Association between Bone Mass and Dental Hypomineralization.

The aim of this study was to examine the association between the bone mass (bone mineral content [BMC]) and hypomineralized second primary molars (HSPMs)/molar incisor hypomineralization (MIH) in 6-y-old children. This cross-sectional study was embedded in the Generation R Study, a population-based prospective cohort study, starting from fetal life until adulthood in Rotterdam, Netherlands. The European Academy of Pediatric Dentistry criteria were used to score the intraoral photographs on the presence or absence of HSPMs and MIH. Bone mass was measured with a dual-energy x-ray absorptiometry (DXA) scan. Intraoral photographs and DXA scans were available in 6,510 6-y-old children. Binary logistic regression models were used to study the association between the bone mass and HSPMs/MIH. In total, 5,586 children had their second primary molars assessed and a DXA scan made; 507 children were diagnosed with HSPM. Of 2,370 children with data on their permanent first molars, 203 were diagnosed with MIH. In the fully adjusted model, children with lower BMC (corrected for bone area) were more likely to have HSPMs (odds ratio, 1.13; 95% confidence interval, 1.02 to 1.26 per 1-standard deviation decrease). A lower BMC (corrected for bone area) was not associated with MIH (odds ratio, 1.02; 95% confidence interval, 0.87 to 1.20 per 1-standard deviation decrease). We observed a negative association between BMC (corrected for bone area) and HSPMs. No association was found between BMC (corrected for bone area) and MIH. Future research should focus on investigating the mechanism underlying the negative association between the bone mass and HSPMs. Our study, in a large population of 6-y-old children, adds the finding that BMC (corrected for bone size) is associated with HSPMs but not with MIH in childhood.

Infant dietary patterns and bone mass in childhood: the Generation R Study.

UNLABELLED: Early life nutrition affects peak bone mass attainment. In this prospective cohort study, children with high adherence to a "dairy and whole grains" pattern in infancy had higher bone mineral density at the age of 6 years. Although the observed effects are small, our study provides insight into mechanisms linking early nutrition to bone acquisition in childhood. INTRODUCTION: Nutrition in early life may affect peak bone mass attainment. Previous studies on childhood nutrition and skeletal health mainly focused on individual nutrients, which does not consider the cumulative effects of nutrients. We investigated the associations between dietary patterns in infancy and childhood bone health. METHODS: This study included 2850 children participating in a population-based prospective cohort study. Dietary information was obtained from a food frequency questionnaire at the age of 13 months. Using principal component analysis, three major dietary patterns were extracted, explaining in total 30% of the variation in dietary intake. At the age of 6 years, a total body dual-energy X-ray absorptiometry (DXA) scan was performed, and bone mineral density (BMD), bone mineral content (BMC), area-adjusted BMC (aBMC), and bone area (BA) were analyzed. RESULTS: Higher adherence score to a "dairy and whole grains" pattern was positively associated with BMD and aBMC, but not with BMC and BA. Accordingly, children in the highest quartile of the "dairy and whole grains" pattern had higher BMD (difference 3.98 mg/cm(2), 95% confidence interval (CI) 0.36 to 7.61) and aBMC (difference 4.96 g, 95% CI 1.27 to 8.64) than children in the lowest quartile. Stratification for vitamin D supplementation showed that the positive associations between the "dairy and whole grains" pattern and bone outcomes were only observed in children who did not receive vitamin D supplementation. A "potatoes, rice, and vegetables" and a "refined grains and confectionery" pattern were not consistently associated with bone outcomes. CONCLUSIONS: An infant dietary pattern characterized by high intakes of dairy and cheese, whole grains, and eggs is positively associated with bone development in childhood. Further research is needed to investigate the consequences for bone health in later life.

Does fetal smoke exposure affect childhood bone mass? The Generation R Study.

UNLABELLED: We assessed the intrauterine influence of maternal smoking on childhood bone mass by comparing parental prenatal and postnatal smoking habits. We observed higher bone mass in children exposed to maternal smoking, explained by higher body weight. Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth. INTRODUCTION: Maternal smoking during pregnancy may adversely affect bone health in later life. By comparing the associations of maternal and paternal smoking and of prenatal and postnatal exposure with childhood bone measures, we aimed to explore whether the suggested association could be explained by fetal programming or reflects confounding by familial factors. METHODS: In 5565 mothers, fathers and children participating in a population-based prospective cohort study, parental smoking habits during pregnancy and current household smoking habits were assessed by postal questionnaires. Total body bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry (DXA) at the median age of 6.0 years (IQR 0.37). RESULTS: In confounder-adjusted models, maternal smoking during pregnancy was associated with a higher BMC of 11.6 g (95 % confidence interval (CI) 5.6, 17.5), a larger BA of 9.7 cm(2) (95 % CI 3.0, 16.4), a higher BMD of 6.7 g/cm(2) (95 % CI 2.4, 11.0) and a higher BMC of 5.4 g (95 % CI 1.3, 9.6) adjusted for BA of the child. Current weight turned out to mediate these associations. Among mothers who did not smoke, paternal smoking did not show evident associations with childhood bone measures. Also, household smoking practices during childhood were not associated with childhood bone measures. CONCLUSIONS: Our results do not support the hypothesis of fetal smoke exposure affecting childhood bone mass via intrauterine mechanisms. Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth.

Parental smoking during pregnancy and total and abdominal fat distribution in school-age children: the Generation R Study.

OBJECTIVE: Fetal smoke exposure may influence growth and body composition later in life. We examined the associations of maternal and paternal smoking during pregnancy with total and abdominal fat distribution in school-age children. METHODS: We performed a population-based prospective cohort study among 5243 children followed from early pregnancy onward in the Netherlands. Information about parental smoking was obtained by questionnaires during pregnancy. At the median age of 6.0 years (90% range: 5.7-7.4), we measured anthropometrics, total fat and android/gynoid fat ratio by dual-energy X-ray absorptiometry, and preperitoneal and subcutaneous abdominal fat were measured by ultrasound. RESULTS: The associations of maternal smoking during pregnancy were only present among girls (P-value for sex interaction<0.05). Compared with girls from mothers who did not smoke during pregnancy, those from mothers who smoked during the first trimester only had a higher android/gynoid fat ratio (difference 0.23 (95% confidence interval (CI): 0.09-0.37) s.d. scores (SDS). Girls from mothers who continued smoking throughout pregnancy had a higher body mass index (difference: 0.24 (95% CI: 0.14-0.35) SDS), total fat mass (difference: 0.23 (95% CI: 0.14-0.33) SDS), android/gynoid fat ratio (difference: 0.34 (95% CI: 0.22-0.46) SDS), subcutaneous abdominal fat (difference: 0.22 (95% CI: 0.11-0.33) SDS) and preperitoneal abdominal fat (difference: 0.20 (95% CI: 0.08-0.31) SDS). Similar associations with body fat distribution outcomes were observed for paternal smoking during pregnancy. Both continued maternal and paternal smoking during pregnancy may be associated with an increased risk of childhood overweight. The corresponding odds ratios were 1.19 (95% CI: 0.98-1.46) and 1.32 (1.10-1.58), respectively. CONCLUSIONS: Maternal and paternal smoking during pregnancy are associated with an adverse body and abdominal fat distribution and increased risk of overweight in children. Similar effects of maternal and paternal smoking suggest that direct intrauterine mechanisms and common family-based lifestyle-related factors explain the associations.

Maternal fish consumption during pregnancy and risks of wheezing and eczema in childhood: the Generation R Study.

BACKGROUND/OBJECTIVES: Maternal fish consumption during pregnancy might influence the fetal immune system through anti-inflammatory effects of omega-3 fatty acids, and might affect the risks of childhood asthma and atopy. In Generation R, a prospective cohort study in the Netherlands, we examined the associations of first trimester fish consumption with childhood wheezing and eczema in the first 4 years of life. METHODS: In total, 2976 mothers completed a 293-item semiquantitative food frequency questionnaire covering dietary intake in the first trimester. The occurrence of wheezing and eczema was yearly assessed by questionnaires. RESULTS: Median weekly fish consumption was 83 (95% range 0-316) grams per week. We observed no consistent associations of maternal total-, lean- or fatty-fish consumption during pregnancy with the risks of childhood wheezing. Maternal shellfish consumption of 1-13 g per week was associated with overall increased risks of childhood wheezing and eczema (OR 1.20 (1.04, 1.40) and OR 1.18 (1.01, 1.37), respectively). Maternal fatty fish consumption of 35-69 g per week was associated with increased overall risks of childhood eczema (OR 1.17 (1.00, 1.38)), but maternal total- or lean-fish consumption was not. CONCLUSIONS: During pregnancy, shellfish consumption was associated with increased risks of wheezing and eczema, while fatty fish consumption was associated with a higher risk of eczema only. Maternal total fish or lean fish consumption were not associated with wheezing or eczema. Further studies are needed to replicate these findings and to explore underlying mechanisms.

Bone age assessment by dual-energy X-ray absorptiometry in children: an alternative for X-ray?

OBJECTIVE: The aim of the study was to validate dual-energy X-ray absorptiometry (DXA) as a method to assess bone age in children. METHODS: Paired dual-energy X-ray absorptiometry (DXA) scans and X-rays of the left hand were performed in 95 children who attended the paediatric endocrinology outpatient clinic of University Hospital Rotterdam, the Netherlands. We compared bone age assessments by DXA scan with those performed by X-ray. Bone age assessment was performed by two blinded observers according to the reference method of Greulich and Pyle. Intra-observer and interobserver reproducibility were investigated using the intraclass correlation coefficient (ICC), and agreement was tested using Bland and Altman plots. RESULTS: The intra-observer ICCs for both observers were 0.997 and 0.991 for X-ray and 0.993 and 0.987 for DXA assessments. The interobserver ICC was 0.993 and 0.991 for X-ray and DXA assessments, respectively. The mean difference between bone age assessed by X-ray and DXA was 0.11 years. The limits of agreement ranged from -0.82 to 1.05 years, which means that 95% of all differences between the methods were covered by this range. CONCLUSIONS: Results of bone age assessment by DXA scan are similar to those obtained by X-ray. The DXA method seems to be an alternative for assessing bone age in a paediatric hospital-based population.