Pediatric whole-body magnetic resonance imaging: comparison of STIR and T2 Dixon sequences in the detection and grading of high signal bone marrow changes.

OBJECTIVES: To compare short time inversion recovery (STIR) and T2 Dixon in the detection and grading of high signal intensity areas in bone marrow on whole-body MRI in healthy children. METHODS: Prospective study, including whole-body 1.5-T MRIs from 77 healthy children. Two experienced radiologists in consensus identified and graded areas of high bone marrow signal on STIR and T2-weighted (T2W) turbo spin echo (TSE) Dixon images (presence, extension) in two different sessions at an interval of at least 3 weeks. In a third session, a third observer joined the two readers for an additional consensus reading with all sequences available (substitute gold standard). RESULTS: Four hundred ninety of 545 (89.9%) high signal areas were visible on both sequences, while 27 (5.0%) were visible on STIR only and 28 (5.1%) on T2W Dixon only. Twenty-four of 27 (89%) lesions seen on STIR only, and 25/28 (89%) seen on T2W Dixon only, were graded as mildly increased signal intensity. The proportion of true positive high signal lesions was higher for the T2W Dixon images as compared to STIR (74.2% vs. 68.2%) (p = 0.029), while the proportion of false negatives was lower (25.9% vs. 31.7% (p = 0.035) for T2W Dixon and STIR, respectively). There was a moderate agreement between the T2W Dixon and STIR-based extension scores on a 0-4 scale, with a kappa of 0.45 (95% CI = 0.34-0.56). CONCLUSIONS: Most high signal bone marrow changes identified on a 1.5-T whole-body MRI were seen on both STIR and water-only T2W Dixon, underscoring the importance of using identical protocols when following bone-marrow signal changes over time. KEY POINTS: • Whole-body MRI is increasingly being used to diagnose and monitor diseases in children, such as chronic non-bacterial osteomyelitis, malignant/metastatic disease, and histiocytosis. • Standardized and validated imaging protocols, as well as reference standards by age for the growing skeleton are lacking. • Prospective single-center study showed that 90% of high signal bone marrow areas identified on a 1.5-T whole-body MRI in healthy children is seen on both STIR and water-only T2W Dixon, while 5% is seen on STIR only and 5% on T2W Dixon only.

In children and adolescents with temporomandibular disorder assembled with juvenile idiopathic arthritis - no association were found between pain and TMJ deformities using CBCT.

BACKGROUND: Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer from temporomandibular disorder (TMD). Due to this, imaging diagnosis is crucial in JIA with non-symptomatic TM joint (TMJ) involvement. The aim of the study was to examine the association between clinical TMD signs/symptoms and cone-beam computed tomography (CBCT) findings of TMJ structural deformities in children and adolescents with JIA. METHODS: This cross-sectional study is part of a longitudinal prospective multi-centre study performed from 2015-2020, including 228 children and adolescents aged 4-16 years diagnosed with JIA, according to the International League of Associations for Rheumatology (ILAR). For this sub-study, we included the Bergen cohort of 72 patients (32 female, median age 13.1 years, median duration of JIA 4.5 years). Clinical TMD signs/symptoms were registered as pain on palpation, pain on jaw movement, and combined pain of those two. The severity of TMJ deformity was classified as sound (no deformity), mild, or moderate/severe according to the radiographic findings of CBCT. RESULTS: Of 72 patients, 21 (29.2%) had pain on palpation at and around the lateral pole, while 41 (56.9%) had TMJ pain upon jaw movement and 26 (36.1%) had pain from both. Of 141 TMJs, 18.4% had mild and 14.2% had moderate/severe structural deformities visible on CBCT. CBCT findings were not significantly associated with either the pain on palpation or the pain on jaw movement. A significant difference was found between structural deformities in CBCT and the combined pain outcome (pain at both palpation and movement) for both TMJs for the persistent oligoarticular subtype (p = 0.031). CONCLUSIONS: There was no association between painful TMD and CBCT imaging features of the TMJ in patients with JIA, but the oligoarticular subtype of JIA, there was a significant difference associated with TMJ pain and structural CBCT deformities.

Prevalence of temporomandibular disorder in children and adolescents with juvenile idiopathic arthritis - a Norwegian cross- sectional multicentre study.

BACKGROUND: Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer pain from temporomandibular disorder (TMD). Still, routines for the assessment of temporomandibular joint (TMJ) pain in health and dental care are lacking. The aims of this study were to examine the prevalence of TMD in children and adolescents with JIA compared to their healthy peers and to investigate potential associations between JIA and TMD. METHODS: This comparative cross-sectional study is part of a longitudinal multicentre study performed during 2015-2020, including 228 children and adolescents aged 4-16 years with a diagnosis of JIA according to the ILAR criteria. This particular substudy draws on a subset of data from the first study visit, including assessments of TMD as part of a broader oral health examination. Children and adolescents with JIA were matched with healthy controls according to gender, age, and centre site. Five calibrated examiners performed the clinical oral examinations according to a standardised protocol, including shortened versions of the diagnostic criteria for TMD (DC/TMD) and the TMJaw Recommendations for Clinical TMJ Assessment in Patients Diagnosed with JIA. Symptoms were recorded and followed by a clinical examination assessing the masticatory muscles and TMJs. RESULTS: In our cohort of 221 participants with JIA and 221 healthy controls, 88 (39.8%) participants with JIA and 25 (11.3%) healthy controls presented with TMD based on symptoms and clinical signs. Painful TMD during the last 30 days was reported in 59 (26.7%) participants with JIA vs. 10 (5.0%) of the healthy controls (p <  0.001). Vertical unassisted jaw movement was lower in participants with JIA than in controls, with means of 46.2 mm vs. 49.0 mm, respectively (p <  0.001). Among participants with JIA, a higher proportion of those using synthetic disease-modifying antirheumatic-drugs and biologic disease-modifying antirheumatic-drugs presented with painful masticatory muscles and TMJs at palpation. CONCLUSION: Symptoms and clinical signs of TMD were seen in approximately half of the JIA patients compared to about one fourth of their healthy peers. Painful palpation to masticatory muscles and decreased vertical unassisted jaw movement were more frequent in participants with JIA than among healthy controls and should be part of both medical and dental routine examinations in patients with JIA.

Imaging in juvenile idiopathic arthritis (JIA): an update with particular emphasis on MRI.

Juvenile idiopathic arthritis (JIA) is a heterogeneous condition encompassing all forms of chronic arthritis of unknown origin and with onset before 16 years of age. During the last decade new, potent therapeutic agents have become available, underscoring the need for accurate monitoring of therapeutic response on both disease activity and structural damage to the joint. However, so far, treatment efficacy is based on clinical ground only, although clinical parameters are poor markers for disease activity and progression of structural damage. Not so for rheumatoid arthritis patients where the inclusion of radiographic assessment has been required by FDA to test the disease-modifying potential of new anti-rheumatic drugs. In imaging of children with JIA there has been a shift from traditional radiography towards newer techniques such as ultrasound and MRI, however without proper evaluation of their accuracy and validity. We here summarize present knowledge and discuss future challenges in imaging children with JIA.

Trajectories of weight disturbances during adolescence in relation to gender in a Swedish cohort.

AIM: To explore developmental trajectories among adolescents of thinness and overweight in relation to gender. METHODS: A group-based procedure was used to determine patterns of weight disturbances in a school-based sample of 3020 Swedish adolescents followed from age 11 to 18. A sensitivity analysis was performed to compensate for an increasing number of missing height and weight data after grade 8. RESULTS: Six trajectories represented the best description of developmental weight disturbances with the exception of thinness among boys, which was best described by four trajectories. Concerning thinness, 5.9% of girls and 4.2% of boys developed this condition during the study period, while 1.9% of girls and 3.0% of boys recovered from their initial thinness. For overweight, (including obesity) 1.5% of girls and 3.1% of boys developed this weight disturbance during the study period, while 10.1% of girls and 9.3% of boys recovered from overweight/obesity. Non-reporting of height and weight was biased towards an underestimation of the true prevalence of overweight and obesity in girls and of thinness in boys. CONCLUSIONS: Developmental trajectories provide a novel method to describe the dynamics of weight disturbances during adolescence. Similar patterns were found for overweight and thinness in boys and girls but group sizes varied between genders. Non-reporting of height and weight was found in a gender-specific pattern.

Digital radiography: optimization of image quality and dose using multi-frequency software.

BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. OBJECTIVE: To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. MATERIALS AND METHODS: A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. RESULTS: Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. CONCLUSION: By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

The paediatric wrist revisited: redefining MR findings in healthy children.

OBJECTIVES: During a multicentre study on juvenile idiopathic arthritis, wide variations were observed in bone shape, signal intensity and volume of joint fluid as shown by MRI which in part appeared to be unrelated to disease activity. A study was undertaken to examine these features in a cohort of healthy children. METHODS: 88 children of mean age 9.8 years (range 5-15) underwent MRI imaging (T1-weighted Spin Echo and Spectral Selection Attenuated Inversion Recovery (SPAIR)) of the left wrist. The number of bony depressions, distribution and amount of joint fluid and the presence of bone marrow changes were assessed. RESULTS: Bony depressions were present in all children, increasing with age from a mean of 4.0 in children aged 4-6 years to 9.2 in those aged 12-15 years (p<0.001)). 45 of 84 children (53.6%) had a high signal on SPAIR with a corresponding low signal on T1 in at least one bone. No associations were seen between bone marrow change (present or not) and sex (p=0.827) or sports club membership (p=0.616). All children had visible joint fluid in at least one of the joints assessed. No associations were seen between the presence of joint fluid and age group, except for the radius/scaphoid and capitate-scaphoid joints and a recess lateral to the hamate. CONCLUSIONS: It is important to be aware of the high prevalence of bony depressions, signal changes suggestive of bone marrow oedema and the volume of joint fluid seen in normal children. Such findings must be interpreted with care in children with suspected disease such as juvenile arthritis.

Neonatal bronchopulmonary dysplasia predicts abnormal pulmonary HRCT scans in long-term survivors of extreme preterm birth.

BACKGROUND: There is an increasing understanding that extreme preterm birth carries a risk of long-term pulmonary sequelae. A study was undertaken to investigate if, and in what way, neonatal factors were associated with subsequent abnormalities on pulmonary high-resolution CT (HRCT) scanning and if pulmonary function was related to these abnormalities. METHODS: HRCT scanning and pulmonary function tests were performed less than 2 weeks apart in 74/86 eligible subjects (86%) born at a gestational age of < or =28 weeks or with a birth weight of < or =1000 g within a defined area in Western Norway in 1982-5 (n = 42) or 1991-2 (n = 32). Mean age at examination was 18 and 10 years, respectively. HRCT scans were interpreted by a paediatric radiologist blinded to the clinical data using a structured system allowing scores from 0 to 50. RESULTS: Lung parenchymal abnormalities were found in 64 subjects (86%), the median (interquartile range) score being 3.0 (1.75-5.0) points. Prolonged neonatal requirement for oxygen treatment predicted poor outcome, and an increase of 100 days increased the average HRCT score by 3.8 points (p<0.001). There was also a positive association of the severity of pulmonary function abnormalities with the extent of HRCT abnormalities, exemplified by the relation between forced expiratory volume in 1 s and total HRCT score (beta = -0.090; p<0.001). CONCLUSIONS: In area-based cohorts of long-term survivors of extremely preterm birth, prolonged neonatal requirements for oxygen treatment predicted subsequent structural abnormalities on HRCT scans and in pulmonary function, and these two outcome measures were interrelated.

Antenatal ultrasound and postnatal autopsy findings in terminations after 12 weeks' gestation due to fetal abnormality: population-based study in Western Norway, 1988-2002.

BACKGROUND: Ultrasound screening has been part of antenatal care for several decades, and warrants high expertise to meet the criteria for a worthwhile screening program. In particular, the rate of false positives should be low. PURPOSE: To examine time trends of pregnancy terminations for fetal abnormality after 12 weeks' gestation, and to assess the agreement between antenatal ultrasound and post-termination autopsy findings for the main pathologies leading to termination. MATERIAL AND METHODS: During the period 1988 to 2002, 198 pregnancies were terminated for fetal abnormality after 12 weeks' gestation. We reviewed the case notes for those 151 who were autopsied (male/female/undetermined ;= ;91/56/4). Annual rates of live births and stillbirths were retrieved from the Medical Birth Registry of Norway. RESULTS: Antenatal ultrasound provided a correct diagnosis of the major abnormality in 149/151 cases (99%), based on post-termination autopsy findings. The annual rate of terminations after 12 weeks' gestation varied between 0.6 and 3.4 (mean 1.8) per 1000 live births, with a trend toward higher rates over the study period (P=0.001, chi-square test for linear-by-linear association). CONCLUSION: The specificity of antenatal ultrasound for major abnormalities was high, as compared to postnatal autopsy findings. The mean annual rates of termination after 12 weeks' gestation tended to increase over the 14-year study period.

A mutation in the receptor binding site of GDF5 causes Mohr-Wriedt brachydactyly type A2.

BACKGROUND: Brachydactyly type A2 (OMIM 112600) is characterised by hypoplasia/aplasia of the second middle phalanx of the index finger and sometimes the little finger. BDA2 was first described by Mohr and Wriedt in a large Danish/Norwegian kindred and mutations in BMPR1B were recently demonstrated in two affected families. METHODS: We found and reviewed Mohr and Wriedt's original unpublished annotations, updated the family pedigree, and examined 37 family members clinically, and radiologically by constructing the metacarpo-phalangeal profile (MCPP) pattern in nine affected subjects. Molecular analyses included sequencing of BMPR1B, linkage analysis for STS markers flanking GDF5, sequencing of GDF5, confirmation of the mutation by a restriction enzyme assay, and localisation of the mutation inferred from the very recently reported GDF5 crystal structure, and by superimposing the GDF5 protein sequence onto the crystal structure of BMP2 bound to Bmpr1a. RESULTS: A short middle phalanx of the index finger was found in all affected individuals, but other fingers were occasionally involved. The fourth finger was characteristically spared. This distinguishes Mohr-Wriedt type BDA2 from BDA2 caused by mutations in BMPR1B. An MCPP analysis most efficiently detected mutation carrier status. We identified a missense mutation, c.1322T>C, causing substitution of a leucine with a proline at amino acid residue 441 within the active signalling domain of GDF5. The mutation was predicted to reside in the binding site for BMP type 1 receptors. CONCLUSION: GDF5 is a novel BDA2 causing gene. It is suggested that impaired activity of BMPR1B is the molecular mechanism responsible for the BDA2 phenotype.

Juvenile idiopathic arthritis and the temporomandibular joint: A comprehensive review.

Juvenile idiopathic arthritis is the most common inflammatory rheumatic disease of childhood and represents a series of chronic inflammatory arthritides of unknown cause. Involvement of the temporomandibular joint has been reported in up to 87% of children with juvenile idiopathic arthritis when based on magnetic tomography imaging; it can be asymptomatic and may lead to severe long term complications. In this review a summary of the contemporary literature of imaging of the temporomandibular joint in children with juvenile idiopathic arthritis will be provided, including ultrasound which is a valuable method for guided joint injections, but does not necessarily allow detection of acute inflammation, cone beam computed tomography, which has emerged as a feasible and accurate low-dose alternative as compared to conventional computed tomography to detect destructive change, and magnetic resonance imaging which is considered the method of choice for assessing acute, inflammatory change, although the lack of normative standards remains a challenge in children.

Ultrasound screening for developmental dysplasia of the hip in the neonate: the effect on treatment rate and prevalence of late cases.

OBJECTIVE: To assess the effect of ultrasound screening on primary diagnosis, management, and prevalence of late cases of developmental dysplasia of the hip (DDH). DESIGN: A randomized, controlled trial, including 11,925 newborn infants who were allocated to receive either general, or selective or no ultrasound screening in addition to the clinical examination. In the selectivity screened group only infants with risk factors or clinical findings of DDH received an ultrasound examination. The infants were at least 27 months old at the conclusion of the study. Those with risk factors for DDH had a radiograph examination of the hips at 4.5 months of age. RESULTS: The three study groups did not differ in terms of sex distribution or positive Barlow/Ortolani tests. General ultrasound screening resulted in a higher treatment rate than in either the selective or in the no ultrasound screening groups (3.4% vs 2.0% and 1.8%, P < .0001). For infants not subjected to treatment, ultrasound screening resulted in a higher follow-up rate because of nonconclusive early findings (13%, 1.8%, 0%, respectively; P < .0001). The prevalence of late subluxation or dislocation was lower for subjects assigned to general ultrasound screening than for those subjected to selective or no ultrasound screening, but the differences were not statistically significant (0.3, 0.7, 1.3 per 1000, respectively; P = .11, test for trend). CONCLUSION: The effect of ultrasound screening in reducing the prevalence of late DDH was at best marginal despite a considerable increase in diagnostic and therapeutic efforts.

Cost-effectiveness of alternative screening strategies for developmental dysplasia of the hip.

OBJECTIVE: To compare the cost-effectiveness of adding either a general or a selective ultrasound screening program to the routine clinical examination for developmental dysplasia of the hip (DDH) with use of the data from a large, randomized study of 11,925 newborns. METHODS: Our previous study comparing the clinical outcomes of three strategies for screening infants for DDH suggested (but results were not statistically significant) that general ultrasound screening resulted in fewer children requiring hospitalization and surgery for DDH than did a strategy based on ultrasound screening of the 11.8% of infants considered to be at increased risk of DDH or one with no ultrasound screening. General ultrasound screening led to early splinting of 3.4% of the newborns compared with 2.0% for the selectively screened group and 1.8% for the group not receiving ultrasound screening. Using these data, we decided on sequences and intervals of diagnostic and therapeutic actions considered to be sufficient for each regimen. We applied estimates of the costs of screening, treatment of DDH discovered early and late, and follow-up examinations to arrive at total program costs for each strategy. RESULTS: Total program costs were similar for each of the three screening strategies (costs varied by < 5%). However, treatment of late cases accounted for only 22% of total costs in the group undergoing general screening vs 65% in the two latter groups. The cost estimates were sensitive to several variables. Application of the data to a hypothetical ultrasound program in which all girls and only boys at increased risk for DDH underwent an ultrasound examination showed substantially reduced total program costs. CONCLUSIONS: Application of costs from other centers to our data regarding frequency of clinical outcomes may yield different comparative program costs. If the findings of our clinical study can be generalized to other centers, a strategy of screening all girls and boys with risk factors for DDH may be the most cost-effective approach.

Impaired platelet binding of fibrinogen due to a lower number of GPIIB/IIIA receptors in polycythemia vera.

We have previously described a stimulus-specific defect in platelet aggregation in polycythaemia vera (PV) after stimulation with surface receptor dependent agonists such as platelet activating factor (PAF). In contrast, responses to phorbol myristate acetate (PMA) were normal. We now report that after PAF stimulation, using flow cytometry, the amount of fibrinogen bound to its receptor was significantly lower in PV platelets with a median MFI of 6.0 (range 4.1-17.3) compared to controls, 12.8 (range 8-21.3; n=11; p<0.01). We found no evidence of preactivation of PV platelets. Quantitative analysis of GPIIIa gave a significantly lower number of GPIIIa on resting PV platelets, 14300 subunits of GPIIIa (range 8500-15500) vs. 19800 for controls (range 13400-26800; n=12; p<0.01). Both patients and controls increased their number of receptors on the cell surface after stimulation with PAF and PMA, but the significant difference in the number of receptors per cell remained. Indirect evaluation of PAF receptor function showed that activation of CD 62 did not differ in PV and controls after PAF stimulation. Additionally, although the basal level of serotonin in platelet-rich plasma was significantly lower in PV, there was a threefold increase of the basal level after stimulation with PAF for both PV and control platelets, also indicating a normal interaction of PAF with its receptor. Although our results indicate both an impaired PAF induced aggregation in PV and a lower number of GPIIb/IIIa complexes on single platelets, whether these phenomena are related remains uncertain.

Microheterogeneity of serum alkaline phosphatase isoenzymes as revealed by isoelectric focusing.

The microheterogeneity of human serum alkaline phosphatase (ALP) was investigated by means of isoelectric focusing. Liver and bone isoenzymes focused in a similar pattern, with about 10 bands located between pH 3.7 and 4.9, but differed in the relative intensity of the various bands. Intestinal ALP exhibited 7 to 8 bands at pH 4.9-5.1, and the placental enzyme showed 2 to 3 bands at pH 4.9. Mild digestion with neuraminidase revealed that the banding of liver and bone isoenzymes was at least partly due to differences in the sialic acid content of the various fractions. Extensively desialylated liver and bone isoenzymes showed apparently identical patterns with 6 to 7 bands focused at pH 6.2-6.7. Isoelectric focusing is a useful method for characterizing the microheterogeneity of alkaline phosphatase isoenzymes. The clinical value of this method seems to be limited, however, since it did not distinguish between liver and bone isoenzymes and failed to detect 'specific' isoelectric fractions correlated to various diseases.

Inherited occurrence of a heat stable alkaline phosphatase in the absence of malignant disease.

We describe a family with an inherited persistent elevation of serum alkaline phosphatase activity in the absence of malignant disease, observed for at least 15 yr. Isoenzyme studies revealed that this increased activity was due to an enzyme which showed similarities to serum placental alkaline phosphatase from pregnant women having the following properties: high heat stability; reactivity to anti-placental alkaline phosphatase antiserum; lack of inhibition by L-homoarginine; moderate inhibition by EDTA; and lack of interaction with wheat germ lectin. The enzyme was less sensitive than placental alkaline phosphatase to inhibition by L-phenylalanine, L-tryptophan, L-leucine, L-leucyl-glycyl-glycine and L-phenylalanyl-glycyl-glycine. The enzyme also differed from the placental alkaline phosphatase in its electrophoretic mobility, isoelectric heterogeneity and apparent molecular mass. We conclude that the enzyme is an inherited heat stable alkaline phosphatase variant which might correspond to a rare phenotype of placental alkaline phosphatase.

Further characterization of a heat-stable alkaline phosphatase with low sensitivity to L-phenylalanine.

A heat-stable alkaline phosphatase, hitherto found in two families with inherited hyperphosphatasemia, was further characterized. The enzyme was similar to serum placental alkaline phosphatase from pregnant women concerning its apparent affinity constant (Km) for 4-nitrophenyl phosphate and its reactivity with H7 monoclonal anti-placental alkaline phosphatase (PLAP) antibodies, but different in the following respects: it exhibited greater heat stability, a higher pH optimum, lower sensitivity to inhibition by L-phenylalanine, and no reactivity with C2 monoclonal anti-PLAP antibodies. The low sensitivity to L-phenylalanine suggests that the enzyme might correspond to a rare phenotype of placental alkaline phosphatase found in human term placenta.

Diagnostic value of radiography in cases of perinatal death: a population based study.

OBJECTIVE: To examine the yield of radiographic abnormalities in a population based set of perinatal deaths, the diagnostic value of whole body postmortem radiographs in the same set, and previous factors that may increase the proportion of useful examinations. DESIGN: Retrospective population based study. SETTING: A region of Norway. PATIENTS: All infants from a well defined geographical area who were stillborn or had died soon after birth over an 11 year period (n=542), who had routinely undergone whole body radiography and autopsy. MAIN OUTCOME MEASURES: (a) Proportion of cases with abnormal radiographic findings. (b) Proportion of abnormal radiographs providing new information that was useful for postmortem diagnosis. RESULTS: Radiographs were abnormal in 162/542 cases (30%). These provided new information about, but did not help to confirm, the pathological process leading to death in 14/162 (8.6%), may have helped to confirm, but not establish, the cause(s) of death in 1/162 (0.6%), and were of vital importance for establishing the cause(s) of death in 5/162 (3.1%). Among infants with external malformations, the proportion of useful radiographs was 12/100 (12%), and among the remainder it was 8/436 (1.8%), a difference of 10.2% (95% confidence interval 3.7% to 16.7%; data missing for six cases). CONCLUSIONS: The diagnostic value of postmortem radiography in this population based set was low. However, radiographic findings were of vital importance for establishing the cause(s) of death in 5/542 cases (0.9%).

Smoking mothers and snuffing fathers: behavioural influences on youth tobacco use in a Swedish cohort.

OBJECTIVE: To analyse the influences of parental use of cigarettes and snus (the Swedish variety of smokeless tobacco) on offspring's behaviour. DESIGN: Prospective cohort study. SETTING: The Stockholm County of Sweden. SUBJECTS: 2232 adolescents recruited in the fifth grade (mean age 11.6 years) with follow up in the eighth grade. MAIN OUTCOME MEASURES: Self reported tobacco use (ever and current use of cigarettes and/or snus) in the eighth grade. RESULTS: Parents' tobacco use was associated with adolescents' current use of cigarettes and snus (odds ratio (OR) 2.7, 95% confidence interval (CI) 1.8 to 3.9 if both parents used tobacco v neither parent). Mother's cigarette smoking was associated with adolescents' current exclusive smoking (OR 2.4, 95% CI 1.6 to 3.6). Father's use of snus was associated with current exclusive use of snus among boys (OR 3.0, 95% CI 1.4 to 6.4), but not with current cigarette use. The overall prevalence of current smoking was lower among children whose fathers used snus than among those whose fathers smoked. CONCLUSIONS: Parental smoking, especially maternal smoking, enhances the risk of tobacco experimentation in youths, as does paternal use of smokeless tobacco. However, the transition to regular cigarette smoking is not likely to be affected by paternal use of smokeless tobacco. Contextual factors, in particular declining smoking trends and negative social acceptance of smoking, can explain most of these findings.

The alpha angle in cam-type femoroacetabular impingement: new reference intervals based on 2038 healthy young adults.

We report on gender-specific reference intervals of the alpha angle and its association with other qualitative cam-type findings in femoroacetabular impingement at the hip, according to a population-based cohort of 2038 19-year-olds, 1186 of which were women (58%). The alpha angle was measured on standardised frog-leg lateral and anteroposterior (AP) views using digital measurement software, and qualitative cam-type findings were assessed subjectively on both views by independent observers. In all, 2005 participants (837 men, 1168 women, mean age 18.6 years (17.2 to 20.1) were included in the analysis. For the frog-leg view, the mean alpha angle (right hip) was 47° (26 to 79) in men and 42° (29 to 76) in women, with 97.5 percentiles of 68° and 56°, respectively. For the AP view, the mean values were 62° (40 to 105) and 52° (36 to 103) for men and women, respectively, with 97.5 percentiles of 93° and 94°. Associations between higher alpha angles and all qualitative cam-type findings were seen for both genders on both views. The reference intervals presented for the alpha angle in this cross-sectional study are wide, especially for the AP view, with higher mean values for men than women on both views.