Aggregated data from the same laboratories participating in two glucose external quality assessment schemes show that commutability and transfers of values to control materials are decisive for the biases found.

OBJECTIVES: We report the results of glucose measurements performed during one year by the same measurement procedures (MPs) in 58 Norwegian hospital laboratories using control materials provided by external quality assessment (EQA) schemes from two different providers. The providers used materials with presumed vs. verified commutability and transfers of values using reference material vs. using a highest-order reference MP. METHODS: Data from six Labquality and three Noklus glucose EQA surveys were aggregated for each MP (Abbott Alinity, Abbott Architect, Roche Cobas, and Siemens Advia) in each scheme. For each EQA result, percent difference from target value (% bias) was calculated. Median percent bias for each MP per scheme was then calculated. RESULTS: The median % biases observed for each MP in the Labquality scheme were significantly larger than those in the Noklus scheme, which uses verified commutable control materials and highest-order reference MP target values. The difference ranged from 1.2 (Roche Cobas, 2.9 vs. 1.7 %) to 4.4 percentage points (Siemens Advia, 3.2 % vs. -1.2 %). The order of bias size for the various MPs was different in the two schemes. In contrast to the Labquality scheme, the median % biases observed in the Noklus scheme for Abbott Alinity (-0.1 %), Abbott Architect (-0.5 %), and Siemens Advia (-1.2 %) were not significantly different from target value (p>0.756). CONCLUSIONS: This study underlines the importance of using verified commutable EQA materials and target values traceable to reference MPs in EQA schemes designed for assessment of metrological traceability of laboratory results.

Trends in overweight and obesity in Bergen, Norway, using data from routine child healthcare 2010-2022.

AIM: Trends in childhood overweight, obesity and severe obesity have been lacking in Norway. This study assessed pre-pandemic trends from 2010 to 2019 and evaluated differences in prevalence during the 2020-2022 pandemic years. METHODS: Routine height and weight measurements from child and school health centres were extracted retrospectively from children aged 2, 4, 6, 8 and 13 years. Overweight, obesity and severe obesity was classified according to the International Obesity Task Force cut-offs. Pre-pandemic trends were estimated using linear regression. The prevalence during the pandemic was compared to the 95% prediction interval of this model. RESULTS: We obtained 181 527 body mass index measurements on 78 024 children (51.0% boys). There was a decrease in the prevalence of overweight including obesity from 2010 to 2019 in boys and this was statistically significant at 4 and 13 years of age. We found no significant trends in girls during this period. During the pandemic, the prevalence of overweight including obesity exceeded the prediction intervals for boys aged 4, 6, and 8 years, and for 6-year-old girls. CONCLUSION: From 2010-2019, overweight including obesity plateaued in girls and decreased in boys but increased during the pandemic among prepubertal boys. Routine healthcare data is useful for estimating the prevalence of different weight status.

Parental income gradients in adult health: a national cohort study.

BACKGROUND: Disparities in health by adult income are well documented, but we know less about the childhood origins of health inequalities, and it remains unclear how the shape of the gradient varies across health conditions. This study examined the association between parental income in childhood and several measures of morbidity in adulthood. METHODS: We used administrative data on seven complete Norwegian birth cohorts born in 1967-1973 (N = 429,886) to estimate the association between parental income from birth to age 18, obtained from tax records available from 1967, linked with administrative registries on health. Health measures, observed between ages 39 and 43, were taken from registry data on consultations at primary health care services based on diagnostic codes from the International Classification of Primary Care (ICPC-2) and hospitalizations and outpatient specialist consultations registered in the National Patient Registry (ICD-10). RESULTS: Low parental income during childhood was associated with a higher risk of being diagnosed with several chronic and pain-related disorders, as well as hospitalization, but not overall primary health care use. Absolute differences were largest for disorders related to musculoskeletal pain, injuries, and depression (7-9 percentage point difference). There were also differences for chronic disorders such as hypertension (8%, CI 7.9-8.5 versus 4%, CI 4.1-4.7) and diabetes (3.2%, CI 3.0-3.4 versus 1.4%, CI 1.2-1.6). There was no difference in consultations related to respiratory disorders (20.9%, CI 20.4-21.5 versus 19.7%, CI 19.2-20.3). Childhood characteristics (parental education, low birth weight, and parental marital status) and own adult characteristics (education and income) explained a large share of the association. CONCLUSIONS: Children growing up at the bottom of the parental income distribution, compared to children in the top of the income distribution, had a two- to threefold increase in somatic and psychological disorders measured in adulthood. This shows that health inequalities by socioeconomic family background persist in a Scandinavian welfare-state context with universal access to health care.

Evaluation of eleven rapid tests for detection of antibodies against SARS-CoV-2.

Objectives: SARS-CoV-2, causing COVID-19, has emerged to cause a human pandemic. Detection of SARS-CoV-2 in respiratory samples by using PCR is the standard laboratory diagnostic tool. Our aim was to perform a limited evaluation of the diagnostic performance and user-friendliness of eleven rapid tests for detection of antibodies against SARS-CoV-2. Methods: All participants were tested with PCR against SARS-CoV-2 at a clinical microbiology laboratory. Comparing with results from PCR tests, we evaluated the rapid tests' performances in three arms; 1) 20 hospitalized patients with PCR-confirmed COVID-19, 2) 23 recovered outpatients with former PCR-confirmed COVID-19, and 3) 49 participants with suspected COVID-19 presenting at a primary care emergency room. Results: All eleven tests detected antibodies in hospitalized COVID-19 patients, though with varying sensitivities. In former outpatients recovered from COVID-19, there were differences between tests in the immunoglobulin type G (IgG) sensitivity, with five tests having a sensitivity below 65%. In participants with suspected COVID-19 infection, the rapid tests had very low sensitivities. Most rapid tests were easy to perform and interpret. Conclusions: Rapid tests were not suited as stand-alone tests to detect present infection in a Norwegian primary care emergency room population. All the rapid tests were able to detect SARS-CoV-2 antibodies, although sensitivities varied and were generally higher in the study arm of more severely affected participants. Rapid tests with high IgG sensitivity (and specificity) may be useful for confirmation of past infection. An independent evaluation should be performed in the intended population before introducing a rapid test.

Availability and analytical quality of hemoglobin A1c point-of-care testing in general practitioners' offices are associated with better glycemic control in type 2 diabetes.

Background It is not clear if point-of-care (POC) testing for hemoglobin A1c (HbA1c) is associated with glycemic control in type 2 diabetes. Methods In this cross-sectional study, we linked general practitioner (GP) data on 22,778 Norwegian type 2 diabetes patients to data from the Norwegian Organization for Quality Improvement of Laboratory Examinations. We used general and generalized linear mixed models to investigate if GP offices' availability (yes/no) and analytical quality of HbA1c POC testing (average yearly "trueness score", 0-4), as well as frequency of participation in HbA1c external quality assurance (EQA) surveys, were associated with patients' HbA1c levels during 2014-2017. Results Twenty-eight out of 393 GP offices (7%) did not perform HbA1c POC testing. After adjusting for confounders, their patients had on average 0.15% higher HbA1c levels (95% confidence interval (0.04-0.27) (1.7 mmol/mol [0.5-2.9]). GP offices participating in one or two yearly HbA1c EQA surveys, rather than the maximum of four, had patients with on average 0.17% higher HbA1c levels (0.06, 0.28) (1.8 mmol/mol [0.6, 3.1]). For each unit increase in the GP offices' HbA1c POC analytical trueness score, the patients' HbA1c levels were lower by 0.04% HbA1c (-0.09, -0.001) (-0.5 mmol/mol [-1.0, -0.01]). Conclusions Novel use of validated patient data in combination with laboratory EQA data showed that patients consulting GPs in offices that perform HbA1c POC testing, participate in HbA1c EQA surveys, and maintain good analytical quality have lower HbA1c levels. Accurate HbA1c POC results, available during consultations, may improve diabetes care.

Parental education and the risk of cerebral palsy for children: an evaluation of causality.

AIM: To explore whether increasing parental education has a causal effect on risk of cerebral palsy (CP) in the child, or whether unobserved confounding is a more likely explanation. METHOD: We used data from Norwegian registries on approximately 1.5 million children born between 1967 and 2011. We compared results from a traditional cohort design with results from a family-based matched case-control design, in which children with CP were matched to their first cousins without CP. In addition, we performed a simulation study to assess the role of unobserved confounding. RESULTS: In the cohort design, the odds of CP were reduced in children of mothers and fathers with higher education (adjusted odds ratio [OR] 0.67, 95% confidence interval [CI] 0.60-0.75 for maternal education, and adjusted OR 0.75, 95% CI 0.67-0.85 for paternal education). In the family-based case-control design, only an association for maternal education remained (adjusted OR 0.80, 95% CI 0.64-0.99). Results from a simulation study suggested that this association could be explained by unobserved confounding. INTERPRETATION: A causal effect of obtaining higher education on risk of CP in the child is unlikely. Results stress the importance of continued research on the role of genetic and environmental risk factors that vary by parents' educational level. WHAT THIS PAPER ADDS: Children of higher-educated parents had significantly lower odds of cerebral palsy (CP). There was no evidence of difference in risk of CP within first cousins whose mothers or fathers had different educational levels. Association between parental education and odds of CP did not reflect a causal effect.

Spirometry in chronic obstructive pulmonary disease in Norwegian general practice.

BACKGROUND: General practitioners (GPs) in Norway increasingly use spirometry diagnostically as well as in follow up of patients with respiratory complaints, but little is known about their skills and knowledge in this area. The aim of the present study was to investigate how GPs interpret a case history and spirometry recordings of a patient with chronic obstructive pulmonary disease (COPD), and their knowledge about their own spirometer. METHODS: A web-based survey, consisting of a case history and spirometry recordings of a patient with COPD, was distributed to the 4700 members of the Norwegian GP Association. In addition to background information about themselves and their spirometer, topics included whether they requested, and how they interpreted, a spirometry reversibility-test, identification of the of most likely diagnosis, and recognition of the spirometry parameters used to diagnose COPD and grade airway obstruction. Immediate feedback was provided for educational purposes. RESULTS: Six hundred thirty GPs responded. Twenty six percent would not request a reversibility test, but 81% identified COPD as the most likely diagnosis. Less than 50% correctly identified the spirometry parameters used for diagnosis of COPD and grading the airway obstruction. One in five (21%) did not know which spirometer was used in their own practice, and 49 and 61% did not know which reference values were used for adults and children, respectively. Participants evaluated the survey as useful (average 74 points on a 0-100 scale) and would like more case-based surveys concerning use of spirometry in the future (average 91 points). CONCLUSION: In this cohort of self-selected GPs, probably more interested in respiratory medicine than the average GP, we identified several problem areas and gaps in knowledge regarding the use of spirometry.

Disease burden in Norway in 2016. / Sykdomsbyrden i Norge i 2016.

BAKGRUNN: For å kunne møte helseutfordringer i befolkningen trenger vi oversikt over befolkningens helsetilstand. I Norge har vi tradisjonelt hatt god oversikt over dødsårsaker, men vi vet mindre om byrden fra tilstander som medfører sykelighet, såkalt ikke-dødelig helsetap. Vårt mål var å beskrive den totale sykdomsbyrden i Norge i 2016, utviklingen de siste ti årene samt kjønnsforskjeller i sykdomsbyrde. MATERIALE OG METODE: Vi brukte resultater fra det globale sykdomsbyrdeprosjektet Global Burden of Diseases, Injuries and Risk Factors Study (GBD), som kvantifiserer ikke-dødelig helsetap slik at det kan måles på samme skala som dødelighet i form av tapte leveår. Summen av tapte leveår og ikke-dødelig helsetap gir sykdomsbyrdemålet helsetapsjusterte leveår (DALY). RESULTATER: Ikke-smittsomme sykdommer som hjerte- og karsykdom, kreft, kronisk obstruktiv lungesykdom og demens var viktige årsaker til tapte leveår hos begge kjønn i Norge i 2016. Ikke-dødelig helsetap utgjorde 52 % av sykdomsbyrden målt i helsetapsjusterte leveår. Spesielt muskel- og skjelettsykdommer, psykiske lidelser og ruslidelser var viktige. De siste ti årene har sykdomsbyrden (i aldersjusterte rater) sunket for mange tilstander som medfører tapte leveår, men ikke for tilstander som gir ikke-dødelig helsetap. FORTOLKNING: Ikke-dødelig helsetap utgjør en stor og økende andel av sykdomsbyrden i den norske befolkningen, noe som vil gi nye utfordringer for helsevesenet.

Intake of Caffeinated Soft Drinks before and during Pregnancy, but Not Total Caffeine Intake, Is Associated with Increased Cerebral Palsy Risk in the Norwegian Mother and Child Cohort Study.

BACKGROUND: Postnatal administration of caffeine may reduce the risk of cerebral palsy (CP) in vulnerable low-birth-weight neonates. The effect of antenatal caffeine exposure remains unknown. OBJECTIVE: We investigated the association of intake of caffeine by pregnant women and risk of CP in their children. METHODS: The study was based on The Norwegian Mother and Child Cohort Study, comprising >100,000 live-born children, of whom 222 were subsequently diagnosed with CP. Mothers reported their caffeine consumption in questionnaires completed around pregnancy week 17 (102,986 mother-child pairs), week 22 (87,987 mother-child pairs), and week 30 (94,372 mother-child pairs). At week 17, participants were asked about present and prepregnancy consumption. We used Cox regression models to estimate associations between exposure [daily servings (1 serving = 125 mL) of caffeinated coffee, tea, and soft drinks and total caffeine consumption] and CP in children, with nonconsumers as the reference group. Models included adjustment for maternal age and education, medically assisted reproduction, and smoking, and for each source of caffeine, adjustments were made for the other sources. RESULTS: Total daily caffeine intake before and during pregnancy was not associated with CP risk. High consumption (≥6 servings/d) of caffeinated soft drinks before pregnancy was associated with an increased CP risk (HR: 1.9; 95% CI: 1.2, 3.1), and children of women consuming 3-5 daily servings of caffeinated soft drinks during pregnancy weeks 13-30 also had an increased CP risk (HR: 1.7; 95% CI: 1.1, 2.8). A mean daily consumption of 51-100 mg caffeine from soft drinks during the first half of pregnancy was associated with a 1.9-fold increased risk of CP in children (HR: 1.9; 95% CI: 1.1, 3.6). CONCLUSIONS: Maternal total daily caffeine consumption before and during pregnancy was not associated with CP risk in children. The observed increased risk with caffeinated soft drinks warrants further investigation.

Evaluation of 32 rapid tests for detection of antibodies against SARS-CoV-2.

AIMS: To evaluate the analytical performance of 32 rapid tests for detection of antibodies against coronavirus SARS-CoV-2. MATERIALS AND METHODS: We used at total of 262 serum samples (197 pre-pandemic and 65 convalescent COVID-19), and three criteria to evaluate the rapid tests under standardized and optimal conditions: (i) Immunoglobulin G (IgG) specificity "good" if lower limit of the 95% confidence interval was ≥ 97.0%, "acceptable" if point estimate was ≥ 97.0%, otherwise "not acceptable". (ii) IgG sensitivity "good" if point estimate was ≥ 90.0%, "acceptable" if ≥ 85.0%, otherwise "not acceptable". (iii) User-friendliness "not acceptable" if complicated to perform or difficult to read result, otherwise "good". We also included partial evaluations of three automated immunoassay systems. RESULTS: Sensitivity and specificity varied considerably; IgG specificity between 90.9% (85.9-94.2) and 100% (97.7-100.0), and IgG sensitivity between 53.8% (41.9-65.4) and 98.5% (91.0-100.0). Combining our evaluation criteria, none of the 28 rapid tests that detected IgG had an overall performance considered "good", seven tests were considered "acceptable", while 21 tests were considered "not acceptable". Four tests detected only total antibodies and were not given an overall evaluation. IgG sensitivity and/or specificity of the automated immunoassays did not exceed that of many rapid tests. CONCLUSION: When prevalence is low, the most important analytical property is a test's IgG specificity, which must be high to minimize false positive results. Out of 32 rapid tests, none had a performance classified as "good", but seven were classified as "acceptable".

Maternal Chronic Conditions and Risk of Cerebral Palsy in Offspring: A National Cohort Study.

BACKGROUND AND OBJECTIVES: Previous studies suggest that children of mothers with certain chronic conditions may be at increased risk of cerebral palsy (CP). We explored possible associations between 17 maternal chronic conditions and CP in offspring. METHODS: We conducted a prospective cohort study of Norwegian children born in 1990-2012 and surviving to 2 years of age. Information on maternal chronic conditions during pregnancy were extracted from the Medical Birth Registry of Norway (1990-2012). Information on chronic conditions in mothers and fathers recorded in the Norwegian Patient Registry (2008-2014) was available for a subset of children. CP diagnoses were extracted from the National Insurance Scheme (1990-2014) and the Norwegian Patient Registry (2008-2014). We estimated relative risks (RRs) and 95% confidence intervals (CIs) of CP in offspring of parents with chronic conditions compared with the general population using log binominal regression models. RESULTS: A total of 1 360 149 Norwegian children, including 3575 children with CP (2.6 per 1000 live births), fulfilled the inclusion criteria. The highest risk of CP was among offspring of mothers with type 2 diabetes (RR 3.2; 95% CI 1.8-5.4), lupus erythematosus (RR 2.7; 95% CI 0.9-8.3), type 1 diabetes (RR 2.2; 95% CI 1.4-3.4), and Crohn disease (RR 2.1; 95% CI 1.0-4.1) during pregnancy. No increased risks were seen for offspring of fathers with chronic conditions. CONCLUSIONS: Several maternal chronic conditions were associated with increased risk of CP in offspring. Maternal autoimmune disorders carried a particular risk.

Alcohol-attributed disease burden in four Nordic countries between 2000 and 2017: Are the gender gaps narrowing? A comparison using the Global Burden of Disease, Injury and Risk Factor 2017 study.

INTRODUCTION AND AIMS: The gender difference in alcohol use seems to have narrowed in the Nordic countries, but it is not clear to what extent this may have affected differences in levels of harm. We compared gender differences in all-cause and cause-specific alcohol-attributed disease burden, as measured by disability-adjusted life-years (DALY), in four Nordic countries in 2000-2017, to find out if gender gaps in DALYs had narrowed. DESIGN AND METHODS: Alcohol-attributed disease burden by DALYs per 100 000 population with 95% uncertainty intervals were extracted from the Global Burden of Disease database. RESULTS: In 2017, all-cause DALYs in males varied between 2531 in Finland and 976 in Norway, and in females between 620 in Denmark and 270 in Norway. Finland had the largest gender differences and Norway the smallest, closely followed by Sweden. During 2000-2017, absolute gender differences in all-cause DALYs declined by 31% in Denmark, 26% in Finland, 19% in Sweden and 18% in Norway. In Finland, this was driven by a larger relative decline in males than females; in Norway, it was due to increased burden in females. In Denmark, the burden in females declined slightly more than in males, in relative terms, while in Sweden the relative decline was similar in males and females. DISCUSSION AND CONCLUSIONS: The gender gaps in harm narrowed to a different extent in the Nordic countries, with the differences driven by different conditions. Findings are informative about how inequality, policy and sociocultural differences affect levels of harm by gender.

Cesarean section and risk of severe childhood asthma: a population-based cohort study.

OBJECTIVE: To explore the possible association between delivery by cesarean section (CS) and later development of asthma. STUDY DESIGN: A population-based cohort study of 1,756,700 singletons reported to the Medical Birth Registry of Norway between 1967 and 1998, followed up to age 18 years or the year 2002. Exposure was the mode of delivery (spontaneous vaginal, instrumental vaginal, or CS, with planned and emergency CS separately from 1988 onward). Outcome was asthma registered in the National Insurance Scheme, which provides cash benefits to families of children with severe chronic illnesses. We used multivariate Cox proportional hazard models to examine associations between exposure and outcome. RESULTS: The cumulative incidence of asthma was 4.0/1000. Children delivered by CS had a 52% increased risk of asthma compared with spontaneously vaginally delivered children (adjusted hazard ratio [HR] = 1.52; 95% confidence interval [CI] = 1.42 to 1.62). Between 1988 and 1998, planned and emergency CS was associated with a 42% (HR = 1.42; 95% CI = 1.25 to 1.61) and 59% (HR = 1.59; 95% CI = 1.44 to 1.75) increased risk of asthma, respectively. CONCLUSION: We found a moderately increased risk of asthma in the children delivered by CS. The possibly stronger association with emergency CS compared with planned CS could be worth pursuing to investigate possible causal mechanisms.

Reduced fertility after cesarean delivery: a maternal choice.

OBJECTIVE: To explore the association between mode of delivery and subsequent fertility. METHODS: Deliveries registered in the Medical Birth Registry of Norway were linked to mothers through national identification numbers. The study population was 596,341 women who had their first delivery during 1967-1996, and who were followed up through 2003. We compared rates of continuation to a subsequent birth according to mode of previous delivery (cesarean compared with vaginal). RESULTS: If the first child survived the first year of life, cesarean delivery was associated with a significantly reduced probability of a second birth (relative risk [RR] 0.82, 95% confidence interval [CI] 0.81-0.83 during 1967-1981, and RR 0.88, 95% CI 0.88-0.89 during 1982-1996). Following a stillbirth or an infant loss, the association was less strong during 1967-1981 (RR 0.93, 95% CI 0.89-0.97) and no longer significant during 1982-1996 (RR 1.00, 95% CI 0.97-1.03). A similar pattern was observed from the second to the third birth and in subgroup analyses of women with preeclampsia or breech presentation and in an obstetric low-risk group. CONCLUSION: Cesarean delivery was more strongly associated with reduced fertility if the infant survived than if it was stillborn or died. This suggests that the reduced fertility was to a large degree voluntary and not related to the indication, nor to any physical consequence, of the cesarean delivery. LEVEL OF EVIDENCE: II.

Neurodevelopmental Disorders or Early Death in Siblings of Children With Cerebral Palsy.

OBJECTIVES: To explore the presence of shared underlying causes of cerebral palsy (CP) and other neurodevelopmental disorders, by examining risks of other disorders in siblings of children with CP. METHODS: We used Norwegian national registries to identify 1.4 million pairs of full siblings (singletons) and 28 000 sets of twins born from 1967 to 2006, identify stillbirths and neonatal deaths, and find individuals with CP, epilepsy, intellectual disability, autism spectrum disorders, attention-deficit/hyperactivity disorder, blindness, deafness, schizophrenia, and bipolar disorder. Associations between CP in 1 sibling and neurodevelopmental disorders or early death in other siblings were estimated using logistic regression models. RESULTS: There were 5707 neonatal survivors (beyond 28 days) with CP (2.5/1000). These children had substantial comorbidity (eg, 29% had epilepsy). Singleton siblings of (singleton) children with CP had increased risks of neurodevelopmental problems, including epilepsy (odds ratio [OR], 1.8 [95% confidence interval (CI), 1.5-2.5]), intellectual disability (OR, 2.3 [95% CI, 1.8-2.9]), autism spectrum disorders (OR, 1.6 [95% CI, 1.1-2.2]), attention-deficit/hyperactivity disorder (OR 1.3 [95% CI, 1.1-1.6]), blindness (OR 2.4 [95% CI, 1.1-5.4]), and schizophrenia (OR 2.0 [95% CI, 1.2-3.2]). There was no increase in risk of bipolar disorder (OR 1.0 [95% CI, 0.6-1.6]). Families with children with CP also had increased risk of losing another child in the perinatal period (stillbirth OR, 1.8 [95% CI, 1.5- 2.3]; neonatal death OR, 1.7 [95% CI, 1.3-2.2]). Associations were stronger within sets of twins. CONCLUSIONS: Siblings of a child with CP were at increased risk for a variety of other neurodevelopmental morbidities, as well as early death, indicating the presence of shared underlying causes.

Cohort profile: cerebral palsy in the Norwegian and Danish birth cohorts (MOBAND-CP).

PURPOSE: The purpose of MOthers and BAbies in Norway and Denmark cerebral palsy (MOBAND-CP) was to study CP aetiology in a prospective design. PARTICIPANTS: MOBAND-CP is a cohort of more than 210 000 children, created as a collaboration between the world's two largest pregnancy cohorts-the Norwegian Mother and Child Cohort study (MoBa) and the Danish National Birth Cohort. MOBAND-CP includes maternal interview/questionnaire data collected during pregnancy and follow-up, plus linked information from national health registries. FINDINGS TO DATE: Initial harmonisation of data from the 2 cohorts has created 140 variables for children and their mothers. In the MOBAND-CP cohort, 438 children with CP have been identified through record linkage with validated national registries, providing by far the largest such sample with prospectively collected detailed pregnancy data. Several studies investigating various hypotheses regarding CP aetiology are currently on-going. FUTURE PLANS: Additional data can be harmonised as necessary to meet requirements of new projects. Biological specimens collected during pregnancy and at delivery are potentially available for assay, as are results from assays conducted on these specimens for other projects. The study size allows consideration of CP subtypes, which is rare in aetiological studies of CP. In addition, MOBAND-CP provides a platform within the context of a merged birth cohort of exceptional size that could, after appropriate permissions have been sought, be used for cohort and case-cohort studies of other relatively rare health conditions of infants and children.

Maternal Prepregnancy BMI and Risk of Cerebral Palsy in Offspring.

OBJECTIVES: To investigate the association between maternal pre-pregnancy BMI and risk of cerebral palsy (CP) in offspring. METHODS: The study population consisted of 188 788 children in the Mothers and Babies in Norway and Denmark CP study, using data from 2 population-based, prospective birth cohorts: the Norwegian Mother and Child Cohort Study and the Danish National Birth Cohort. Prepregnancy BMI was classified as underweight (BMI <18.5), lower normal weight (BMI 18.5-22.9), upper normal weight (BMI 23.0-24.9), overweight (BMI 25.0-29.9), and obese (BMI ≥30). CP diagnoses were obtained from the national CP registries. Associations between maternal prepregnancy BMI and CP in offspring were investigated by using log-binomial regression models. RESULTS: The 2 cohorts had 390 eligible cases of CP (2.1 per 1000 live-born children). Compared with mothers in the lower normal weight group, mothers in the upper normal group had a 40% excess risk of having a child with CP (relative risk [RR], 1.35; 95% confidence interval [CI], 1.03-1.78). Excess risk was 60% (RR, 1.56; 95% CI, 1.21-2.01) for overweight mothers and 60% (RR, 1.55; 95% CI 1.11-2.18) for obese mothers. The risk of CP increased ∼4% for each unit increase in BMI (RR, 1.04; 95% CI, 1.02-1.06). Estimates changed little with adjustment for mother's occupational status, age, and smoking habits. CONCLUSIONS: Higher prepregnancy maternal BMI was associated with increased risk of CP in offspring.

Familial risk of cerebral palsy: population based cohort study.

OBJECTIVE: To investigate risks of recurrence of cerebral palsy in family members with various degrees of relatedness to elucidate patterns of hereditability. DESIGN: Population based cohort study. SETTING: Data from the Medical Birth Registry of Norway, linked to the Norwegian social insurance scheme to identify cases of cerebral palsy and to databases of Statistics Norway to identify relatives. PARTICIPANTS: 2,036,741 Norwegians born during 1967-2002, 3649 of whom had a diagnosis of cerebral palsy; 22,558 pairs of twins, 1,851,144 pairs of first degree relatives, 1,699,856 pairs of second degree relatives, and 5,165,968 pairs of third degree relatives were identified. MAIN OUTCOME MEASURE: Cerebral palsy. RESULTS: If one twin had cerebral palsy, the relative risk of recurrence of cerebral palsy was 15.6 (95% confidence interval 9.8 to 25) in the other twin. In families with an affected singleton child, risk was increased 9.2 (6.4 to 13)-fold in a subsequent full sibling and 3.0 (1.1 to 8.6)-fold in a half sibling. Affected parents were also at increased risk of having an affected child (6.5 (1.6 to 26)-fold). No evidence was found of differential transmission through mothers or fathers, although the study had limited power to detect such differences. For people with an affected first cousin, only weak evidence existed for an increased risk (1.5 (0.9 to 2.7)-fold). Risks in siblings or cousins were independent of sex of the index case. After exclusion of preterm births (an important risk factor for cerebral palsy), familial risks remained and were often stronger. CONCLUSIONS: People born into families in which someone already has cerebral palsy are themselves at elevated risk, depending on their degree of relatedness. Elevated risk may extend even to third degree relatives (first cousins). The patterns of risk suggest multifactorial inheritance, in which multiple genes interact with each other and with environmental factors. These data offer additional evidence that the underlying causes of cerebral palsy extend beyond the clinical management of delivery.

Establishing a network of specialist Porphyria centres - effects on diagnostic activities and services.

BACKGROUND: The porphyrias are a heterogeneous group of rare metabolic diseases. The full spectrum of porphyria diagnostics is usually performed by specialized porphyria laboratories or centres. The European Porphyria Initiative (EPI), a collaborative network of porphyria centres formed in 2001, evolved in 2007 into the European Porphyria Network (EPNET), where participating centres are required to adhere to agreed quality criteria. The aim of this study was to examine the state and distribution of porphyria diagnostic services in 2009 and to explore potential effects of increased international collaboration in the field of these rare diseases in the period 2006-2009. METHODS: Data on laboratory, diagnostic and clinical activities and services reported to EPI/EPNET in yearly activity reports during 2006 through 2009 were compared between reporting centres, and possible time trends explored. RESULTS: Thirty-five porphyria centres from 22 countries, five of which were non-European associate EPNET members, filed one or more activity reports to EPI/EPNET during the study period. Large variations between centres were observed in the analytical repertoire offered, numbers of analyses performed and type and number of staff engaged. The proportion of centres fulfilling the minimum criteria set by EPNET to be classified as a specialist porphyria centre increased from 80% to 94% during the study period. CONCLUSIONS: Porphyria services are unevenly distributed, and some areas are probably still lacking in specialized porphyria services altogether. However, improvements in the quality of diagnostic services provided by porphyria centres participating in EPI/EPNET were observed during 2006 through 2009.

Caesarean section among relatives.

BACKGROUND: Caesarean section rates are increasing. It is not clear whether a familial predisposition to caesarean section exists. METHODS: Births registered in the Medical Birth Registry of Norway during 1967-2005 were linked to construct 440,236 grandmother-parent units and 275,001 same sex full sibling units. Log-binomial regression models were used to explore associations. RESULTS: A mother born by caesarean section had a 55% increased risk of having her first child by caesarean section [adjusted relative risk (RR) 1.55, 95% CI 1.48-1.62]. The same was not found for fathers born by caesarean section (RR 1.02, 95% CI 0.96-1.10). A younger sister, whose older sister had her first child by caesarean section, had a 45% increased risk of having her first child by caesarean section (RR 1.45, 95% CI 1.40-1.51). If an older brother had his first child by caesarean, this did not constitute an increased risk for the younger brother's partner (RR 1.02, 95% CI 0.97-1.08). Similar associations were found in the subgroups of obstetric low risk deliveries. CONCLUSIONS: A female-to-female familial predisposition to caesarean section was observed. It could be caused by biologic inheritance, primarily working through maternal alleles and/or environmental factors. The results imply that both mechanisms could be important.