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.

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.

[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.

Associations between fatty acids and low-grade inflammation in children from the LISAplus birth cohort study.

BACKGROUND/OBJECTIVES: Assessing fatty acid (FA) composition in relation to inflammatory markers can shed light on the role of different FA and their metabolism in low-grade inflammation. Existing exploratory studies in children are scarce, and findings inconsistent. We hence aim to analyse associations of FA with common inflammatory markers, high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6), in 10-year-old children. SUBJECTS/METHODS: Complete data were available for 958 participants from the 10-year follow-up of the LISAplus (Influence of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus the Influence of Traffic Emissions and Genetics) birth cohort study. FA composition was assessed in serum glycerophospholipids. Hs-CRP and IL-6 were categorised into three levels. Associations of FA with inflammatory markers were assessed using multinomial logistic regression, adjusting for potential confounders. Additionally, sex-stratified analyses were carried out. RESULTS: FA exposures associated with significantly higher low-grade inflammation, as indicated by higher hs-CRP or IL-6 levels, included: palmitic acid (PA) (IL-6: P<0.001, 95% confidence interval: 1.30; 2.43), arachidonic acid (AA) (hs-CRP: P=0.002, 1.07; 1.31), n-6 highly unsaturated FA (HUFA) (hs-CRP: P=0.002, 1.06; 1.27), ratio of AA to linoleic acid (AA/LA) (hs-CRP: P<0.001, 1.16; 1.62) and total saturated FA (SFA) (IL-6: P<0.001, 1.77; 3.15). FA exposures associated with reduced levels of inflammatory markers included LA (hs-CRP: P=0.001, 0.84; 0.96; IL-6: P<0.001, 0.69; 0.90) and total polyunsaturated FA (PUFA) (IL-6: P<0.001, 0.57; 0.78). CONCLUSIONS: These findings suggest that higher SFA and minor n-6 HUFA, namely PA and AA, are associated with increased low-grade inflammation in children, whereas the major dietary n-6 PUFA and total PUFA are associated with reduced inflammation. Elevated desaturase activity, estimated by the ratio AA/LA, may be associated with higher inflammation, particularly in boys.

Mother's body mass index and food intake in school-aged children: results of the GINIplus and the LISAplus studies.

BACKGROUND/OBJECTIVES: Mother's body mass index (BMI) is a strong predictor of child BMI. Whether mother's BMI correlates with child's food intake is unclear. We investigated associations between mother's BMI/overweight and child's food intake using data from two German birth cohorts. SUBJECTS/METHODS: Food intakes from 3230 participants were derived from parent-completed food frequency questionnaires. Intakes of 11 food groups were categorized into three levels using group- and sex-specific tertile cutoffs. Mother's BMI and overweight were calculated on the basis of questionnaire data. Multinomial regression models assessed associations between a child's food intake and mother's BMI/overweight. Linear regression models assessed associations between a child's total energy intake and mother's BMI. Models were adjusted for study region, maternal education, child's age, sex, pubertal status and energy intake and the BMIs of the child and father. RESULTS: Mothers' BMI was associated with high meat intake in children (adjusted relative risk ratio (RRR (95% confidence interval))=1.06 (1.03; 1.09)). Mothers' overweight was associated with the meat intake (medium versus low RRR=1.30 (1.07; 1.59); high versus low RRR=1.50 (1.19; 1.89)) and egg intake (medium versus low RRR=1.24 (1.02; 1.50); high versus low RRR=1.30 (1.07; 1.60)) of children. There were no consistent associations for rest of the food groups. For every one-unit increase in mothers' BMI, the total energy intake in children increased by 9.2 kcal (3.7; 14.7). However, this effect was not significant after adjusting for children's BMI. CONCLUSIONS: Our results suggest that mother's BMI and mother's overweight are important correlates of a child's intake of energy, meat and eggs.

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.