Metabolic bone disease risk factors strongly contributing to long bone and rib fractures during early infancy: A population register study

Abstract

BackgroundThe aim of this study was to assess the incidence of fractures in infancy, overall and by type of fracture, its association with accidents, metabolic bone disease risk factors, and abuse diagnosis.MethodsThe design was a population-based register study in Sweden. Participants: Children born 1997–2014, 0–1 years of age diagnosed with fracture-diagnosis according to International Classification of Diseases (ICD10) were retrieved from the National Patient Register and linked to the Swedish Medical Birth Register and the Death Cause Register. Main outcome measures were fractures of the skull, long bone, clavicle and ribs, categorized by age (younger or older than 6 months), and accident or not.FindingsThe incidence of fractures during infancy was 251 per 100 000 infants (n = 4663). Major fracture localisations were long bone (44·9%), skull (31·7%), and clavicle (18·6%), while rib fractures were few (1·4%). Fall accidents were reported among 71·4%. One-third occurred during the first 6 months. Metabolic bone disease risk factors, such as maternal obesity, preterm birth, vitamin D deficiency, rickets, and calcium metabolic disturbances, had increased odds of fractures of long bones and ribs in early infancy (0–6 months): birth 32–36 weeks and long bone fracture [AOR 2·13 (95%CI 1·67–2·93)] and rib fracture [AOR 4·24 (95%CI 1·40–12·8)]. Diagnosis of vitamin D deficiency/rickets/disorders of calcium metabolism had increased odds of long bone fracture [AOR 49·5 (95%CI 18·3–134)] and rib fracture [AOR 617 (95%CI 162–2506)]. Fractures without a reported accident had higher odds of metabolic risk factors than those with reported accidents. Abuse diagnosis was registered in 105 infants, with overrepresentation of preterm births, multiple births and small-for-gestational age.InterpretationMetabolic bone disease risk factors are strongly associated with fractures of long bone and ribs in early infancy. Fracture cases with abuse diagnosis had a metabolic bone risk factor profile.

Medical diagnoses among infants at entry in out‐of‐home care: A Swedish population‐register study

“…Given that only a small proportion (1.8%) of the infants had superficial injuries of the body indicating violence, it is possible that a considerable proportion of those infants had such underlying medical conditions. This assumption is further supported by the fact that diagnoses of SDH, long bone, and rib fracture that were associated with abuse only constituted a minor part of all those fractures found in the population, as shown in our previous studies …”

“…This is the first Swedish study addressing medical diagnoses and out‐of‐home care among infants. Medical diagnoses were infrequent among the total number of infants entered; 2.4% had diagnoses compatible with SBS/AHT criteria as SDH, RH, rib fracture, or long bone fracture, and 0.9% had an abuse diagnosis without any of those SBS/AHT criteria, similar to the proportions reported from Western Australia and Manitoba …”

“…The high proportion (37%) of fall accidents among those having SDH, RH, rib fracture, or long bone fracture is intriguing. Swedish population data show that fall accidents, mostly with slight or moderate trauma, are reported for 34% of all SDH diagnoses and for 71% of all long bone fractures . However, the diagnostic considerations of abuse while parents have reported a fall accident cannot be addressed by this study design.…”

“…Biological risk factors such as smoking, SGA, obesity, and prematurity are known to be more prevalent among socioeconomically disadvantaged individuals, and socioeconomic factors are also associated with child morbidity and child mortality . SGA and prematurity are associated with SDH, and in addition to these, obesity is associated with infant metabolic bone disease . Thus, biological risk factors might, at least to some extent, account for the relative overrepresentation of low socioeconomic status in the SBS/AHT criteria sample, compared with the reference population.…”

“…We defined the following perinatal (for the index pregnancy and birth) and parental variables according to current knowledge: Maternal and perinatal information: sex of infant; single/multiple birth, term, or preterm born (<37 gestational week); small‐for‐gestational age (SGA) (<2.5 percentiles); maternal body mass index (BMI) at start of index pregnancy, defining underweight (BMI < 19) or overweight (BMI ≥ 25); and maternal smoking in pregnancy weeks 30 to 32. Sociodemographic information: mother married/cohabiting or single living; maternal age <20, 20 to 34, >35 years; parity 1 and parity 2+; maternal birth country, either the Nordic countries (Denmark, Finland, Iceland, Norway, or Sweden) or outside these countries; and highest level of education for mother and father at time of birth of the index child as basic, secondary, or postsecondary education. …”