Childhood and adolescent lymphoma in Spain: incidence and survival trends over 20 years

Background: Lymphoma is the third most common malignancy in children (0-14 years) and the first in adolescents (15-19 years). This population-based study-the largest ever done in Spain-analyses incidence and survival of lymphomas among Spanish children and adolescents. Patients and methods 1664 lymphoma cases (1983-2007) for incidence and 1030 for survival (1991-2005) followed until 31/12/2010, were provided by 11 cancer registries. Age-adjusted incidence rates (ASRw) to the world standard population were obtained; incidence trends were modelled using the Joinpoint programme, observed survival (OS) was estimated with Kaplan-Meier and trends tested with a log-rank test. Results are presented according to the International Classification of Childhood Cancer-3. Results: In Spain, the ASRw0-14 for lymphomas was 17.5 per 1.000.000 child-years and 50.0 the specific rate for adolescents. Overall incidence increased significantly during 1983-1997 with no increases thereafter. Patients over 9 years old showed significant rising trends for all subtypes, except for Burkitt lymphoma (BL) in adolescents. During 2001-2005 (age 0-19 years), 5-year OS was 94 (90-98), 73 (64-83) and 86 (78-94) for Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL) and BL, respectively. No improvement in survival was found. The incidence in Spain was higher than overall European rates, but within the range of that in Southern Europe. Comparing OS in Spain 1991-1995 and 2001-2005 with results for Europe of the Automated Childhood Cancer Information System (ACCIS) (1988-1997) and the European cancer registry-based study on survival and care of cancer patients (EUROCARE) (2000-2007), it was similar for HL and lower for NHL and BL. Conclusions: Systematic monitoring and analysis of lymphoma paediatric data would provide clinical and epidemiological information to improve the health care of these patients and the outcomes for these malignancies in Spain

No disponible

Childhood and adolescent lymphoma in Spain: incidence and survival trends over 20 years.

BACKGROUND: Lymphoma is the third most common malignancy in children (0-14 years) and the first in adolescents (15-19 years). This population-based study-the largest ever done in Spain-analyses incidence and survival of lymphomas among Spanish children and adolescents. PATIENTS AND METHODS: 1664 lymphoma cases (1983-2007) for incidence and 1030 for survival (1991-2005) followed until 31/12/2010, were provided by 11 cancer registries. Age-adjusted incidence rates (ASRw) to the world standard population were obtained; incidence trends were modelled using the Joinpoint programme, observed survival (OS) was estimated with Kaplan-Meier and trends tested with a log-rank test. Results are presented according to the International Classification of Childhood Cancer-3. RESULTS: In Spain, the ASRw0-14 for lymphomas was 17.5 per 1.000.000 child-years and 50.0 the specific rate for adolescents. Overall incidence increased significantly during 1983-1997 with no increases thereafter. Patients over 9 years old showed significant rising trends for all subtypes, except for Burkitt lymphoma (BL) in adolescents. During 2001-2005 (age 0-19 years), 5-year OS was 94 (90-98), 73 (64-83) and 86 (78-94) for Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL) and BL, respectively. No improvement in survival was found. The incidence in Spain was higher than overall European rates, but within the range of that in Southern Europe. Comparing OS in Spain 1991-1995 and 2001-2005 with results for Europe of the Automated Childhood Cancer Information System (ACCIS) (1988-1997) and the European cancer registry-based study on survival and care of cancer patients (EUROCARE) (2000-2007), it was similar for HL and lower for NHL and BL. CONCLUSIONS: Systematic monitoring and analysis of lymphoma paediatric data would provide clinical and epidemiological information to improve the health care of these patients and the outcomes for these malignancies in Spain.

Geographical variability in survival of European children with central nervous system tumours.

Survival for childhood central nervous system (CNS) tumours varies across Europe, partly because of the difficulty of distinguishing malignant from non-malignant disease. This study examines bias in CNS tumours survival analysis to obtain the reliable and comparable survival figures. We analysed survival data for about 15,000 children (age <15) diagnosed with CNS between 2000 and 2007, from 71 population-based cancer registries in 27 countries. We selected high-quality data based on registry-specific data quality indicators and recorded observed 1-year and 5-year survival by countries and CNS entity. We provided age-adjusted survival and used a Cox model to calculate the hazard ratios (HRs) of death, adjusting by age, site and grading by country. Recording of non-malignant lesions, use of appropriate morphology codes and completeness of life status follow-up differed among registries. Five-year survival by countries varied less when non-malignant tumours were included, with rates between 79.5% and 42.8%. The HRs of dying, for registries with good data, adjusting by age and grading, were between 0.7 and 1.2; differences were similar when site (supra- and infra-tentorial) was included. Several sources of bias affect the correct definition of CNS tumours, the completeness of incidence series and the goodness of follow-up. The European Network of Cancer Registries needs to improve childhood cancer registration and stress the need to update the International Classification for Cancer. Since survival differences persisted even when restricting the analysis to registries with satisfactory data, and since diagnosis of CNS tumours is difficult and treatment complex, national plans must aim for the revision of the diagnosis and the coordination of care, with adequate national and international networks.

Cancer incidence in Spain, 2015

Purpose. Periodic cancer incidence estimates of Spain from all existing population-based cancer registries at any given time are required. The objective of this study was to present the current situation of cancer incidence in Spain. Methods. The Spanish Network of Cancer Registries (REDECAN) estimated the numbers of new cancer cases occurred in Spain in 2015 by applying the incidence-mortality ratios method. In the calculus, incidence data from population-based cancer registries and mortality data of all Spain were used. Results. In 2015, nearly a quarter of a million new invasive cancer cases were diagnosed in Spain, almost 149,000 in men (60.0%) and 99,000 in women. Globally, the five most common cancers were those of colon-rectum, prostate, lung, breast and urinary bladder. By gender, the four most common cancers in men were those of prostate (22.4%), colon-rectum (16.6%), lung (15.1%) and urinary bladder (11.7%). In women, the most common ones were those of breast (28.0%), colon-rectum (16.9%), corpus uteri (6.2%) and lung (6.0%). In recent years, cancer incidence in men seems to have stabilized due to the fact that the decrease in tobacco-related cancers compensates for the increase in other types of cancer like those of colon and prostate. In women, despite the stabilization of breast cancer incidence, increased incidence is due, above all, to the rise of colorectal and tobacco-related cancers. Conclusion. To reduce these incident cancer cases, improvement of smoking control policies and extension of colorectal cancer screening should be the two priorities in cancer prevention for the next years (AU)

No disponible

Incidence and survival time trends for Spanish children and adolescents with leukaemia from 1983 to 2007

Objective. We have analysed incidence and survival trends of children and adolescents with leukaemia registered in Spanish population-based cancer registries during the period 1983-2007. Methods. Childhood and adolescent leukaemia cases were drawn from the 11 Spanish population-based cancer registries. For survival, registries with data for the period 1991-2005 and follow-up until 31-12-2010 were included. Overall incidence trends were evaluated using joinpoint analysis. Observed survival rates were estimated using Kaplan-Meier, and trends were tested using the log-rank test. Results. Based on 2606 cases (2274 children and 332 adolescents), the overall age-adjusted incidence rate (ASRw) of leukaemia was 47.9 cases per million child-years in children and 23.8 in adolescents. The ASRw of leukaemia increased with an annual percentage change of 9.6 % (95 % CI: 2.2-17.6) until 1990 followed by a stabilisation of rates. In adolescents, incidence did not increase. Five-year survival increased from 66 % in 1991-1995 to 76 % in 2001-2005. By age, survival was dramatically lower in infants (0) and adolescents (15−19) than in the other age groups and no improvement was observed. In both children and adolescents, differences in 5-year survival rates among major subgroups of leukaemias were significant. Conclusions. The increasing incidence trends observed in childhood leukaemias during the study period were confined to the beginning of the period. Remarkable improvements in survival have been observed in Spanish children with leukaemias. However, this improvement was not observed in infants and adolescents (AU)

No disponible

Incidence and survival time trends for Spanish children and adolescents with leukaemia from 1983 to 2007.

OBJECTIVE: We have analysed incidence and survival trends of children and adolescents with leukaemia registered in Spanish population-based cancer registries during the period 1983-2007. METHODS: Childhood and adolescent leukaemia cases were drawn from the 11 Spanish population-based cancer registries. For survival, registries with data for the period 1991-2005 and follow-up until 31-12-2010 were included. Overall incidence trends were evaluated using joinpoint analysis. Observed survival rates were estimated using Kaplan-Meier, and trends were tested using the log-rank test. RESULTS: Based on 2606 cases (2274 children and 332 adolescents), the overall age-adjusted incidence rate (ASRw) of leukaemia was 47.9 cases per million child-years in children and 23.8 in adolescents. The ASRw of leukaemia increased with an annual percentage change of 9.6 % (95 % CI: 2.2-17.6) until 1990 followed by a stabilisation of rates. In adolescents, incidence did not increase. Five-year survival increased from 66 % in 1991-1995 to 76 % in 2001-2005. By age, survival was dramatically lower in infants (0) and adolescents (15-19) than in the other age groups and no improvement was observed. In both children and adolescents, differences in 5-year survival rates among major subgroups of leukaemias were significant. CONCLUSIONS: The increasing incidence trends observed in childhood leukaemias during the study period were confined to the beginning of the period. Remarkable improvements in survival have been observed in Spanish children with leukaemias. However, this improvement was not observed in infants and adolescents.

Childhood cancer incidence and survival in Spain.

BACKGROUND: This article affords an overview of the patterns and time trends of childhood cancer incidence (1983-2002) and survival (1991-2002) in Spain. PATIENTS AND METHODS: A population-based study was conducted, including 5936 cases for incidence and 3257 for survival analyses. Differences in incidence were tested with the standardised incidence ratio. Trends were analysed for all tumours, and for all malignant, haematological, central nervous system (CNS) (all and only malignant) and other solid tumours. Incidence trends were analysed using Poisson and Bayesian joinpoint models. Observed, relative and age-adjusted survival rates were calculated, and trends were tested using the log-rank test. RESULTS: The incidence pattern in Spain was similar to that in Europe. Rates, both overall and for leukaemias, lymphomas, CNS, soft tissue and, remarkably, for sympathetic nervous system and bone tumours, were high. Upward incidence trends were present for all tumour groups. All groups, except solid tumours (excluding CNS), displayed a change-point centred around 1990-95, after which the trend stopped rising. Five-year survival increased significantly across the period for all groups, except for CNS tumours. Recent survival results were in line with Italy, the UK and the European average. CONCLUSIONS: To confirm these results, ongoing surveillance of incidence and survival trends, and studies targeting specific tumours are called for.

Population-based cancer registries in Spain and their role in cancer control.

Population-based cancer registries (PBCRs) are a key element for cancer control. They measure cancer incidence and trends, provide indicators for planning and evaluating cancer control activities, and undertake research. The first two PBCRs in Spain were established in Zaragoza in 1960 and Navarre in 1970, but it was from 1980 to 1995 when most of the existing registries went into operation. Today, 26.5% of the Spanish population is served by a cancer registry. All registries' quality-control indicators meet the inclusion criteria for comparability and quality of data required by the International Agency for Research on Cancer, and indeed some fulfil most of the excellence criteria for gold standard certification. After their initiation into recording accurate and complete information targeted at ascertaining cancer incidence in their catchment areas, PBCRs are progressively broadening their scope and becoming increasingly involved in collecting and analysing additional data on patient care, diagnosis, disease stage, treatment and follow-up. Spanish registries have become actively engaged in research projects, domestic and international, at a rate that has risen remarkably in the past decade. The creation of a network of Spanish cancer registries is being considered, with the aim of its becoming a key player in developing standards for cancer registration, providing training and technical assistance, undertaking quality audits and promoting the use of cancer surveillance data to reduce the burden of cancer in Spain.

Incidencia y supervivencia del cáncer infantil / Incidence and survival of childhood cancer

En la Unión Europea, la mortalidad por cáncer infantil cayó un 60% entre los años sesenta y finales de la pasada centuria y las tasas de mortalidad siguen disminuyendo progresivamente en los años recientes, pero a pesar de estos logros, el cáncer sigue siendo la primera causa de muerte por enfermedad a partir del primer año de vida, durante la infancia y la adolescencia. En 2006, el cáncer ocasionó el 24 % de la muertes entre 1 y 14 años de edad y el 13% entre 15 y 19 años (AU)

In the European Union, mortality due to childhood cancer fell 60% between the 1960´s and the end of the last century and the mortality rates have continued to decrease progressively in recent years. However, in spite of these achievements, cancer continues to be the first cause of death due to disease after the first year of life, during infancy and in adolescence. In 2006, cancer caused 24% of the deaths between age 1 and 14 years and 13% between 15 and 19 years of age (AU)

Up-to-date monitoring of childhood cancer long-term survival in Europe: central nervous system tumours.

BACKGROUND: Tumours of the central nervous system (CNS) account for 15-20% of all malignant childhood tumours in developed countries. Steady improvement of survival of children with CNS tumours has been reported for the past decades. However, these results, obtained by cohort analysis of survival, do not reflect the full extent of recent improvement. METHODS: Using selected registries from the database of the Automated Childhood Cancer Information System (ACCIS), we calculated period survival estimates for the years 1995-99 for children diagnosed with a malignant CNS tumour. RESULTS: The overall 10-year period survival estimate for the years 1995-99 was 59% for children with all CNS tumours combined, 73% for children with astrocytoma, 53% for children with ependymoma and 45% for children with primitive neuroectodermal tumours. On average, estimates derived by cohort analysis (pertaining to children diagnosed in 1985-89) were around 4% units lower. Region-specific analysis revealed that recent progress was largest in Eastern Europe, where prognosis nevertheless remained lower than in other European regions. In Northern and Southern Europe, 10-year survival remained essentially unchanged. CONCLUSION: Although period survival of children with CNS tumours is higher than previously reported cohort survival, their long-term prognosis remains modest compared to other childhood malignancies.

Beauty product-related exposures and childhood brain tumors in seven countries: results from the SEARCH International Brain Tumor Study.

Data from 1218 cases of childhood brain tumors (CBT) diagnosed between 1976 and 1994 and 2223 matched controls from the general population were included in an analysis of maternal beauty product exposure and beauty-related employment in 9 centers in 7 countries. A 50% increased odds ratio (OR) [95% confidence interval (CI) = 1.0-2.1] for CBT was observed among children of mothers who were exposed via personal use of and/or possible ambient contact with beauty products during the 5 years preceding the index child's birth compared with children of mothers never exposed to beauty products during this time period. Overall maternal personal use of hair-coloring agents in the month before or during the pregnancy of the index child's birth was not associated with CBT (OR = 1.0, CI = 0.83-1.3) or with astroglial (OR = 1.1, CI = 0.85-1.4), PNET (OR = 1.0, CI = 0.71-1.5) and other glial subtypes (OR = 1.0, CI = 0.62-1.0). Similarly, no statistically increased ORs or discernable pattern of risk estimates were observed for period of use or for number of applications per year for maternal personal use of hair-coloring agents overall or by histologic type. Among children born on or after 1980, increased ORs for CBT were associated with maternal non-work-related exposure to any beauty products (OR = 2.6, CI = 1.2-5.9), hair-dyes (OR = 11, CI = 1.2-90), and hair sprays (OR = 3.4, CI = 1.0-11). No overall increased OR for CBT was observed among children of mothers employed in beauty-related jobs during the 5 years preceding the index child's birth compared with those who reported no beauty-related employment. In general, other specific beauty product-related exposures were not associated with increased ORs for CBT. Data from our study provide little evidence of an increased risk for CBT with mothers' exposures to beauty products.

Parental exposure to polycyclic aromatic hydrocarbons and the risk of childhood brain tumors: The SEARCH International Childhood Brain Tumor Study.

Experimental evidence suggests that parental exposure to polycyclic aromatic hydrocarbons (PAH), which occurs primarily through tobacco smoke, occupational exposure, and air pollution, could increase the risk of cancer during childhood. Population-based case-control studies carried out in seven countries as part of the SEARCH Program compared data for 1,218 cases of childhood brain tumors and 2,223 controls (1976-1994). Parental occupational exposure to PAH during the 5-year period before birth was estimated with a job exposure matrix. Risk estimates were adjusted for child's age, sex, and study center. Paternal preconceptional occupational exposure to PAH was associated with increased risks of all childhood brain tumors (odds ratio (OR) = 1.3, 95% confidence interval: 1.1, 1.6) and astroglial tumors (OR = 1.4, 95% confidence interval: 1.1, 1.7). However, there was no trend of increasing risk with predicted level of exposure. Paternal smoking alone (OR = 1.4) was also associated with the risk of astroglial tumors in comparison with nonsmoking, non-occupationally-exposed fathers. Risks for paternal occupational exposure were higher, with (OR = 1.6) or without (OR = 1.7) smoking. Maternal occupational exposure to PAH before conception or during pregnancy was rare, and this exposure was not associated with any type of childhood brain tumor. This large study supports the hypothesis that paternal preconceptional exposure to PAH increases the risk of brain tumors in humans.

Indicadores de calidad mínimos para la mejora de la gestión de la hipertensión arterial en Atención Primaria / Minimun quality indicators for improving the management of hypertension in Primary Care

Propósito. La hipertensión arterial (HTA) sigue siendo un problema sanitario de primer orden por su alta prevalencia, morbimortalidad y alto coste económico, lo que hace necesario un método que permita una mejor gestión de la misma. Desde esta perspectiva hemos planteado un trabajo para la selección de los indicadores de calidad mínimos (ICM) para evaluar, controlar y seguir adecuadamente al paciente hipertenso y cuya supervisión permita evaluar la calidad asistencial que recibe la población hipertensa. Material y métodos. Tras definir el problema, revisar la bibliografía y consultar a expertos en hipertensión, la selección de indicadores se realizó a partir de las principales guías nacionales e internacionales de hipertensión. Para la selección de los ICM utilizamos tres criterios: cumplir requisitos que definen un indicador de calidad, concordancia entre guías y evidencia científica y actualización en función del año de aparición en guía. Resultados. Inicialmente obtuvimos 113 indicadores potenciales; de entre ellos seleccionamos 32 ICM que incluían elementos de anamnesis, exploración física, exploraciones complementarias y tratamiento (de primera visita y visita anual). Conclusiones. La intervención mediante la definición de ICM en HTA y la medición de la cumplimentación de los mismos debe ser el primer paso para el control del paciente hipertenso en Atención Primaria (AU)

Childhood cancer survival in Europe.

BACKGROUND: EUROCARE-3 collected data from 45 population-based cancer registries in 20 countries on 24 620 European children aged from 0 to 14 years diagnosed with malignancy in the period 1990-1994. METHODS: Five-year survival between countries was compared for all malignancies and for the major diagnostic categories, adjusting for age, and estimated average European survival weighting for differences in childhood populations. RESULTS: For all cancers combined, survival variation was large (45% in Estonia to 90% in Iceland), and was generally low (60-70%) in eastern Europe and high (> or =75%) in Switzerland, Germany and the Nordic countries (except Denmark). The Nordic countries had the highest survival for four of the seven major tumour types: nephroblastoma (92%), acute lymphoid leukaemia (85%), CNS tumours (73%) and acute non-lymphocytic leukaemia (62%). The eastern countries had lowest survival: 89% for Hodgkin's disease, 71% for nephroblastoma, 68% for acute lymphoid leukaemia, 61% for non-Hodgkin's lymphoma, 57% for central nervous system (CNS) tumours and 29% for acute non-lymphocytic leukaemia. CONCLUSIONS: The Nordic countries represent a survival gold standard to which other countries can aspire. Since most childhood cancers respond well to treatment, survival differences are attributable to differences in access (including referral and timely diagnosis) and use of modern treatments; however, the obstacles to access and application of standard treatments probably vary markedly with country.

Parental occupations and childhood brain tumors: results of an international case-control study.

OBJECTIVE: To evaluate the role of parental occupations in the etiology of childhood brain tumors (CBT). METHODS: Population-based case-control studies were conducted concurrently in seven countries under the coordination of the International Agency for Research on Cancer, gathering 1,218 cases and 2,223 controls. We report here the findings related to parental occupations during the 5-year period before the child's birth. Risk estimates related to a number of paternal and maternal occupations were obtained by unconditional logistic regression adjusted for age, sex, year of birth, and center, for all types of CBT combined and for the subgroups of astroglial, primitive neuroectodermal tumors (PNET), and other glial tumors. RESULTS: An increased risk in relation with agricultural work was seen for all CBT combined and for other glial tumors. Increased risks for all tumors and PNET were seen for paternal occupation as an electrician; the same pattern held for maternal occupation when children under 5 were selected. Paternal occupation as a driver or mechanic, and maternal work in an environment related to motor-vehicles were associated with an increased risk for all CBT and astroglial tumors. More case mothers compared to control mothers were employed in the textile industry. CONCLUSION: Our study reinforces previous findings relative to the role of parental work in agriculture, electricity, or motor-vehicle related occupations and maternal work in the textile industry. It does not confirm previous associations with work environments including aerospace, the chemical industry, or the food industry, or with maternal occupation as a hairdresser, a nurse, or a sewing machinist, and paternal occupation as a welder.

SEARCH international case-control study of childhood brain tumours: role of index pregnancy and birth, and mother's reproductive history.

A series of co-ordinated population-based case-control studies of childhood brain tumours (CBT) was undertaken under the auspices of the Surveillance of Environmental Aspects Related to Cancer in Humans (SEARCH) programme of the International Agency for Research on Cancer (IARC) to evaluate, inter alia, the risk in relation to characteristics of the index pregnancy and birth, and maternal reproductive history. Subjects comprised 1218 cases aged 0-19 years and 2223 controls. Risk estimates were calculated by unconditional logistic regression, adjusted for age, sex, centre and mother's years of schooling, for all types of CBT combined as well as for four groups defined by histopathology (astrologlial tumours, primitive neuroectodermal tumours of the brain, 'other glial' tumours and 'other histological types') and for five age groups (0-1, 0-4, 5-9, 10-14, 15-19 years). Use of anaesthetic 'gas' was associated with an increased risk of CBT (OR = 1.5, 95% CI [1.1, 2.0]), apparent in children aged 0-4 years (OR = 2.4, 95% CI [1.4, 4.1]) and for astroglial tumours (OR = 1.6, 95% CI [1.1, 2.2]) with non-significantly increased relative risks for each of the other histological groups. However, not all centre-specific relative risks were elevated. No other aspect of the index pregnancy, delivery and early neonatal period or of the mother's previous reproductive history was associated with risk for CBT.

Population density and childhood leukaemia: results of the EUROCLUS Study.

The EUROCLUS study assembled incidence data for 13,551 cases of childhood leukaemia (CL) diagnosed between 1980 and 1989 in 17 countries (or regions of countries). These were referenced by location at diagnosis to small census areas of which there were 25,723 in the study area. Population counts, surface area and, hence, population density were available for all these small areas. Previous analyses have shown limited extra-Poisson variation (EPV) of case counts within small areas; this is most pronounced in areas of intermediate population density (150-499 persons/km2). In this study, the data set was examined in more detail for evidence that variations in incidence and EPV of CL are associated with population density. Incidence showed a curvilinear association with population density and was highest in areas which were somewhat more densely populated (500-750 persons/km2), where the incidence rate ratio relative to areas having > or = 1000 persons/km2 was 1.16 (95% confidence interval 1.07-1.26) and the P value for quadratic trend across eight strata of population density was 0.02. Incidence in these areas is uniformly elevated and showed no evidence of heterogeneity (i.e. EPV). Statistically significant evidence of EPV was evident amongst some of the areas previously classified as intermediate density areas (specifically, those with a density of 250-499 persons/km2, P < 0.001 for CL). These results were interpreted in terms of the current aetiological hypotheses for CL which propose that exposure to localised epidemics of one or more common infectious agent may contribute to the development of leukaemia. They suggest that such epidemics arise regularly in moderately densely populated areas and also sporadically in areas which are somewhat less densely populated. Although other interpretations are possible, these results may assist in the identification of characteristics which infectious agents must possess if direct or indirect causes of CL.

Prenatal vitamin supplementation and pediatric brain tumors: huge international variation in use and possible reduction in risk.

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976-1994 and mothers of population controls. Data are available on maternal vitamin use during pregnancy for 1051 cases and for 1919 controls in eight geographic areas of North America, Europe and Israel. While risk estimates varied by study center, combined results suggest that maternal supplementation for two trimesters may decrease risk of brain tumor [odds ratio (OR)=0.7; 95% confidence interval (CI)=0.5-0.9], with a trend toward less risk with longer duration of use (P trend= 0.0007). The greatest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all three trimesters (OR=0.5; CI=0.3- 0.8). This effect did not vary by histology and was seen for supplementation during pregnancy rather than during the month before pregnancy or while breast feeding. These findings are largely driven by data from the US, where most mothers took vitamins. The proportion of control mothers who took vitamins during pregnancy varied tremendously, from 3% in Israel and in France through 21% in Italy, 33% in Canada, 52% in Spain to 86-92% at the three US centers. The composition of the various multivitamin compounds taken also varied: daily dose of vitamin C ranged from 0 up to 600 mg; vitamin E from 0 to 70 mg; vitamin A from 0 to 30,000 IU and folate from 0 to 2000 mg. Mothers also took individual micronutrient supplements (e.g., vitamin C tablets), but most mothers who took these also took multivitamins, making it impossible to determine potential independent effects of these micronutrients.

Results from an international case-control study of childhood brain tumors: the role of prenatal vitamin supplementation.

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976 to 1994 and mothers of population controls. Data are available on maternal vitamin use during pregnancy for 1051 cases and 1919 controls from eight geographic areas in North America, Europe, and Israel. Although risk estimates varied by study center, combined results suggest that maternal supplementation for two trimesters may decrease risk of brain tumor (odds ratio [OR] 0.7, 95% confidence interval [CI] 0.5-0.9), with a trend of less risk with longer duration of use (p trend = 0.0007). The greatest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all three trimesters (OR 0.5, CI 0.3-0.8). This effect did not vary by histology and was seen for supplementation during pregnancy rather than during the month before pregnancy or while breast feeding. These findings are largely driven by data from the United States, where most mothers took vitamins. The proportion of control mothers who took vitamins during pregnancy varied tremendously: from 3% in Israel and France, 21% in Italy, 33% in Canada, 52% in Spain and 86 to 92% at the three U.S. centers. The composition of the various multivitamin compounds taken also varied: the daily dose of vitamin C ranged from 0 to 600 mg, vitamin E ranged from 0 to 70 mg, vitamin A ranged from 0 to 30,000 IU, and folate ranged from 0 to 2000 micrograms. Mothers also took individual micronutrient supplements (e.g., vitamin C tablets), but most mothers who took these also took multivitamins, making it impossible to determine potential independent effects of these micronutrients.

Spatial temporal patterns in childhood leukaemia: further evidence for an infectious origin. EUROCLUS project.

The EUROCLUS project included information on residence at diagnosis for 13351 cases of childhood leukaemia diagnosed in the period 1980-89 in defined geographical regions in 17 countries. A formal algorithm permits identification of small census areas as containing case excesses. The present analysis examines spatial-temporal patterns of the cases (n = 970) within these clustered areas. The objectives were, first, to compare these results with those from an analysis conducted for UK data for the period 1966-83, and, second, to extend them to consider infant leukaemias. A modification of the Knox test investigates, within the small areas, temporal overlap between cases in a subgroup of interest at a putative critical time and all other cases at any time between birth and diagnosis. Critical times were specified in advance as follows: for cases of acute lymphoblastic leukaemia aged 2-4 years, the 18-month period preceding diagnosis; for cases of total leukaemia aged 5-14 years, 1 year before to 1 year after birth; and for infant cases (diagnosed < 1 year), 1 year before to 6 months after birth. Each of the analyses found evidence of excess space-time overlap compared with that expected; these were 10% (P = 0.005), 15% (P= 0.0002) and 26% (P= 0.03) respectively. The results are interpreted in terms of an infectious origin of childhood leukaemia.