Antenatal hydronephrosis and the risk of pyelonephritis hospitalization during the first year of life

OBJECTIVES

To assess the risk of hospitalization for pyelonephritis within the first year of life among infants with and without antenatal hydronephrosis.

METHODS

A retrospective cohort analysis was performed using linked birth-hospital discharge records from Washington State for 1987 to 2002 to evaluate the risk of hospitalization in the first year of life for pyelonephritis among infants with and without hydronephrosis. Eligible infants had mothers who had prenatal ultrasound screening. A total of 522 singleton infants with antenatal hydronephrosis (International Classification of Diseases, Ninth Revision code 753.2) at the birth hospitalization were identified. For comparison, 2610 singletons without hydronephrosis were selected. We screened hospital discharge records for 1 year after delivery to identify hospitalizations for pyelonephritis and estimate the relative risk (RR) among infants with and without hydronephrosis.

RESULTS

Five percent of infants with antenatal hydronephrosis and 1% of those without had pyelonephritis-related hospitalizations in their first year (RR 11.8, 95% confidence interval [CI] 6.8 to 20.5). Among girls the RR was 36.3 (95% CI 10.6 to 124.0); among boys it was 5.3 (95% CI 2.2 to 13.1). In infants with hydronephrosis, girls were more likely to be hospitalized with pyelonephritis (odds ratio 2.9, 95% CI 1.2 to 6.9).

CONCLUSIONS

Infants with antenatal hydronephrosis are nearly 12 times more likely to have pyelonephritis-related hospitalizations in the first year of life. This association is stronger in girls. Parents and healthcare providers of infants with this diagnosis should be vigilant for the signs and symptoms of urinary tract infections.

Fetal deaths and proximity to hazardous waste sites in Washington State

BACKGROUND

The in utero period is one of increased susceptibility to environmental effects. The effects of prenatal exposure to environmental toxicants on various adverse pregnancy outcomes, including fetal death, are not well understood.

OBJECTIVE

We examined the risk of fetal death in relation to maternal residential proximity to hazardous waste sites.

METHODS

We conducted a population-based case-control study using Washington State vital records for 1987-2001. Cases were women with fetal deaths at > or = 20 weeks (n = 7,054). Ten controls per case were randomly selected from live births. Locations of 939 hazardous waste sites were identified from the Department of Ecology registry. We measured distance from maternal residence at delivery to the nearest hazardous waste site, and calculated odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The risk of fetal death for women residing < or = 0.5 miles, relative to > 5 miles, from a hazardous waste site was not increased (adjusted OR = 1.06; 95% CI, 0.90-1.25). No associations were observed for any proximity categories < or = 5 miles from sites with contaminated air, soil, water, solvents, or metals; however, fetal death risk increased among women residing < or = 1 mile from pesticide-containing sites (OR = 1.28; 95% CI, 1.13-1.46).

CONCLUSION

These results do not suggest that fetal death is associated with residential proximity to hazardous waste sites overall; however, close proximity to pesticide-containing sites may increase the risk of fetal death.

Maternal and perinatal characteristics in relation to neuroblastoma

BACKGROUND

Neuroblastoma is the most common malignancy among infants, but risk factors remain poorly understood. Because most patients present in the first few years of life, it has been hypothesized that prenatal and perinatal exposures may contribute to the pathogenesis of neuroblastoma.

METHODS

A population-based case-control study was conducted by using linked birth and cancer registry records from 1980 to 2004 in Washington State. Maternal and infant characteristics from birth and hospital discharge records for 240 cases of neuroblastoma and 2400 controls were compared.

RESULTS

Neuroblastoma was associated with the presence of major congenital abnormalities (odds ratio [OR], 6.86; [95% CI], 2.92-16.08), particularly with cardiac abnormalities (OR, 5.84; 95% CI, 1.93-17.66), even after excluding abnormalities near the primary tumor. A borderline association was observed with maternal gestational diabetes (OR, 1.84; 95% CI, 0.98-3.47). The magnitude of both associations was greater when the analysis was limited to children who were diagnosed at age <1 year.

CONCLUSIONS

The findings from this population-based study supported prior case-control studies that identified an etiologic link between neuroblastoma and congenital abnormalities. However, to the authors' knowledge, the association between neuroblastoma and maternal diabetes has not been reported previously and requires further study.

Risk of malformations associated with residential proximity to hazardous waste sites in Washington State

Hazardous waste sites often contain substances harmful to fetal development. Using linked birth-hospital discharge and hazardous sites data for Washington State, we evaluated the association between malformation occurrence and maternal residential proximity to hazardous waste sites. Cases (N=63,006) were infants born 1987-2001 with malformations. Controls (N=315,030) were randomly selected infants without malformations born during these years. Distance between maternal residence and nearest hazardous waste site was measured using geographic information systems (GIS) software. Odds ratio (OR) estimates of the relative risk of malformation at varying distances were calculated. Relative to living >5 miles from a site, living < or = 5 miles was associated with increased risk of any malformations in offspring (for >2- < or = 5 miles: OR 1.15: 95% Confidence Interval (CI): 1.10, 1.21; for >1- < or = 2 miles: OR 1.26, 95% CI: 1.20, 1.32; for >0.5- < or = 1 miles: OR 1.28, 95% CI: 1.22, 1.35; for < or = 0.5 miles: OR 1.33, 95% CI: 1.27, 1.40.) Risk estimates varied by urban vs. rural maternal residence and by specific malformation type. Hazardous waste sites are often located within populated areas. Thus, the possibility of increased malformation occurrence among those in close proximity deserves closer scrutiny.

Maternal and birth characteristics in relation to childhood leukaemia

Our objective was to investigate the association of childhood leukaemia with selected maternal and birth characteristics by conducting a population-based case-control study using linked cancer registry and birth certificate records for Washington State. We compared maternal and infant characteristics of 595 Washington-born residents <20 years old with leukaemia diagnosed during 1981-2003, and 5,950 control children, using stratified analysis and logistic regression. Maternal age 35+ years (odds ratio [OR] 1.5; 95% confidence interval [CI] 1.1, 2.0), infant birthweight 4,000+ g (OR 1.4; 95% CI 1.1, 1.8), neonatal jaundice (OR 1.5; 95% CI 1.1, 2.1), and Down's syndrome (OR 31.3; 95% CI 6.4, 153.4) were associated with an increased risk of leukaemia. Among women with 2+ pregnancies, having at least two prior early (<20 weeks' gestation) fetal deaths was also associated with an increased risk (OR 1.5; 95% CI 0.97, 2.1). Maternal unmarried status (OR 0.7; 95% CI 0.6, 0.9) and African American race (OR 0.5; 95% CI 0.3, 0.9) were associated with a decreased risk. These results were more marked for acute lymphocytic leukaemia (ALL) than for acute myeloid leukaemia (AML), and for leukaemia diagnosed <5 years of age. These results may provide clues to the aetiology of childhood leukaemia. Genetic epidemiological studies are needed to expand our knowledge of inherent and possibly prenatal influences on the occurrence of this disease.

Maternal medication use and the risk of brain tumors in the offspring: the SEARCH international case-control study

N-nitroso compounds (NOC) have been associated with carcinogenesis in a wide range of species, including humans. There is strong experimental data showing that nitrosamides (R(1)NNO.COR(2)), a type of NOC, are potent neuro-carcinogens when administered transplacentally. Some medications are a concentrated source of amides or amines, which in the presence of nitrites under normal acidic conditions of the stomach can form NOC. Therefore, these compounds, when ingested by women during pregnancy, may be important risk factors for tumors of the central nervous system in the offspring. The aim of the present study was to test the association between maternal use of medications that contain nitrosatable amines or amides and risk of primary childhood brain tumors (CBT). A case-control study was conducted, which included 1,218 cases and 2,223 population controls, recruited from 9 centers across North America, Europe and Australia. Analysis was conducted for all participants combined, by tumor type (astroglial, primitive neuroectodermal tumors and other glioma), and by age at diagnosis (< or =5 years; >5 years). There were no significant associations between maternal intake of medication containing nitrosatable amines or amides and CBT, for all participants combined and after stratification by age at diagnosis and histological subtype. This is the largest case-control study of CBT and maternal medications to date. Our data provide little support for an association between maternal use of medications that may form NOC and subsequent development of CBT in the offspring.

The association of temporomandibular disorder pain with history of head and neck injury in adolescents

AIMS

To evaluate the risk of self-reported temporomandibular disorder (TMD) pain among adolescents in relation to previous head and/or neck injury.

METHODS

3,101 enrollees (11 to 17 years of age) of a nonprofit integrated health-care system were interviewed by telephone. Two hundred four cases with self-reported TMD pain and 194 controls without self-reported TMD pain frequency-matched to the cases by age and gender completed standardized in-person interviews and physical examinations in which reports of previous head/neck injuries were recorded. Odds ratio (OR) estimates and 95% confidence intervals (CIs) of the relative risks of TMD pain associated with prior head and/or neck injuries were calculated using logistic regression.

RESULTS

A greater proportion of subjects reporting TMD pain (36%) than controls (25%) had a history of head and/or neck injuries (OR = 1.8, 95% CI, 1.1-2.8). In a separate analysis, the presence of TMD based upon the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was assessed in relation to prior head and/or neck injury. Cases reporting TMD pain and meeting the RDC/TMD criteria for myofascial pain and/or arthralgia or arthritis were 2.0 (CI, 1.0-3.8) times more likely to have had a prior head injury than were controls with neither self-reported nor RDC/TMD pain diagnoses.

CONCLUSION

The results suggest a modest association of prior head injuries with both self-reported and clinically diagnosed TMD pain in adolescents.

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.

Validity of maternal and perinatal risk factors reported on fetal death certificates

We sought to estimate the accuracy, relative to maternal medical records, of perinatal risk factors recorded on fetal death certificates. We conducted a validation study of fetal death certificates among women who experienced fetal deaths between 1996 and 2001. The number of previous births, established diabetes, chronic hypertension, maternal fever, performance of autopsy, anencephaly, and Down syndrome had very high accuracy, while placental cord conditions and other chromosomal abnormalities were reported inaccurately. Additional population-based studies are needed to identify strategies to improve fetal death certificate data.

Risk of brain tumors in children and susceptibility to organophosphorus insecticides: the potential role of paraoxonase (PON1)

Prior research suggests that childhood brain tumors (CBTs) may be associated with exposure to pesticides. Organophosphorus insecticides (OPs) target the developing nervous system, and until recently, the most common residential insecticides were chlorpyrifos and diazinon, two OPs metabolized in the body through the cytochrome P450/paraoxonase 1 (PON1) pathway. To investigate whether two common PON1 polymorphisms, C-108T and Q192R, are associated with CBT occurrence, we conducted a population-based study of 66 cases and 236 controls using DNA from neonatal screening archive specimens in Washington State, linked to interview data. The risk of CBT was nonsignificantly increased in relation to the inefficient PON1 promoter allele [per PON1(-108T) allele, relative to PON1(-108CC): odds ratio (OR) = 1.4; 95% confidence interval (CI), 1.0-2.2; p-value for trend = 0.07]. Notably, this association was strongest and statistically significant among children whose mothers reported chemical treatment of the home for pests during pregnancy or childhood (per PON1(-108T) allele: among exposed, OR = 2.6; 95% CI, 1.2-5.5; among unexposed, OR = 0.9; 95% CI, 0.5-1.6) and for primitive neuroectodermal tumors (per PON1(-108T) allele: OR = 2.4; 95% CI, 1.1-5.4). The Q192R polymorphism, which alters the structure of PON1 and influences enzyme activity in a substrate-dependent manner, was not associated with CBT risk, nor was the PON1(C-108T/Q192R) haplotype. These results are consistent with an inverse association between PON1 levels and CBT occurrence, perhaps because of PON1's ability to detoxify OPs common in children's environments. Larger studies that measure plasma PON1 levels and incorporate more accurate estimates of pesticide exposure will be required to confirm these observations.

A comparison of record linkage yield for health research using different variable sets

As part of a study on childbearing and survival, we linked records of young women with invasive breast cancer identified through three population-based cancer registries, to state birth certificate records. In Michigan prior to 1989, only maternal social security number (SSN) was available for matching; other data became available in 1989 including name, birth date, address, and infant's surname. To examine the quality of the linkage using SSN as the sole matching criterion, we conducted two procedures using data for 1989-1994 to compare linkages identified by SSN, to linkages identified using other available variables. Linkage was conducted using a deterministic approach based on seven variables and 14 steps. In each step a string of relevant variables was created and in successive phases selected variables were substituted or removed with decreasingly stringent requirements. A manual review was done to check for accuracy. Utilizing all available variables, the linkage process yielded 793 matches (live births) among 4496 patients, 780 [98%] of which would have been identified using SSN alone. Five of seven matches identified by SSN were not confirmed by manual review. SSN appears to be fairly accurate for linkage and can be valuable for linking cancer registries to other data sources.

Hypospadias in Washington State: maternal risk factors and prevalence trends

OBJECTIVE

Maternal risk factors for hypospadias are poorly defined, and there is debate about temporal trends in hypospadias prevalence. We examined select maternal characteristics as possible risk factors for hypospadias among male offspring and evaluated yearly prevalence rates in Washington State.

METHODS

We performed a population-based, case-control study using linked birth-hospital discharge data from Washington State for 1987-1997 and prevalence data for 1987-2002. All cases of hypospadias were identified on the basis of International Classification of Diseases, Ninth Revision, codes from the birth hospitalization (N = 2155). Five control subjects were randomly selected for each case subject from the remaining singleton births, frequency matched according to year of birth (N = 10775). Maternal and infant characteristics were ascertained from the birth certificate. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Yearly prevalence was determined by dividing the total number of hypospadias cases by the number of male singleton live births for each year.

RESULTS

The risk of delivering an affected male infant increased with advancing maternal age; relative to women <20 years of age, those >40 years of age were at greatest risk (OR: 1.70; 95% CI: 1.17-2.48). Infants of nonwhite women were generally at decreased risk. Infants born to women with preexisting diabetes mellitus were at greater risk than those born to women without diabetes (OR: 2.18; 95% CI: 1.03-4.60); however, this was not observed for infants born to women with gestational diabetes. The birth prevalence of hypospadias in 2002 was 5.0 cases per 1000 male births, not significantly different from that in 1987.

CONCLUSION

Older maternal age, white race, and preexisting diabetes were associated with increased risk of hypospadias among male offspring. The prevalence of hypospadias in Washington State did not increase significantly between 1987 and 2002.

Gun storage practices and risk of youth suicide and unintentional firearm injuries

CONTEXT

Household firearms are associated with an elevated risk of firearm death to occupants in the home. Many organizations and health authorities advocate locking firearms and ammunition to prevent access to guns by children and adolescents. The association of these firearm storage practices with the reduction of firearm injury risk is unclear.

OBJECTIVE

To measure the association of specific household firearm storage practices (locking guns, locking ammunition, keeping guns unloaded) and the risk of unintentional and self-inflicted firearm injuries.

DESIGN AND SETTING

Case-control study of firearms in events identified by medical examiner and coroner offices from 37 counties in Washington, Oregon, and Missouri, and 5 trauma centers in Seattle, Spokane, and Tacoma, Wash, and Kansas City, Mo. CASES AND CONTROLS: Case firearms were identified by involvement in an incident in which a child or adolescent younger than 20 years gained access to a firearm and shot himself/herself intentionally or unintentionally or shot another individual unintentionally. Firearm assaults and homicides were excluded. We used records from hospitals and medical examiners to ascertain these incidents. Using random-digit dial telephone sampling, control firearms were identified by identification of eligible households with at least 1 firearm and children living or visiting in the home. Controls were frequency matched by age group and county.

MAIN EXPOSURE MEASURES

The key exposures of interest in this study were: (1) whether the subject firearm was stored in a locked location or with an extrinsic lock; (2) whether the firearm was stored unloaded; (3) whether the firearm was stored both unloaded in a locked location; (4) whether the ammunition for the firearm was stored separately; and (5) whether the ammunition was stored in a locked location. Data regarding the storage status of case and control guns were collected by interview with respondents from the households of case and control firearms.

RESULTS

We interviewed 106 respondents with case firearms and 480 with control firearms. Of the shootings associated with the case firearms, 81 were suicide attempts (95% fatal) and 25 were unintentional injuries (52% fatal). After adjustment for potentially confounding variables, guns from case households were less likely to be stored unloaded than control guns (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.16-0.56). Similarly, case guns were less likely to be stored locked (OR, 0.27; 95% CI, 0.17-0.45), stored separately from ammunition (OR, 0.45; 95% CI, 0.34-0.93), or to have ammunition that was locked (OR, 0.39; 95% CI, 0.23-0.66) than were control guns. These findings were consistent for both handguns and long guns and were also similar for both suicide attempts and unintentional injuries.

CONCLUSIONS

The 4 practices of keeping a gun locked, unloaded, storing ammunition locked, and in a separate location are each associated with a protective effect and suggest a feasible strategy to reduce these types of injuries in homes with children and teenagers where guns are stored.

Maternal infection and risk of cerebral palsy in term and preterm infants

OBJECTIVE

We tested the hypothesis that term and preterm infants exposed to maternal infection at the time of delivery are at increased risk of developing cerebral palsy (CP).

STUDY DESIGN

A population-based case-control study was conducted using Washington State birth certificate data linked to hospital discharge data. Cases (688) were children <or=6 years old, singleton births, hospitalized during 1987 to 1999 with an ICD-9 diagnosis code for CP. Controls were 3,068 singleton birth infants randomly selected from birth records for the same years without CP-related hospitalizations. Infection information was available only for the birth hospitalization.

RESULTS

Infants of women who had any infection during their hospitalization for delivery were at increased risk of CP (odds ratio (OR) 3.1, 95% confidence interval (CI) 2.3 to 4.2). This was observed for term deliveries (OR 1.8, 95% CI 1.1 to 2.8) and preterm deliveries (OR 2.3, 95% CI 1.3 to 4.2).

CONCLUSIONS

Our results suggest that maternal infection is a risk factor for CP in both term and preterm infants.

Household water source and the risk of childhood brain tumours: results of the SEARCH International Brain Tumor Study

BACKGROUND

The period in utero is a time of increased vulnerability. Offspring of pregnant women exposed to carcinogenic substances in drinking water may be more likely to develop cancer. We examined whether household water source and the presence of nitrates or nitrites in residential water were associated with increased risks of childhood brain tumours (CBT).

METHODS

We used data from a multicentre, case-control study with maternal information on residential water source, and nitrate/nitrite levels of tap water measured by dipstick. Subjects included 836 CBT cases and 1485 controls from five countries.

RESULTS

The risks of CBT associated with reliance on well water (versus public water) during pregnancy varied widely, with significantly increased risks noted in two (of seven) regions and a decreased risk observed in one region. CBT risk did not increase with increasing nitrate levels. However, our results based on tap water tested in the pregnancy residences suggest the risk of astrocytoma may be associated with increasing levels of nitrite (odds ratio [OR] = 4.3, 95% CI: 1.4, 12.6 for nitrite levels of 1-<5 mg/l nitrite ion; OR = 5.7, 95% CI: 1.2, 27.2 of nitrite > or =5 mg/l).

CONCLUSIONS

These results should be interpreted with caution because women's recollection of water sources may have contained inaccuracies, and nitrate and nitrite measurements, available for only a portion of subjects, were often obtained years after the pregnancies occurred. However, our results suggest a need for closer evaluation of well water content in some regions and the possibility that a nitrite-related water exposure may be associated with CBT.

Weight Change and the Risk of Gestational Diabetes in Obese Women

BACKGROUND

Obesity is an established risk factor for gestational diabetes. It is not known whether this risk might be reduced through weight loss between pregnancies. We sought to determine whether weight loss between pregnancies reduced the risk of gestational diabetes among obese women.

METHODS

We conducted a population-based cohort study of 4102 women with 2 or more singleton live births in Washington State between 1992 and 1998. All subjects were nondiabetic and obese (at least 200 lbs) at their first birth during these years. Weight change was calculated as the difference between prepregnancy weight for the 2 pregnancies. We estimated relative risks of gestational diabetes at the subsequent delivery through stratified analyses and Mantel-Haenszel estimates.

RESULTS

Thirty-two percent of women lost weight between pregnancies, with a mean weight loss of 23 lbs. Women who lost at least 10 lbs between pregnancies had a decreased risk of gestational diabetes relative to women whose weight changed by less than 10 lbs (relative risk = 0.63; 95% confidence interval = 0.38-1.02, adjusted for age and weight gain during each pregnancy). Of the 61% of women who gained weight between pregnancies, the mean weight gain was 22 lbs. Women who gained at least 10 lbs had an increased risk of gestational diabetes (1.47; 1.05-2.04).

CONCLUSIONS

Even moderate changes in prepregnancy weight can apparently affect the risk of gestational diabetes among obese women. This may offer further motivation for interventions aimed at reducing obesity among women of reproductive age.

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.

J/psi polarization in 800-GeV p-Cu interactions

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).

Childbearing and survival after breast carcinoma in young women

BACKGROUND

Many young patients with breast carcinoma have not started, or completed, their desired families. How childbearing after a diagnosis of breast carcinoma affects survival is of importance to these women and their families. The authors measured relative mortality among young patients with breast carcinoma with and without births occurring after diagnosis.

METHODS

The authors conducted a cohort study using data from three population-based cancer registries in the U.S. (Seattle, Detroit, and Los Angeles), linked to birth certificate data in each state. Four hundred thirty-eight women younger than 45 years of age with primary invasive breast carcinoma were identified as having births after diagnosis. In addition, 2775 comparison women, matched on the basis of age at the time of diagnosis, race/ethnicity, diagnosis year, disease stage, and presence of previous nonbreast primary tumors, were identified among those with breast carcinoma without births after diagnosis. Relative mortality was assessed using multivariable statistical methods.

RESULTS

After adjustment for stage of disease, age at diagnosis, study region, diagnosis year, and race/ethnicity, women with births occurring 10 months or more after diagnosis had a significantly decreased risk of dying (relative Risk [RR] = 0.54, 95% confidence interval [CI], 0.41-0.71) compared to women without subsequent births. Women pregnant at the time of diagnosis had a mortality rate similar to those who did not give birth (RR = 1.10, 95% CI, 0.80-1.60).

CONCLUSIONS

The results of the current study, in light of growing evidence from other studies using various methods, may provide some reassurance to young women with breast carcinoma that subsequent childbearing is unlikely to increase their risk of mortality.

The relationship of placenta previa and history of induced abortion

OBJECTIVES

We evaluated the risk of placenta previa being associated with a history of induced abortion by different surgical procedures.

METHODS

Cases (n=192) were women who had a singleton delivery complicated by placenta previa at a major obstetric care hospital in western Washington state between April 1, 1990 and December 31, 1992. Controls (n=622) were women with singleton deliveries not complicated by placenta previa or abruption. Odds ratios, determined by logistic regression, approximate the relative risks.

RESULTS

Vacuum aspiration abortion was not associated with an increased risk of placenta previa (OR 0.9, 95% CI 0.6-1.5). However, the risk of placenta previa increased with the number of sharp curettage abortions (OR 2.9, 95% CI 1.0-8.5 for > or =3).

CONCLUSIONS

Risk of placenta previa may be increased in a dose response fashion by multiple sharp curettage abortions. However, vacuum aspiration does not confer an increased risk, and may be a better alternative.

Maternal prenatal exposure to nitrosatable drugs and childhood brain tumours

BACKGROUND

A compelling hypothesis was proposed that childhood brain tumours are associated with maternal exposure to N-nitroso compounds during the prenatal period. Many common drugs, such as antihistamines, aspirin, and antibiotics, are nitrosatable and depending upon the product, potentially carcinogenic. We hypothesized that maternal ingestion of certain subgroups of nitrosatable drug products during pregnancy increases the risk of brain tumour development in offspring.

METHODS

Data were collected as part of a population-based case-control study of childhood brain tumours and mothers' self-reported exposure to therapeutic drugs and dietary nitrites. Cases were enrolled from three US West Coast SEER tumour registries: Seattle-Puget sound, Los Angeles County, and the San Francisco-Oakland Bay Area. Tumours were grouped into three major histological tumour subtypes: astroglial, primitive neural ectodermal tumours, and all remaining glial tumours ('other glial'). Therapeutic drugs reported by mothers were translated into active chemical compounds and classified as secondary amines, tertiary amines, amides, or none of the three. Risk estimates were computed according to classes of nitrosatability, potential carcinogenicity, teratogenicity, and predicted end product.

RESULTS

We found no significant association between maternal use of nitrosatable drugs, either overall or within any of the nitrosatable drug classifications, and subsequent development of brain tumours in children. Nitrite consumption from cured meats was not an effect modifier. However, exposure to nitrosoephedrine during pregnancy was associated with significantly increased risk of 'other glial' tumours (OR = 3.1; 95% CI: 1.1-9.2).

CONCLUSIONS

These findings do not support an association between maternal use of nitrosatable drugs during pregnancy and brain tumour risk in offspring. While exposure to the nitrosation end product nitrosoephedrine was associated with increased risk for other glial tumours, the finding was not specific to any one type of tumour.

Farm-related exposures and childhood brain tumours in seven countries: results from the SEARCH International Brain Tumour Study

A total of 1218 cases of childhood brain tumours (CBT) and 2223 control subjects from the general population were included in a population-based case-control study conducted in nine centres in seven countries. Mothers were asked about farm- or agriculture-related exposures. Significantly elevated odds ratios (OR) for CBT were associated with children's personal and maternal prenatal exposure while living on a farm with pigs (child OR = 1.7, mother OR = 2.3), horses (child OR = 1.6, mother OR = 1.8), dogs (child OR = 1.5, mother OR = 1.5) and cats (child OR = 1.5, mother OR = 1.7). Children who were exposed to pigs, horses and cats combined, while living on a farm, had a threefold elevated OR for CBT. Increased ORs for primitive neuroectodermal tumours (PNET) were associated with children's farm exposure to dogs (OR = 1.9) and cats (OR = 2.2), and maternal farm exposure to pigs (OR = 4.2). The OR for CBT was elevated (OR = 2.3) for children of mothers who had preconception/prenatal farm- or agriculture-related employment involving potential contact with animals, relative to no farm- or agriculture-related employment. In particular, increased ORs for CBT were observed for children of mothers who were employed as general farmers (OR = 4.1) or general farm workers (OR = 3.8). During the 5 years preceding the index child's birth, maternal exposures were related to CBT, relative to no maternal exposure to agricultural chemicals or animal products: fertilisers (OR = 1.8), pesticides (OR = 2.0), animal manure (OR = 2.0) and unprocessed wool (OR = 3.0). Our findings suggest that various farm-related exposures are positively associated with CBT and warrant further investigation into the public health importance of these associations.

Relation of childhood brain tumors to exposure of parents and children to tobacco smoke: the SEARCH international case-control study. Surveillance of Environmental Aspects Related to Cancer in Humans

The etiology of childhood brain tumors (CBTs) remains unknown. Tobacco smoke contains several known carcinogens and can induce DNA adducts in human placenta and hemoglobin adducts in fetuses. We present the results of an international case-control study to evaluate the association between CBTs and exposure of parents and children to cigarette smoke. The study was undertaken as part of the SEARCH program of the IARC. Nine centers in 7 countries were involved. The studies mainly covered the 1980s and early 1990s. Cases (1,218, ages 0-19 years) were children newly diagnosed with a primary brain tumor; there were 2,223 population-based controls. Most mothers who agreed to participate were interviewed in person at home. Odds ratios (ORs) were calculated by unconditional logistic regression, adjusted for age, sex and center, for all types of CBT combined, 4 CBT histotypes, 5 age groups and each center. There was no association between the risk of brain tumors in the child and parental smoking prior to pregnancy, maternal smoking or regular exposure to others' cigarette smoke during pregnancy at home or at work, or passive smoking by the child during the first year of life. These results did not change considering the child's age at diagnosis, the histologic type of tumor or center.

West Coast study of childhood brain tumours and maternal use of hair-colouring products

The immature nervous system of the fetus is characterised by rapid cell growth and division and is particularly vulnerable to carcinogens and mutagens. Several epidemiological studies have reported an increased risk for childhood brain tumours (CBT) associated with exposure to N-nitroso compounds (NOC). Hair-colouring products (hair "dyes") that contain NOC-related aromatic amines have shown mutagenicity in vitro and carcinogenic properties in vivo. The potential public health impact of the relationship between hair dye use and carcinogenesis has prompted epidemiological research, given that a large proportion of American women have used hair dyes. A large population-based case-control study was conducted on the west coast of the USA to investigate risk factors for CBT including exposure to NOC. Eligible CBT patients (<20 years of age and diagnosed between 1984 and 1991) were identified from cancer registries in Los Angeles County, the San Francisco Bay Area in California and the Seattle area in Washington state. A total of 540 biological mothers of these children were interviewed, and 801 control subjects who were frequency matched to the CBT patients on birth year and sex were obtained using random digit dialling. Mothers were asked details about personal use of hair dyes during the index pregnancy including frequency of use, trimester of use and type of dye used. Results from age- and sex-adjusted unconditional logistic regression analyses showed no association between risk for CBT and use of hair dyes 1 month before and/or during pregnancy nor during specific trimesters. A nearly twofold increased risk for CBT was associated with single-interval use during the 1 month before pregnancy, but the confidence interval (CI) was imprecise and the estimate was not different from unity (OR = 1.9, 95% CI [0.5, 7.0]). Exclusive use of permanent dye, temporary dye or hair darkeners was not associated with risk for CBT. A twofold increased risk (OR = 2.0, 95% CI [0.83, 4.7]) was observed with exclusive use of semi-permanent dye during the month before or during pregnancy. Exclusive use of semi-permanent dye during the month before pregnancy and/or first trimester also was associated with an elevated risk for CBT, again not different from unity and with an imprecise CI (OR = 2.5, 95% CI = [0.58, 10.3]). There was no evidence of an association between risk for CBT by histological subtypes and use of hair dyes during the index pregnancy or the month before conception. Together with results from previous studies, these results provide no consistent evidence of an association between risk for CBT and use of hair dyes during pregnancy.

The association between breast carcinoma and meningioma in women

BACKGROUND

Published case reports of a possible association between meningioma and breast carcinoma are not uncommon in the literature. Four published analytic studies have addressed this suggested association specifically. Three of these studies reported significant associations, with relative risk estimates mostly between 1.5 and 2.0. The other study reported relative risk point estimates near 1.5, but confidence intervals included 1.0. The current study was a population-based, retrospective cohort analysis that evaluated the risk of subsequent breast carcinoma in women who were diagnosed with meningioma and the risk of subsequent meningioma in women who were diagnosed with breast carcinoma.

METHODS

The measure of association is the relative risk and is reported as the standardized incidence ratio (SIR). Using western Washington State cancer registry data and intercensal population estimates for western Washington State, incidence rates of second primary tumor were compared between identified meningioma and breast carcinoma cohorts and the general population for the years 1992-1998.

RESULTS

The risk of breast carcinoma after patients were diagnosed with meningioma (SIR) was 1.54 (95% confidence interval [95% CI], 0.77-2.75). The risk of meningioma after patients were diagnosed with breast carcinoma was 1.40 (95% CI, 0.67-2.58), and the risk of meningioma after patients were diagnosed with invasive breast carcinoma was 1.64 (95% CI, 0.79-3.02). In each combination for age groups ages > 50 years, risks were elevated, but the confidence intervals included 1.0.

CONCLUSIONS

These results suggest that the risk of meningioma among women who have experienced breast carcinoma and the risk of breast carcinoma among women who have experienced meningioma are elevated moderately. Shared risk factors may account for the relatively week bidirectional associations seen in this and other studies.