The role of early life variables on the risk of fractures from birth to early adolescence: a prospective birth cohort study

Is there an association between birth characteristics and fractures in young adults? The HUNT Study, Norway

This population study investigated the association between birth characteristics and fracture risk in 11,099 young adults (aged 19-54 years). Our findings indicate that birth weight, gestational age, and birth weight for gestational age were not associated with fractures in the wrist, humerus, hip, and spine in this population.

PURPOSE

Skeletal development starts during fetal life, and it is estimated that most bone formation occurs in the 3rd trimester. This study examined the association between birth characteristics and fractures of the wrist, humerus, hip, and spine, in young adults (19-54 years).

METHODS

11.099 participants in the 3rd survey of the HUNT Study (2006-2008) were linked with the Medical Birth Registry of Norway and hospital records. Fractures of the wrist, humerus, hip, and spine were identified using ICD9/10 codes between 1988 and 2021. Follow-up was from date of participation in HUNT until a first fracture, emigration, death, or end of study. Cox regression was used to estimate hazard ratios (HR) of fracture associated with birth characteristics (95% CI), adjusted for birth year, sex, maternal age, and maternal morbidity. In a secondary analysis, follow-up started in 1988.

RESULTS

During a median follow-up of 14.0 years (153,657 person-years), 290 fractures occurred. Mean age at first fracture was 41.4 years (SD 7.4). Overall, there were no clear associations between birth characteristics and fractures in these data. HR for fracture was 0.43 (0.15-1.24) for those with a birth weight < 2.5 kg (reference birth weight 3.5 - 3.9 kg); 1.04 (0.74 - 1.46) for those born small for gestational age (< 10th percentile, reference 10 - 90th percentile); and 0.63 (0.33 - 1.23) for those born preterm (reference term births). The secondary analysis from 1988, including 539 fractures, gave similar results as the main analysis.

CONCLUSION

Birth weight, gestational age, or birth weight for gestational age was not associated with an increased risk of fractures of the wrist, humerus, hip, and spine in young adults.

Birth weight and birth length affect future fracture risk differently in men and women

We wanted to determine if there are any associations between birth factors and adult fracture risk. For women only, shorter birth length was associated with lower relative fracture risk. For women and men, individuals who were long at birth as well as tall in adulthood had a substantially higher relative fracture risk.

PURPOSE

We aimed to examine associations between birth anthropometry and adult fracture risk and to investigate if developmental mismatch is associated with fracture risk.

METHODS

We included 4635 participants (476 women and 4159 men; born 1921-1950) with hospital and national registry-based data on birth anthropometry and adult fractures (≥ 50 years). We tested associations by Cox proportional hazards regressions and present hazard ratios (HR) with 95% confidence intervals.

RESULTS

In total, 1215 (26%) suffered ≥ 1 fracture during a mean observation period of 26 years. In women, unadjusted analyses indicated that both higher birth weight (HR 1.42 per kg (1.10-1.84)) and birth length (1.10 per cm (1.05-1.17)) were associated to higher adult fracture risk. After adjustment (year of birth and gestational age), statistical significance remained only for birth length, HR 1.10 per cm (1.04-1.17). For men, no associations were apparent. We found no associations between developmental mismatch (lower birth weight followed by higher adult weight) and adult fracture risk. However, for both sexes, being born tall and staying tall into adulthood was associated with a markedly higher (55-105%) relative fracture risk (HR women 2.09 (1.18-3.68), men 1.55 (1.19-2.03)) compared to being born short and remaining short in adulthood.

CONCLUSION

In this study, being born shorter and lighter was associated with a lower risk for fractures ≥ 50 years in women. However, analyses indicated that tall adults who were also long at birth may be at markedly higher risk of fractures; this warrants further examinations.

Fractures in Childhood and Young Adulthood According to Maternal Smoking in Late Pregnancy. A Danish Cohort Study

Fractures account for the most frequent cause of hospitalization during childhood and numbers have increased over time. Of all fractures in childhood and young adulthood, 66% are recurrent fractures, suggesting that some people are predestined for fractures. The aim of this study was to investigate the association between maternal smoking during late pregnancy and the risk of fractures in the children.The study included 11,082 mothers and their children from the cohort "Healthy Habits for Two" born between 1984 and 1987. Information about maternal smoking during pregnancy came from questionnaires filled out in pregnancy, while information about fractures was derived from the Danish National Patient Registry. Over a follow-up of 24 years (1994-2018), Cox regression with multiple failures was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for fractures in childhood and young adulthood according to maternal smoking in late pregnancy. Information about body mass index (BMI) and smoking status in young adulthood was included as time variant covariates.During an age span of 8-32 years, 6,420 fractures were observed. Of the mothers, 39.1% smoked during late pregnancy. Compared to children of mothers who did not smoke, children of mothers who smoked 1-9 cigarettes per day and 10+ cigarettes per day had an increased risk of fractures (HR 1.14 [CI: 1.06; 1.21] and HR 1.14 [CI: 1.07; 1.22], respectively). After adjusting for BMI and smoking status in young adulthood, the findings were slightly strengthened, showing an increased risk of fractures of 23 and 25% in children of mothers smoking 1-9 cigarettes per day and 10+ cigarettes per day, respectively.Maternal smoking during late pregnancy was associated with a higher risk of fractures in the child. This result indicates that exposure to cigarette smoke in utero may play a role in lifelong bone health.

Exposure to Cigarette Smoke Impedes Human Osteoblast Differentiation Independently of Nicotine

INTRODUCTION

Tobacco smoking has been implicated in an array of adverse health outcomes, including those that affect adult bone. However, little is known about the impact of tobacco products on developing bone tissue as it develops in the embryo.

AIMS AND METHODS

Here, human embryonic stem cells were differentiated into osteoblasts in vitro and concomitantly exposed to various concentrations of smoke solutions from two conventional, one additive-free and two harm-reduction brands of cigarettes. Differentiation inhibition was determined by calcium assays that quantified matrix mineralization and compared to the cytotoxicity of the tobacco product.

RESULTS

Exposure to mainstream smoke from conventional and additive-free cigarettes caused no inhibition of cell viability or mineralization, while sidestream smoke (SS) concentration-dependently produced cell death. In contrast, mineralization was inhibited only by the highest mainstream concentration of harm-reduction smoke solution. Additionally, sidestream smoke solution from the harm-reduction cigarettes impeded calcification at concentrations lower than those determined to be cytotoxic for conventional products.

CONCLUSIONS

Sidestream smoke impaired in vitro osteogenesis at subtoxic concentrations. In addition, though often perceived as safer, smoke from harm-reduction cigarettes was more potent in inhibiting in vitro osteogenesis than smoke from conventional cigarettes.

IMPLICATIONS

This study adds to a growing list of adverse outcomes associated with pre-natal tobacco exposure. Specifically, in vitro exposure to tobacco products interfered with osteogenic differentiation of human embryonic stem cells, a well-established surrogate model for human embryonic bone development. Contrasting a diverse array of tobacco products unveiled that sidestream smoke was generally more developmentally osteotoxic than mainstream smoke and that harm-reduction products may not be less harmful than conventional products, adverse effects that were seemingly independent of nicotine.

Birth weight is positively associated with adult osteoporosis risk: observational and Mendelian randomization studies

The relationship between birth weight and osteoporosis was inconsistent in previous observational studies. Therefore, we performed a systematic evaluation to determine the inconsistent relationship and further make causal inference based on the UK Biobank datasets (~500,000 individuals) and individual/summary-level genetic datasets. Observational analyses found consistent negative associations either between birth weight and estimated bone mineral density (eBMD) or between genetic risk score (GRS) of birth weight and eBMD in total subjects, and sex-stratified subgroups. Mediation analyses detected significant mediation effects of adult weight and height on associations between birth weight and eBMD. Birth weight was causally associated not only with three BMD phenotypes (eBMD, total body [TB]-BMD, and femoral neck [FN]-BMD) under two effect models (total and fetal effect), but also with the risk of fracture using different Mendelian randomization (MR) methods. Multivariable MR analyses detected the pleiotropic effects of some environmental factors (e.g., gestational duration, head circumference, hip circumference) on the associations between birth weight and BMD/fracture. Three BMD phenotypes (eBMD, TB-BMD, and FN-BMD) have significant mediation effects on the associations between birth weight and fracture by using a novel mediation MR analysis under the multivariable MR framework. This multistage systematic study found consistent causal associations between birth weight and osteoporosis risk, fetal origin of genetic effects underlying the associations, and several mediation factors on the detected associations. The results enhanced our understanding of the effects of fetal original phenotypes on outcomes in late adulthood and provided helpful clues for early prevention research on osteoporosis. © 2021 American Society for Bone and Mineral Research (ASBMR).

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.

Maternal alcohol consumption during pregnancy associates with bone fractures in early childhood. A birth-cohort study of 6718 participants

Fractures are common injuries in children, but their underlying biological and environmental risk factors are not well known. Maternal alcohol consumption during pregnancy is a known risk factor for bone malformations and impaired growth, in connection with Fetal Alcohol Spectrum Disorders (FASD). There is evidence that even lower doses of alcohol than what is needed for FASD can cause changes in the developing bone. Birth weight and length may also associate to childhood fractures. The aim of this study was to find out whether there exist associations between maternal alcohol use during pregnancy, birth weight or length and fractures of the long bones in childhood. A prospective birth cohort was performed, including all women in Northern Finland with an expected date of delivery between July 1985 and June 1986, and their offspring (N = 9432). The National Hospital Discharge Register (NHDR) provided the information on inpatient treated fractures. The subjects who declined participation or were treated as outpatient were excluded. The final study population consisted of 6718 children (71.2%). 98 (1.5%) of them suffered from inpatient treated fracture of a long bone (N = 105). Maternal alcohol consumption during pregnancy was inquired by questionnaires during late pregnancy or shortly after parturition. The birth length and weight were recorded immediately after birth. Binomial regression analysis was used to determine the association between the potential explanatory variables and bone fractures. Gender, socioeconomic status of the family, maternal age, premature birth, body mass index (BMI) of the children and maternal smoking during pregnancy were taken as possible confounders. In this study, the maternal alcohol consumption during pregnancy was associated to 2.22-fold (CI 1.09-4.12, p < 0.02) increased risk of a long bone fracture before the age of eight. Birth weight or length did not associate to childhood fractures. Bone fractures are an important cause of morbidity in childhood. Their prevention should start from the prenatal period by protecting the fetus from the alcohol exposure.

Video-based kinetic analysis of calcification in live osteogenic human embryonic stem cell cultures reveals the developmentally toxic effect of Snus tobacco extract

Epidemiological studies suggest tobacco consumption as a probable environmental factor for a variety of congenital anomalies, including low bone mass and increased fracture risk. Despite intensive public health initiatives to publicize the detrimental effects of tobacco use during pregnancy, approximately 10-20% of women in the United States still consume tobacco during pregnancy, some opting for so-called harm-reduction tobacco. These include Snus, a type of orally-consumed yet spit-free chewing tobacco, which is purported to expose users to fewer harmful chemicals. Concerns remain from a developmental health perspective since Snus has not reduced overall health risk to consumers and virtually nothing is known about whether skeletal problems from intrauterine exposure arise in the embryo. Utilizing a newly developed video-based calcification assay we determined that extracts from Snus tobacco hindered calcification of osteoblasts derived from pluripotent stem cells early on in their differentiation. Nicotine, a major component of tobacco products, had no measurable effect in the tested concentration range. However, through the extraction of video data, we determined that the tobacco-specific nitrosamine N'-nitrosonornicotine caused a reduction in calcification with similar kinetics as the complete Snus extract. From measurements of actual nitrosamine concentrations in Snus tobacco extract we furthermore conclude that N'-nitrosonornicotine has the potential to be a major trigger of developmental osteotoxicity caused by Snus tobacco.

A Systematic Review of Longitudinal Cohort Studies Examining Unintentional Injury in Young Children

Objective. Injury is the leading cause of death and long-term disability in children. Longitudinal cohorts are designed to follow subjects longitudinally in order to determine if early-life exposures are related to certain health outcomes. Methods. We conducted a systematic review to identify studies of children from birth through 5 years who were followed longitudinally with unintentional injury as an outcome of interest. Results. Of the 1892 unique references based on the search criteria, 12 (published between 2000 and 2013) were included. The studies varied on the population of focus, injury definition, and incidence rates. Existing studies that longitudinally follow children aged 0 to 5 years are limited in number, scope, and generalizability. Conclusions. Further study using population-based longitudinal cohorts is necessary to more comprehensively estimate incidence of injury in young children.

Sexual Dimorphism and the Origins of Human Spinal Health

Recent observations indicate that the cross-sectional area (CSA) of vertebral bodies is on average 10% smaller in healthy newborn girls than in newborn boys, a striking difference that increases during infancy and puberty and is greatest by the time of sexual and skeletal maturity. The smaller CSA of female vertebrae is associated with greater spinal flexibility and could represent the human adaptation to fetal load in bipedal posture. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities. This review summarizes the potential endocrine, genetic, and environmental determinants of vertebral cross-sectional growth and current knowledge of the association between the small female vertebrae and greater risk for a broad array of spinal conditions across the lifespan.

Maternal smoking during pregnancy is associated with childhood bone fractures in offspring - A birth-cohort study of 6718 children

In children there is limited understanding about the biological and environmental risk factors of fractures. Therefore, we aimed to study the effect of maternal smoking on preschool children's fractures hypothesizing that the fracture risk might be programmed during intrauterine growth in means of disturbed bone formation. A prospective birth cohort included women living in Northern Finland with an expected date of delivery between July 1st, 1985 and June 30th, 1986 (N=9362), and their offspring (N=9432). Smoking was inquired during pregnancy and when the offspring reached seven years of age. Information on in-hospital-treated fractures among the children was collected from the National Hospital Discharge Register (NHDR). The cases who declined to participate or suffered from any bone dysplasia such as osteogenesis imperfecta or any malignancy were excluded, thus 6718 subjects (71.2%) were finally included. Poisson regression analysis with adjustment for gender, asthma, rheumatoid arthritis, socioeconomic status of the family, maternal age and body mass index (BMI) of the children was used to determine the association between maternal smoking during pregnancy and bone fractures. Maternal smoking during pregnancy was associated with a 1.83-fold (95% CI 1.06-3.02, p=0.022) increased risk of in-hospital-treated fractures at pre-school age. The fracture risk in childhood is perhaps increased as a result of modified bone development of the fetus due to maternal smoking.

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

Background: Whether antenatal and neonatal vitamin D status have clinical relevance in fracture prevention has not been examined extensively, although observational studies indicate that fetal life may be a sensitive period in relation to bone growth and mineralization during childhood.Objective: We examined whether 25-hydroxyvitamin D₃ [25(OH)D₃] concentrations in stored neonatal dried blood spot (DBS) samples are associated with pediatric fracture risk. We hypothesized that in particular, low neonatal vitamin D status may be a risk factor for fracture incidence among children.Design: In a register-based case-cohort study design, the case group was composed of 1039 individuals who were randomly selected from a total of 82,154 individuals who were born during 1989-1999 and admitted to a Danish hospital with a fracture of the forearm, wrist, scaphoid bone, clavicle, or ankle at age 6-13 y. The subcohort was composed of 1600 individuals randomly selected from all Danish children born during 1989-1999. The neonatal 25(OH)D₃ concentrations in DBS samples were assessed by using highly sensitive chromatography-tandem mass spectrometry.Results: The mean ± SD 25(OH)D₃ concentration for all subjects was 27.7 ± 18.9 nmol/L [median (IQR): 23.5 nmol/L (13.3, 37.3 nmol/L)] and showed significant monthly variation (P < 0.0001) with the highest values in July and August. Individuals in the middle quintile of neonatal 25(OH)D₃ had lower odds of sustaining a fracture than did those in the lowest quintile (adjusted OR: 0.75; 95% CI: 0.58, 0.96), but a global test did not show any significant overall association (adjusted P = 0.13).Conclusions: This study suggested that neonatal vitamin D status does not influence subsequent fracture risk in childhood. This is in accordance with studies that report no association between antenatal maternal vitamin D status and childhood fractures. Further studies are needed to examine fracture risk in relation to prenatal vitamin D status in a randomized controlled setting.

Vertebral cross-sectional area: an orphan phenotype with potential implications for female spinal health

A high priority in imaging-based research is the identification of the structural basis that confers greater risk for spinal disorders. New evidence indicates that factors related to sex influence the fetal development of the axial skeleton. Girls are born with smaller vertebral cross-sectional area compared to boys-a sexual dimorphism that is present throughout life and independent of body size. The smaller female vertebra is associated with greater flexibility of the spine that could represent the human adaptation to fetal load. It also likely contributes to the higher prevalence of spinal deformities, such as exaggerated lordosis and progressive scoliosis in adolescent girls when compared to boys, and to the greater susceptibility for spinal osteoporosis and vertebral fractures in elderly women than men.

Risk factors for long-bone fractures in children up to 5 years of age: a nested case-control study

AIM

To investigate risk factors for first long-bone fractures in children up to 5 years old in order to provide evidence about which families could benefit from injury prevention interventions.

METHODS

Population-based matched nested case-control study using The Health Improvement Network, a UK primary care research database, 1988-2004. Maternal, household and child risk factors for injury were assessed among 2456 children with long-bone fractures (cases). 23,661 controls were matched to cases on general practice. Adjusted ORs and 95% CIs were estimated using conditional logistic regression.

RESULTS

Fractures of long-bones were independently associated with younger maternal age and higher birth order, with children who were the fourth-born in the family, or later, having a threefold greater odds of fracture compared to first-born children (adjusted OR 3.12, 95% CI 2.08 to 4.68). Children over the age of 1 year had a fourfold (13-24 months, adjusted OR 4.09 95% CI 3.51 to 4.76) to fivefold (37+ months, adjusted OR 4.88 95% CI 4.21 to 5.66) increase in the odds of a long-bone fracture compared to children aged 0-12 months. Children in families with a history of maternal alcohol misuse had a raised odds of long-bone fracture (adjusted OR 2.33, 95% CI 1.13 to 4.82) compared to those with no documented history.

CONCLUSIONS

Risk factors for long-bone fractures in children less than 5 years old included age above 1 year, increasing birth order, younger maternal age and maternal alcohol misuse. These risk factors should be used to prioritise families and communities for injury prevention interventions.

Birth weight is not associated with risk of fracture: results from two Swedish cohort studies

Development and growth in utero has been suggested to influence bone health. However, the relationship with risk of fracture in old age is largely unknown. Using Cox proportional hazards regression, we studied the association between birth weight and fractures at ages 50-94 among 10,893 men and women (48% women) from the Uppsala Birth Cohort Study (UBCoS, born 1915-29) and 1334 men from the Uppsala Longitudinal Study of Adult Men (ULSAM, born 1920-24). Measured birth weight was collected from hospital or midwives' records and fractures from the Swedish National Patient Register. We observed 2796 fractures (717 of these were hip fractures) in UBCoS and 335 fractures (102 hip fractures) in ULSAM. In UBCoS, the hazard ratio (HR) per 1 kg increase in birth weight, adjusted for sex and socioeconomic status at birth, was 1.01 [95% confidence interval (CI), 0.94-1.09] for any fracture and 1.06 (95% CI, 0.91-1.23) for hip fracture. Estimates in ULSAM were similar. We did not observe a differential association of birth weight with fractures occurring before age 70 or after age 70 years. Neither birth weight standardized for gestational age nor gestational duration was associated with fracture rate. In linear regression, birth weight was not associated with bone mineral density among 303 men who were 82-years-old in ULSAM but showed positive associations with total body bone mineral content (β per kg increase in birth weight, adjusted for social class and age, 133; 95% CI, 30-227). This association was attenuated after further adjustment for body mass index and height (β, 41; 95% CI, -43-126). We conclude that birth weight is associated with bone mineral content but this association does not translate into an association with risk of fracture in men and women aged 50-94 years.

Bone fractures in children with autistic spectrum disorder

BACKGROUND

Bone fractures in children represent a source of significant disability and morbidity. Are children with autistic spectrum disorder (ASD) at an altered risk of fractures compared with typically developing children?

METHODS

Using the General Practice Research Database, the authors assessed the prevalence of fractures in boys with ASD diagnosed between 2 and 8 years. A cross-sectional design was used to compare the prevalence of fractures among children with ASD and age-matched controls, conditional logistic regression to explore the relative risk of having a fracture in association with diagnosed ASD.

RESULTS

The study population comprised 3,219 boys with a first-time diagnosis of ASD and 12,265 matched controls. ASD was associated with a significantly decreased risk of developing a fracture at any time in childhood (odds ratio [OR], 0.68, 95% confidence interval [CI], 0.59-0.77, p < .0001). The relative risk estimates were lower for the time period after ASD diagnosis (OR, 0.56, 95% CI, 0.48-0.66, p < .0001) but were not different for the time period before ASD diagnosis (OR, 0.96, 95% CI, 0.78-1.18, p = .6866). Adjusting for use of different drugs did not change the estimates.

CONCLUSION

The relative risk of experiencing a fracture at any time in childhood is lower for boys with ASD compared with healthy boys.

Advancing maternal age is associated with lower bone mineral density in young adult male offspring

SUMMARY

Advancing maternal age has been related to increased risk of fetal death and morbidity, as well as higher fracture risk during childhood, in the offspring. In the present study, we demonstrate that advancing maternal age is independently associated with reduced bone mass in the young adult male offspring.

INTRODUCTION

In Sweden the maternal age in both primi- and multipara mothers has steadily increased during the last three decades. It has been previously reported that advancing maternal age increases the risk of fetal death, but also of morbidity in the offspring, such as chromosome abnormalities, leukemia, diabetes mellitus type 1, and schizophrenia. Whether or not maternal age influences peak bone mass has not been reported. The aim of the present study was to investigate whether a high maternal age was associated with lower peak bone mass, as measured using DXA in a large cohort of male offspring [the Gothenburg Osteoporosis and Obesity Determinants study (GOOD)].

METHODS

Through the Swedish multi-generation register, we identified the mothers of 1,009 GOOD study subjects. From the Swedish medical birth register detailed information about the medical circumstances at the time of child birth were obtained, including maternal and offspring anthropometrics (birth height and weight), maternal age, and smoking habits, parity and length of pregnancy.

RESULTS

Maternal age was inversely correlated to areal BMD (aBMD) at the total body (r =-0.07, p = 0.03) and the lumbar spine (r =-0.09, p < 0.01). Using a linear regression model (with covariates including current physical activity, smoking, calcium intake, weight, present height and birth height, total body lean and fat mass in the offspring, and length of pregnancy), we found that maternal age negatively independently predicted lumbar spine aBMD (β =-0.08, p < 0.01) in the male offspring.

CONCLUSIONS

In conclusion, our results suggest that advancing maternal age could negatively affect bone mass in young adult men.

Rachitic changes, demineralization, and fracture risk in healthy infants and toddlers with vitamin D deficiency

PURPOSE

To examine radiographic findings in children with vitamin D deficiency in comparison with biochemical marker levels and prevalence of fractures.

MATERIALS AND METHODS

The parents or guardians of all participants provided written informed consent at the time of enrollment. The institutional review board approved the protocol, and HIPAA guidelines were followed. From a prospective sample of children seen for routine clinical care, 40 children with vitamin D deficiency (25-hydroxyvitamin D [25-OHD] level, ≤ 20 ng/mL) were identified, and high-detail computed radiographs of the wrists and knees were obtained. The children ranged in age from 8 to 24 months. Radiographs were scored by three readers with use of the 10-point Thacher score for rachitic changes and a five-point scale for demineralization. Serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels were determined. Fracture history was obtained for 35 of the 40 patients (88%).

RESULTS

All readers identified rachitic changes at both readings in two patients (5%) and demineralization in two patients (5%). Interrater agreement was 65% for rachitic changes (κ = 0.33) and 70% for demineralization (κ = 0.37). When the majority of the raters determined that rachitic changes were absent at both readings, alkaline phosphatase levels were lower than those with other assessments (median, 267 vs 515 U/L [4.4589 vs 8.6005 μkat/L]; P = .01). When most raters determined that demineralization was present at both readings, serum 25-OHD levels were lower than those at other assessments (median, 9.0 vs 17.5 ng/mL [22.464 vs 43.68 nmol/L]; P = .02). No fractures were reported or identified radiographically.

CONCLUSION

In infants and toddlers with vitamin D deficiency, rachitic changes and definite demineralization are uncommon and fracture risk is low.

Pattern of fractures across pediatric age groups: analysis of individual and lifestyle factors

Background

Knowledge of the epidemiology of children's fractures is essential to develop preventive strategies. The aim of this study was to analyze the individual/lifestyle determinants of fractures across pediatric age groups.

Methods

A cross-sectional study was performed in the first six months of 2008 through questionnaire on a sample of children from an outpatient clinic for pediatric fractures. Differences in gender, anatomic site, circumstances and location of fracture occurrence, behavioural lifestyle, and calcium intake were investigated among three different age classes (pre-school children, school children, and adolescents).

Results

The sample consisted of 382 subjects (2-14 years of age) sustaining a fracture after low or moderate trauma. Males were at a higher risk of fractures than females; greater than two-thirds of injuries occurred after low-energy trauma and the upper limb was more frequently involved. With increasing age, the male/female ratio and time spent in sports participation increased (p < 0.001), while calcium intake and time spent in sedentary behaviors decreased (p < 0.001 and < 0.003, respectively). Gender discordance existed in pre-school children with respect to the anatomic location, and in school children and adolescents with respect to the dynamics. In the adolescent group, males were more physically active and also more sedentary than females. Fractures most frequently occurred in homes (41.6%), followed by playgrounds and footpaths (26.2%), sports facilities (18.3%), and educational facilities (13.9%), with gender differences existing only in adolescence. Twenty-three percent of the subjects sustained one or more fractures in the past. The percentage of recurrent fractures increased with age (p = 0.001), with a similar trend in both genders.

Conclusions

Gender differences were shown in the prevalence of injuries, characteristics, and circumstances across ages. These differences may be explained by the related changes in behaviors, together with attending different places. Individual and lifestyle factors can in part explain the variability in the occurrence of fractures and can also address targeted preventive strategies.