The long-term impact of very preterm birth on adult bone mineral density

Appendicular Muscle Mass Index as the Most Important Determinant of Bone Mineral Content and Density in Small for Gestational Age Children

Preterm small for gestational age (SGA) children are at increased risk for low bone mineral content later in life; however, data on SGA children born at term are scarce. We included 44 SGA and 57 adequate for gestational age (AGA) children aged 6 to 11 years to compare bone mineral density (BMD) and bone mineral content (BMC) and to identify which anthropometric and biochemical values influence bone mineralization in these children. Fat mass, appendicular skeletal muscle mass index (ASMMI), BMC, and BMD were significantly lower in SGA children than in AGA (P ≤ .005). Appendicular muscle mass index correlated with BMC(TBLH,FN,L1-L4) and BMD(TBLH,FN,L1-L4) in both groups (r2 = 0.7, P < .05). In multivariate analysis, ASMMI was strongly associated with BMC and BMD in both groups. There were no differences in clinical biomarkers, calcium intake, and physical activity between the groups. Achieving adequate muscle mass contributes to adequate bone mineralization and a lower risk for low BMC and BMD in SGA children.

Body composition in adults born preterm with very low birth weight

BACKGROUND

Studies on body composition in preterm very low birth weight (VLBW < 1500 g) survivors are inconsistent and trajectories later in life unknown. We assessed body composition and its change from young to mid-adulthood in VLBW adults.

METHODS

We studied 137 VLBW adults and 158 term-born controls from two birth cohorts in Finland and Norway at mean age 36 years. Body composition was assessed by 8-polar bioelectrical impedance. We compared results with dual-energy x-ray absorptiometry measurements at 24 years.

RESULTS

In mid-adulthood, VLBW women and men were shorter than controls. Fat percentage (mean difference in women 1.1%; 95% CI, -1.5% to 3.5%, men 0.8%; -2.0% to 3.6%) and BMI were similar. VLBW women had 2.9 (0.9 to 4.8) kg and VLBW men 5.3 (2.7 to 8.1) kg lower lean body mass than controls, mostly attributable to shorter height. Between young and mid-adulthood, both groups gained fat and lean body mass (p for interaction VLBW x age>0.3).

CONCLUSION

Compared with term-born controls, VLBW adults had similar body fat percentage but lower lean body mass, largely explained by their shorter height. This could contribute to lower insulin sensitivity and muscular fitness previously found in VLBW survivors and predispose to functional limitations with increasing age.

IMPACT

In mid-adulthood, individuals born preterm with very low birth weight had similar body fat percentage but lower lean body mass than those born at term. This was largely explained by their shorter height. First study to report longitudinal assessments of body size and composition from young to mid-adulthood in very low birth weight adults. Lower lean body mass in very low birth weight adults could contribute to lower insulin sensitivity and muscular fitness and lead to earlier functional limitations with increasing age.

[Association between birth conditions and bone mineral density in adults from the 1982 and 1993 birth cohorts in Pelotas, Rio Grande do Sul State, Brazil]

This study assessed the association of birth weight, gestational age, and intrauterine growth with bone mineral density (BMD) at 22 and 30 years of age in the 1982 and 1993 birth cohorts in Pelotas, Rio Grande do Sul State, Brazil. BMD was measured by dual-energy X-ray absorptiometry (DXA) and the association was assessed using analysis of variance. Multiple linear regression was used to control for confounding factors: sex; household income at birth; maternal smoking during pregnancy; maternal schooling; maternal ethnicity/skin color; and pre-pregnancy body mass index. The study tested whether body fat in adulthood was a mediator of the association analyzed, using the G-computation Formula. A total of 6,803 participants from the 1982 and 1993 cohorts were evaluated at 30 and 22 years of age, respectively. Birth weight was associated with BMD at all sites, with a greater difference at the femoral neck. Individuals born weighing less than 2,000g had on average -0.036g/cm2 (95%CI: -0.064; -0.008) of BMD in the femoral neck than individuals weighing more than 3,500g. Individuals with an intrauterine growth z-score at least 1.28 standard deviation below the mean had an average of -0.013g/cm2 (95%CI: -0.024; -0.002) of BMD in the lumbar spine compared with individuals with an above-average z-score. The mediation analysis showed that body fat in adulthood did not mediate the association. Birth conditions have been associated with BMD in adulthood and the identification of early factors related to bone loss is essential due to the demographic inversion that has been taking place in low- and middle-income countries.

Quantifying Bone Strength Deficits in Young Adults Born Extremely Preterm or Extremely Low Birth Weight

The long-term bone health of young adults born extremely preterm (EP; <28 weeks' gestation) or extremely low birth weight (ELBW; <1000 g birth weight) in the post-surfactant era (since the early 1990s) is unclear. This study investigated their bone structure and estimated bone strength using peripheral quantitative computed tomography (pQCT)-based finite element modeling (pQCT-FEM). Results using this technique have been associated with bone fragility in several clinical settings. Participants comprised 161 EP/ELBW survivors (46.0% male) and 122 contemporaneous term-born (44.3% male), normal birth weight controls born in Victoria, Australia, during 1991-1992. At age 25 years, participants underwent pQCT at 4% and 66% of tibia and radius length, which was analyzed using pQCT-FEM. Groups were compared using linear regression and adjusted for height and weight. An interaction term between group and sex was added to assess group differences between sexes. Parameters measured included compressive stiffness (kcomp ), torsional stiffness (ktorsion ), and bending stiffness (kbend ). EP/ELBW survivors were shorter than the controls, but their weights were similar. Several unadjusted tibial pQCT-FEM parameters were lower in the EP/ELBW group. Height- and weight-adjusted ktorsion at 66% tibia remained lower in EP/ELBW (mean difference [95% confidence interval] -180 [-352, -8] Nm/deg). The evidence for group differences in ktorsion and kbend at 66% tibia was stronger among males than females (pinteractions  <0.05). There was little evidence for group differences in adjusted radial models. Lower height- and weight-adjusted pQCT-FEM measures in EP/ELBW compared with controls suggest a clinically relevant increase in predicted long-term fracture risk in EP/ELBW survivors, particularly males. Future pQCT-FEM studies should utilize the tibial pQCT images because of the greater variability in the radius possibly related to lower measurement precision. © 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).

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).

Early Life Programming of Skeletal Health

PURPOSE OF REVIEW

Increasing bone mineral accrual during childhood might delay the onset of osteoporosis. We discuss the scientific evidence for early life approaches to optimising skeletal health.

RECENT FINDINGS

There is an ever-growing body of evidence from observational studies suggesting associations between early life exposures, particularly during foetal development, and bone mineral density (BMD). The findings of such studies are often heterogeneous, and for some exposures, for example, maternal smoking and alcohol intake in pregnancy or age at conception, intervention studies are not feasible. The most frequently studied exposures in intervention studies are calcium or vitamin D supplementation in pregnancy, which overall suggest positive effects on offspring childhood BMD. Maternal calcium and/or vitamin D supplementation during pregnancy appear to have positive effects on offspring BMD during early childhood, but further long-term follow-up is required to demonstrate persistence of the effect into later life.

The impact of an early intervention home-based program on body composition in preterm-born preschoolers with very low birth weight

Background and aims

Early child interventions focused on the family prevented neurodevelopmental and behavioral delays and can provide more knowledge regarding responsive feeding, thus creating learning opportunities to promote better quality nutrition and preventing failure to thrive. The aim is to verify the impact of a continuous program of early home-based intervention on the body composition of preschool infants who were born preterm with very low birth weight (VLBW).

Methods

This is a longitudinal analysis from a randomized controlled trial, including VLBW preterm children, born in a tertiary hospital in Southern Brazil and followed up at the high-risk institutional ambulatory clinic. Participants were divided into the intervention group (IG): skin-to-skin care with the mother (kangaroo care), breastfeeding policy, and tactile-kinesthetic stimulation by mothers until hospital discharge. Subsequently, they received a program of early intervention with orientation and a total of 10 home visits, independently from the standard evaluation and care that was performed following the 18 months after birth; conventional group (CG): standard care according to the routine of the newborn intensive care unit (NICU), which includes kangaroo care, and attending to their needs in the follow-up program. Body composition estimation was performed using bioelectrical impedance analyses (BIA), and physical activity and feeding practices questionnaires were evaluated at preschool age, as well as anthropometric measurements and biochemical analysis.

Results

Data of 41 children at 4.6 ± 0.5 years old were evaluated (CG n = 21 and IG n = 20). Body weight, height, body mass index, waist and arm circumferences, and triceps and subscapular skinfold did not differ between groups. The IG presented higher segmented fat-free mass (FFM) when compared to the CG (right arm FFM: 0.74 vs. 0.65 kg, p = 0.040; trunk FFM: 6.86 vs. 6.09 kg, p = 0.04; right leg FFM: 1.91 vs. 1.73 kg, p = 0.063). Interaction analyses showed that segmented FFM and FFM Index were associated with higher iron content in the IG. In the CG, interaction analyses showed that increased visceral fat area was associated with higher insulin resistance index.

Conclusion

An early intervention protocol from NICU to a home-based program performed by the mothers of VLBW preterm children of low-income families presents a small effect on FFM.

Osteopenia of prematurity and associated nutritional factors: case-control study

BACKGROUND

Preterm newborn nutrition affects postnatal skeletal growth and bone mineralization, but studies have not yet fully concluded the relationship between nutrition and osteopenia. This study was intended to investigate the impact of nutritional factors on osteopenia in preterm newborns.

METHODS

This is a case-control study with babies born with gestational age ≤ 32 weeks in a high-risk maternity hospital, between 2018 and 2019. The population consisted of 115 newborns, being 46 cases (40%) and 69 controls (60%). Disease outcome was based on serum alkaline phosphatase levels > 900UL/l and hypophosphatemia < 4 mg/dl. Gestational data at birth and clinical and nutritional follow-up data during 8 weeks postnatally were assessed. Variables were assessed using regressive logistic models.

FINDINGS

Preterm infants who were fed pasteurized fresh human milk with acidity ≥ 4 ºDornic are 5.36 times more likely to develop osteopenia (p = 0.035). Higher calcium intake, compared to controls, also increased the probability of disease occurrence [OR 1.05 (CI 1.006-1.1); p = 0.025], while the presence of a partner [OR 0.10 (CI 0.02-0.59); p = 0.038] and the shortest time using sedatives [OR 0.89 (CI 0.83-0.98); p = 0.010] were protective factors associated with osteopenia. Extremely low birth weight [OR 5.49 (CI 1.20-25.1); p = 0.028], sepsis [OR 5.71 (CI 1.35-24.2); p = 0.018] and invasive ventilatory support [OR 1.09 (CI 1.03-1.18); p = 0.007] were risk factors.

CONCLUSIONS

Acidity and high calcium intake are the main nutritional factors associated with osteopenia of prematurity. Further studies on the use of human milk with lower acidity, recommendation and nutritional supplementation of calcium should be accomplished to guide prevention strategies in newborns at risk for osteopenia during hospital stay.

Bone mineral density in very low birthweight adults-A sibling study

BACKGROUND

Children and adults born very low birthweight (VLBW, <1500 g) at preterm gestations have lower bone mineral density (BMD) and/or bone mineral content (BMC) than those born at term, but causality remains unknown.

OBJECTIVES

Our aim was to assess BMD and BMC in adults born at VLBW in a sibling comparison setting to account for shared genetic and environmental confounders.

METHODS

We conducted a cohort study of 77 adults born VLBW and 70 same-sex term-born siblings at mean age of 29 years. The primary outcome variables were BMD Z-scores, and BMC, of the femoral neck, lumbar spine, and whole body, measured using dual-energy X-ray absorptiometry. We analysed data by linear mixed models.

RESULTS

The VLBW adults had a 0.25 (95% CI 0.02, 0.47) Z-score unit lower femoral neck BMD, and 0.35 (95% CI 0.16, 0.54) grams lower femoral neck BMC than their term-born siblings, after adjustment for sex, age, and maternal smoking. Additional adjustment for adult body size attenuated the results. Lumbar spine, and whole body BMC were also lower in the VLBW group.

CONCLUSIONS

Individuals born at VLBW had lower BMC values at all three measurement sites, as well as lower femoral neck BMD Z-scores, compared to term-born siblings, partly explained by their smaller adult body size, but the differences were smaller than those reported previously with unrelated controls. This suggests that genetic or environmental confounders explain partly, but not exclusively, the association between preterm VLBW birth and adult bone mineralisation.

Catch it before it breaks!: managing metabolic bone disease of prematurity

PURPOSE OF REVIEW

Metabolic bone disease of prematurity, commonly referred to as osteopenia of prematurity, remains prevalent in the neonatal intensive care unit (NICU) despite recent medical advances. It is estimated that up to 60% of extreme low birth weight and 20% of very low-birth-weight infants have metabolic bone disease of prematurity. Often silent, it typically presents with poor growth, increased ventilator dependency and fractures. Clinical sequalae, such as short stature can extend into young adulthood. There is no universal consensus by neonatal intensive care unit clinicians on the screening, diagnosis, or treatment for metabolic bone disease of prematurity. The disease is often diagnosed late by radiographs or incidentally in this highly fragile population.

RECENT FINDINGS

Suggest screening using DEXA (dual-energy X-ray absorptiometry) scans or ultrasound, in combination with serum markers like alkaline phosphatase, phosphorous levels, parathyroid hormone, and tubular reabsorption of phosphate, might identify at-risk babies earlier. The use of protocol-based screenings may aid in early diagnosis.

SUMMARY

We present a review of the risk factors, recent screening methods, diagnosis and management of this prevalent, clinically relevant diagnosis, as well as propose a protocol for the early screening and management of this silent disease.

Adults Born Preterm: Long-Term Health Risks of Former Very Low Birth Weight Infants

BACKGROUND

Advances in neonatology now enable increasing numbers of very low birth weight neonates (<1500 g) to survive into early adulthood and beyond. What are the implications for their long-term care?

METHODS

Selective literature search on the outcome of very low birth weight neonates in adulthood ("adults born preterm").

RESULTS

Robust data are available on the pulmonary, metabolic, cardiovascular, renal, neurocognitive, sensory-visual, social-emotional, mental, reproductive, and musculoskeletal long-term risks. On the somatic level, elevated rates have been documented for asthma (odds Ratio [OR] 2.37), diabetes mellitus (OR 1.54), and chronic renal disease (hazard ratio [HR] 3.01), along with the cardiovascular and cerebrovascular sequelae of a tendency toward arterial hypertension. On the psychosocial level, the main findings are deficits in romantic partnerships (OR 0.72) and a lower reproduction rate (relative risk [RR] male/female 0.24/0.33). The affected women also have an elevated risk of preterm delivery.

CONCLUSION

A risk profile with both somatic and psychosocial aspects can be discerned for adults who were born prematurely, even if some of these risks are present in low absolute numbers. As the ability to compensate for latent deficits declines with age, such adults may suffer from "premature aging as the late price of premature birth." A holistic approach to care with personalized prevention strategies-which for most of them was discontinued at discharge from pediatric follow-up-therefore seems appropriate in adulthood as well.

The incidence of osteopenia of prematurity in preterm infants without phosphate supplementation: A prospective, observational study

To meet their requirements for bone mineralization, it is recommended that preterm infants receive nutritional support containing calcium and phosphate. There are no clear data on the incidence of osteopenia of prematurity (OFP) in preterm infants without phosphate supplementation.This study aimed to investigate the incidence of OFP in preterm infants without phosphate supplementation and its relationship with the duration of parenteral nutrition (PN).This was a prospective and observational study.This study included 30 infants aged <32 gestational weeks and weighed <1500 g at birth. All infants received PN according to a standard protocol, beginning on day 1 with calcium, without phosphate. Starting from the first day of life, all infants received human milk without fortifiers. Oral vitamin D (400 IU/d) was administered when enteral nutrition reached 100 mL/kg/d.The diagnosis of OFP was based on radiographs that were taken of both wrists. Serum alkaline phosphatase (ALP) was measured 3 times: at the start of PN (ALP 1), at the end of PN (ALP 2), and at discharge or the expected due date (ALP 3). Radiographs were obtained on the same day as ALP 3. The duration of PN was analyzed in the presence of OFP using receiver operating characteristic curve analysis.Among the 30 infants, 13 (43%) were diagnosed with OFP. The duration of PN was significantly longer in the OFP group than in the group without OFP (16 vs 12 days; P < .05). The provision of PN for >15 days significantly increased the risk of OFP (odds ratio, 5.40; 95% confidence interval, 1.12-26.04; P = .035).We found a high incidence of OFP in preterm infants without phosphate supplementation. An association was found between the duration of PN and the incidence of OFP. Further research is needed to prevent the development of osteopenia in preterm infants.

Update on Calcium and Phosphorus Requirements of Preterm Infants and Recommendations for Enteral Mineral Intake

Background: With current Ca and P recommendations for enteral nutrition, preterm infants, especially VLBW, fail to achieve a bone mineral content (BMC) equivalent to term infants. During the first 3 years, most notably in light at term equivalent age (<−2 Z score) VLBW infants’ BMC does not catch up. In adults born preterm with VLBW or SGA, lower adult bone mass, lower peak bone mass, and higher frequency of osteopenia/osteoporosis have been found, implying an increased risk for future bone fractures. The aim of the present narrative review was to provide recommendation for enteral mineral intake for improving bone mineral accretion. Methods: Current preterm infant mineral recommendations together with fetal and preterm infant physiology of mineral accretion were reviewed to provide recommendations for improving bone mineral accretion. Results: Current Ca and P recommendations systematically underestimate the needs, especially for Ca. Conclusion: Higher enteral fortifier/formula mineral content or individual supplementation is required. Higher general mineral intake (especially Ca) will most likely improve bone mineralization in preterm infants and possibly the long-term bone health. However, the nephrocalcinosis risk may increase in infants with high Ca absorption. Therefore, individual additional enteral Ca and/or P supplementations are recommended to improve current fortifier/formula mineral intake.

Associated neonatal and maternal factors of osteopenia of prematurity in low resource setting: A cross-sectional study

Objective

Determining neonatal and maternal factors that are associated with the incidence of OFP.

Methods

This study employed a cross-sectional design, in which the participants were identified for clinical variables (sex, gestational age, birth weight, etc.), neonatal morbidity (sepsis, necrotizing enterocolitis (NEC), etc.), and maternal risk factors (premature rupture of membranes, preeclampsia, etc.). The data were analyzed using Chi-square test, independent t-test, and logistic regression test with p < 0.05.

Results

The birth weight ranged from 800 to 1495 g (1219 ± 225 g), of which 5 newborns (17%) were <1000 g. The gestational age ranged from 27 to 32 weeks, with a mean of 29 ± 1.5 weeks. The signs of OFP were observed in 13 (43%) infants, of which 2 (15%) OFP infants had a birth weight <1000 g. There was significant difference in parenteral nutrition duration (p = 0.018), onset of vitamin D supplementation (p = 0.019), and ALP level (p = 0.012) of infants between the OFP group and the non-OFP group. The variables associated with the incidence of OFP were parenteral nutrition duration >15 days (OR = 5.4; 95% CI 1.120-26.044; p = 0.036), ALP level >500 U/L (OR = 2.889; 95% CI 1.703-4.900; p = 0.014), and PROM (OR = 5.4; 95% CI 1.039-28.533; p = 0.045).

Conclusion

The lack of phosphate intake, prolonged parenteral nutrition, ALP level >500 U/L, onset of vitamin D supplementation, and premature rupture of membranes are associated with the incidence of OFP.

Bone Mineral Density, Body Composition, and Metabolic Health of Very Low Birth Weight Infants Fed in Hospital Following Current Macronutrient Recommendations during the First 3 Years of Life

The present study longitudinally evaluated growth, bone mineral density, body composition, and metabolic health outcome in very low birth weight (VLBW) infants whose in-hospital target nutrient intake was within recent recommendations. From six months to three years, bone mineral density (dual-energy X-ray absorptiometry, DXA), body composition, and metabolic health outcome were compared with a reference group of term infants. The aim was to test whether in-hospital achieved weight gain until 36 weeks of gestation (light or appropriate for term equivalent age; LTEA or ATEA) predicts later growth, bone mineral density (BMD), abdominal obesity, or metabolic health outcomes such as insulin resistance, relative to term infants, during the first three years of life. Target in-hospital energy and protein intake was not achieved. Growth in weight, length and head circumference, mid arm circumference, adiposity, fat free mass (FFM), and bone mineralization in VLBW infants was less than those in term infants and influenced by nutritional status at discharge. Preterm infants had poorer motor and cognitive outcomes. Post-discharge body composition patterns indicate FFM proportional to height but lower fat mass index in LTEA preterm infants than term infants, with no evidence of increased truncal fat in preterm infants. The hypothesis of early BMD catch-up in VLBW infants after discharge was not supported by the present data. The clinical significance of these findings is unclear. The data may suggest a reduced obesity risk but an increased osteoporosis risk. Since postnatal growth restriction may have permanent negative health effects, LTEA VLBW infants would especially appear to benefit from targeted preventive interventions. Further follow-up of the infants is required.

Bone health in young adult survivors born extremely preterm or extremely low birthweight in the post surfactant era

BACKGROUND

Most infants born extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g birthweight) in the post surfactant era (early 1990s) are now surviving into adulthood. Preterm birth/low birthweight are risk factors for reduced bone growth and mineralisation in infants and children. However, little is known about their bone health around peak bone mass and through adult life.

OBJECTIVE

To compare bone health (bone mineral measures, bone structure and strength) in young adults born EP/ELBW with controls (>2499 g birthweight), and within the EP/ELBW group examine perinatal and later variables associated with long term bone health.

METHODS

A geographic cohort comprising all 297 survivors born EP/ELBW in 1991-92 in the state of Victoria, Australia, and 260 contemporaneous controls (>2499 g birthweight) were recruited into a longitudinal study from birth. At age 25 years, investigations included dual energy X ray absorptiometry and peripheral quantitative computed tomography to measure bone, muscle and soft tissue variables, and fasting blood samples to measure serum 25 hydroxyvitamin D (25(OH)D) and bone turnover markers (BTM). Linear regression analysis, with models fitted using generalised estimating equations, was used to compare outcomes between groups, adjusting for height and weight.

RESULTS

Compared with controls (n = 129), young adults born EP/ELBW (n = 162) had lower areal bone mineral density (g/cm²) (mean difference [MD] -0.044; 95% confidence interval [CI] -0.076,-0.013) and Z-scores (MD -0.53; 95% CI -0.75, -0.30) in the femoral neck, and lower total hip Z-score (MD -0.35; 95% CI -0.54, -0.15) after adjusting for height and weight. EP/ELBW males generally displayed more bone and soft tissue deficits than females, compared with their respective controls. Within the EP/ELBW group, early growth, male sex, height and lean mass, muscle measures, 25(OH)D levels, and BTM were independently associated with bone mineral measures, structure or strength.

CONCLUSIONS

Young adults born EP/ELBW had evidence of impaired bone health around the age of peak bone mass compared with controls. Further follow-up of the EP/ELBW groups will determine if they have a heightened low-trauma fracture risk in later life.

Armed conflict and birth weight

This paper investigates the hidden yet persistent cost of conflict to birth weight outcomes for 53 developing countries experiencing conflict in the past three decades (1990-2018). Exploiting the variation across districts and conception months-years, we find that intrauterine exposure to armed conflict in the first trimester of pregnancy reduces child's weight at birth by 2.8% and raises the incidence of low birth weight by 3.2 percentage points. Infants born to poor and low educated mothers are especially vulnerable to the adverse repercussions of armed conflict. Given the long-lasting consequences of poor infant health over the life cycle, our findings call for global efforts in the prevention and mitigation of conflict. Extra attention should be directed to children and women from disadvantaged backgrounds.

Cellular senescence mediates the detrimental effect of prenatal dexamethasone exposure on postnatal long bone growth in mouse offspring

Background

Prenatal dexamethasone exposure (PDE) induces low birth weight and retardation of fetal bone development which are associated with lower peak bone mass in adult offspring. Here we evaluated whether and how PDE affects postnatal long bone growth in mouse offspring.

Methods

Pregnant mice were injected subcutaneously with dexamethasone (1.2 mg/kg/day) every morning from gestational days (GD) 12–14. Femurs and tibias of 2-, 4-, 6-, and 12-week-old female offspring were harvested for histological, immunofluorescence, flow cytometric analysis, or microcomputed tomography (μCT) measurement.

Results

PDE leads to impaired bone remodeling as well as decreased bone mass in the long bone of female mouse offspring. During postnatal bone growth, significant decrease of CD45⁻CD29⁺CD105⁺Sca-1⁺ bone marrow mesenchymal stem cells (BMSCs) and CD45⁻Nestin⁺ cells, loss of type H vessels, and increment of cellular senescence were found in metaphysis of long bone in mouse offspring after PDE. We further show that eliminating the excessive senescent cells with dasatinib (5 mg/kg/day) and quercetin (50 mg/kg/day) during GD 12–14 rescues the above toxic effect of PDE on the postnatal long bone growth in female mouse offspring.

Conclusion

Cellular senescence mediates the toxic effect of PDE on postnatal long bone growth in mouse offspring, and inhibition of cellular senescence may be proposed for treating the retardation of bone growth caused by PDE.

Increased Incidence but Lack of Association Between Cardiovascular Risk Factors in Adults Born Preterm

Preterm birth incurs an increased risk of early cardiovascular events and death. In the general population, cardiovascular risk factors cluster in the context of inflammation and oxidative stress. Whether this also occurs in young adults born preterm is unknown. We analyzed 101 healthy young adults (ages 18–29) born preterm (≤29 weeks of gestation) and 105 full-term controls, predominantly (90%) white. They underwent a comprehensive clinical and biological evaluation, including measurement of blood pressure, lung function (spirometry), glucose metabolism (fasting glucose, glycated hemoglobin, and oral glucose tolerance test), as well as biomarkers of inflammation and oxidative stress. Individuals born preterm were at higher risk than those born full-term of stage ≥1 hypertension (adjusted odds ratio, 2.91 [95% CI, 1.51–5.75]), glucose intolerance (adjusted odds ratio, 2.22 [95% CI, 1.13–4.48]), and airflow limitation (adjusted odds ratio, 3.47 [95% CI, 1.76–7.12]). Hypertension was strongly associated with adiposity and with glucose intolerance in participants born full-term but not in those born preterm. We did not find any group difference in levels of biomarkers of inflammation and oxidative stress. In individuals born preterm, inflammation, and oxidative stress were not related to hypertension or glucose intolerance but were associated with adiposity. In those born preterm, cardiovascular risk factors were not related to each other suggesting different pathophysiological pathways leading to the development of cardiovascular risk following preterm birth. Clinicians should consider screening for these abnormalities irrespectively of other risk factors in this at-risk population.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov . Unique identifier: NCT03261609.

Discovery and Identification of Serum Succinyl-Proteome for Postmenopausal Women with Osteoporosis and Osteopenia

OBJECTIVE

For the purpose of providing evidence for the treatment of osteoporosis and osteopenia, this study retrospectively identified succinylation-modified sites and proteins in postmenopausal women, and bioinformatics analysis were performed.

METHODS

From January 2016 to June 2018, a total of 30 postmenopausal women aged from 55 to 70 years old were assigned to three groups: 10 cases with osteoporosis; 10 cases with osteopenia; and 10 cases with normal bone mass. Subsequently, the serum samples were collected from all cases for succinyl-proteome. Measures comprised label-free quantitative analysis, succinylation enrichment techniques, the liquid chromatograph-mass spectrometer/mass spectrometer (LC-MS/MS) methods, and bioinformatics.

RESULTS

A total of 113 succinylation sites on 35 proteins were identified based on quantitative information. The variation of the different multiple folds were more than 1.2 times as a significant increase for up-regulated and less than 1/1.2 times as a significant decrease for down-regulated. Among the quantified succinylation sites, 66 were up-regulated and 11 down-regulated in the Osteopenia/Normal comparison group, 24 were up-regulated and 44 down-regulated in the Osteoporosis/Osteopenia comparison group, 45 were up-regulated and 32 down-regulated in the Osteoporosis/Normal comparison group. Among the quantified succinylation proteins, 24 were up-regulated and 7 down-regulated in the Osteopenia/Normal comparison group, 15 were up-regulated and 20 down-regulated in the Osteoporosis/Osteopenia comparison group, 20 were up-regulated and 17 down-regulated in the Osteoporosis/Normal comparison group. The percentage of proteins differed in immune response, signaling pathway, proteolysis, lymphocyte, leukocyte, and cell activation. Four differentially expressed proteins (apolipoprotein A-I, apolipoprotein A-II, hemoglobin subunit alpha, and haptoglobin) contained quantitative information; they were mediated with receptors, factors, mechanisms, that related to bone metabolism. Hemoglobin subunit alpha was screened for diagnosis of osteopenia.

CONCLUSIONS

The succinyl-proteome experimental data indicated that apolipoprotein A-I, apolipoprotein A-II, hemoglobin subunit alpha, and haptoglobin were valuable for diagnosis and treatment in postmenopausal women with osteoporosis and osteopenia.