Don't Forget the Bones: Incidence and Risk Factors of Metabolic Bone Disease in a Cohort of Preterm Infants

European survey showed wide variations in diagnostic procedures and management strategies for metabolic bone disease of prematurity in 22 countries

AIM

The aim of this study was to evaluate the clinical relevance, diagnostic procedures and treatment strategies for metabolic bone disease in preterm infants across Europe.

METHODS

An e-survey was distributed by email to 545 neonatal units in 38 European countries between July and October 2021. The protocol was based on the Checklist for Reporting Results of Internet E-Surveys.

RESULTS

In total, 76 neonatal units (14%) from 22 European countries (58%) completed the e-survey. In the 12 months prior to the survey, 29% of 76 units reported at least one symptomatic case of fracture associated with metabolic bone disease of prematurity, and 18% of 76 units reported at least one case of craniofacial deformity. Most centres followed local guidelines for diagnosis (77% of 73 units) and treatment (63% of 72 units). Alkaline phosphatase was the blood marker most used for treatment indication (81% of 72 units), and phosphate supplementation was the treatment most used (82% of 71 units).

CONCLUSION

Metabolic bone disease of prematurity remains clinically relevant. Wide variations in diagnostic procedures and management strategies were observed in European neonatal units. Evidence-based consensus guidelines appear urgently needed to reduce the number of symptomatic cases.

Analysis of clinical risk factors for metabolic bone disease of prematurity

Objective

To analyze clinical data related to preterm infants and identify risk factors for metabolic bone disease of prematurity (MBDP).

Methods

This study involved 856 newborns with a gestational age of less than 37 weeks or a weight of less than 1,500g at the Second Hospital of Jilin University. Multifactorial analysis was performed using logistic regression models to explore the risk factors for MBDP. Linear regression was used to investigate the factors affecting the time of alkaline phosphatase (ALP) exceedance and the peak value of ALP in the MBDP group.

Results

In the MBDP group, ALP excesses occurred in preterm infants at an average of 39.33 days after birth, and the mean value of peak ALP was 691.41 IU/L. Parenteral nutrition and the application of assisted ventilation were independent risk factors for MBDP, with ORs of 1.02 and 1.03 respectively. Gestational age was found to be a protective factor for earlier time of onset of ALP exceedance (β = 2.24,) and the increase in the peak value of ALP (β = -16.30).

Conclusion

Parenteral nutrition and the application of assisted ventilation are independent risk factors for MBDP. Gestational age is a major factor influencing the time of onset of ALP exceedance and the peak value of ALP in infants with MBDP.

Neurodevelopment Outcomes in Very-Low-Birth-Weight Infants with Metabolic Bone Disease at 2 Years of Age

Metabolic bone disease (MBD) predominantly affects preterm infants, particularly very-low-birth-weight (VLBW) infants weighing <1500 g. However, there are limited reports on MBD and neurodevelopmental outcomes. This study aimed to analyze the risk factors for MBD and understand its impact on neurodevelopmental outcomes at 2 years of corrected age. Overall, 749 VLBW infants weighing <1350 g at birth were enrolled. Exclusion criteria were major congenital abnormalities, chromosomal abnormalities, and loss of follow-up on the Bayley Scales of Infant Development, Third Edition (BSID-III) test at 24 months of corrected age. Infants were retrospectively assessed by a trained case manager using the BSID-III test at 6, 12, and 24 months old. Infants were categorized as with or without MBD according to radiographic signs. Of those enrolled, 97 VLBW infants were diagnosed with MBD, compared to 362 VLBW infants without MBD. The proportion of infants that completed three follow-ups was 86%. At the assessment at 2 years of age, infants with MBD had lower and more significant differences in motor, language, and cognitive composites. MBD is associated with poor neurodevelopmental outcomes in cognitive, motor, and language composites for VLBW infants at 24 months of corrected age.

Calcium and Phosphorus: All You Need to Know but Were Afraid to Ask

Inadequate intake of calcium and phosphorus during the perinatal period can result in metabolic bone disease (MBD), characterized by decreased bone mass, altered bone mineralization, and increased risk for fractures. Preterm neonates have higher risk of developing MBD. Treating MBD involves ensuring adequate calcium and phosphorus intake, early fortification, and vitamin D supplementation. Health care providers should closely monitor nutrient intake, postnatal growth, and screening of preterm neonates at risk for MBD. This review summarizes the critical roles of calcium and phosphorus in regulating bone physiology, how they regulate bone formation and resorption, and their influence on overall bone health.

Association of Preterm Birth and Low Birthweight with Bone Fractures during Childhood

Preterm birth and low birthweight have been associated with increased fracture risk in children. Our aim was to analyze bone fractures during childhood in preterm, and low-birthweight newborns compared to full-term and normal-birthweight newborns. We conducted a nationwide register-based cohort study in Finland from 1998 to 2017 and utilized the Medical Birth Register and Care Register for Health Care. All newborns alive 28 days after birth were included, and data on all fracture visits in specialized healthcare units were gathered. Incidences per 100,000 person-years with 95% confidence intervals (CI) were calculated, and comparisons were made by incidence rate ratios (IRRs). Kaplan-Meier analysis was used to analyze the timing of fractures during childhood (0-20 years). We included a total of 997,468 newborns and 95,869 fractures; the mean follow-up was 10.0 years, and the overall incidence of fractures was 963 per 100,000 person-years. Very preterm (<32 gestational weeks) newborns had 23% lower fracture incidence than term newborns (IRR 0.77; CI: 0.70-0.85). Preterm newborns (32 to 36 gestational weeks) had a fracture rate (IRR 0.98; CI: 0.95-1.01) similar to that of term newborns. Birthweight showed a linear increase in the fracture rates as newborns with birthweight less than 1000 g had the lowest fracture incidence of 773 per 100,000 person-years and the highest incidence (966 per 100,000 person-years) was among newborns with birthweight 2500 g or more. Children born very preterm or with extremely low birthweight have in general a lower fracture incidence during childhood compared to children born full term and with normal birthweight. These findings possibly reflect, in addition to improvements of neonatal intensive care and early nutrition, the fact that childhood fracture incidences are more dependent on issues other than early life events. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Interaction effects of night-time temperature and PM2.5 on preterm birth in Huai River Basin, China

Nocturnal temperature is observed increasing with global warming. However, evidence on night-time non-optimal temperature on the risk of preterm birth (PTB) is limited, and the potential interactions with air pollution on PTB has not been well clarified. We therefore conducted a population-based retrospective cohort study to evaluate the effect of night-time temperature extremes on the risk of PTB and its interaction with air pollution. Records of 196,780 singleton births from 4 counties in Huai River Basin (2013-2018) were obtained. Gridded data on night-time temperature were collected from a high-quality Chinese Air Quality Reanalysis dataset. We used a multivariate logistic regression to evaluate the effects of night-time heat and cold exposure on the risk of PTB as well as its subtypes. Potential interactions between night-time temperature extremes and fine particulate matter < 2.5 µm (PM_2.5) were examined using the relative excess risk due to interaction (RERI). We found that the risk of PTB was positively associated with third trimester night-time extremely heat and cold exposure, with adjusted OR of 1.898 (95 %CI: 1.655-2.177) and 2.044 (95 %CI: 1.786-2.339). Similar effects were observed for PTB subtypes, moderately PTB (mPTB) and very PTB (vPTB). Synergistic effects (RERI greater than 0) of each trimester night-time temperature extremes exposure and PM_2.5 on PTB were observed. We identified consistent positive interactions between night-time temperature extremes and PM_2.5 on mPTB. No significant interaction of night-time temperature extremes and PM_2.5 on vPTB was found. In conclusion, this large retrospective cohort study found that third trimester night-time heat and cold exposure significantly increased the risk of PTB and its subtypes. There is a synergistic effect between night-time temperature extremes and high PM_2.5 levels on PTB and mPTB. In the context of climate warming, our results add new evidence to the current understanding of night-time non-optimal temperature exposure on PTB.