted at age 6 years: a CART analysis in German cohorts.

OBJECTIVE: To examine, whether overweight in adolescents can be predicted from the body mass index (BMI) category, at the age of 6, the mother's education level and mother's obesity and to quantify the proportion of overweight at the age of 14 that can be explained by these predictors. METHOD: Pooled data from three German cohorts providing anthropometric and other relevant data to a total of 1 287 children. We used a classification and regression tree (CART) approach to identify the contribution of BMI category at the age of 6 (obese: BMI > 97th percentile (P97); overweight: P90 < BMI ≤ P97; high normal weight: P75P90) at the age of 14. RESULTS: While 4.8% [95%CI: 3.2;7.0] of 651 boys and 4.1% [95%CI: 2.6;6.2] of 636 girls with a BMIP97 (similar results for girls). BM I ≥ P75 at the age of 6 explained 63.5% [95%CI: 51.1;74.5]) and 72.0% [95%CI: 60.4;81.8] of overweight/obesity at the age of 14 in boys and girls, respectively. CONCLUSIONS: Overweight/obesity in adolescence can be predicted by BMI category at the age of 6 allowing for parent counselling or risk guided interventions in children with BMI ≥ P75, who accounted for >2/3 of overweight/obesity in adolescents.

Relevance of hospital characteristics as performance indicators for treatment of very-low-birth-weight neonates.

BACKGROUND: Current attempts at centralization of neonatal care in Germany focus on a minimum volume of 30 very-low-birth-weight (VLBW, weighing <1250 g) neonate admissions per year. However, the evidence for a selective referral strategy based on hospital volume is unclear. METHOD: A total of 5575 neonates weighing <1250 g treated in 31 hospitals in Bavaria between 2000 and 2011 were analysed using population-based data. The relevance of different hospital characteristics (i.e. hospital volume, bed capacity and teaching status) for explaining individual in-hospital mortality as well as interhospital variation in mortality rates was analysed using multilevel logistic regression analysis. RESULTS: In a risk-adjusted model, only dichotomized hospital volume (<30 admissions) was significantly associated with higher mortality in VLBW neonates (odds ratio: 1.74; 95% confidence interval: 1.02-2.99). However, the higher mortality risk only applied to neonates with higher Clinical Risk Index for Babies (CRIB) scores. There was considerable heterogeneity in mortality rates between Bavarian hospitals. The median odds ratio for mortality between two neonates treated in a randomly chosen low-performing versus high-performing hospital was 1.62 in the null model (without explanatory variables). Hospital volume only explained 15.1% of interhospital variation in mortality rates after adjustment for case-mix. Other hospital characteristics were of minor relevance. A funnel plot of the standardized mortality ratio against the number of admissions showed that 41% of small-volume hospitals performed better than expected. CONCLUSION: A selective referral strategy based solely on hospital volume will fall short of the task of optimal allocation of neonatal care by means of centralization.

Breastfeeding and its prospective association with components of the GH-IGF-Axis, insulin resistance and body adiposity measures in young adulthood--insights from linear and quantile regression analysis.

BACKGROUND: Breastfeeding may lower chronic disease risk by long-term effects on hormonal status and adiposity, but the relations remain uncertain. OBJECTIVE: To prospectively investigate the association of breastfeeding with the growth hormone- (GH) insulin-like growth factor- (IGF) axis, insulin sensitivity, body composition and body fat distribution in younger adulthood (18-37 years). DESIGN: Data from 233 (54% female) participants of a German cohort, the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study, with prospective data on infant feeding were analyzed. Multivariable linear as well as quantile regression were performed with full breastfeeding (not: ≤ 2, short: 3-17, long: >17 weeks) as exposure and adult IGF-I, IGF binding proteins (IGFBP) -1, -2, -3, homeostasis model assessment of insulin resistance (HOMA-IR), fat mass index, fat-free mass index, and waist circumference as outcomes. RESULTS: After adjustment for early life and socio-economic factors, women who had been breastfed longer displayed higher adult IGFBP-2 (p(trend) = 0.02) and lower values of HOMA-IR (p(trend) = 0.004). Furthermore, in women breastfeeding duration was associated with a lower mean fat mass index (p(trend) = 0.01), fat-free mass index (p(trend) = 0.02) and waist circumference (p(trend) = 0.004) in young adulthood. However, there was no relation to IGF-I, IGFBP-1 and IGFBP-3 (all p(trend) > 0.05). Associations for IGFBP-2 and fat mass index were more pronounced at higher, for waist circumference at very low or high percentiles of the distribution. In men, there was no consistent relation of breastfeeding with any outcome. CONCLUSIONS: Our data suggest that breastfeeding may have long-term, favorable effects on extremes of adiposity and insulin metabolism in women, but not in men. In both sexes, breastfeeding does not seem to induce programming of the GH-IGF-axis.

Effectiveness of 2+1 PCV7 vaccination schedules in children under 2 years: a meta-analysis of impact studies.

Although a case control study suggested high effectiveness of the 2+1 PCV-7 vaccination, schedule against invasive pneumococcal disease (IPD) in children the results of impact studies in, different countries yield considerable differences in the magnitude of the effects. A systematic, literature review was conducted to identify all relevant studies on IPD incidence reduction after onset, of PCV7 vaccination programmes in children younger than 2 years of age given in the 2+1 schedule. The incidence rate ratio between IPI incidences for vaccine serotypes before and after beginning of the, vaccination programme was calculated for each study. Heterogeneity was assessed and attempts to, identify causes for heterogeneity were made. In the literature search 4 studies which fulfilled inclusion, criteria were identified. The summary estimates yielded an IRR 0.10 [0.04; 0.30] suggesting a 90%, incidence reduction. Heterogeneity was high with I(2)=93%. Heterogeneity might be explained by, differences in vaccination rates, the way vaccination rates were assessed, matching of the periods of, vaccination and case ascertainment, time between onset of the vaccination programme and onset of, case ascertainment during the vaccination period and the length of the observation period after onset, of the vaccination programme. A study which started 3 years after onset of the vaccination programme, with vaccination rates ≥80% throughout the ascertainment period of the incidence rates reported a, 98% reduction in the incidence rates. A meta-analysis on IRR studies on reductions of the IPD, incidence in children <2 years of age suggested high effectiveness of the 2+1 vaccination schedule for PCV 7.

Interactions of genetic and environmental risk factors with respect to body fat mass in children: results from the ALSPAC study.

OBJECTIVE: To evaluate if percentile-specific effects of genetic, environmental and lifestyle obesity risk factors on body mass index (BMI) might reflect gene-environment interactions with respect to the development of overweight. DESIGN AND METHODS: Retrospective study with data of 2,346 children from the Avon Longitudinal Study of Parents and Children (ALSPAC), using quantile regression with body fat mass index (FMI) for children at the age of 9 years as outcome variable. We assessed interactions of an "obesity-risk-allele-score" with environmental and nutritional factors. RESULTS: There was no evidence of interactions between the obesity-risk-allele score and the environmental variables except for maternal overweight. However, we found a significant interaction with respect to intake of mono- and polyunsaturated fatty acids at the age of 7. In children with low intake, genetic risk was associated with increasing effect sizes by FMI percentile. CONCLUSIONS: Our results suggest an interaction between a low dietary content of unsaturated fatty acids and genetic risk factors for overweight on FMI. This effect is likely to be stronger in children with higher FMI.

Prevention of headache in adolescents: population-attributable risk fraction for risk factors amenable to intervention.

INTRODUCTION: Several risk factors for headache have been identified, some of which are potentially amenable to interventions. The potential effect of such interventions can be predicted by the population-attributable risk fraction (PARF). We assessed PARFs of the the following risk factors: neck muscle pain, chronic stress, alcohol consumption, smoking, coffee consumption, and physical inactivity. We studied the maximal possible effect achievable by avoidance of these risk factors. METHODS: Two approaches to estimate PARFs are compared, which assess their cumulative and individual impact of risk factors by age: the Levin formula and the average attributable fraction. RESULTS: The overall impact for removal of all six risk factors amounts to 19.7% for the average attributable fraction. Neck tension and consumption of alcohol ranked as the strongest population-attributable risk factor for any headache. The potential impact for migraine was considerably higher (43.8%). With increasing age, the overall impact of risk factors on headache increases by 18.9%. CONCLUSION: Based on the estimations of the most appropriate approach, up to 20% of headaches in general and up to 43% of migraine in adolescents might be preventable by removing risk factors amenable to intervention, with increasing proportions by age.

Determinants of Long-term protection after hepatitis B vaccination in infancy: a meta-analysis.

BACKGROUND: The duration of protection after hepatitis B vaccination in early infancy is unclear and may be related to vaccination schedule, dosage, vaccine type and population characteristics. Factors potentially influencing waning immunity were assessed. METHODS: A systematic review was performed. The main outcomes were prevalence of anti-hepatits B antibodies ≥ 10 mIU/mL after primary or booster vaccination. Factors potentially influencing protection were assessed in an adjusted random-effects meta-analysis model by age for both outcomes. Results of both meta-analyses were combined in a prognostic model. RESULTS: Forty-six studies reporting on the anti-hepatits B antibodies ≥ 10 mIU/mL 5 to 20 years after primary immunization and 29 on booster response were identified. The adjusted meta-analyses identified maternal carrier status (odds ratio [OR]: 2.37 [1.11; 5.08]), lower vaccine dosage than presently recommended (OR: 0.14 [0.06; 0.30]) and gap time between last and preceding dose of the primary vaccine series (OR: 0.44 [0.22; 0.86]) as determinants for persistence of anti-hepatits B antibodies ≥ 10. A lower vaccine dosage was also associated with failure to respond to booster (OR: 0.20 [0.10; 0.38]). The prognostic model predicted long-term protection of 90% [77%; 100%] at the age of 17 years for offspring of noncarrier mothers vaccinated with a presently recommended dose and vaccination schedule. CONCLUSIONS: Based on meta-analyses, predictors of waning immunity after hepatitis B vaccination in infancy could be identified. A prognostic model for long-term protection after hepatitis B vaccination in infancy was developed.

Impact of maternal carrier status on immunologic markers for protection after hepatitis B vaccination in infancy: a meta-analysis.

Better protection against hepatitis B infection in offspring of carrier mothers has been postulated because of a booster effect by close maternal contact. Empirical evidence, however, is inconclusive. Immunologic markers for protection against hepatitis B are anti-HBs ≥ 10 mIU/ml or response to booster in case anti-HBs had fallen below 10 mIU/ml. The objective of this paper was to asses whether immunologic markers suggest a higher protection after hepatitis B vaccination in offspring of carrier mothers. A systematic review was performed in order to identify all studies in offspring of carrier and non-carrier mothers reporting the proportions of individuals with anti-HBs ≥ 10 mIU/ml after infant hepatitis B vaccination with a presently recommended dose in children aged 5 years or older or response to a booster dose in case anti-HBs was below 10 mIU/ml. Associations between carrier status and the proportions of anti-HBs ≥ 10 mIU/ml or booster response were analysed by random effects models with adjustment for age and potential confounders. We identified 19 studies providing proportions of anti-HBs ≥ 10 mIU/ml with explicit information regarding the maternal carrier status. These studies reported 3245 children of carrier mothers aged up to 20 years and 4602 children of non-carrier mothers aged up to 14 years. Antibody titres ≥ 10 mIU/ml were detected in 75.8% of children of carrier and 63.6% of non-carrier mothers. A random effects model with adjustment for confounding yielded an odds ratio of 2.43 (95% CI 1.24-4.75) suggesting a markedly higher probability of anti-HBs ≥ 10 mIU/ml in offspring of carrier compared to non-carrier mothers. The distribution of proportions of individuals with post booster increase of anti-HBs titres ≥ 10 mIU/ml stratified by age at booster (≤ 10 years and >10 years) showed no differences between offspring of carrier and non carrier mothers up to the age of 10 years and only marginal differences thereafter. In conclusion the proportions of anti-HBs ≥ 10 mIU/ml were clearly higher in offspring of carrier mothers years after infant vaccination but there appeared to be no clinically relevant difference in response to booster. It is unclear to which extent higher proportions of breakthrough infections contribute to the higher proportions of protective antibody titres in offspring of carrier mothers.