Neonatal vitamin D status from archived dried blood spots and future risk of fractures in childhood: results from the D-tect study, a population-based case-cohort study

Is the stability of folates in dried blood microsamples sufficient to perform home-sampling studies?

Dried blood microsampling is increasingly used for home-sampling and epidemiological studies because of its multiple advantages, including an often greatly improved analyte stability. However, a critical assessment of the stability under realistic conditions should always be performed as part of the validation, especially for unstable molecules like folates (vitamin B9). Here, the objective was to determine whether folate stability in dried blood microsamples is sufficient to allow the set-up of home-sampling studies for the monitoring of folate status in e.g., women of reproductive age. An extensive set of stability experiments was performed to evaluate the stability of the main folate vitamer 5-methyltetrahydrofolate (5MTHF), its oxidation product MeFOX and the minor non-methyl folate vitamers 10-formylfolic acid (10FoFA), 5,10-methenyltetrahydrofolate (5,10CH+THF) and tetrahydrofolate (THF) in dried blood microsamples using volumetric absorptive microsampling (VAMS) or regular dried blood spots (DBS). The evaluations included (EDTA-anticoagulated blood was collected from a single donor measured in four replicates per condition and time point): (i) the effect of temperature (-20 °C, 4 °C, ambient temperature and 37 °C), (ii) the effect of light (during drying and storage) and humidity, and (iii) the effect of storage under vacuum and pretreatment of the microsamples with stabilizing agents on folate stability. At -20 °C and 4 °C, all folate levels were within 85 to 115% of the baseline value up till two weeks of storage in both VAMS samples and DBS. However, at room temperature the stability of the analyzed folates was only consistently observed up till three days in VAMS samples, and for none of the folates at 37 °C. Humidity had a major impact on 5,10CH+THF stability, but this could be easily improved by using desiccant. Both vacuum treatment and pretreatment of microsamples with 0.1% DL-dithiothreitol and 5% butylated hydroxytoluene improved the stability at room temperature in VAMS samples, but these effects were limited at 37 °C and in DBS. Overall, the stability of the individual folate vitamers proved to be challenging and strongly temperature- and time-dependent. Nonetheless, if controlled transport (temperature and duration) can be assured, the set-up of home-sampling studies to evaluate the folate status using dried blood microsamples can still be beneficial.

Liquid chromatography-tandem mass spectrometry in fat-soluble vitamin deficiency

Fat-soluble vitamins, including vitamins A, D, E, and K, are essential for maintaining normal body function and metabolism. Fat-soluble vitamin deficiency may lead to bone diseases, anemia, bleeding, xerophthalmia, etc. Early detection and timely interventions are significant for preventing vitamin deficiency-related diseases. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is developing into a potent instrument for the precise detection of fat-soluble vitamins due to its high sensitivity, high specificity, and high resolution.

Furan fatty acid metabolite in newborns predicts risk of asthma

BACKGROUND

Intake of fish-oil and fatty fish during pregnancy has been shown to reduce the risk of childhood asthma but biomarkers of such intake are lacking.

OBJECTIVE

To establish biomarkers of prenatal fish-oil exposure from newborn dry blood spot metabolomics profiles and assess their relevance for childhood asthma risk stratification.

METHODS

The Danish COPSAC₂₀₁₀ mother-child cohort was utilized to investigate the effect of a double-blinded randomized controlled trial of fish-oil supplementation during pregnancy on dry blood spot liquid-chromatography mass spectrometry-based metabolomics profiles of 677 newborns. We thereafter investigated the association between fish-oil associated biomarkers in the newborn and development of asthma-related outcomes. Replication was sought in the independent observational COPSAC₂₀₀₀ cohort with 387 newborn metabolomics profiles.

RESULTS

The newborn metabolomics profiles differed between children in the fish-oil vs. placebo group in COPSAC₂₀₁₀ (area under the receiver operator curve = 0.94 ± 0.03, p < .001). The fish-oil metabolomics profile and the top biomarker, 3-carboxy-4-methyl-5-propyl-2-furan propanoic acid (CMPF) were both associated with a decreased risk of asthma by age 6 years (HR = 0.89, p = .002 and HR = 0.67, p = .005, respectively). In COPSAC₂₀₀₀ , newborn CMPF level was also inversely associated with asthma risk by age 6 years (HR = 0.69, p = .01). Troublesome lung symptoms and common infections in the first 3 years were also inversely associated with newborn CMPF levels in both cohorts.

CONCLUSIONS

Newborn children's blood levels of the furan fatty acid metabolite CMPF reflect fish-oil and fatty fish intake during pregnancy and are associated with a lower risk of asthma across two cohorts, which could aid newborn screening for childhood asthma.

Vitamin D intakes and health outcomes in infants and preschool children: Summary of an evidence report

BACKGROUND

A systematic review was commissioned to support an international expert group charged to update the Food and Agriculture Organisation of the United Nations (FAO)/World Health Organisation (WHO)'s vitamin D intake recommendations for children aged 0-4 years.

MATERIALS AND METHODS

Multiple electronic databases were searched to capture studies published from database inception to the 2^nd week of June 2020 according to key questions formulated by the FAO/WHO. Relevant studies were summarised and synthesised by key questions and by health outcomes using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

The 146 included studies examined the effects of different vitamin D intake levels on a variety of health outcomes (e.g. infectious disease, growth, neurodevelopment, rickets, and bone mineral density), and on outcomes for setting vitamin D upper limits (e.g. hypercalcemia, hypercalciuria, and nephrocalcinosis). For most outcomes, the strength of evidence was low or very low. Evidence was rated moderate for the effect of daily vitamin D supplementation on raising serum 25(OH)D concentrations, and a random-effects meta-regression analysis of 28 randomised controlled trials (mostly in infants 0-12 months) showed that each 100 IU/d increase in vitamin D supplementation was associated with an average of 1.92 (95% CI 0.28, 3.56) nmol/L increase in achieved 25-hydroxy-vitaminn D (25[OH]D) concentration (n = 53 intervention arms; p = .022) with large residual heterogeneity (I² = 99.39%). Evidence was very low on two of the upper limit outcomes - hypercalcemia and hypercalciuria.

CONCLUSIONS

The evidence report provided the expert group with a foundation and core set of data to begin their work to set vitamin D nutrient reference values. To move the field forward, future studies should use standardised 25(OH)D assay measurements and should examine the relationship between long-term vitamin D status and health outcomes.Key MessagesResults of a large complex systematic review suggest the current totality of evidence from trials and prospective observational studies do not reach sufficient certainty level to support a causal relationship between vitamin D intake and asthma, wheeze, eczema, infectious diseases, or rickets (most trials reported no rickets) in generally healthy infants and young children.In this systematic review, the only body of evidence that reached a moderate level of certainty was regarding the effect of daily vitamin D supplementation (vitamin D₃ or D₂ supplements to infants/children) on increasing serum 25(OH)D concentrations. However, currently there is no consensus on the definitions of vitamin D status, e.g. deficiency, insufficiency, sufficiency and toxicity, based on serum 25(OH)D concentrations.This systematic review provided an international expert group a foundation and core set of data through intake-response modelling to help set vitamin D nutrient reference values for infants and children up to 4 years of age.

Developmental exposure to vitamin D deficiency and subsequent risk of schizophrenia

Over the last half century, a body of convergent evidence has accumulated linking disruption of early brain development with an increased risk of mental disorders, including schizophrenia. The orderly cascade of brain development may be disrupted by exposure to suboptimal concentrations of a range of biological substrates and micronutrients. We hypothesized that those exposed to vitamin D deficiency during early life, have an increased risk of neurodevelopmental disorders, including schizophrenia. The hypothesis was based on the link between an increased risk of schizophrenia in (a) those born in winter and spring, when vitamin D deficiency is more prevalent, and (b) the offspring of dark-skinned migrants living in cold climates, who have a markedly increased risk of vitamin D deficiency. In this review, we summarize evidence from analytic epidemiology related to this hypothesis. Two case-control studies based on Danish neonatal dried blood spots have found that neonatal vitamin deficiency is associated with an increased risk of schizophrenia. However, recent genetic analyses have also suggested that common variants linked to schizophrenia may lead to lower vitamin D concentrations (possibly mediated via reduced outdoor activity). We summarize limitations of the current evidence and outline suggestions that can guide future research. Based on currently available data, there is insufficient evidence to support public health recommendations related to this topic. However, we cannot reject the hypothesis that the provision of vitamin D supplementation to pregnant women and/or offspring in groups vulnerable to vitamin D deficiency may subsequently reduce the incidence of schizophrenia in the offspring.

A method to correct for the influence of bovine serum albumin-associated vitamin D metabolites in protein extracts from neonatal dried blood spots

Objective

We developed an assay to measure the concentration of 25 hydroxyvitamin D₂ and D₃ in protein extracts derived from stored neonatal dried blood spots. During this study, we postulated that these samples had been contaminated with exogenous vitamin D metabolites because of the addition of bovine serum albumin (BSA) as part of an extraction step undertaken 7 years earlier. The aim of the current study was to develop methods in order to adjust for this contamination.

Results

We identified between-plate variations in 25 hydroxyvitamin D₂ and D₃ concentrations which suggested the presence of three different BSA batches. Based on repeat extraction (without the addition of BSA) and testing of 395 samples, we developed models to correct for the exogenous 25 hydroxyvitamin D₂ and D_3. The regression models were Diff_25OHD3 = − 8.2 + 1.8* Diff_25OHD2 for low contamination, Diff_25OHD3 = 23.8 + 1.7* Diff_25OHD2 for middle contamination, and Diff_25OHD3 = 14.3 + 3.0* Diff_25OHD2 for high contamination. After these corrections, the three subsamples had comparable distributions within the expected range for both 25 hydroxyvitamin D₂ and D₃.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06077-1.

Measurement of vitamin D in dried blood spots stored under different temperature conditions

BACKGROUND

As part of the Survey of Health, Ageing and Retirement in Europe (SHARE) study, dried blood spot samples were obtained for measurement of potential biological biomarkers, among those vitamin D. Unfortunately, no studies describe the impact of high temperatures on dried blood spot samples and vitamin D measurements.

MATERIALS AND METHODS

Capillary samples were collected on dried blood spot cards from 40 outpatients (median age 78 years) along with venous blood samples. To mimic the different environmental and temporal challenges during collection and shipment until final storage in the SHARE study, dried blood spot cards were stored at different temperatures, at time span and with/without freeze-thaw. Vitamin D concentrations in venous plasma samples were measured by conventional immunoassay (on Architect i2000SR), while vitamin D concentrations in dried blood spot samples were measured using LC-MS/MS with a well-described extraction method and with relevant calibration and comparison with a reference method.

RESULTS

Vitamin D measured in dried blood spot samples did not differ significantly from venous plasma measurements under the different storage conditions tested. The optimal vitamin D correlation between the two matrices was by storage at either 21°C or 35°C for four days (r = 0.9060 and 0.9026, respectively). Freeze-thaw of the dried blood spot samples did not have any significant effect.

CONCLUSION

We find that vitamin D measured in dried blood spot samples do not differ significantly from venous plasma measurements despite storage at different temperatures and freeze-thaw, which enables the use of dried blood spot in multicentre studies taking place under alternating temperature conditions.

Bisphosphonates to reduce bone fractures in stage 3B+ chronic kidney disease: a propensity score-matched cohort study

BACKGROUND

Bisphosphonates are contraindicated in patients with stage 4+ chronic kidney disease. However, they are widely used to prevent fragility fractures in stage 3 chronic kidney disease, despite a lack of good-quality data on their effects.

OBJECTIVES

The aims of each work package were as follows. Work package 1: to study the relationship between bisphosphonate use and chronic kidney disease progression. Work package 2: to study the association between using bisphosphonates and fracture risk. Work package 3: to determine the risks of hypocalcaemia, hypophosphataemia, acute kidney injury and upper gastrointestinal events associated with using bisphosphonates. Work package 4: to investigate the association between using bisphosphonates and changes in bone mineral density over time.

DESIGN

This was a new-user cohort study design with propensity score matching.

SETTING AND DATA SOURCES

Data were obtained from UK NHS primary care (Clinical Practice Research Datalink GOLD database) and linked hospital inpatient records (Hospital Episode Statistics) for work packages 1-3 and from the Danish Odense University Hospital Databases for work package 4.

PARTICIPANTS

Patients registered in the data sources who had at least one measurement of estimated glomerular filtration rate of < 45 ml/minute/1.73 m2 were eligible. A second estimated glomerular filtration rate value of < 45 ml/minute/1.73 m2 within 1 year after the first was requested for work packages 1 and 3. Patients with no Hospital Episode Statistics linkage were excluded from work packages 1-3. Patients with < 1 year of run-in data before index estimated glomerular filtration rate and previous users of anti-osteoporosis medications were excluded from work packages 1-4.

INTERVENTIONS/EXPOSURE

Bisphosphonate use, identified from primary care prescriptions (for work packages 1-3) or pharmacy dispensations (for work package 4), was the main exposure.

MAIN OUTCOME MEASURES

Work package 1: chronic kidney disease progression, defined as stage worsening or starting renal replacement. Work package 2: hip fracture. Work package 3: acute kidney injury, hypocalcaemia and hypophosphataemia identified from Hospital Episode Statistics, and gastrointestinal events identified from Clinical Practice Research Datalink or Hospital Episode Statistics. Work package 4: annualised femoral neck bone mineral density percentage change.

RESULTS

Bisphosphonate use was associated with an excess risk of chronic kidney disease progression (subdistribution hazard ratio 1.12, 95% confidence interval 1.02 to 1.24) in work package 1, but did not increase the probability of other safety outcomes in work package 3. The results from work package 2 suggested that bisphosphonate use increased fracture risk (hazard ratio 1.25, 95% confidence interval 1.13 to 1.39) for hip fractures, but sensitivity analyses suggested that this was related to unresolved confounding. Conversely, work package 4 suggested that bisphosphonates improved bone mineral density, with an average 2.65% (95% confidence interval 1.32% to 3.99%) greater gain in femoral neck bone mineral density per year in bisphosphonate users than in matched non-users.

LIMITATIONS

Confounding by indication was a concern for the clinical effectiveness (i.e. work package 2) data. Bias analyses suggested that these findings were due to inappropriate adjustment for pre-treatment risk. work packages 3 and 4 were based on small numbers of events and participants, respectively.

CONCLUSIONS

Bisphosphonates were associated with a 12% excess risk of chronic kidney disease progression in participants with stage 3B+ chronic kidney disease. No other safety concerns were identified. Bisphosphonate therapy increased bone mineral density, but the research team failed to demonstrate antifracture effectiveness.

FUTURE WORK

Randomised controlled trial data are needed to demonstrate antifracture efficacy in patients with stage 3B+ chronic kidney disease. More safety analyses are needed to characterise the renal toxicity of bisphosphonates in stage 3A chronic kidney disease, possibly using observational data.

STUDY REGISTRATION

This study is registered as EUPAS10029.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 17. See the NIHR Journals Library website for further project information. The project was also supported by the National Institute for Health Research Biomedical Research Centre, Oxford.

Nutrients, Diet, and Other Factors in Prenatal Life and Bone Health in Young Adults: A Systematic Review of Longitudinal Studies

Optimizing skeletal health in early life has potential effects on bone health later in childhood and in adulthood. We aimed to evaluate the existing evidence that maternal exposures during pregnancy have an impact on the subsequent bone health among offspring in young adults aged between 16 and 30 years. The protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO) (ID: CRD42019126890). The search was conducted up to 2 April 2019. We included seven observational prospective cohort studies that examined the association between maternal dietary factors, vitamin D concentration, age, preeclampsia, and smoking with any bone indices among offspring. The results indicated that high concentrations of maternal vitamin D; low fat intake; and high intakes of calcium, phosphorus, and magnesium may increase the bone mineral density in offspring at age 16. Evidence also suggests that the offspring of younger mothers may have a higher peak bone mass. It remains inconclusive whether there is an influence of preeclampsia or maternal smoking on bone health among young adults. Our assessment of internal validity warrants a cautious interpretation of these results, as all of the included studies were judged to have serious risks of bias. High-quality studies assessing whether prenatal prognostic factors are associated with bone health in young adults are needed.

Cord Blood Vitamin D Levels and Early Childhood Blood Pressure: The Healthy Start Study

Background Vitamin D deficiency is associated with cardiovascular events among adults, but it is unclear whether early-life vitamin D deficiency influences cardiovascular risk factors in children. Methods and Results We measured total and bioavailable 25-dihydroxyvitamin D (25OHD) in cord blood and in blood from 4- to 6-year-old children, and we assessed cardiovascular risk factors (blood pressure, arterial stiffness, body size, and adiposity) at 4 to 6 years. We tested for racial/ethnic differences in total and bioavailable 25OHD (n=715) and modeled the adjusted association between cord blood 25OHD and childhood cardiovascular risk factors (n=171). We observed racial/ethnic differences in total and bioavailable 25OHD levels in both cord and child blood samples (all P<0.05). Each 25-nmol/L increase in cord blood total 25OHD was associated with a 2.5-mm Hg (SE 0.8) decrease in systolic blood pressure ( P=0.002) and a 1.7-mm Hg (SE 0.6) decrease in diastolic blood pressure ( P=0.01), independent of childhood 25OHD levels, race/ethnicity, and other covariates. There was no association between cord blood total 25OHD and any other cardiovascular risk factors. Cord blood levels of bioavailable and free 25OHD were not associated with any cardiovascular risk factor in childhood. Conclusions In this diverse prebirth cohort, we observed lower systolic and diastolic blood pressure among children with higher total 25OHD levels at birth. Our findings suggest that intrauterine exposure to vitamin D may contribute to early-life programming of offspring blood pressure. Intervention studies are needed to determine whether increasing fetal vitamin D exposure can reduce the risk of elevated blood pressure in childhood.

Neonatal vitamin D status and myopia in young adult men

PURPOSE

The prevalence of myopia is increasing worldwide, and modifiable risk factors are thus important to identify. Season of birth has been associated with later myopia risk. Neonatal vitamin D status is highly dependent on season of birth due to maternal sun exposure late in gestation. We hypothesize that prenatal exposure to low levels of vitamin D can interfere with visual development in term-born infants and that this might contribute to adult visual dysfunction. The aim of this study was thus to compare neonatal vitamin D levels from stored dried blood spots taken shortly after birth among young term-born men with myopia (cases) and random controls with emmetropia.

METHODS

In this case-control study, we analysed neonatal 25(OH)D₃ levels of 457 myopic male cases and 1280 emmetropic male controls assessed for myopia at the mandatory Danish conscript examination. Data were analysed using logistic regression analysis and results presented as crude and adjusted for potential confounders namely maternal age, maternal ethnicity, maternal and paternal education and season of birth.

RESULTS

We did not observe a seasonal variation in myopia risk, neither did we observe increased odds of myopia in relation to low neonatal 25(OH)D₃ levels.

CONCLUSION

The rapid increase in myopia does not seem related to neonatal vitamin D status.

Vitamin D and Calcium in Children 0-36 Months: A Scoping Review of Health Outcomes

METHODS

Updated literature searches were conducted across 5 electronic databases to identify all randomized controlled trials, cohort studies, nested case-control or case-cohort studies, and systematic reviews published after the 2009 U.S. Agency for Healthcare Research and Quality's (AHRQ) evidence report, Vitamin D and Calcium: a Systematic Review of Health Outcomes. In total, 65 studies were summarized and analyzed in the present review.

RESULTS

There was a steady increasing trend in the number of publications reporting outcomes related to skeletal health, growth, and infectious disease from 2008 to 2019, although the number of published vitamin D studies was much larger than calcium studies.

CONCLUSIONS

The data presented in this review can facilitate assessment of the variety of outcomes and the amount of potentially useful literature available for each outcome. The results of this scoping review can be used to guide the undertaking of the subsequent systematic reviews.

Characterization of a Swine Model of Birth Weight and Neonatal Nutrient Restriction

Background

Evidence indicates that birth weight and neonatal nutrition have lifelong effects. Animal models are required to improve our understanding of these factors.

Objectives

We aimed to develop and validate a swine model of birth weight and neonatal undernutrition.

Methods

At birth, a total of 112 piglets were identified as low (LBW; 1.22 ± 0.28 kg SEM) or normal birth weight (NBW; 1.70 ± 0.27 kg). From day 3 to weaning (day 28), piglets received normal nutrition (NN) or restricted nutrition (RN) via intermittent suckling, where piglets were isolated from the sow for 6 h/d. After weaning, pigs were fed a common diet for 28 d. Body weight (BW) was determined for the duration of the study. On days 28 and 56, empty carcass, viscera, and individual organ weights were determined in 8 pigs/treatment.

Results

LBW pigs remained smaller than NBW pigs, regardless of nutrient restriction (P &lt; 0.05). Within birth weight category, RN reduced BW by day 7 after birth, which was maintained until weaning (P &lt; 0.05); however, at 7 d postweaning there was no difference in BW due to RN (P &gt; 0.05). At weaning, empty carcass, viscera, heart, liver, and lung weights were lower in LBW than in NBW pigs, whereas empty carcass, heart, small intestine, liver, kidneys, lung, and spleen weights were lower in RN than in NN pigs (P &lt; 0.05). Brain weight was highest in NBW-NN and lowest in NBW-RN, with LBW intermediate, regardless of nutrient restriction (P &lt; 0.05). Postweaning, LBW had lower empty carcass, viscera, heart, stomach, large intestine, liver, and kidney weights than NBW, whereas RN had a higher small intestine weight than NN (P &lt; 0.05).

Conclusions

Intermittent suckling is an effective means of inducing nutrient restriction in a swine model.

Neonatal vitamin D status and risk of childhood epilepsy

OBJECTIVE

Epilepsy is a nervous system abnormality that may be caused by unknown exposures during fetal development. Studies have shown neuroprotective effects of early exposure to vitamin D in other neurological disorders, and seasonal variation in birth of children with epilepsy. We aimed to investigate if neonatal 25(OH)D₃ was associated with risk of childhood epilepsy.

METHODS

This case-cohort study compared neonatal 25(OH)D₃ levels from children with epilepsy (n = 403) and a random selected cohort of controls (n = 1163), assessing the hazard of first epilepsy diagnosis between 1 and 4 years of age from a weighted Cox proportional hazard model. Analyses were adjusted for parental education, maternal age, maternal epilepsy, maternal ethnicity, and gestational age, and additionally for season of birth and smoking during pregnancy.

RESULTS

The mean (standard deviation [SD]) of neonatal 25(OH)D₃ levels were 30.8(19.6) nmol/L among cases and 28.5(19.4) nmol/L among the cohort. The hazard ratio (HR) of epilepsy was in a dose-response pattern higher among children from the highest neonatal 25(OH)D₃ quintiles (P-trend = .004). Results were unchanged after including season of birth in the analysis, where a significantly higher HR of epilepsy was observed among children in the two highest quintiles compared to children in the lowest quintile (Q4: HR_adj  1.62, 95% CI 1.07-2.47 and Q5: HR_adj  1.86, 95% CI 1.21-2.86).

SIGNIFICANCE

In this study, the risk of childhood epilepsy increased with neonatal 25(OH)D₃ categories in a dose-response pattern, suggesting an association between a high neonatal 25(OH)D₃ and the risk of childhood epilepsy. Considering that adjusting for season of birth strengthened the results, we conclude that maternal intake of vitamin D, and not vitamin D from sun exposure, was the vitamin D source associated with epilepsy. Although we cannot, in the present study, control for compounds in the diet like pollutants or heavy metals, which may correlate with dietary vitamin D, future studies investigating fetal origin of epilepsy should focus on compounds correlating with vitamin D.

Alendronate use and bone mineral density gains in women with moderate-severe (stages 3B-5) chronic kidney disease: an open cohort multivariable and propensity score analysis from Funen, Denmark

Bisphosphonates are contraindicated in moderate-to-severe chronic kidney disease patients. However, they are used to prevent fragility fractures in patients with impaired kidney function, despite a lack of evidence on their effects on bone density in these patients. We demonstrated that Alendronate had a positive effect on bone in these patients.

PURPOSE

This study aimed to assess the association between alendronate use and bone mineral density (BMD) change in subjects with moderate-severe chronic kidney disease (CKD).

METHODS

We created a cohort of CKD stage 3B-5 patients by linking all DXA-based measurements in the Funen area, Denmark, to biochemistry, national health registries and filled prescriptions. Exposure was dispensation of alendronate and the outcome was annualized percentage change in BMD at the femoral neck, total hip and lumbar spine. Individuals were followed from first BMD to the latest of subsequent DXA measurements. Alendronate non-users were identified using incidence density sampling and matched groups were created using propensity scores. Linear regression was used to estimate average differences in the annualized BMD.

RESULTS

Use of alendronate was rare in this group of patients: propensity score matching (PSM) resulted in 71 alendronate users and 142 non-users with stage 3B-5 CKD (as in the 1 year before DXA). Whilst alendronate users gained an average 1.07% femoral neck BMD per year, non-users lost an average of 1.59% per annum. The PSM mean differences in annualized BMD were + 2.65% (1.32%, 3.99%), + 3.01% (1.74%, 4.28%) and + 2.12% (0.98%, 3.25%) at the femoral neck, total hip and spine BMD, respectively, all in favour of alendronate users.

CONCLUSION

In a real-world cohort of women with stage 3B-5 CKD, use of alendronate appears associated with a significant improvement of 2-3% per year in the femoral neck, total hip and spine BMD. More data are needed on the anti-fracture effectiveness and safety of bisphosphonate therapy in moderate-severe CKD.

Vitamin D deficiency exacerbates bleomycin-induced pulmonary fibrosis partially through aggravating TGF-β/Smad2/3-mediated epithelial-mesenchymal transition

Background

Our earlier report indicated that active vitamin D3 inhibited epithelial-mesenchymal transition (EMT) in bleomycin (BLM)-induced pulmonary fibrosis. The objective of this study was to further investigate whether vitamin D deficiency exacerbates BLM-induced pulmonary fibrosis.

Methods

This study consists of two independent experiments. Experiment 1, male mice were fed with vitamin D deficient (VDD) fodder. Experiment 2, Cyp27b1^+/+, Cyp27b1^+/− and Cyp27b1^−/− mice were fed with standard diet. For pulmonary fibrosis, mice were intratracheally instilled with a single dose of BLM (1.5 mg/kg). Serum 25(OH) D level was measured. Pulmonary collagen deposition was assessed by Sirius red staining. EMT was measured and transforming growth factor-beta (TGF-β)/Smad3 signaling was evaluated in the lungs of BLM-treated mice.

Results

The relative weight of lungs was elevated in BLM-treated mice. Col1α1 and Col1α2, two collagen protein genes, were upregulated, and collagen deposition, as determined by Sirius red staining, was observed in the lungs of BLM-treated mice. E-cadherin, an epithelial marker, was downregulated. By contrast, vimentin and α-SMA, two EMT markers, were upregulated in the lungs of BLM-treated mice. Pulmonary TGF-β/Smad3 signaling was activated in BLM-induced lung fibrosis. Further analysis showed that feeding VDD diet, leading to vitamin D deficiency, aggravated elevation of BLM-induced relative lung weight. Moreover, feeding VDD diet aggravated BLM-induced TGF-β/Smad3 activation and subsequent EMT in the lungs. In addition, feeding VDD diet exacerbated BLM-induced pulmonary fibrosis. Additional experiment showed that Cyp27b1 gene knockout, leading to active vitamin D3 deficiency, exacerbated BLM-induced pulmonary fibrosis. Moreover, Cyp27b1 gene knockout aggravated pulmonary TGF-β/Smad2/3 activation and subsequent EMT in BLM-induced lung fibrosis.

Conclusion

Vitamin D deficiency exacerbates BLM-induced pulmonary fibrosis partially through aggravating TGF-β/Smad2/3-mediated EMT in the lungs.

Neonatal vitamin D levels and cognitive ability in young adulthood

PURPOSE

Intelligence has a strong influence on life capability, and thus, identifying early modifiable risk factors related to cognitive ability is of major public health interest. During pregnancy, vitamin D is transported from the mother to the fetus through the placenta in the form of 25-hydroxyvitamin D (25(OH)D). Levels of 25(OH)D have in some studies been associated with childhood neurodevelopment; however, results from all studies are not in agreement. We investigated if neonatal 25(OH)D₃ concentrations were associated with Børge Priens IQ test score (BPP) in young adulthood.

METHODS

In this nested cohort study, 25(OH)D₃ concentrations were measured in dried blood spots from 818 newborns. We followed the children for their IQ BPP test scores in the Danish Conscription Register, which holds information on test results from the BPP test on individuals who have been recruited for Danish mandatory military draft board examination. Using general linear models, we investigated the crude and adjusted relationship between quintiles of 25(OH)D₃ concentrations and BPP IQ test results.

RESULTS

The study population consisted of 95.8% men, with a mean age of 19.4 years. The median and range of the neonatal 25(OH)D₃ levels were 26.2 nmol/L (0-104.7 nmol/L). The overall Wald test did not show an association between neonatal 25(OH)D₃ levels and BPP IQ scores (p = 0.23); however, individuals within the 3rd (BPP IQ = 101.0, 98.0-103.9) and 4th (BPP IQ = 101.2, 99.1-104.3) quintiles had slightly higher BPP IQ scores than individuals from the first quintile (BPP IQ = 97.6, 94.6-100.6).

CONCLUSIONS

Our results support the hypothesis that individuals with the lowest levels of neonatal vitamin D might have slightly lower BPP. However, more studies are needed with larger study populations to confirm our results.

BMAL1 deficiency promotes skeletal mandibular hypoplasia via OPG downregulation

OBJECTIVES

Skeletal mandibular hypoplasia (SMH), a common type of developmental deformities, results in impaired aesthetics of facial profile, occlusal dysfunction and poor life quality. In this study, BMAL1 deficiency leads to SMH formation, and we aim to investigate the mechanism by which BMAL1 deficiency induces SMH.

MATERIALS AND METHODS

Circadian rhythm-disordered mouse models were constructed by placing animals in a jet lag schedule of 6-h light advance every 7 days for 4 or 8 weeks. The OPG expression was evaluated by histomorphometry, immunohistochemistry and western blot analysis. The mechanism by which BMAL1 affects OPG expression was investigated by chromatin immunoprecipitation and luciferase reporter assays. The phenotypes caused by BMAL1 knockout can be rescued by exogenous supplementation with OPG.

RESULTS

We demonstrate that the expressions of BMAL1 and OPG decreased in SMH patients. Circadian rhythm-disordered mice and Bmal1-/- mice exhibited decreased expression of OPG, reduced bone mass and bone size of mandibles. Our results revealed that BMAL1 bound directly to the Opg promoter and upregulated its expression, thus inhibiting osteoclast differentiation. BMAL1 deficiency increased osteoclast differentiation by downregulating OPG expression. In vitro, the enhancement effect of osteoclast differentiation caused by BMAL1 knockdown was significantly reversed by exogenous supplementation with OPG. Importantly, bone loss caused by BMAL1 knockout can be partially reversed by injecting OPG Intraperitoneally.

CONCLUSIONS

These results indicate that the circadian clock plays a critical role in the growth and development of mandible by regulating OPG expression, and present a potential therapeutic strategy to prevent SMH.