H Dolk

Publications of H Dolk

• Termination of pregnancy for fetal anomaly after 23 weeks of gestation: a European register-based study.

  Authors: E Garne, B Khoshnood, M Loane, Pa Boyd, H Dolk

  BJOG : an international journal of obstetrics and gynaecology. 05/2010; 117(6):660-6.

  To determine the prevalence of termination of pregnancy for fetal anomaly (TOPFA) after 23 weeks of gestation in European countries, and describe the spectrum of anomalies for which late TOPFA isTo determine the prevalence of termination of pregnancy for fetal anomaly (TOPFA) after 23 weeks of gestation in European countries, and describe the spectrum of anomalies for which late TOPFA is recorded. Population-based study. Twelve European countries. Nineteen registries of congenital anomaly in 12 European countries between 2000 and 2005. The number of total births covered was 2 695 832. TOPFAs in singleton pregnancies from the European Surveillance of Congenital Anomalies and Twins (EUROCAT) database. The prevalence of TOPFA and type of anomaly. There were 10 233 TOPFAs, 678 (6.6%) of which were performed at 24 weeks or more. The rate of TOPFA before 24 weeks was 3.4 per 1000 births, at 24-25 weeks 0.14 per 1000 births and at 26 weeks or more 0.11 per 1000 births. There was significant variation in the prevalence of TOPFA at >or=24 weeks between countries (P < 0.001), with all countries in the range 0-0.55 per 1000 births, except France (Paris) at 2.65 per 1000 births. The large majority of late TOPFAs had a gestational age of 24-27 weeks (516/678, 76%). The proportion of TOPFAs from 24 weeks or more varied by type of anomaly, with 4% of all TOPFAs for chromosomal anomalies and 9% of all TOPFAs for nonchromosomal anomalies resulting in late TOPFA (P < 0.001). For transposition of the great arteries, single ventricle, hypoplastic left heart and hydrocephaly, the percentage of late TOPFA was 12-23%. The median time interval between diagnosis and late TOPFA was 2 weeks for most anomalies, but longer (>or=5 weeks) for diaphragmatic hernia, omphalocoele, arthrogryposis multiplex and Turner's syndrome. Late TOPFA is rare in Europe, and varies in prevalence between countries. Compared with earlier TOPFA, late TOPFA is more often performed for a nonchromosomal isolated major structural anomaly and less often for a fetus with a chromosomal syndrome or multiple anomalies.

• Maternal age-specific risk of non-chromosomal anomalies.

  Authors: M Loane, H Dolk, J.K. Morris

  BJOG : an international journal of obstetrics and gynaecology. 07/2009; 116(8):1111-9.

  OBJECTIVES: To determine the excess risk of non-chromosomal congenital anomaly (NCA) among teenage mothers and older mothers. DESIGN AND SETTING: Population-based prevalence study using data fromOBJECTIVES: To determine the excess risk of non-chromosomal congenital anomaly (NCA) among teenage mothers and older mothers. DESIGN AND SETTING: Population-based prevalence study using data from EUROCAT congenital anomaly registers in 23 regions of Europe in 15 countries, covering a total of 1.75 million births from 2000 to 2004. PARTICIPANTS: A total of 38,958 cases of NCA that were live births, fetal deaths with gestational age > or = 20 weeks or terminations of pregnancy following prenatal diagnosis of a congenital anomaly. MAIN OUTCOME MEASURES: Prevalence of NCA according to maternal age, and relative risk (RR) of NCA and 84 standard NCA subgroups compared with mothers aged 25-29. RESULTS: The crude prevalence of all NCA was 26.5 per 1000 births in teenage mothers (<20 years), 23.8 for mothers 20-24 years, 22.5 for mothers 25-29 years, 21.5 for mothers 30-34 years, 21.4 for mothers 35-39 years and 22.6 for mothers 40-44 years. The RR adjusted for country for teenage mothers was 1.11 (95% CI 1.06-1.17); 0.99 (95% CI 0.96-1.02) for mothers 35-39; and 1.01 (95% CI 0.95-1.07) for mothers 40-44. The pattern of maternal age-related risk varied significantly between countries: France, Ireland and Portugal had higher RR for teenage mothers, Germany and Poland had higher RR for older mothers. The maternal age-specific RR varied for different NCAs. Teenage mothers were at a significantly greater risk (P < 0.01) of gastroschisis, maternal infection syndromes, tricuspid atresia, anencephalus, nervous system and digestive system anomalies while older mothers were at a significantly greater risk (P < 0.01) of fetal alcohol syndrome, encephalocele, oesophageal atresia and thanatophoric dwarfism. CONCLUSIONS: Clinical and public health interventions are needed to reduce environmental risk factors for NCA, giving special attention to young mothers among whom some risk factors are more prevalent. Reassurance can be given to older mothers that their age in itself does not confer extra risk for NCA.

• Does lamotrigine use in pregnancy increase orofacial cleft risk relative to other malformations?

  Authors: H Dolk, J. Jentink, M Loane, J Morris, L.T.W. de Jong-van den Berg

  Neurology. 09/2008; 71(10):714-22.

  To investigate whether first trimester exposure to lamotrigine (LTG) monotherapy is specifically associated with an increased risk of orofacial clefts (OCs) relative to other malformations, inTo investigate whether first trimester exposure to lamotrigine (LTG) monotherapy is specifically associated with an increased risk of orofacial clefts (OCs) relative to other malformations, in response to a signal regarding increased OC risk. Population-based case-control study with malformed controls based on EUROCAT congenital anomaly registers. The study population covered 3.9 million births from 19 registries 1995-2005. Registrations included congenital anomaly among livebirths, stillbirths, and terminations of pregnancy following prenatal diagnosis. Cases were 5,511 nonsyndromic OC registrations, of whom 4,571 were isolated, 1,969 were cleft palate (CP), and 1,532 were isolated CP. Controls were 80,052 nonchromosomal, non-OC registrations. We compared first trimester LTG and antiepileptic drug (AED) use vs nonepileptic non-AED use, for mono and polytherapy, adjusting for maternal age. An additional exploratory analysis compared the observed and expected distribution of malformation types associated with LTG use. There were 72 LTG exposed (40 mono- and 32 polytherapy) registrations. The ORs for LTG monotherapy vs no AED use were 0.67 (95% CI 0.10-2.34) for OC relative to other malformations, 0.80 (95% CI 0.11-2.85) for isolated OC, 0.79 (95% CI 0.03-4.35) for CP, and 1.01 (95% CI 0.03-5.57) for isolated CP. ORs for any AED use vs no AED use were 1.43 (95% CI 1.03-1.93) for OC, 1.21 (95% CI 0.82-1.72) for isolated OC, 2.37 (95% CI 1.54-3.43) for CP, and 1.86 (95% CI 1.07-2.94) for isolated CP. The distribution of other nonchromosomal malformation types with LTG exposure was similar to non-AED exposed. We find no evidence of a specific increased risk of isolated orofacial clefts relative to other malformations due to lamotrigine (LTG) monotherapy. Our study is not designed to assess whether there is a generalized increased risk of malformations with LTG exposure.

• Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome.

  Authors: P A Boyd, C DeVigan, B Khoshnood, M Loane, E Garne, H Dolk

  BJOG : an international journal of obstetrics and gynaecology. 06/2008; 115(6):689-96.

  OBJECTIVE: To 'map' the current (2004) state of prenatal screening in Europe. DESIGN: (i) Survey of country policies and (ii) analysis of data from EUROCAT (European Surveillance of CongenitalOBJECTIVE: To 'map' the current (2004) state of prenatal screening in Europe. DESIGN: (i) Survey of country policies and (ii) analysis of data from EUROCAT (European Surveillance of Congenital Anomalies) population-based congenital anomaly registers. SETTING: Europe. POPULATION: Survey of prenatal screening policies in 18 countries and 1.13 million births in 12 countries in 2002-04. METHODS: (i) Questionnaire on national screening policies and termination of pregnancy for fetal anomaly (TOPFA) laws in 2004. (ii) Analysis of data on prenatal detection and termination for Down's syndrome and neural tube defects (NTDs) using the EUROCAT database. MAIN OUTCOME MEASURES: Existence of national prenatal screening policies, legal gestation limit for TOPFA, prenatal detection and termination rates for Down's syndrome and NTD. RESULTS: Ten of the 18 countries had a national country-wide policy for Down's syndrome screening and 14/18 for structural anomaly scanning. Sixty-eight percent of Down's syndrome cases (range 0-95%) were detected prenatally, of which 88% resulted in termination of pregnancy. Eighty-eight percent (range 25-94%) of cases of NTD were prenatally detected, of which 88% resulted in termination. Countries with a first-trimester screening policy had the highest proportion of prenatally diagnosed Down's syndrome cases. Countries with no official national Down's syndrome screening or structural anomaly scan policy had the lowest proportion of prenatally diagnosed Down's syndrome and NTD cases. Six of the 18 countries had a legal gestational age limit for TOPFA, and in two countries, termination of pregnancy was illegal at any gestation. CONCLUSIONS: There are large differences in screening policies between countries in Europe. These, as well as organisational and cultural factors, are associated with wide country variation in prenatal detection rates for Down's syndrome and NTD.

• Trends and geographic inequalities in the prevalence of Down syndrome in Europe, 1980-1999.

  Authors: H Dolk, M Loane, E Garne, H de Walle, A Queisser-Luft, C De Vigan, M C Addor, B Gener, M Haeusler, H Jordan, D Tucker, C Stoll, M Feijoo, D Lillis, F Bianchi

  Revue d'épidémiologie et de santé publique. 11/2005; 53 Spec No 2:2S87-95.

  EUROCAT is a network of population-based registries for the epidemiologic surveillance of congenital anomalies covering approximately one quarter of births in the European Union. Down syndromeEUROCAT is a network of population-based registries for the epidemiologic surveillance of congenital anomalies covering approximately one quarter of births in the European Union. Down syndrome constitutes approximately 8% of cases of registered congenital anomaly in Europe, with over 7000 affected pregnancies in the 15 current member states of the European Union each year. In this paper, we aim to examine trends in the live birth prevalence of Down syndrome in Europe in the light of trends in maternal age and in prenatal diagnosis. Descriptive analysis of data from 24 EUROCAT registries, covering 8.3 million births 1980-99. Cases include live births, stillbirths and terminations of pregnancy following prenatal diagnosis. Since 1980, the proportion of births to mothers of 35 years of age and over has risen quite dramatically from 8 to 14% for the European Union as a whole, with steeper rises in some regions. By 1995-1999, the proportion of "older" mothers varied between regions from 10% to 25%, and the total prevalence (including terminations of pregnancy) of Down syndrome varied from 1 to 3 per 1000 births. Some European regions have shown a more than twofold increase in total prevalence of Down syndrome since 1980. The proportion of cases of Down syndrome which were prenatally diagnosed followed by termination of pregnancy in 1995-1999 varied from 0% in the three regions of Ireland and Malta where termination of pregnancy is illegal, to less than 50% in 14 further regions, to 77% in Paris. The extent to which terminations of pregnancy were concen trated among older mothers varied between regions. The live birth prevalence has since 1980 increasingly diverged from the rising total prevalence, in some areas remaining approximately stable, in others decreasing over time. The rise in average maternal age in Europe has brought with it an increase in the number of pregnancies affected by Down syndrome. The widespread practice of prenatal screening and termination of pregnancy has in most of the regions covered by EUROCAT counteracted the effect of maternal age in its effect on live birth prevalence. Under the joint influences of maternal age and prenatal screening the pattern of geographic inequalities in Down syndrome live birth prevalence in Europe has also been changed.

• Prevalence of congenital anomalies in five British regions, 1991-99.

  Authors: J Rankin, S Pattenden, L Abramsky, P Boyd, H Jordan, D Stone, M Vrijheid, D Wellesley, H Dolk

  Archives of disease in childhood. Fetal and neonatal edition. 10/2005; 90(5):F374-9.

  AIMS: To describe trends in total and live birth prevalence, regional differences in prevalence, and outcome of pregnancy of selected congenital anomalies. METHODS: Population based registry study ofAIMS: To describe trends in total and live birth prevalence, regional differences in prevalence, and outcome of pregnancy of selected congenital anomalies. METHODS: Population based registry study of 839,521 births to mothers resident in five geographical areas of Britain during 1991-99. Main outcome measures were: total and live birth prevalence; pregnancy outcome; proportion of stillbirths due to congenital anomalies; and secular trends. RESULTS: The sample consisted of 10,844 congenital anomalies, giving a total prevalence of 129 per 10,000 registered births (95% CI 127 to 132). Live birth prevalence was 82.2 per 10,000 births (95% CI 80.3 to 84.2) and declined significantly with time. The proportion of all stillbirths with a congenital anomaly was 10.5% (453 stillbirths). The proportion of pregnancies resulting in a termination increased from 27% (289 cases) in 1991 to 34.7% (384 cases) in 1999, whereas the proportion of live births declined from 68.2% (730 cases) to 58.5% (648 cases). Although similar rates of congenital anomaly groups were notified to the registers, variation in rates by register was present. There was a secular decline in the total prevalence of non-chromosomal and an increase in chromosomal anomalies. CONCLUSIONS: Regional variation exists in the prevalence of specific congenital anomalies. For some anomalies this can be partially explained by ascertainment variation. For others (neural tube defects, diaphragmatic hernia, gastroschisis), higher prevalence rates in the northern regions (Glasgow and Northern) were true differences. Live birth prevalence declined over the study due to an increase in terminations of pregnancy.

• EUROCAT: 25 years of European surveillance of congenital anomalies.

  Authors: H Dolk

  Archives of disease in childhood. Fetal and neonatal edition. 10/2005; 90(5):F355-8.

  The surveillance of congenital anomalies serves two main purposes: to facilitate the identification of teratogenic (malformation causing) exposures and to assess the impact of primary prevention andThe surveillance of congenital anomalies serves two main purposes: to facilitate the identification of teratogenic (malformation causing) exposures and to assess the impact of primary prevention and prenatal screening policy and practice at a population level. EUROCAT, the European network of population based registers for the epidemiological surveillance of congenital anomalies, now covers 1.2 million births per year, a quarter of births in Europe. The added value of European collaboration is particularly great for congenital anomalies, coming from the opportunity to pool data, to compare data between regions and countries, to give a common response to European public health questions, and to share expertise and resources, including computing tools. EUROCAT provides essential epidemiological information on congenital anomalies in Europe, facilitates the early warning of teratogenic exposures, evaluates the effectiveness of primary prevention, assesses the impact of developments in prenatal screening, acts as an information and resource centre regarding clusters, provides a ready collaborative network and infrastructure for research, and acts as a catalyst for the setting up of registries throughout Europe.

• Congenital anomaly surveillance in England--ascertainment deficiencies in the national system.

  Authors: P A Boyd, B Armstrong, H Dolk, B Botting, S Pattenden, L Abramsky, J Rankin, M Vrijheid, D Wellesley

  BMJ (Clinical research ed.). 02/2005; 330(7481):27.

  OBJECTIVE: Firstly, to assess the completeness of ascertainment in the National Congenital Anomaly System (NCAS), the basis for congenital anomaly surveillance in England and Wales, and its variationOBJECTIVE: Firstly, to assess the completeness of ascertainment in the National Congenital Anomaly System (NCAS), the basis for congenital anomaly surveillance in England and Wales, and its variation by defect, geographical area, and socioeconomic deprivation. Secondly, to assess the impact of the lack of data on pregnancies terminated because of fetal anomaly. DESIGN: Comparison of the NCAS with four local congenital anomaly registers in England. SETTING: Four regions in England covering some 109,000 annual births. PARTICIPANTS: Cases of congenital anomalies registered in the NCAS (live births and stillbirths) and independently registered in the four local registers (live births, stillbirths, fetal losses from 20 weeks' gestation, and pregnancies terminated after prenatal diagnosis of fetal anomaly). MAIN OUTCOME MEASURE: The ratio of cases identified by the national register to those in local registry files, calculated for different specified anomalies, for whole registry areas, and for hospital catchment areas within registry boundaries. RESULTS: Ascertainment by the NCAS (compared with data from local registers, from which terminations of pregnancy were removed) was 40% (34% for chromosomal anomalies and 42% for non-chromosomal anomalies) and varied markedly by defect, by local register, and by hospital catchment area, but not by area deprivation. When terminations of pregnancy were included in the register data, ascertainment by NCAS was 27% (19% for chromosomal anomalies and 31% for non-chromosomal anomalies), and the geographical variation was of a similar magnitude. CONCLUSION: The surveillance of congenital anomalies in England is currently inadequate because ascertainment to the national register is low and non-uniform and because no data exist on termination of pregnancy resulting from prenatal diagnosis of fetal anomaly.

• Prenatal diagnosis of severe structural congenital malformations in Europe.

  Authors: E Garne, M Loane, H Dolk, C De Vigan, G Scarano, D Tucker, C Stoll, B Gener, A Pierini, V Nelen, C Rösch, Y Gillerot, M Feijoo, R Tincheva, A Queisser-Luft, M C Addor, C Mosquera, M Gatt, I Barisic

  Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 02/2005; 25(1):6-11.

  OBJECTIVES: To assess at a population-based level the frequency with which severe structural congenital malformations are detected prenatally in Europe and the gestational age at detection, and toOBJECTIVES: To assess at a population-based level the frequency with which severe structural congenital malformations are detected prenatally in Europe and the gestational age at detection, and to describe regional variation in these indicators. METHODS: In the period 1995-1999, data were obtained from 17 European population-based registries of congenital malformations (EUROCAT). Included were all live births, fetal deaths and terminations of pregnancy diagnosed with one or more of the following malformations: anencephalus, encephalocele, spina bifida, hydrocephalus, transposition of great arteries, hypoplastic left heart, limb reduction defect, bilateral renal agenesis, diaphragmatic hernia, omphalocele and gastroschisis. RESULTS: The 17 registries reported 4366 cases diagnosed with the 11 severe structural malformations and of these 2300 were live births (53%), 181 were fetal deaths (4%) and 1863 were terminations of pregnancy (43%); in 22 cases pregnancy outcome was unknown. The overall prenatal detection rate was 64% (range, 25-88% across regions). The proportion of terminations of pregnancy varied between regions from 15% to 59% of all cases. Gestational age at discovery for prenatally diagnosed cases was less than 24 weeks for 68% (range, 36-88%) of cases. There was a significant relationship between high prenatal detection rate and early diagnosis (P < 0.0001). For individual malformations, the prenatal detection rate was highest for anencephalus (469/498, 94%) and lowest for transposition of the great arteries (89/324, 27%). Termination of pregnancy was performed in more than half of the prenatally diagnosed cases, except for those with transposition of the great arteries, diaphragmatic hernia and gastroschisis, in which 30-40% of the pregnancies with a prenatal diagnosis were terminated. CONCLUSION: European countries currently vary widely in the provision and uptake of prenatal screening and its quality, as well as the "culture" in terms of decision to continue the pregnancy. This inevitably contributes to variation between countries in perinatal and infant mortality and in childhood prevalence and cost to health services of congenital anomalies.

• An aetiological classification of birth defects for epidemiological research.

  Authors: D Wellesley, P Boyd, H Dolk, S Pattenden

  Journal of medical genetics. 02/2005; 42(1):54-7.

  BACKGROUND: Congenital anomaly registers collect data on antenatally and postnatally detected anomalies for surveillance, research, and public health purposes. Each anomaly is coded using theBACKGROUND: Congenital anomaly registers collect data on antenatally and postnatally detected anomalies for surveillance, research, and public health purposes. Each anomaly is coded using the International Statistical Classification of Diseases and Related Health Problems (ICD-9/ICD-10) based on body systems, allowing accurate comparisons between registers for individual anomalies. When commencing an environmental, epidemiological study, it became clear to us that there is no standard classification that takes aetiology into account. This paper describes a new classification for use in studies addressing aetiology. METHOD: A classification system was evolved and piloted using cases in a study of geographical variation in congenital anomaly prevalence.1 Cases that were difficult to categorise were noted, and after discussion with a team of experts, the classification was adjusted accordingly.Results and CONCLUSION: A robust, hierarchical method of classifying birth defects into eight categories has been produced, for use at source of data registration in conjunction with, but independent of, ICD coding.

• What influences physiotherapy use by children with cerebral palsy?

  Authors: J Parkes, N Hill, H Dolk, M Donnelly

  Child: care, health and development. 04/2004; 30(2):151-60.

  AIM: To investigate factors that influence the frequency of physiotherapy currently used by a population of children with moderate to severe cerebral palsy (CP). METHODS: A survey using a postalAIM: To investigate factors that influence the frequency of physiotherapy currently used by a population of children with moderate to severe cerebral palsy (CP). METHODS: A survey using a postal questionnaire was sent to 212 parents of children with moderate to severe CP. The families were identified from a geographically defined case register of children with CP in Northern Ireland (the Northern Ireland Cerebral Palsy Register). Eighty-five per cent of parents responded. One-third of parent responses regarding their child's use of physiotherapy were validated with their child's physiotherapist and the level of agreement was high. RESULTS: Ninety-four per cent (169/180) of children received conventional physiotherapy from a statutory source during the school term. Of these, 61% (104/169) used 'intense' levels of physiotherapy (defined as at least twice a week). A higher proportion of intense users were children with severe CP compared with moderate CP (69% vs. 47%; P < 0.01); with moderate intellectual impairment (IQ </= 70 > 50) compared with severe (IQ </= 50) or no intellectual impairment (IQ > 70) (81% vs. 64% vs. 39% respectively; P < 0.01) and at schools for physical disability (PD) compared with severe learning disability (SLD) or mainstream (MS) schools (82% vs. 66% vs. none respectively; P < 0.001). After controlling for severity of motor impairment and the presence and severity of intellectual impairment, children with CP at MS schools used on average significantly less physiotherapy compared with children with similar levels of motor impairment at PD schools (P < 0.001). CONCLUSIONS: Children with CP in MS schools use less physiotherapy compared with children with similar levels of disability in special schools. Organizing services around special schools may limit the degree to which children with CP and other disabilities are successfully integrated into MS education.

• Risk of hypospadias in relation to maternal occupational exposure to potential endocrine disrupting chemicals.

  Authors: M Vrijheid, B Armstrong, H Dolk, M van Tongeren, B Botting

  Occupational and environmental medicine. 09/2003; 60(8):543-50.

  BACKGROUND: Reported rises in the prevalence of hypospadias and other abnormalities of the male reproductive system may be a result of exposure to endocrine disrupting chemicals. AIMS: To analyse theBACKGROUND: Reported rises in the prevalence of hypospadias and other abnormalities of the male reproductive system may be a result of exposure to endocrine disrupting chemicals. AIMS: To analyse the relation between risk of hypospadias and maternal occupation, particularly with regard to exposure to potential endocrine disrupting chemicals (EDCs). METHODS: Data (1980-96) from the National Congenital Anomaly System (NCAS) were used to analyse the proportion of all congenital anomaly cases (n = 35 962) which were notified with hypospadias (n = 3471) by occupational codes (348 individual job titles) and by categories of exposure to potential EDCs from a job exposure matrix. RESULTS: Five individual occupations (of 348) showed nominally statistically significant excesses, none of which had possible or probable exposure to potential EDCs. Odds ratios for "possible" or "probable" compared to "unlikely" exposure to potential EDCs did not show statistically significant increases in any of the EDC categories after adjustment for social class of the mother and father, nor was there evidence of an upward trend in risk with likelihood of exposure. In the 1992-96 time period odds ratios were increased for hairdressers (the largest group exposed to potential EDCs) and for probable exposure to phthalates (of which hairdressers form the largest group) before social class adjustment. CONCLUSIONS: There was little evidence for a relation between risk of hypospadias and maternal occupation or occupational exposure to potential EDCs, but as the exposure classification was necessarily crude, these findings should be interpreted with caution.

• Hazard potential ranking of hazardous waste landfill sites and risk of congenital anomalies.

  Authors: M Vrijheid, H Dolk, B Armstrong, G Boschi, A Busby, T Jorgensen, P Pointer

  Occupational and environmental medicine. 12/2002; 59(11):768-76.

  BACKGROUND: A 33% increase in the risk of congenital anomalies has been found among residents near hazardous waste landfill sites in a European collaborative study (EUROHAZCON). AIMS: To develop andBACKGROUND: A 33% increase in the risk of congenital anomalies has been found among residents near hazardous waste landfill sites in a European collaborative study (EUROHAZCON). AIMS: To develop and evaluate an expert panel scoring method of the hazard potential of EUROHAZCON landfill sites, and to investigate whether sites classified as posing a greater potential hazard are those with a greater risk of congenital anomaly among nearby residents relative to more distant residents. METHODS: A total of 1270 cases of congenital anomaly and 2308 non-malformed control births were selected in 14 study areas around 20 landfill sites. An expert panel of four landfill specialists scored each site in three categories-overall, water, and air hazard-based on readily available, documented data on site characteristics. Tertiles of the average ranking scores defined low, medium, and high hazard sites. Calculation of odds ratios was based on distance of residence from the sites, comparing a 0-3 km "proximate" with a 3-7 km "distant" zone. RESULTS: Agreement between experts measured by intraclass correlation coefficients was 0.50, 0.44, and 0.20 for overall, water, and air hazard before a consensus meeting and 0.60, 0.56, and 0.53 respectively after this meeting. There was no evidence for a trend of increasing odds ratios with increasing overall hazard or air hazard. For non-chromosomal anomalies, odds ratios by water hazard category showed an increasing trend of borderline statistical significance (p = 0.06) from 0.79 in the low hazard category, 1.43 in the medium, to 1.60 in the high water hazard category. CONCLUSIONS: There is little evidence for a relation between risk of congenital anomaly in proximate relative to distant zones and hazard potential of landfill sites as classified by the expert panel, but without external validation of the hazard potential scoring method interpretation is difficult. Potential misclassification of sites may have reduced our ability to detect any true dose-response effect.

• Use of physiotherapy and alternatives by children with cerebral palsy: a population study.

  Authors: J Parkes, M Donnelly, H Dolk, N Hill

  Child: care, health and development. 12/2002; 28(6):469-77.

  OBJECTIVES: To describe the use of physiotherapy services and alternative therapies by a population of children with moderate to severe cerebral palsy (CP). DESIGN: Descriptive cross-sectionalOBJECTIVES: To describe the use of physiotherapy services and alternative therapies by a population of children with moderate to severe cerebral palsy (CP). DESIGN: Descriptive cross-sectional survey. SUBJECTS: A total of 212 parents of children aged 4-14 years with moderate to severe CP were identified from the Northern Ireland Cerebral Palsy Register (NICPR) and a random subsample of their paediatric physiotherapists. MAIN MEASURES: A standardized description of motor impairment or assessment form; a postal questionnaire to parents and paediatric physiotherapists (to validate parents' reports of service use). RESPONSE RATES: In total, 85% of parent questionnaires were returned and 100% of paediatric physiotherapists responded. RESULTS: Service use among families was high; on average the families had contact with approximately seven services in a 6-month time interval. The overwhelming majority of children (96%) received physiotherapy during the school term and most (59%) received treatment at least twice a week for 30 min; 43% of children had their physiotherapy discontinued over the summer holidays. Over one-quarter (28%) of families had opted out of the NHS and bought alternatives like conductive education (21%) or private forms of conventional physiotherapy (16%). Children with more severe forms of CP, in special education, particularly at schools for physical disability, were high-intensity users of the physiotherapy service. Despite this, 74% of parents wanted more physiotherapy for their child. CONCLUSIONS AND IMPLICATIONS: The demand for physiotherapy services is likely to continue given the relatively stable prevalence rate of CP, the proportion of children with disabling CP and the level of parent interest in the service. A number of quality aspects and gaps in the service have been identified.

• Assessing epidemiological evidence for the teratogenic effects of anticonvulsant medications.

  Authors: H Dolk, P McElhatton

  Journal of medical genetics. 05/2002; 39(4):243-4.

• Chromosomal congenital anomalies and residence near hazardous waste landfill sites.

  Authors: M Vrijheid, H Dolk, B Armstrong, L Abramsky, F Bianchi, I Fazarinc, E Garne, R Ide, V Nelen, E Robert, J E S Scott, D Stone, R Tenconi

  Lancet. 02/2002; 359(9303):320-2.

  Previous findings of the EUROHAZCON study showed a 33% increase in risk of non-chromosomal anomalies near hazardous waste landfill sites. Here, we studied 245 cases of chromosomal anomalies and 2412Previous findings of the EUROHAZCON study showed a 33% increase in risk of non-chromosomal anomalies near hazardous waste landfill sites. Here, we studied 245 cases of chromosomal anomalies and 2412 controls who lived near 23 such sites in Europe. After adjustment for confounding by maternal age and socioeconomic status, we noted a higher risk of chromosomal anomalies in people who lived close to sites (0-3 km) than in those who lived further away (3-7 km; odds ratio 1.41, 95% CI 1.00-1.99). Our results suggest an increase in risk of chromosomal anomalies similar to that found for non-chromosomal anomalies.

• Cerebral palsy, low birthweight and socio-economic deprivation: inequalities in a major cause of childhood disability.

  Authors: H Dolk, S Pattenden, A Johnson

  Paediatric and perinatal epidemiology. 11/2001; 15(4):359-63.

  There is currently little and conflicting evidence concerning the existence of socio-economic inequalities in cerebral palsy prevalence, or the extent to which this is influenced by socio-economicThere is currently little and conflicting evidence concerning the existence of socio-economic inequalities in cerebral palsy prevalence, or the extent to which this is influenced by socio-economic inequalities in low birthweight, a strong risk factor for cerebral palsy. The study is based on 753 children registered with cerebral palsy, resident in the former Oxford Regional Health Authority area and born in the years 1984-90. Two population definitions were used: 1. Children with cerebral palsy resident at birth in the area, with resident births as denominator, 2. Children with cerebral palsy resident at age 5 in the area, with children of ages 1-7 resident in the area in the 1991 census as denominator. Children with cerebral palsy and all births/children were classified according to the Carstairs area deprivation index (grouped into quintiles) of their ward of residence. The prevalence among residents at birth varied from 2.08 per 1000 births in the most affluent quintile to 3.33 in the most deprived quintile (trend P < 0.001). Although there was a tendency for children to move to more affluent areas during early childhood, the socio-economic gradient was similar at age 5. A greater proportion of births in the more deprived quintiles were of low or very low birthweight, the proportion rising from 5.6% in the most affluent quintile to 8.2% in the most deprived. Within the normal birthweight category there was a trend for higher prevalence of cerebral palsy in more deprived quintiles, from 1.29 per 1000 in the most affluent quintile to 2.42 in the most deprived quintile (trend P < 0.001). Within the low birthweight and very low birthweight groups, separately or combined, there was no evidence of any relationship between cerebral palsy prevalence and deprivation. We estimate that up to 17% of cerebral palsy cases might be "preventable" in terms of the reduction to be expected if the whole population had the rate of cerebral palsy of the most affluent quintile. Although the strong socio-economic gradient for cerebral palsy was restricted to the normal birthweight category, we estimate that two-thirds of the excess cases in the population associated with greater socio-economic deprivation were normal birthweight cases, and one-third were low birthweight cases owing to the greater prevalence of low birthweight in more deprived populations. The pattern of socio-economic inequalities should be further explored in other regions, and should be taken into account in aetiological research, and in the effective delivery and evaluation of services.

• Stillbirth and neonatal mortality due to congenital anomalies: temporal trends and variation by small area deprivation scores in England and Wales, 1986-96.

  Authors: D Neasham, H Dolk, M Vrijheid, T Jensen, N Best

  Paediatric and perinatal epidemiology. 11/2001; 15(4):364-73.

  We investigated the variation of stillbirth and neonatal mortality due to congenital anomalies in relation to small-area measures of deprivation in a population-based study in England and Wales,We investigated the variation of stillbirth and neonatal mortality due to congenital anomalies in relation to small-area measures of deprivation in a population-based study in England and Wales, 1986-96. We found 10 954 stillbirths and neonatal deaths from all non-chromosomal and chromosomal anomalies during the study period out of a total of 7 487 007 live and stillbirths. The extended perinatal mortality rate (EPM rate) (defined as babies who were stillborn or died within 28 completed days after birth per 10 000 total live and stillbirths) for all chromosomal and all non-chromosomal anomalies was 1.5/10 000 and 13.2/10 000, respectively, over the whole period. The rate for non-chromosomal anomalies halved over the decade while the rate for chromosomal anomalies remained unchanged. The relative risks of EPM for chromosomal and non-chromosomal anomalies were 0.71 [0.80, 0.95] and 1.17 [95%CI 1.06, 1.30], respectively, in the group of wards with highest deprivation compared with the least deprived group. Increasing gradients of EPM with increasing deprivation were observed for (1) grouped non-chromosomal anomalies including neural tube defects, all renal and urinary anomalies, all musculoskeletal anomalies, and multiple anomalies, and (2) several specific non-chromosomal anomalies including anencephaly, limb reduction defects, diaphragm and abdominal wall defects. This study provides strong evidence that increased deprivation is associated with increased EPM due to most non-chromosomal anomalies; the finding of decreased relative risk for chromosomal anomalies is probably related to differences in maternal age distribution between deprivation groups.

• Cerebral palsy in Northern Ireland: 1981--93.

  Authors: J Parkes, H Dolk, N Hill, S Pattenden

  Paediatric and perinatal epidemiology. 07/2001; 15(3):278-86.

  This paper describes the method of compilation of the Northern Ireland Cerebral Palsy Register (NICPR) and outlines the epidemiology of cerebral palsy (CP) in Northern Ireland in 1981--93 based on anThis paper describes the method of compilation of the Northern Ireland Cerebral Palsy Register (NICPR) and outlines the epidemiology of cerebral palsy (CP) in Northern Ireland in 1981--93 based on an analysis of 784 cases. Multiple and overlapping sources of notification were used to compile the NICPR. Each case was followed up with a standardised assessment completed at age 5 years and validated by a paediatrician. Over 70% of cases were multiply notified, and paediatricians were the most important source of notification. Cases of CP most likely to be under-ascertained included those very mildly affected, cases who died before the register began (death certificates were searched but found to be unreliable) and cases who moved out of the area before their diagnosis was confirmed. The prevalence of CP for the birth period 1981--93 was 2.24 per 1000 livebirths [95% CI 2.08, 2.40]. There were no statistically significant temporal or geographic variations in the rate of CP. Almost half the cases of CP were of low birthweight (<2500 g), and this proportion increased during 1987--89, but decreased (P < 0.01) more recently (1990--93). The proportion of cases weighing <1000 g trebled from 3% in 1981--83 to 10% in 1990--93 (P < 0.01). The most common CP subtype was bilateral spastic cerebral palsy (55%). Just over a quarter (29%) of cases were unable to walk (with/without aids), and one-fifth (22%) had no useful hand/arm function. Almost half (49%) the cases had at least one other impairment (intellectual, sensory impairment or active seizures) in association with their CP. Prevalence rates and the pattern of disability in populations of people with CP can only be evaluated on the basis of the methods of case definition and ascertainment. We have demonstrated the methods necessary to ensure valid, standard and detailed information on CP for the purposes of surveillance, service planning and research.

• Socioeconomic inequalities in risk of congenital anomaly.

  Authors: M Vrijheid, H Dolk, D Stone, L Abramsky, E Alberman, J E Scott

  Archives of disease in childhood. 06/2000; 82(5):349-52.

  AIMS: To investigate socioeconomic inequalities in the risk of congenital anomalies, focusing on risk of specific anomaly subgroups. METHODS: A total of 858 cases of congenital anomaly and 1764AIMS: To investigate socioeconomic inequalities in the risk of congenital anomalies, focusing on risk of specific anomaly subgroups. METHODS: A total of 858 cases of congenital anomaly and 1764 non-malformed control births were collected between 1986 and 1993 from four UK congenital malformation registers, for the purposes of a European multicentre case control study on congenital anomaly risk near hazardous waste landfill sites. As a measure of socioeconomic status, cases and controls were given a value for the area level Carstairs deprivation index, by linking the postcode of residence at birth to census enumeration districts (areas of approximately 150 households). RESULTS: Risk of non-chromosomal anomalies increased with increasing socioeconomic deprivation. The risk in the most deprived quintile of the deprivation index was 40% higher than in the most affluent quintile. Some malformation subgroups also showed increasing risk with increasing deprivation: all cardiac defects, malformations of the cardiac septa, malformations of the digestive system, and multiple malformations. No evidence for socioeconomic variation was found for other non-chromosomal malformation groups, including neural tube defects and oral clefts. A decreasing risk with increasing deprivation found for all chromosomal malformations and Down's syndrome in unadjusted analyses, occurred mainly as a result of differences in the maternal age distribution between social classes. CONCLUSION: Our data, although based on limited numbers of cases and geographical coverage, suggest that more deprived populations have a higher risk of congenital anomalies of non-chromosomal origin and some specific anomalies. Larger studies are needed to confirm these findings and to explore their aetiological implications.