Search PubMed⌕ Search

Biomedical subjects

B A Mueller

Publications and source records attributed to B A Mueller.

At least 73 records · Page 4Linked to original sources

Brain tumor risk in children in relation to use of electric blankets and water bed heaters. Results from the United States West Coast Childhood Brain Tumor Study.

The possible relation between the occurrence of brain tumors in children and exposure to electric blankets or electrically heated water beds was investigated in a multicenter, population-based case-control study conducted on the West Coast of the United States. Information on maternal exposure during pregnancy or direct exposure to the subject child was collected by in-person interview from the mothers of 540 case children and 801 control children. Cases were 19 years of age or younger and were diagnosed between 1984 and 1991. Controls were recruited using a random digit dialing procedure. The risk of brain tumor occurrence from in utero exposure to either electric blankets (odds ratio (OR) = 0.9, 95% confidence interval (Cl) 0.6-1.2) or heated water beds (OR = 0.9, 95% Cl 0.6-1.3) was not elevated. Brain cancer risk did not vary by use in any trimester of pregnancy, and children with mothers who reported use throughout their pregnancy had no increased risk. Similar results were observed for exposure to the child, in that no association between brain cancer and use of electric blankets (OR = 1.0, 95% Cl 0.6-1.7) or heated water beds (OR = 1.2, 95% Cl 0.7-2.0) was observed. Risks did not vary significantly by age, sex, race, socioeconomic status, or histologic category for either in utero exposure or child's exposure. This study provides no evidence to support the hypothesis that there is a relation between brain cancer occurrence in children and 50-/60-Hz magnetic field exposure from the use of electric blankets and heated water beds.

Adolescent↗

Childhood brain tumor occurrence in relation to residential power line configurations, electric heating sources, and electric appliance use.

To assess the relation between childhood brain tumor occurrence and exposure to potential sources of residential magnetic fields, a population-based case-control study of incident brain tumors was conducted in the Seattle, Washington, area at the Fred Hutchinson Cancer Research Center from 1989 to 1994 among children younger than age 20 years who were diagnosed from 1984 to 1990. The specific aims were to evaluate whether proximity to high-current residential power lines, as defined by the Wertheimer-Leeper code, or use of electric appliances or electric heating sources by the mother while pregnant or by the child before diagnosis were associated with increased risks of brain tumor occurrence. The mothers of 133 cases and 270 controls (recruited by random digit dialing) participated. Risk of brain tumor occurrence did not increase with increasing exposure, as indicated by the five-level Wertheimer-Leeper code. When exposure was dichotomized as high versus low, the odds ratio was 0.9 (95% confidence interval 0.5-1.5) and did not vary significantly by sex, age, or histology. No elevations in risk were found for ever versus never use of electric blankets, water beds, or electric heating sources. Odds ratios were slightly elevated for nine appliances and were at or below 1.0 for eight others. These data do not support the hypothesis that exposure to magnetic fields from high-current power lines, electric heating sources, or electric appliances is associated with the subsequent occurrence of brain tumors in children.

Adolescent↗

Occupational injuries and medication use.

Recent medication use of 3,394 members of the Group Health Cooperative of Puget Sound (GHC) diagnosed with an incident work-related injury was compared to that of two controls selected from the GHC membership and matched on age, gender, and Standard Industrial Classification Code of their employer. Medication use was determined from the GHC pharmacy data base. The injuries of the cases included 496 fractures or dislocations, 2,728 open wounds, crushing injuries, or superficial injuries, 176 burns, and 64 internal or intracranial injuries. The risk of injury was elevated among users of antihistamines [odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.1-1.9], antibiotics (OR = 1.2, 95% CI = 1.0-1.5), and diabetes medications (OR = 1.3, 95% CI = 0.9-1.9). The patterns of risk were similar for males and females, but varied by type of injury. No consistent associations between use of antidepressants, antianxiety medication, or narcotics and work-related injury were observed. The use of some medications, or conditions requiring medications, may contribute to the risk of a work-related injury.

Accidents, Occupational↗

The validity of police assessment of driver intoxication in motor vehicle crashes leading to hospitalization.

We evaluated the accuracy of the field sobriety assessment of police officers following a motor vehicle crash. Using linked data from a statewide traffic crash database and the trauma center registry, the results of a field sobriety evaluation for each driver were compared with a blood alcohol concentration (BAC) drawn in the emergency department. BAC values served as the "gold standard" in which drivers with values over 0.1 mg/dl were classified as intoxicated. The subjects were drivers over age 15 years who were admitted or died at Level I trauma center as a results of motor vehicle crash injuries during 1986-1993. A total of 1336 subjects had both a recorded BAC and a police sobriety assessment. Seventy percent of subjects were male and 79% under the age of 35 years. Overall, 40% of all subjects were judged by police to have been impaired, based on the scene sobriety assessment. Among all drivers, the field assessment had a sensitivity of 91%, a specificity of 90% and a predictive value positive of 85%. After excluding the 419 drivers which had breath testing as part of their assessment, the field assessment had a sensitivity of 74% and a specificity of 97%. The sensitivity of the field assessment did not vary appreciably by gender but was lower among older drivers, and higher among severely injured drivers and those involved in weekend and nighttime crashes. Police officers in this sample appear to recognize drunk driving with a high degree of accuracy when investigating crashes in which the driver is transported to a trauma center.

Accidents, Traffic↗

Falsely elevated serum vancomycin concentrations in hemodialysis patients.

Fluorescence polarization immunoassay (FPIA) is the most widely used clinical vancomycin assay in the United States. Questions exist regarding the accuracy of this polyclonal assay in patients with end-stage renal disease (ESRD). While several studies have reported discrepancies in vancomycin serum concentrations determined by FPIA compared with other vancomycin assays, no study has investigated the accuracy of vancomycin serum concentrations determined by FPIA in patients with ESRD undergoing maintenance hemodialysis. Therefore, we compared the assay performance of FPIA and enzyme multiplied immunoassay technique (EMIT) in six subjects with ESRD receiving high-efficiency hemodialysis. Subjects underwent 6 consecutive weeks of hemodialysis treatment with a cellulose acetate dialyzer (CA210) and received 1 g vancomycin intravenously once weekly during the last hour of dialysis. Vancomycin serum concentrations were determined by both EMIT and FPIA methodologies. From the serum concentration results of both assays, vancomycin dosing recommendations were calculated to achieve a desired steady-state peak concentration of 35 mg/L and trough concentration of 10 mg/L. Overall, vancomycin serum concentrations reported by FPIA were significantly higher than those reported by EMIT. The mean difference between assays in the peak serum concentrations at weeks 1, 4, and 6 was 7.5, 11.5, and 11.2 mg/L, respectively. The mean difference in trough serum concentrations at weeks 1, 4, and 6 was 4.2, 6.2, and 5.2 mg/L, respectively. The FPIA overestimation of the EMIT values (calculated as FPIA-EMIT) varied widely among study subjects with a range of 0.0 mg/L to 27.0 mg/L for peak serum concentrations and 0.0 mg/L to 12.8 mg/L for trough serum concentrations. The mean doses calculated based on FPIA results were significantly lower than the EMIT-derived doses. No significant difference was observed in the calculated dosing intervals. These results demonstrate that FPIA significantly overestimates vancomycin serum concentrations compared with EMIT in patients with ESRD undergoing high-efficiency hemodialysis. The overestimation by FPIA may result in significantly different vancomycin dosing recommendations, leading to underdosing and the potential for therapeutic failures. Due to the unpredictability of the overestimation by FPIA, we were unable to formulate vancomycin dosing guidelines for institutions that use FPIA. Therefore, we recommend that the EMIT vancomycin assay be used in patients with ESRD to ensure appropriate dosing.

Adult↗

The risk of diabetes in a subsequent pregnancy associated with prior history of gestational diabetes or macrosomic infant.

Prior studies suggest that diagnosis of gestational diabetes is associated with increased risk for development of gestational diabetes in future pregnancies, and with subsequent onset of established diabetes. The magnitudes of these risks have not been measured. Using linked birth certificate data from Washington State it is possible to identify all women with two or more births occurring during 1984-91. All women with gestational diabetes (n=1375) or with established diabetes (n=220), during their pregnancy for the second or greater birth were identified, and a control group consisting of women whose second or greater birth was not complicated by either condition was randomly selected (n=6380). Data from the birth certificate, for the previous birth, were compared in order to estimate the risks of developing gestational or established diabetes in a subsequent pregnancy among women with prior gestational diabetes relative to women without gestational diabetes. The age-adjusted risk of developing gestational diabetes in the pregnancy for the subsequent birth associated with prior gestational diabetes was 23.2 (95% (confidence interval) CI = 17.2-31.2); the risk of having developed established diabetes by the time of the subsequent birth was 55.5 (95% CI = 34.4-89.4). Women who had a macrosomic infant (>4000 gm) in the prior birth were also at increased risk for developing gestational diabetes (odds ratio OR = 3.3, 95% CI = 2.9-3.8) or established diabetes (OR = 5.8, 95% CI = 4.0-8.5). When data were restricted to patients with only one prior birth, to patients with early prenatal care, to delivery at facilities with long-established protocols for diagnosing gestational diabetes, or to more recent years, the risk estimates remained similarly elevated. The 23-fold increased risk of gestational diabetes associated with having gestational diabetes indicated on the birth certificate of a woman's previous baby, although not unexpected, is still remarkable and reinforces the importance of careful monitoring of women with this history. Although changes in how screening is conducted may account for some of the elevation in risk, our results stayed consistently elevated even when restrictions were made within the data to control for this. The fact that there was a 56-fold increased risk of having developed established diabetes by the time of the subsequent birth on record, associated with prior gestational diabetes, and a 6-fold increased risk associated with a macrosomic infant, supports the idea that these may be early steps in the development of established diabetes, and identifies a group that may benefit from close monitoring and possible intervention.

Birth Weight↗

Semen quality of men employed at a lead smelter.

OBJECTIVE: To evaluate the effects of recent and long term occupational lead exposure on indicators of male reproductive health. METHODS: In a cross sectional study of male employees of a lead smelter (n = 2469), blood samples were obtained from 152 workers including 119 who also provided semen samples. Semen analysis and serum concentrations of testosterone, follicle stimulating hormone, and luteinising hormone were used as indicators of reproductive health. Semen and hormone variables were examined in relation to measures of current and long term body lead burden estimated from current blood lead concentrations and historical blood lead monitoring data. RESULTS: For current blood lead concentration groups of < 15, 15-24, 25-39, > 40 micrograms/dl, the geometric mean sperm concentrations were, respectively, 79.1, 56.5, 62.7, and 44.4 million cells/ml and geometric mean total sperm counts were 186, 153, 137, and 89 million cells (P for trend 0.04). Compared with workers with blood lead concentrations less than 15 micrograms/dl, workers with current blood lead concentrations of 40 micrograms/dl or more had an increased risk of below normal sperm concentration (odds ratio (OR) 8.2, 95% confidence interval (95% CI) 1.2-57.9) and total sperm count (OR 2.6, 95% CI 0.4-15.7), based on World Health Organisation standards. Independent of current lead exposure, sperm concentration, total sperm count, and total motile sperm count were inversely related to measures of long term lead exposure. No association was found between lead exposure and measures of sperm motility, sperm morphology, or serum concentrations of reproductive hormones. CONCLUSIONS: Blood lead concentrations below the currently accepted worker protection criteria seem to adversely affect spermatogenesis.

Adult↗

Maternal smoking during pregnancy and the risk of congenital urinary tract anomalies.

To study maternal smoking during pregnancy and the risk of congenital urinary tract anomalies, we interviewed mothers of 118 affected infants born to residents of western Washington State during 1990 and 1991 and mothers of 369 control infants randomly selected from those without birth defects delivered during those years in five hospitals in King County, Washington. Maternal smoking was associated with an increased risk of congenital urinary tract anomalies in offspring (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.2, 4.5). This risk was higher among light smokers (1-1000 cigarettes during the pregnancy) (OR = 3.7; 95% CI = 1.7, 8.6) than among heavy smokers (OR = 1.4; 95% CI = 0.6, 3.3). Our results corroborate previous findings and support the hypothesis of a causal relation.

Adult↗

Maternal consumption of cured meats and vitamins in relation to pediatric brain tumors.

Brain tumors are the leading cause of death from childhood cancer, yet the causes of most of these tumors remain obscure. Few chemicals are effective in causing brain tumors experimentally after systemic administration of low doses; a notable exception is one group of N-nitroso compounds, the nitrosamides (in particular the nitrosoureas). Feeding pregnant animals nitrosamide precursors (e.g., sodium nitrite and an alkylamide such as ethylurea) causes a high incidence of nervous system tumors in offspring. This population-based epidemiological study was designed to test the hypothesis that maternal consumption during pregnancy of meats cured with sodium nitrite increases the risk of brain tumors among offspring. The intake of vitamins C and E blocks endogenous formation of nitroso compounds and was expected to be protective. Mothers of 540 children under age 20 with a primary brain tumor diagnosed during 1984-1991 and 801 control children in the same 19 counties on the U.S. West Coast were interviewed. Risk increased with increasing frequency of eating processed meats [odds ratio (OR) = 2.1 for eating at least twice a day compared to not eating; 95% confidence interval (CI) = 1.3-3.2; P = 0.003). Risk also increased with increasing average daily grams of cured meats or mg of nitrite from cured meats (P for each <0.005) but not with nitrate from vegetables. Daily use of prenatal vitamins throughout the pregnancy decreased risk (OR = 0.54; CI = 0.39-0.75). Risk among mothers who consumed above the median level of nitrite from cured meat was greater if vitamins were not taken (OR = 2.4; CI = 1.4-3.6) than if they were (OR = 1.3). These effects were evident for each of three major histological types and across social classes, age groups, and geographic areas. This largest study to date of maternal diet and childhood brain tumors suggests that exposure during gestation to endogenously formed nitroso compounds may be associated with tumor occurrence. Laboratory exploration is needed to: (a) define dietary sources of exposure to alkylamides; (b) investigate the reactivity of nitrite in high concentration such as around bits of cured meats in the stomach after ingestion compared to nitrite in dilute solution; and (c) confirm that simultaneous ingestion of alkylamides and cured meats leads to the endogenous formation of nitrosamides.

Adolescent↗

Prenatal exposure to tobacco smoke and childhood brain tumors: results from the United States West Coast childhood brain tumor study.

Data from a large, population-based case-control study were analyzed to investigate the relationship between prenatal exposure to tobacco smoke and childhood brain tumors (CBTs). A total of 540 CBT patients, diagnosed between 1984 and 1991, were identified from population-based tumor registries in 19 West Coast counties that included Seattle, WA (13 counties), San Francisco, CA (5 counties), and Los Angeles, CA (1 county). Random digit dial was used to select 801 control subjects from the three geographical regions to obtain a case:control ratio of 1:2 in San Francisco and Seattle and 1:1 in Los Angeles. The data first were analyzed separately by geographical site and then were combined with adjustments made for gender, age at the time of diagnosis (or reference date of control subjects), birth year of the index child, and maternal race. No association was found between the risk of CBTs and maternal or paternal smoking before pregnancy and there was no association between CBTs and maternal smoking during pregnancy [odds ratio (OR) = 0.98; 95% confidence interval (CI) = 0.72-1.3]. A slightly increased OR for CBTs was found for paternal smoking during pregnancy in the absence of maternal smoking (OR = 1.2; 95% CI = 0.90-1.5) and for maternal exposure to passive smoke from any source (OR = 1.2; 95% CI = 0.95-1.6). The results of this analysis are consistent with results from several prior epidemiological studies that showed no significant association between CBTs and maternal smoking before or during pregnancy or maternal exposure to passive smoke during pregnancy.

Adolescent↗

Head injury as a risk factor for brain tumors in children: results from a multicenter case-control study.

We evaluated the risk of brain tumor occurrence in relation to previous head injury in a population-based case-control study of 540 children with a primary brain tumor and 801 control children. The risk of a brain tumor among children with a previous head injury that resulted in medical attention was slightly elevated when compared with children with no reported head injury [odds ratio (OR) = 1.4; 95% confidence limits (CL) = 1.0, 1.9]. This effect was stronger when we restricted the head-injured group to the few children with loss of consciousness (OR = 1.6; 95% CL = 0.6, 3.9) or an overnight admission to a hospital (OR = 1.7; 95% CL 0.7, 4.6), relative to those with no head injury. We observed no appreciable association between brain tumor occurrence and birth injury involving the head or a forceps delivery. Among the few children with either a birth injury or forceps delivery and a subsequent head injury, we observed approximately twofold elevations in risk. The OR was 2.6 (95% CL = 1.1, 6.9) for those with a birth injury and subsequent head injury, relative to those with neither a birth injury nor head injury. Our results provide only weak evidence in support of head injury as an etiologic agent for brain tumor occurrence in children, although most of our exposed group had only mild head injury.

Adolescent↗

Kawasaki syndrome in Washington State. Race-specific incidence rates and residential proximity to water.

OBJECTIVES: To calculate race-specific incidence rates of Kawasaki syndrome (KS) and to assess the association of KS with residential proximity to water in Washington State. DESIGN: Incidence study over 4 1/2 years, using cases identified with a new statewide hospital data set and a case-control study. SETTING: King, Pierce, and Snohomish counties in Washington State. PATIENTS: One hundred twelve population-based incident cases meeting Centers for Disease Control and Prevention criteria for KS. MAIN OUTCOME MEASURES: Race-specific KS incidence rates and distance to permanent bodies of water among KS cases and matched controls. RESULTS: For the years 1985 through 1986 and 1987 through 1989, the annual KS incidence rates were 6.5 and 15.2 per 100,000 children younger than 5 years, respectively. Rates were highest among Asian Americans (33.3 per 100,000 children younger than 5 years in the 1987-1989 period), followed by blacks and whites (23.4 and 12.7 per 100,000 children younger than 5 years, respectively). The median distance to water did not differ between cases and controls and the proportion of cases living within 150 yd (135 m) of water was no greater than that of controls (odds ratio, 1.0; 95% confidence interval, 0.1 to 20.9). CONCLUSIONS: With complete ascertainment of incident-hospitalized cases of KS, the race-specific rates are among the highest documented in the United States. The rate among Asian Americans was less than that found in Japan, perhaps due to differences in environmental exposures or variations in susceptibility among different Asian ethnic groups. Although we found no association with permanent bodies of water, future studies of KS should include home inspection to assess exposure to temporary collections of standing water.

Black or African American↗

Oral contraceptive use after conception in relation to the risk of congenital urinary tract anomalies.

The authors conducted a case-control study of the relation of OC use after conception to the occurrence of congenital urinary tract anomalies (CUTAs). Singleton CUTA cases with no known chromosomal abnormality from seven counties in western Washington State born during the period January 1, 1990-December 31, 1991 were identified through the Washington State Birth Defect Registry. Controls without birth defects were randomly selected from singleton births that occurred in the same year as the cases in five large hospitals in King County. Mothers of the 118 cases and 369 controls were interviewed to obtain their contraceptive history as well as other information. Mothers of nine cases (7.6%) and eight controls (2.2%) had taken OCs at some time during the pregnancy. After adjustment for birth year and county of maternal residence, OC use after conception was associated with an almost five-fold increased risk of having a baby with a CUTA [odds ratio (OR) = 4.8, 95 percent confidence interval (CI), 1.6-14.1] relative to no contraception at or after conception. Use of other contraceptive methods after conception was not related to the risk of CUTAs. OC use during the 3 or 6 months prior to the conception also was not associated with the risk of CUTAs. Further adjustment for sociodemographic factors, reproductive history, perinatal exposure to exogenous agents, and past OC use did not change the results, nor did restricting the analysis to residents of King County.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗