Maternal and fetal genetic contribution to gestational weight gain.

BACKGROUND: Clinical recommendations to limit gestational weight gain (GWG) imply high GWG is causally related to adverse outcomes in mother or offspring, but GWG is the sum of several inter-related complex phenotypes (maternal fat deposition and vascular expansion, placenta, amniotic fluid and fetal growth). Understanding the genetic contribution to GWG could help clarify the potential effect of its different components on maternal and offspring health. Here we explore the genetic contribution to total, early and late GWG. PARTICIPANTS AND METHODS: A genome-wide association study was used to identify maternal and fetal variants contributing to GWG in up to 10 543 mothers and 16 317 offspring of European origin, with replication in 10 660 mothers and 7561 offspring. Additional analyses determined the proportion of variability in GWG from maternal and fetal common genetic variants and the overlap of established genome-wide significant variants for phenotypes relevant to GWG (for example, maternal body mass index (BMI) and glucose, birth weight). RESULTS: Approximately 20% of the variability in GWG was tagged by common maternal genetic variants, and the fetal genome made a surprisingly minor contribution to explain variation in GWG. Variants near the pregnancy-specific beta-1 glycoprotein 5 (PSG5) gene reached genome-wide significance (P=1.71 × 10-8) for total GWG in the offspring genome, but did not replicate. Some established variants associated with increased BMI, fasting glucose and type 2 diabetes were associated with lower early, and higher later GWG. Maternal variants related to higher systolic blood pressure were related to lower late GWG. Established maternal and fetal birth weight variants were largely unrelated to GWG. CONCLUSIONS: We found a modest contribution of maternal common variants to GWG and some overlap of maternal BMI, glucose and type 2 diabetes variants with GWG. These findings suggest that associations between GWG and later offspring/maternal outcomes may be due to the relationship of maternal BMI and diabetes with GWG.

Long-term exposure to traffic-related air pollution and insulin resistance in children: results from the GINIplus and LISAplus birth cohorts.

AIMS/HYPOTHESIS: Epidemiological studies that have examined associations between long-term exposure to traffic-related air pollution and type 2 diabetes mellitus in adults are inconsistent, and studies on insulin resistance are scarce. We aimed to assess the association between traffic-related air pollution and insulin resistance in children. METHODS: Fasting blood samples were collected from 397 10-year-old children in two prospective German birth cohort studies. Individual-level exposures to traffic-related air pollutants at the birth address were estimated by land use regression models. The association between air pollution and HOMA of insulin resistance (HOMA-IR) was analysed using a linear model adjusted for several covariates including birthweight, pubertal status and BMI. Models were also further adjusted for second-hand smoke exposure at home. Sensitivity analyses that assessed the impact of relocating, study design and sex were performed. RESULTS: In all crude and adjusted models, levels of insulin resistance were greater in children with higher exposure to air pollution. Insulin resistance increased by 17.0% (95% CI 5.0, 30.3) and 18.7% (95% CI 2.9, 36.9) for every 2SDs increase in ambient NO2 and particulate matter ≤10 µm in diameter, respectively. Proximity to the nearest major road increased insulin resistance by 7.2% (95% CI 0.8, 14.0) per 500 m. CONCLUSIONS/INTERPRETATION: Traffic-related air pollution may increase the risk of insulin resistance. Given the ubiquitous nature of air pollution and the high incidence of insulin resistance in the general population, the associations examined here may have potentially important public health effects despite the small/moderate effect sizes observed.

Growth velocity during infancy and onset of asthma in school-aged children.

BACKGROUND: Growth velocities during infancy might affect the risk of asthma in childhood. This study examines the association between peak height and weight velocities during the first 2 years of life and onset of asthma and wheeze up to 10 years of age. METHODS: Data from 9086 children who participated in the GINIplus and LISAplus birth cohorts were analyzed. Information on asthma was requested annually from 1 to 10 years and information on wheeze at 1, 2, 4, 6, and 10 years. Peak height and weight velocities were calculated using height and weight measurements obtained between birth and 2 years of age. Cox proportional hazards models and generalized linear mixed models were calculated after adjustment for potential confounding factors including birth weight and body mass index at 10 years of age. RESULTS: Per interquartile range increase in peak weight velocity (PWV), the risk of asthma increased significantly (adjHR: 1.22; CI: 1.02-1.47). The relationship between peak height velocity (PHV) and onset of asthma was nonsignificant (adjHR: 1.08; CI: 0.88-1.31). Wheeze was not significantly associated with PHV or with PWV (adjOR: 1.07; CI: 0.64-1.77 and adjOR: 1.11; CI: 0.68-1.79, respectively). CONCLUSIONS: Weight gain during infancy is positively associated with physician-diagnosed asthma in school-aged children.

Geographical variation and the determinants of domestic endotoxin levels in mattress dust in Europe.

UNLABELLED: Endotoxin exposures have manifold effects on human health. The geographical variation and determinants of domestic endotoxin levels in Europe have not yet been extensively described. To investigate the geographical variation and determinants of domestic endotoxin concentrations in mattress dust in Europe using data collected in the European Community Respiratory Health Survey follow-up (ECRHS II). Endotoxin levels were measured in mattress dust from 974 ECRHS II participants from 22 study centers using an immunoassay. Information on demographic, lifestyle, and housing characteristics of the participants was obtained in face-to-face interviews. The median endotoxin concentration in mattress dust ranged from 772 endotoxin units per gram (EU/g) dust in Reykjavik, Iceland, to 4806 EU/g in Turin, Italy. High average outdoor summer temperature of study center, cat or dog keeping, a high household crowding index, and visible damp patches in the bedroom were significantly associated with a higher endotoxin concentrations in mattress dust. There is a large variability in domestic endotoxin levels across Europe. Average outdoor summer temperature of study center, which explains only 10% of the variation in domestic endotoxin level by center, is the strongest meteorological determinant. The observed variation needs to be taken into account when evaluating the health effects of endotoxin exposures in international contexts. PRACTICAL IMPLICATIONS: The incoherent observations of the health effects of endotoxin may be partly owing to the geographical heterogeneity of endotoxin exposure. Therefore, the observed variation should be considered in further studies. Measurements of indoor endotoxin are recommended as an indicator for the level of exposures of individual domestic environments.

[Two German Birth Cohorts: GINIplus and LISAplus]. / Die zwei deutschen Geburtskohorten GINIplus und LISAplus.

Numerous chronic diseases in childhood and adulthood have their origins in perinatal life and are potentially influenced by trans-generational epigenetic processes. Therefore, prospective birth cohorts can substantially contribute to our knowledge about the etiology of diseases including modifiable risk factors. The two population-based German birth cohorts GINIplus and LISAplus aim to describe the natural course of chronic diseases and intermediate phenotypes in childhood and its determinants, and to identify potential genetic effect modifications. In the mid-1990s, 5,991 (GINIplus) and 3,097 (LISAplus) healthy, term newborns were recruited for long-term follow-up in four regions of Germany. The follow-up rate for the first 10 years was about 55%. We analyzed the growth and development of overweight, infections and allergic diseases, mental and oral health, metabolic and inflammatory parameters and the role of potential risk factors including genetics. The results of these two birth cohorts substantially contribute to the current knowledge about the natural course of these health parameters. These data were included in many international projects and consortia for purposes of international comparisons of prevalence and consistency of findings, and to increase the power of the analyses.

Meta-analysis of mould and dampness exposure on asthma and allergy in eight European birth cohorts: an ENRIECO initiative.

BACKGROUND: Several cross-sectional studies during the past 10 years have observed an increased risk of allergic outcomes for children living in damp or mouldy environments. OBJECTIVE: The objective of this study was to investigate whether reported mould or dampness exposure in early life is associated with the development of allergic disorders in children from eight European birth cohorts. METHODS: We analysed data from 31 742 children from eight ongoing European birth cohorts. Exposure to mould and allergic health outcomes were assessed by parental questionnaires at different time points. Meta-analyses with fixed- and random-effect models were applied. The number of the studies included in each analysis varied based on the outcome data available for each cohort. RESULTS: Exposure to visible mould and/or dampness during first 2 years of life was associated with an increased risk of developing asthma: there was a significant association with early asthma symptoms in meta-analyses of four cohorts [0-2 years: adjusted odds ratios (aOR), 1.39 (95% CI, 1.05-1.84)] and with asthma later in childhood in six cohorts [6-8 years: aOR, 1.09 (95% CI, 0.90-1.32) and 3-10 years: aOR, 1.10 (95% CI, 0.90-1.34)]. A statistically significant association was observed in six cohorts with symptoms of allergic rhinitis at school age [6-8 years: aOR, 1.12 (1.02-1.23)] and at any time point between 3 and 10 years [aOR, 1.18 (1.09-1.28)]. CONCLUSION: These findings suggest that a mouldy home environment in early life is associated with an increased risk of asthma particularly in young children and allergic rhinitis symptoms in school-age children.

Elevated serum 25(OH)-vitamin D levels are negatively correlated with molar-incisor hypomineralization.

To date, the precise etiology of molar-incisor hypomineralization (MIH) is uncertain. Vitamin D plays a key role in hard tissue formation. Therefore, this study aimed to analyze the relationship between serum 25-hydroxy-vitamin D (25(OH)D) status and dental health data obtained from 1,048 children in a 10-year follow-up of the Munich GINIplus and LISAplus birth cohorts. The dental examination included the diagnosis of MIH and recording of (non-)cavitated caries lesions in primary and permanent teeth. Serum 25(OH)D concentrations were taken from blood samples of the 10-year investigation and measured with a fully automated, modular system. Different logistic regression and Poisson hurdle models were calculated. MIH was diagnosed in 13.6% of the study population. Approximately 16.4% of the children demonstrated caries-related defects (D3-4MFS > 0). The mean season-adjusted concentration of 25(OH)D was 75.8 nmol/l (standard deviation 22.0 nmol/l). After adjusting for sex, age, body mass index, parental education, equivalent income, and television/personal computer (TV/PC) viewing hours, a 10 nmol/l increase in serum 25(OH)D concentrations was significantly associated with a lower odds ratio of having MIH (OR = 0.89; P = 0.006). Furthermore, higher 25(OH)D values were associated with a lower number of caries-affected permanent teeth. It is concluded that elevated serum 25(OH)D concentrations were associated with better dental health parameters.

Associations between serum 25-hydroxyvitamin D and bone turnover markers in a population based sample of German children.

Severe vitamin D deficiency is known to cause rickets, however epidemiological studies and RCTs did not reveal conclusive associations for other parameters of bone health. In our study, we aimed to investigate the association between serum levels of 25(OH) vitamin D and bone turnover markers in a population-based sample of children. 25(OH)D, calcium (Ca), osteocalcin (OC), and ß-Crosslaps (ß-CTx) were measured in 2798 ten-year-old children from the German birth cohorts GINIplus and LISAplus. Linear regression was used to determine the association between bone turnover markers and 25(OH)D levels. 25(OH)D, OC, and ß-CTx showed a clear seasonal variation. A 10 nmol/l increase in 25(OH)D was significantly associated with a 10.5 ng/l decrease (p < 0.001) in ß-CTx after adjustment for design, sex, fasting status, time of blood drawn, BMI, growth rate, and detectable testosterone/estradiol. For OC alone no significant association with 25(OH)D was observed, whereas the ß-CTx-to-OC ratio was inversely associated with 25(OH)D (-1.7% change, p < 0.001). When stratifying the analyses by serum calcium levels, associations were stronger in children with Ca levels below the median. This study in school-aged children showed a seasonal variation of 25(OH)D and the bone turnover markers OC and ß-CTx. Furthermore a negative association between 25(OH)D and the bone resorption marker ß-CTx was observed.

Is a child's growth pattern early in life related to serum adipokines at the age of 10 years?

BACKGROUND/OBJECTIVES: Growth parameters during infancy and early childhood might predict adipokine levels later in life. This study investigates the association between peak growth velocities, body mass index (BMI) and age at adiposity rebound (AR), with leptin and adiponectin levels at age 10 years. SUBJECTS/METHODS: Peak height (PHV) and weight (PWV) velocities were calculated from height and weight measurements obtained between birth and age 2 years from 2880 children participating in the GINIplus (German Infant Nutritional Intervention plus environmental and genetic influences on allergy development) and LISAplus (Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus Air Pollution and Genetics) birth cohorts. BMI and age at AR were calculated using BMI measurements between age 1.5 and 12 years. Blood samples were collected during a physical examination at age 10. Adiponectin and leptin levels were measured by radioimmunoassay. Linear regression models were fitted after adjustment for potential confounding factors and results are presented per interquartile range increase in the exposure. RESULTS: Age at AR was negatively associated with leptin in males and females (percent difference ß*: -41.71%; 95% confidence interval: (-44.34;-38.96) and ß*: -43.22%; (-45.59; -40.75), respectively). For both males and females PWV (ß*: 14.23%; (7.60; 21.26) and ß*: 18.54%; (10.76; 26.87), respectively) and BMI at AR (ß*: 63.08%; (55.04; 71.53) and ß*: 67.02%; (59.30; 75.10), respectively) were positively associated with leptin levels. PHV showed a positive effect on leptin in females only (ß*: 10.75%; (3.73; 18.25)). Growth parameters were not significantly associated with adiponectin except for age at AR among females (ß: 0.75 ng/ml; (0.42; 1.09)) and PWV among males (ß: 0.45 ng/ml; (0.11; 0.79)). CONCLUSION: Growth patterns in early life may be associated with leptin levels at age 10 years.

Early life risk factors of being overweight at 10 years of age: results of the German birth cohorts GINIplus and LISAplus.

OBJECTIVE: To develop a prediction model that quantifies the risk of being overweight at 10 years of age. SUBJECTS/METHODS: In total, 3121 participants from the GINIplus (German Infant Nutritional Intervention plus environmental and genetic influences on allergy development) and LISAplus (Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus Air Pollution and Genetics) German birth cohorts were recruited. We predicted standardized body mass index (BMI) at 10 years of age using standardized BMIs from birth to 5 years. Parental education, family income and maternal smoking during pregnancy were considered as covariates. Linear and logistic regression models were used to evaluate the impact of risk factors on BMI and on being overweight at 10 years of age, respectively. RESULTS: Birth weight, standardized BMI at 5 years (60-64 months) (ß=0.77; 95% confidence interval (CI): 0.73-0.81) and maternal smoking during pregnancy were positively associated with standardized BMI at 10 years of age. Standardized BMI and overweight at 5 years were strongest predictors of being overweight at 10 years. Conversely, high parental education conferred a protective effect (ß=-0.15; 95% CI: -0.29 to -0.01). Being overweight at 5 years (60-64 months) increased the risk of being overweight at 10 years of age with odds ratios above 10. Among children who were predicted to be overweight at 10 years, cross-validation results showed that 76.8% of female subjects and 68.1% of male subjects would be overweight at 10 years of age. CONCLUSION: BMI and being overweight at 5 years of age are strong predictors of being overweight at 10 years of age. The effectiveness of targeted interventions in children who are overweight at 5 years of age should be explored.