Biomedical subjects

Michael Goodman

Publications and source records attributed to Michael Goodman.

At least 19 recordsLinked to original sources

PubMed2025

Multicenter Evaluation of a New Strip-Based Blood Glucose System for Point-of-Care Testing in Critical and Non-Critical Care Settings.

BACKGROUND: Evaluation of the performance of Cobas® Pulse (Roche Diagnostics GmbH, Mannheim, Germany), a new blood glucose (BG) monitoring system (BGMS; referred to here as BGMSA) intended for point-of-care testing using samples from patients in diverse clinical settings by intended point-of-care test operators. METHODS: Arterial, capillary, venous, or heel stick whole blood (WB) samples from patients in non-critical and critical care settings were collected and analyzed using BGMSA and the Nova StatStrip® BGMS (Nova Biomedical, Waltham, MA; referred to here as BGMSB), and a hexokinase comparator (Cobas 6000 Analyzer Series; Roche Diagnostics GmbH). The blood glucose measurement accuracy was assessed by the Food and Drug Administration guidance criteria. RESULTS: Two studies are presented. In the first, 2678 samples (622 arterial, 706 capillary, 1203 venous, 147 heel stick) were collected from 1577 patients in 14 US and three European sites. All accuracy criteria were met for arterial and venous samples considering all data combined. BGMSA showed better accuracy than BGMSB for arterial, venous, and heel stick, and similar results to BGMSB for capillary WB vs venous comparator. No endogenous interference from pO2, hematocrit, and sodium was identified. BGMSA was also accurate when analyzing contrived samples used to show accuracy over a wide range of glucose concentrations, alone and when combined with extreme hematocrit. In the second study, 117 capillary fingerstick samples collected at one US site were measured on both BGMSA and the comparator, and all accuracy criteria were met. No clinically significant medical risks were observed via Diabetes Technology Society Error Grids. CONCLUSIONS: BGMSA was effective for determining blood glucose in venous, arterial, neonatal arterial, neonatal heel stick, and capillary WB samples.

Humans↗

PubMed2007

Neuroblastoma in adults: Incidence and survival analysis based on SEER data.

PURPOSE: Clinical data on survival outcomes of adult patients (defined as 20 years of age and older) with neuroblastoma are scarce due to the rarity of the disease. Small single institution reports have described worse outcomes for adults than pediatric patients. MATERIALS/METHODS: Data from the public access Surveillance Epidemiology and End Results database were reviewed for a 30-year period between 1973 and 2002 for the diagnosis of neuroblastoma. Analyses compared frequency and survival rates of neuroblastoma among children and adults with particular focus on the incidence, case characteristics, and long-term survival of the adult patients. RESULTS: The observed 3- and 5-year survival rates were lowest among adult patients (45.9% and 36.3%, respectively), whereas infants fared best with 86.0% 3-year and 84.6% 5-year overall survival. There was a steady decline in the incidence of adult neuroblastoma from 0.47 cases per million per year in 1973-1977 to 0.12 cases per million per year in 1998-2002. When the long-term adult neuroblastoma survival was examined in detail for 1-, 3-, 5-, 7-, and 10-year follow-up periods, there was continuous decrease in survival during the first 7 years after the diagnosis with subsequent stabilization for both observed (OS) and relative survival (RS) rates. There was a notable trend towards improved outcome over the past three decades. CONCLUSIONS: Adults with neuroblastoma have significantly worse outcome than children. This may be due to tumor biology, more virulent clinical course, or possibly due to the fact that adults are less sensitive or have poor tolerance to pediatric chemotherapy regimens.

Adolescent↗

PubMed2007

Study design options in evaluating gene-environment interactions: practical considerations for a planned case-control study of pediatric leukemia.

BACKGROUND: We compare methodological approaches for evaluating gene-environment interaction using a planned study of pediatric leukemia as a practical example. We considered three design options: a full case-control study (Option I), a case-only study (Option II), and a partial case-control study (Option III), in which information on controls is limited to environmental exposure only. PROCEDURE: For each design option we determined its ability to measure the main effects of environmental factor E and genetic factor G, and the interaction between E and G. Using the leukemia study example, we calculated sample sizes required to detect and odds ratio (OR) of 2.0 for E alone, an OR of 10 for G alone and an interaction G x E of 3. RESULTS: Option I allows measuring both main effects and interaction, but requires a total sample size of 1,500 cases and 1,500 controls. Option II allows measuring only interaction, but requires just 121 cases. Option III allows calculating the main effect of E, and interaction, but not the main effect of G, and requires a total of 156 cases and 133 controls. CONCLUSIONS: In this case, the partial case-control study (Option III) appears to be more efficient with respect to its ability to answer the research questions for the amount of resources required. The design options considered in this example are not limited to observational epidemiology and may be applicable in studies of pharmacogenomics, survivorship, and other areas of pediatric ALL research.

Age of Onset↗

PubMed2006

Hershey Medical Center Technical Workshop Report: optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure.

Neurodevelopmental disabilities affect 3-8% of the 4 million babies born each year in the U.S. alone, with known etiology for less than 25% of those disabilities. Numerous investigations have sought to determine the role of environmental exposures in the etiology of a variety of human neurodevelopmental disorders (e.g., learning disabilities, attention deficit-hyperactivity disorder, intellectual disabilities) that are manifested in childhood, adolescence, and young adulthood. A comprehensive critical examination and discussion of the various methodologies commonly used in investigations is needed. The Hershey Medical Center Technical Workshop: Optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure provided such a forum for examining these methodologies. The objective of the Workshop was to develop scientific consensus on the key principles and considerations for optimizing the design and interpretation of epidemiologic studies of in utero exposure to environmental chemicals and subsequent neurodevelopmental effects. (The Panel recognized that the nervous system develops post-natally and that critical periods of exposure can span several developmental life stages.) Discussions from the Workshop Panel generated 17 summary points representing key tenets of work in this field. These points stressed the importance of: a well-defined, biologically plausible hypothesis as the foundation of in utero studies for assessing neurodevelopmental outcomes; understanding of the exposure to the environmental chemical(s) of interest, underlying mechanisms of toxicity, and anticipated outcomes; the use of a prospective, longitudinal cohort design that, when possible, runs for periods of 2-5 years, and possibly even longer, in an effort to assess functions at key developmental epochs; measuring potentially confounding variables at regular, fixed time intervals; including measures of specific cognitive and social-emotional domains along with non-cognitive competence in young children, as well as comprehensive measures of health; consistency of research design protocols across studies (i.e., tests, covariates, and analysis styles) in an effort to improve interstudy comparisons; emphasis on design features that minimize introduction of systematic error at all stages of investigation: participant selection, data collection and analysis, and interpretation of results; these would include (but not be limited to) reducing selection bias, using double-blind designs, and avoiding post hoc formulation of hypotheses; a priori data analysis strategies tied to hypotheses and the overall research design, particularly for methods used to characterize and address confounders in any neurodevelopmental study; actual quantitative measurements of exposure, even if indirect, rather than methods based on subject recall; careful examination of standard test batteries to ensure that the battery is tailored to the age group as well as what is known about the specific neurotoxic effects on the developing nervous system; establishment of a system for neurodevelopmental surveillance for tracking the outcomes from in utero exposure across early developmental time periods to determine whether central nervous system injuries may be lying silent until developmentally challenged; ongoing exploration of computerized measures that are culturally and linguistically sensitive, and span the age range from birth into the adolescent years; routine incorporation of narrative in manuscripts concerning the possibility of spurious (i.e., false positive and false negative) test results in all research reportage (this can be facilitated by detailed, transparent reporting of design, covariates, and analyses so that others can attempt to replicate the study); forthright, disciplined, and intellectually honest treatment of the extent to which results of any study are conclusive--that is, how generalizable the results of the study are in terms of the implications for the individual study participants, the community studied, and human health overall; confinement of reporting to the actual research questions, how they were tested, and what the study found, and avoiding, or at least keeping to a minimum, any opinions or speculation concerning public health implications; education of clinicians and policymakers to critically read scientific reports, and to interpret study findings and conclusions appropriately; and recognition by investigators of their ethical duty to report negative as well as positive findings, and the importance of neither minimizing nor exaggerating these findings.

Biomedical Research↗

PubMed2006

The value of digital rectal examination as a predictor of prostate cancer diagnosis among United States Veterans referred for prostate biopsy.

BACKGROUND: As digital rectal examination (DRE) remains an essential part of a routine physical examination, it is important to understand its diagnostic value in different circumstances. AIM: To quantify sensitivity, specificity and predictive value of DRE as a predictor of biopsy-confirmed prostate cancer in the US Veteran population. METHODS: The study group included 628 consecutive patients who underwent transrectal biopsy for suspected prostate cancer due to abnormal digital examination of the prostate, elevated serum prostate specific antigen (PSA) or both. The DRE results reported in this study are documented during physical examinations that were performed after referral for biopsy. The relation between DRE results and positive biopsy was examined while taking into consideration demographic and clinical patient characteristics. RESULTS: Among men with normal PSA the adjusted odds ratio (OR) reflecting the association between abnormal DRE and positive prostate biopsy was 0.53 with a 95% confidence interval (CI) from 0.27 to 1.06. In the presence of a moderately elevated (4.1-10 ng/mL) PSA, the OR was 1.07 (0.72-1.60). When serum PSA exceeded 10 ng/mL, the OR was 2.15 (1.12-4.43). The positive predictive value of an abnormal DRE varied widely from as high as 81% to as low as 14% depending on the other patient characteristics. DISCUSSION: These results indicate that DRE results are most informative when evaluated in conjunction with other clinical and demographic information.

Adult↗

PubMed2006

Radical prostatectomy for clinical T4 prostate cancer.

BACKGROUND: Occasionally, patients with clinical T4 (cT4) prostate cancer undergo surgery. Published data on outcomes after radical prostatectomy (RP) in patients with such advanced stage disease and on the impact of adjuvant radiation therapy (RT) and hormone therapy (HT) are nonexistent. METHODS: Data from the Surveillance Epidemiology and End Results (SEER) data base were reviewed for the 7-year period from 1995 to 2001. Specifically, data were analyzed for 1093 patients with cT4, lymph node-negative or lymph node-positive, M0 prostate cancer without distant lymph node involvement or a history of other cancer. Using follow-up data through 2002, postdiagnosis survival was examined in 5 treatment groups: radical prostatectomy (RP) either alone or in combination with other therapy, radiation therapy (RT) alone, hormone therapy (HT) alone, RT plus HT, and no treatment (NT). All results were expressed as 1-year, 3-year, and 5-year observed survival and corresponding relative survival. Mortality across treatment categories was compared by using a Cox proportionate hazards model controlling for age, year of diagnosis, race, tumor grade, regional lymph node involvement, clinical tumor extension, and SEER registry. RESULTS: Observed and relative survival rates were lowest among patients who received NT and highest among patients who underwent RP. Adding adjuvant RT or HT to RP conferred no survival benefit. Multivariate survival analyses revealed a significant increase in mortality among HT-only patients and among patients who received NT compared with patients who underwent RP. The differences in survival among treatment types were most pronounced in a relatively small group of patients who had positive regional lymph node extension. In all other patients, the results suggested a modest (but not significant) improvement in survival after RT plus HT. CONCLUSIONS: SEER data revealed that patients who underwent RP for cT4 prostate cancer had increased survival compared with patients who received RT alone or HT alone and had a survival comparable to that of patients who received RT plus HT. The benefit of RP appears to be limited to a relatively small subset of patients who have regional lymph node extension.

Aged↗

PubMed2006

Is the association between cigarette smoking and breast cancer modified by genotype? A review of epidemiologic studies and meta-analysis.

Epidemiologic studies have examined the association between cigarette smoking and breast cancer risk according to genotype with increasing frequency, commensurate with the growing awareness of the roles genes play in detoxifying or activating chemicals found in cigarette smoke and in preventing or repairing the damage caused by those compounds. To date, approximately 50 epidemiologic studies have examined the association between smoking and breast cancer risk according to variation in genes related to carcinogen metabolism, modulation of oxidative damage, and DNA repair. Some of the findings presented here suggest possible effect modification by genotype. In particular, 14 epidemiologic studies have tended to show positive associations with long-term smoking among NAT2 slow acetylators, especially among postmenopausal women. Summary analyses produced overall meta-relative risk (RR) estimates for smoking of 1.2 [95% confidence interval (95% CI), 1.0-1.5] for rapid acetylators and 1.5 (95% CI, 1.2-1.8) for slow acetylators. After stratification by menopausal status, the meta-RR for postmenopausal slow acetylators was 2.4 (95% CI, 1.7-3.3), whereas similar analyses for the other categories showed no association. In addition, summary analyses produced meta-RRs for smoking of 1.1 (95% CI, 0.8-1.4) when GSTM1 was present and 1.5 (95% CI, 1.1-2.1) when the gene was deleted. Overall, however, interpretation of the available literature is complicated by methodologic limitations, including small sample sizes, varying definitions of smoking, and difficulties involving single nucleotide polymorphism selection, which likely have contributed to the inconsistent findings. These methodologic issues should be addressed in future studies to help clarify the association between smoking and breast cancer.

Arylamine N-Acetyltransferase↗

PubMed2006

Lycopene intake and prostate cancer risk: effect modification by plasma antioxidants and the XRCC1 genotype.

Lycopene has been associated with reduced prostate cancer risk, although the results of epidemiological studies have varied. We hypothesize that an effect of lycopene may be modified by XRCC1 genotype and other antioxidants. We used a food-frequency questionnaire to assess lycopene intake in a case-control study of prostate cancer in North Carolina. Plasma alpha-tocopherol and beta-carotene levels were measured using high-performance liquid chromatography. XRCC1 genotypes were detected using polymerase chain reaction-restriction fragment length polymorphism. The final dataset included 77 cases and 174 controls with complete questionnaires, genotyping, and plasma analyses. Among men with the Arg/Arg genotype at codon 399, odds ratios (ORs) for prostate cancer risk associated with medium (732-1,529 microg/day) and high (>1,529 microg/day) lycopene intake were 0.59 (95% confidence interval = 0.23-1.50) and 0.21 (0.06-0.71), respectively (P(trend) < 0.01). Similar analyses for persons with Arg/Gln or Gln/Gln genotypes produced null results. Above-median (1,048 microg/day) lycopene intake combined with above-median levels of alpha-tocopherol and beta-carotene was associated with an OR of 0.11 (0.02-0.65) among men with the Arg/Arg genotype but not those with at least one Gln allele (P(interaction) = 0.01). Although limited by small sample size, these findings indicate that the association between lycopene and prostate cancer is complex and may be modified by other antioxidants and by XRCC1 genotype.

Aged↗

PubMed2005

Allelic imbalances of chromosomes 8p and 18q and their roles in distant relapse of early stage, node-negative breast cancer.

INTRODUCTION: Identification of breast cancer patients at risk for postoperative distant relapse is an important clinical issue. Existing pathological markers can predict disease recurrence only to a certain extent, and there is a need for more accurate predictors. METHODS: Using 'counting alleles', a novel experimental method, we determined allelic status of chromosomes 8p and 18q in a case-control study with 65 early stage, node negative, invasive ductal carcinomas (IDCs). The association between allelic imbalance (AI) of both chromosomal markers and distant relapses was examined. RESULTS: Eighty percent of tumors contained 8pAI and sixty-eight percent of tumors contained 18qAI. However, none of the tumor samples retained both chromosome 8p and 18q alleles. More importantly, tumors with 8pAI but not 18qAI were more likely to have distant relapse compared to tumors with 18qAI but not 8pAI. CONCLUSION: Our finding suggests that differential allelic loss of chromosomes 8p and 18q may represent subtypes of early stage IDC with different tumor progression behaviors.

Adult↗

PubMed2005

Active surveillance of vaccine safety: a system to detect early signs of adverse events.

BACKGROUND: There currently are no population-based systems in the United States to rapidly detect adverse events after newly introduced vaccines. To evaluate the feasibility of developing such systems, we used 5 years of data from 4 health maintenance organizations within the Centers for Disease Control and Prevention (CDC) Vaccine Safety Datalink. METHODS: Within every year, each week's vaccinated children were followed for 4 weeks, and rates of adverse events were compared with rates among children of similar ages before the introduction of the new vaccine. We assessed risks for intussusception after rotavirus vaccination and risks for fever, seizures, and other neurologic adverse events after the change from whole cell diphtheria-tetanus-pertussis (DTPw) to acellular DTP vaccine (DTPa). We used sequential probability ratio testing, adjusted for age, sex, calendar time, season, and HMO, and with a stopping value based on the probability of an adverse event under the null hypothesis and under a preset alternative hypothesis. RESULTS: We detected an increase in intussusception after 2589 vaccine doses of rotavirus vaccine, about the same time initial reports of intussusception were made to the Vaccine Adverse Events Reporting System. Decreases in risk for fever, seizures, and other abnormal neurologic events became detectable within 12 weeks, 42 weeks, and 18 months, respectively, after the change from DTPw to DTPa. CONCLUSIONS: We conclude that it is feasible to develop systems for rapid and routine population-based assessments of new vaccine safety.

Databases, Factual↗

PubMed2005

Evaluation of exposure to arsenic in residential soil.

In response to concerns regarding arsenic in soil from a pesticide manufacturing plant, we conducted a biomonitoring study on children younger than 7 years of age, the age category of children most exposed to soil. Urine samples from 77 children (47% participation rate) were analyzed for total arsenic and arsenic species related to ingestion of inorganic arsenic. Older individuals also provided urine (n = 362) and toenail (n = 67) samples. Speciated urinary arsenic levels were similar between children (geometric mean, geometric SD, and range: 4.0, 2.2, and 0.89-17.7 microg/L, respectively) and older participants (3.8, 1.9, 0.91-19.9 microg/L) and consistent with unexposed populations. Toenail samples were < 1 mg/kg. Correlations between speciated urinary arsenic and arsenic in soil (r = 0.137, p = 0.39; n = 41) or house dust (r = 0.049, p = 0.73; n = 52) were not significant for children. Similarly, questionnaire responses indicating soil exposure were not associated with increased urinary arsenic levels. Relatively low soil arsenic exposure likely precluded quantification of arsenic exposure above background.

Adolescent↗

PubMed2005

Postoperative survival and the number of lymph nodes sampled during resection of node-negative non-small cell lung cancer.

STUDY OBJECTIVE: To examine the association between postoperative survival and the number of lymph nodes (LNs) examined during surgery among persons who underwent definitive resection of node-negative (stage IA or stage IB) non-small cell lung cancer (NSCLC). DESIGN AND SETTING: Information on postoperative survival and the number of LNs examined during surgery for stage I NSCLC treated with definitive surgical resection was retrieved from the population-based Surveillance, Epidemiology and End Results database for the period from 1990 to 2000. The association between survival and the number of LNs was examined using multivariate Cox proportional hazard models with adjustment for age, race, sex, type of surgery performed, and tumor size, grade, and histology. RESULTS: A total of 16,800 patients were included in the study. The overall survival analysis for patients without radiation therapy (RT) demonstrated that in comparison to the reference group (one to four LNs), patients with five to eight LNs examined during surgery had a modest but statistically significant increase in survival, with a proportionate hazard ratio (HR) of 0.90 and a 95% confidence interval (CI) of 0.84 to 0.97. Similar results for 9 to 12 LNs and 13 to 16 LNs examined produced further increases in survival, with HRs of 0.86 (95% CI, 0.79 to 0.95) and 0.78 (95% CI, 0.68 to 0.90), respectively. There appeared to be no incremental improvement after evaluating > 16 LNs. The corresponding results for lung cancer-specific mortality and for patients receiving RT were not substantially different. The highest median survival (97 months) occurred in patients with 10 to 11 LNs evaluated. CONCLUSIONS: Our results indicate that patient survival following resection for NSCLC is associated with the number of LNs evaluated during surgery. This is likely due to reduction of staging error: a decreased likelihood of missing positive LNs with an increasing number of LNs sampled. Although we are reluctant to recommend a definitive "optimal number," our data support the conclusion that an evaluation of nodal status should include somewhere from 11 to 16 LNs.

Adult↗

PubMed2005

HIV intervention research for men who have sex with men: a 7-year update.

We conducted a systematic review and meta-analysis to locate, characterize, and summarize effects of behavioral HIV prevention interventions for men who have sex with men (MSM). We found 54 interventions with 16,224 participants that were evaluated in 40 randomized trials and controlled observational studies with independent comparison groups. Formats included 26 small group interventions, 18 individual-level interventions, and 10 community-level interventions. Fifteen interventions focused on HIV-positive individuals including MSM. The 38 interventions that were compared with minimal or no HIV prevention interventions, reduced unprotected sex by 27% (95% confidence interval [CI] = 15-37%). The other 16 interventions reduced unprotected sex by 17% beyond changes observed in standard or other HIV prevention interventions (CI = 5-27%). Behavioral interventions reduce self-reported unprotected sex among MSM.

HIV Infections↗

PubMed2004

Surgical margin and Gleason score as predictors of postoperative recurrence in prostate cancer with or without chromosome 8p allelic imbalance.

BACKGROUND: Identification of prostate cancer patients at risk for postoperative disease recurrence is an important clinical issue. Existing pathological markers can predict disease recurrence only to a certain extent, and there is a need for more accurate predictors. METHODS: Using "counting alleles," a novel experimental method, we determined allelic status of chromosome 8p in 107 prostatectomy specimens. Statistical analyses examined the association between pathologic predictors (Gleason score, stage, surgical margin, etc.) and cancer recurrence in patients with and without 8p allelic imbalance (8p AI). RESULTS: 8p AI cancers were more likely to recur in the presence of a positive surgical margin, whereas recurrence of 8p retaining tumors was associated with the Gleason score, but not with the surgical margin. CONCLUSIONS: Our findings suggest that chromosome 8p allelic status affects the predictive value of "traditional" markers of prostate cancer recurrence. If confirmed by larger studies, these results may have important clinical implications.

Age Factors↗

PubMed2004

Mesothelioma and lung cancer among motor vehicle mechanics: a meta-analysis.

We conducted a systematic review and analysis of the epidemiological literature that examines the risk of lung cancer and mesothelioma among motor vehicle mechanics who may have been engaged in brake repair and, thus, were potentially exposed to asbestos. All relevant studies were classified into three tiers according to their quality. Tier III (lowest quality) studies were cited for completeness, but were not included in the meta-analysis. Meta relative risks (meta-RRs) were calculated for mesothelioma and lung cancer using both fixed and random effects models for Tiers I and II, separately, followed by stratified analyses based on study design or exposure characterization (garage workers versus brake workers) and, for lung cancer studies, based on adequate adjustment for smoking. The meta-analysis for Tier I (higher quality) and Tier II (lower quality) studies of mesothelioma yielded RR estimates of 0.92 (95% CI 0.55-1.56) and 0.81 (95% CI 0.52-1.28), respectively. Further stratification according to exposure characterization did not affect the results. The meta-analysis for lung cancer produced RR estimates of 1.07 (95% CI 0.88-1.31) for Tier I and 1.17 (95% CI 1.01-1.36) for Tier II. When the lung cancer analysis was limited to studies that used adequate control for smoking, the resulting RR estimate was 1.09 (95% CI 0.92-1.28). Based on these findings, we conclude that employment as a motor vehicle mechanic does not increase the risk of developing mesothelioma. Although some studies showed a small increase in risk of lung cancer among motor vehicle mechanics, the data on balance do not support a conclusion that lung cancer risk in this occupational group is related to asbestos exposure.

Asbestos↗

PubMed2004

Elective cesarean delivery and long-term motor function or ambulation status in infants with meningomyelocele.

OBJECTIVE: To determine if elective cesarean delivery, when compared with trial of labor, is associated with better long-term motor function or ambulation status in infants with myelomeningocele. METHODS: This is a retrospective cohort study of patients with myelomeningocele followed at the Spinal Dysfunction Program at Alfred I. duPont Hospital for Children in Wilmington, Delaware. Medical records were reviewed for gestational age at delivery, birthweight, anatomical level of lesion, and initial (0-6 months) and long-term (10 years or longer) motor function. Ambulation status (independent ambulation, ambulant with assistance, or wheelchair-bound) at 2 and 10 years was compared with those delivered by elective cesarean versus those delivered after trial of labor. RESULTS: Of the 106 patients with myelomeningocele that were identified, 87 (82%) had all the data required for this review. There were 44 patients in the elective cesarean group and 43 in the trial of labor group. There was no significant difference in gestational age at delivery or birthweight between the groups. There was statistical difference between the 2 groups when anatomical, initial, and current motor levels were compared. Compared with the elective cesarean group, patients in the trial of labor group were more likely to be ambulatory at 2 years (independently ambulant 7% versus 28%, ambulant with assistance 63% versus 65%, or wheelchair-bound 30% versus 7%, P =.003) and at 10 years (independently ambulant 5% versus 21%, ambulant with assistance 30% versus 54%, or wheelchair-bound 65% versus 25%, P <.001). However, when logistic regression analysis was used to control for motor level of myelomeningocele, no significant association was observed in ambulatory status at ages 2 and 10 years between infants delivered by elective cesarean or after trial of labor. CONCLUSION: Elective cesarean delivery, when compared with delivery after trial of labor, was not associated with better motor function or ambulation status in myelomeningocele patients. LEVEL OF EVIDENCE: II-2

Adolescent↗

PubMed2004

Evaluation of uncontrolled confounding in studies of environmental exposures and neurobehavioral testing in children.

BACKGROUND: Neurobehavioral tests are commonly used in studies of children exposed to low-level environmental concentrations of compounds known to be neurotoxic at higher levels. However, uncontrolled or incomplete control for confounding makes interpretation of results problematic because effects of confounders are often stronger than the effects of primary interest. We examined a priori the potential impact of confounding in a hypothetical study evaluating the association of a potentially neurotoxic environmental exposure with neurobehavioral function in children. METHODS: We used 2 outcome measures: the Bayley Scales of Infant Development Mental Development Index and the Stanford-Binet Intelligence Scale Composite Score. We selected 3 potential confounders: maternal intelligence, home environment, and socioeconomic status as measured by years of parental education. We conducted 3 sets of analyses measuring the effect of each of the 3 confounding factors alone, 2 confounders acting simultaneously, and all 3 confounders acting simultaneously. RESULTS: Relatively small differences (0.5 standard deviations) in confounding variables between "exposed" and "unexposed" groups, if unmeasured and unaccounted for in the analysis, could produce spurious differences in cognitive test scores. The magnitude of this difference (3-10 points) has been suggested to have a meaningful impact in populations. The method of measuring confounders (eg, maternal intelligence) could also substantially affect the results. CONCLUSIONS: It is important to carefully consider the impact of potential confounders during the planning stages of an observational study. Study-to-study differences in neurobehavioral outcomes with similar environmental exposures could be partially explained by differences in the adjustment for confounding variables.

Bias↗

PubMed2004

Mesothelioma among brake mechanics: an expanded analysis of a case-control study.

The U.S. Environmental Protection Agency has begun discussions to consider its assessment of asbestos toxicity related to mineral form and fiber size. Brake workers are typically exposed to short chrysotile fibers. To explore the mesothelioma risk among brake workers, considering other occupational exposures to asbestos, data from a study that was published previously were obtained and the analysis was extended. The National Cancer Institute provided data from a case-control study of mesothelioma. Because many participants with a history of brake work also had employment in other asbestos-related occupations, mesothelioma cases and controls were compared for a history of brake work, controlling for employment in eight occupations with potential asbestos exposure. A stratified analysis was also performed excluding those with any of the eight occupations. Possible interactions between brake work and other occupational exposures related to risk of mesothelioma were also examined. The odds ratio (OR) for employment in brake installation or repair was 0.71 (95% CI: 0.30-1.60) when controlled for insulation or shipbuilding. When a history of employment in any of the eight occupations with potential asbestos exposure was controlled, the OR was 0.82 (95% CI: 0.36-1.80). ORs did not increase with increasing duration of brake work. Exclusion of those with any of the eight exposures resulted in an OR of 0.62 (95% CI: 0.01-4.71) for occupational brake work. There was no evidence of an interaction between brake work and other occupational exposures. These latter analyses were based on small numbers of exposed cases. The results are consistent with the existing literature indicating that brake work does not increase the risk of mesothelioma and adds to the evidence that fiber type and size are important determinants of mesothelioma risk.

Asbestos, Serpentine↗