Estelle Naumburg

Supplementary oxygen and risk of childhood lymphatic leukaemia

Aim: Childhood leukaemia has been linked to several factors, such as asphyxia and birthweight, which in turn are related to newborn resuscitation. Based on the findings from a previous study a population‐based case‐control study was performed to investigate the association between childhood leukaemia and exposure to supplementary oxygen and other birth‐related factors. Methods: Children born in Sweden and diagnosed with lymphatic leukaemia between 1973 and 1989 (578 cases) were individually matched by gender and date of birth to a randomly selected control. Children with Downs syndrome were excluded. Exposure data were blindly gathered from antenatal, obstetric and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated by conditional logistic regression. Results: Resuscitation with 100% oxygen with a facemask and bag immediately postpartum was significantly associated with an increased risk of childhood lymphatic leukaemia (OR = 2.57, 95% CI 1.21–6.82). The oxygen‐related risk further increased if the manual ventilation lasted for 3 min or more (OR = 3.54, 95% CI 1.16–10.80). Low Apgar scores at 1 and 5 min were associated with a non‐significantly increased risk of lymphatic leukaemia. There were no associations between lymphatic leukaemia and supplementary oxygen later in the neonatal period or other birth‐related factors.

Intrauterine exposure to diagnostic X rays and risk of childhood leukemia subtypes

Abstract Naumburg, E., Bellocco, R., Cnattingius, S., Hall, P., Boice, J. D. Jr. and Ekbom, A. Intrauterine Exposure to Diagnostic X Rays and Risk of Childhood Leukemia Subtypes. Radiat. Res. 156, 718–723 (2001). The relationship between childhood leukemia and prenatal exposure to low-dose ionizing radiation remains debatable. This population-based case–control study investigated the association between prenatal exposure to diagnostic X-ray examinations (for different types of examinations and at different stages of pregnancy) and the risk of childhood lymphatic and myeloid leukemia. All children born and diagnosed with leukemia between 1973–1989 in Sweden (578 lymphatic and 74 myeloid) were selected as cases, and each was matched (by sex and year of birth) to a healthy control child (excluding Downs syndrome). Exposure data were abstracted blindly from all available medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression. It was found that prenatal X-ray examinations resulting in direct fetal exposure were not associated with a significant overall increased risk for childhood leukemia (OR = 1.11, 95% CI 0.83–1.47), for lymphatic leukemia (OR = 1.04, 95% CI 0.77–1.40), or for myeloid leukemia (OR = 1.49, 95% CI 0.48–4.72). There was little evidence of a dose response or variation in risk by trimester of exposure or age at diagnosis. Thus X-ray examinations performed during pregnancy in the 1970s and 1980s in Sweden did not affect the risk of childhood leukemia discernibly.

Prenatal ultrasound examinations and risk of childhood leukaemia: case-control study

Obstetric ultrasound examination is part of routine antenatal care and is regarded as safe for both the fetus and the mother. In vitro, however, ultrasound has been shown to cause membrane changes that could affect embryogenesis and late prenatal and postnatal development.1 Studies have also shown an association between exposure to ultrasound and an increased frequency of non-righthandness, indicating that fetal development may be affected by the ultrasonic waves.2 Concerns over a possible association between exposure to ultrasound in utero and an increased risk of childhood malignancies have not been substantiated, but previous studies have been hampered by low statistical power or based on interviews with the parents done retrospectively, or both.3–5 To assess the impact of ultrasound and the risks of childhood lymphatic and myeloid leukaemia, we performed a nationwide population …

Fetal Tachycardia: Intrauterine and Postnatal Course

Eighteen consecutive cases of fetal tachycardia referred to the department of Pediatric Cardiology, Uppsala University, were studied retrospectively. All cases were detected at a routine visit at an antenatal clinic. None of the cases had a structural heart disease. Fetal supraventricular tachycardia was found in 8 cases and atrial flutter in 10 cases. In 7 cases, hydrops and heart failure were diagnosed. Antenatal treatment with digoxin, alone or in combination with other antiarrhythmic drugs, was needed in 15 cases. In 10 cases an obvious effect of the therapy was observed. No intrauterine deaths occurred. One infant died postnatally. At birth, 4 infants were in need of neonatal intensive care when delivered. Antiarrhythmic treatment was started in 13 cases postnatally. Late relapse of tachycardia was reported in 3 children. In 1 of these cases the prenatal tachycardia had resolved spontaneously and the infant was not treated antenatally nor during the neonatal period. Although fetal tachycardia is a serious condition, antenatal treatment in combination with careful monitoring and induction of delivery in cases with deteriorating fetal condition result in a satisfactory outcome for the majority of infants. However, there is a risk of late recurrence.

Childhood leukemia and magnetic fields in infant incubators.

In studies of magnetic field exposure and childhood leukemia, power lines and other electrical installations close to the children’s homes constitute the most extensively studied source of exposure. We conducted a study to assess whether exposure to magnetic fields in infant incubators is associated with an increased leukemia risk. We identified all children with leukemia born in Sweden between 1973 and 1989 from the national Cancer Registry and selected at random one control per case, individually matched by sex and time of birth, from the study base. We retrieved information about treatment in infant incubators from medical records. We made measurements of the magnetic fields inside the incubators for each incubator model kept by the hospitals. Exposure assessment was based on measurements of the magnetic field level inside the incubator, as well as on the length of treatment. For acute lymphoblastic leukemia, the risk estimates were close to unity for all exposure definitions. For acute myeloid leukemia, we found a slightly elevated risk, but with wide confidence intervals and with no indication of dose response. Overall, our results give little evidence that exposure to magnetic fields inside infant incubators is associated with an increased risk of childhood leukemia.

Evaluating national guidelines for the prophylactic treatment of respiratory syncytial virus in children with congenital heart disease

This is the first study to evaluate compliance with the 2003 Swedish national guidelines for prophylactic treatment of respiratory syncytial virus (RSV) in children with congenital heart disease (CHD). We estimated the relative risk (RR) of children with CHD being hospitalised with a RSV infection, studied the extent to which RSV prophylactic treatment with palivizumab corresponded to the guidelines and determined the morbidity of children with CHD who developed RSV infection despite prophylaxis.

Risk factors for pulmonary arterial hypertension in children and young adults

Pulmonary hypertension (PH) has been linked to preterm birth explained by congenital heart defects and pulmonary diseases.

Some neonatal risk factors for adult pulmonary arterial hypertension remain unknown

Pulmonary hypertension has been linked to premature birth, chronic lung disease, bronchopulmonary dysplasia and congenital heart disease. This national population‐based registry study assessed the risk of adult pulmonary hypertension following premature birth, adjusted for known risk factors.

Serious complications in male infant circumcisions in Scandinavia indicate that this always be performed as a hospital-based procedure.

More than 7000 male circumcisions are performed in Scandinavia every year. Circumcision is regulated in different ways in Sweden and Denmark and Norway. This study reviewed and described factors associated with complications of circumcision in infant boys in Scandinavia over the last two decades and discussed how these complications could be avoided.

Respiratory Tract Infection and Risk of Hospitalization in Children with Congenital Heart Defects During Season and Off-Season: A Swedish National Study

Respiratory tract infections (RTI) are common among young children, and congenital heart defect (CHD) is a risk factor for severe illness and hospitalization. This study aims to assess the relative risk of hospitalization due to RTI in winter and summer seasons for different types of CHD. All children born in Sweden and under the age of two, in 2006–2011, were included. Heart defects were grouped according to type. Hospitalization rates for respiratory syncytial virus (RSV) infection and RTI in general were retrieved from the national inpatient registry. The relative risk of hospitalization was calculated by comparing each subgroup to other types of CHD and otherwise healthy children. The relative risk of hospitalization was increased for all CHD subgroups, and there was a greater increase in risk in summer for the most severe CHD. This included RSV infection, as well as RTI in general. The risk of hospitalization due to RTI is greater for CHD children. Prophylactic treatment with palivizumab, given to prevent severe RSV illness, is only recommended during winter. We argue that information to healthcare staff and parents should include how the risk of severe infectious respiratory tract illnesses, RSV and others, is present all year round for children with CHD.