An international survey of polypectomy training and assessment.

Background and study aims Colonic polypectomy is acknowledged to be a technically challenging part of colonoscopy. Training in polypectomy is recognized to be often inconsistent. This study aimed to ascertain worldwide practice in polypectomy training. Patients and methods An electronic survey was distributed to endoscopic trainees and trainers in 19 countries asking about their experiences of receiving and delivering training. Participants were also asked about whether formal polypectomy training guidance existed in their country. Results Data were obtained from 610 colonoscopists. Of these responses, 348 (57.0 %) were from trainers and 262 (43.0 %) from trainees; 6.6 % of trainers assessed competency once per year or less often. Just over half (53.1 %) of trainees had ever had their polypectomy technique formally assessed by any trainer. Approximately half the trainees surveyed (51.1 %) stated that the principles of polypectomy had only ever been taught to them intermittently. Of those trainees with the most colonoscopy experience, who had performed over 500 procedures, 48.2 % had had training on removing large polyps of over 10 mm; 46.2 % (121 respondents) of trainees surveyed held no record of the polypectomies they had performed. Only four of the 19 countries surveyed had specific guidelines on polypectomy training. Conclusions A significant number of competent colonoscopists have never been taught how to perform polypectomy. Training guidelines worldwide generally give little direction as to how trainees should acquire polypectomy skills. The learning curve for polypectomy needs to be defined to provide reliable guidance on how to train colonoscopists in this skill.

Predicted indoor radon concentrations from a Monte Carlo simulation of 1,000,000 granite countertop purchases.

Previous research examining radon exposure from granite countertops relied on using a limited number of exposure scenarios. We expanded upon this analysis and determined the probability that installing a granite countertop in a residential home would lead to a meaningful radon exposure by performing a Monte Carlo simulation to obtain a distribution of potential indoor radon concentrations attributable to granite. The Monte Carlo analysis included estimates of the probability that a particular type of granite would be purchased, the radon flux associated with that type, the size of the countertop purchased, the volume of the home where it would be installed and the air exchange rate of that home. One million countertop purchases were simulated and 99.99% of the resulting radon concentrations were lower than the average outdoor radon concentrations in the US (14.8 Bq m(-3); 0.4  pCi l(-1)). The median predicted indoor concentration from granite countertops was 0.06 Bq m(-3) (1.59 × 10(-3) pCi l(-1)), which is over 2000 times lower than the US Environmental Protection Agency's action level for indoor radon (148 Bq m(-3); 4 pCi l(-1)). The results show that there is a low probability of a granite countertop causing elevated levels of radon in a home.

Comparison of adaptive radiotherapy techniques for the treatment of bladder cancer.

OBJECTIVE: Day-to-day anatomical variations complicate bladder cancer radiotherapy treatment. This work quantifies the impact on target coverage and irradiated normal tissue volume for different adaptive strategies. METHODS: 20 patients were retrospectively planned using different three-dimensional conformal radiotherapy treatment strategies for whole-bladder carcinoma: (i) "conventional" treatment used isotropic expansion of the clinical target volume (CTV) by 15 mm to the planning target volume (PTV) for daily treatment; (ii) "plan of the day" used daily volumetric on-treatment imaging [cone beam CT (CBCT)] to select from four available plans with varying superior PTV margins; (iii) "composite" strategies used on-treatment CBCTs from Fractions 1-3 to inform a composite CTV and adapted PTV (5- and 10-mm margins for composite 1 and composite 2, respectively) for subsequent treatment. Target coverage was evaluated from available CBCTs (the first three fractions then the minimum weekly thereafter), and the reduction in the irradiated volume (i.e. within the 95% isodose) was quantified. RESULTS: Plan of the day improved target coverage (i.e. all of the bladder within the 95% isodose throughout the treatment) relative to conventional treatment (p=0.10), while no such benefit was observed with composite 2. Target coverage was reduced with composite 1 relative to conventional treatment. The mean irradiated volume was reduced by 17.2%, 35.0% and 14.6% relative to conventional treatment, for plan of the day, composite 1 and composite 2, respectively (p<0.01 in all cases). No parameters predictive of large changes in bladder volume later in the treatment were identified. CONCLUSIONS: Adaptive techniques can maintain or improve target coverage while allowing for reduced irradiated volume and possibly reduced toxicity. The plan-of-the-day technique appeared to provide the optimal balance between target coverage and normal tissue sparing. ADVANCES IN KNOWLEDGE: This study suggests that plan-of-the-day techniques will provide optimal outcomes for adaptive bladder radiotherapy.

Adalimumab for maintenance treatment of Crohn's disease: results of the CLASSIC II trial.

BACKGROUND: Adalimumab induced clinical remission after four weeks in patients with active Crohn's disease in the CLASSIC I trial. OBJECTIVE: To evaluate long term efficacy and safety of adalimumab maintenance therapy in Crohn's disease in a follow-on randomised controlled trial (CLASSIC II). METHODS: In the preceding CLASSIC I trial, 299 patients with moderate to severe Crohn's disease naive to tumour necrosis factor antagonists received induction therapy with adalimumab 40 mg/20 mg, 80 mg/40 mg, or 160 mg/80 mg, or placebo, at weeks 0 and 2. In all, 276 patients from CLASSIC I enrolled in CLASSIC II and received open-label adalimumab 40 mg at weeks 0 (week 4 of CLASSIC I) and 2; 55 patients in remission at both weeks 0 and 4 were re-randomised to adalimumab 40 mg every other week, 40 mg weekly, or placebo for 56 weeks. Patients not in remission at both weeks 0 and 4 were enrolled in an open-label arm and received adalimumab 40 mg every other week. With non-response or flare, these patients could have their dosages increased to 40 mg weekly. Patients in the randomised arm with continued non-response or disease flare could switch to open-label adalimumab 40 mg every other week and again to 40 mg weekly. The primary end point was maintenance of remission (CDAI <150) in randomised patients through week 56. RESULTS: Of 55 patients randomised at week 4, 79% who received adalimumab 40 mg every other week and 83% who received 40 mg weekly were in remission at week 56, v 44% for placebo (p<0.05). In all, 204 patients entered the open-label arm. Of these, 93 (46%) were in clinical remission at week 56. Adalimumab was generally well-tolerated in all patients. CONCLUSIONS: Adalimumab induced and maintained clinical remission for up to 56 weeks in patients with moderate to severe Crohn's disease naive to anti-TNF treatment.

Temporal patterns of activities potentially related to pesticide exposure.

Longitudinal information on human activity patterns is required to perform reliable assessments of chronic exposure to pesticides in nonoccupational settings. As part of a longitudinal, multimedia exposure survey in Maryland, USA, we collected 2521 person-days of information on the frequency of five activities that are potentially important to pesticide exposure in residential settings: preparation of pesticides; application of pesticides; contact with soil on the skin; contact with grass on the skin; and contact with carpet. Logistic regression was used to evaluate the data for variability by time of year, day of week, and several demographic factors. Eight percent of the population reported preparing pesticides on at least one occasion over the year, while 24% of the population applied pesticides at least once. The majority of the population reported contact with soil (68%), grass (72%), and carpet (64%) over the course of a year. Skin contact with soil and grass was found to occur approximately twice as frequently (p<0.001) in spring and summer periods than in fall and winter periods. Similarly, contact with soil and grass was about 50% (p<0.05) more likely to occur on weekend days than on weekdays. These results indicate that short-term measurements (e.g., 1-day or 1-week) of these activities for an individual may not be equivalent to long-term average patterns. We also found that selected demographic characteristics were significant predictors of several of these activities. Thus, some demographic characteristics may be useful in categorizing exposure although it is unlikely that a single short-term measurement will suffice to describe annual average activity or multiple short-term activity periods.

Dietary exposure to chlorpyrifos and levels of 3,5,6-trichloro-2-pyridinol in urine.

Information on associations between chlorpyrifos residues in food and personal exposure to chlorpyrifos would be valuable for evaluating the relationship between personal exposure and possible health effects. We used food consumption records, chlorpyrifos levels in duplicate plates, and measures of 3,5,6-trichloro-2-pyridinol (TCPy) in urine obtained from human volunteers in the National Human Exposure Assessment Survey in Maryland (NHEXAS-MD) to evaluate a food consumption-chemical residue model for estimating dietary intake of chlorpyrifos. Model inputs were the NHEXAS-MD food consumption records and chlorpyrifos residues in specific foods measured in the U.S. Food and Drug Administration Total Diet Study (TDS) market baskets from 1993 to 1997. The estimated mean and standard deviation of chlorpyrifos concentration (microg/kg) in duplicate plates (n=203) were within 20% and 50%, respectively, of the corresponding parameters of measured chlorpyrifos levels. However, predicted and measured concentrations in the 78 duplicate plates with detectable levels of chlorpyrifos were not significantly associated according to Spearman correlation analysis (r=0.04, p=0.7667) and linear regression (p=0.2726). Measured and estimated chlorpyrifos intakes for observations with non-zero values for each intake measure (n=71) were moderately associated on a rank (Spearman's r=0.24, p=0.0462) and linear basis (regression r(2)=0.07, p=0.0242). Measured intakes of chlorpyrifos from food and urinary TCPy were significantly correlated in rank order (n=87, Spearman's r=0.30, p=0.0041) and linear (n=87, Pearson's r=0.22, p=0.0409) analyses. Correlation coefficients between estimated intake of chlorpyrifos from food and TCPy were significantly different from zero (n=87; Spearman's r=0.22, p=0.0393; Pearson's r=0.21, p=0.0479). Comparing mean measured chlorpyrifos intake from food (0.46 microg/day) to mean estimated TCPy excretion via urine (6.3 microg/day), dietary intake of chlorpyrifos accounted for approximately 7% of TCPy in this population. These findings suggest the food consumption-chemical residue model can yield reasonably accurate estimates of the population distribution of dietary chlorpyrifos intake, but has little ability to predict dietary exposure for individuals; and that intake of chlorpyrifos from food is a minor contributor to TCPy in urine.

Use of expert judgment in exposure assessment. Part I. Characterization of personal exposure to benzene.

This paper presents the results of the first phase of a study, conducted as an element of the National Human Exposure Assessment Survey (NHEXAS), to demonstrate the use of expert subjective judgment elicitation techniques to characterize the magnitude of and uncertainty in environmental exposure to benzene. In decisions about the value of exposure research or of regulatory controls, the characterization of uncertainty can play an influential role. Classical methods for characterizing uncertainty may be sufficient when adequate amounts of relevant data are available. Frequently, however, data are neither abundant nor directly relevant, making it necessary to rely to varying degrees on subjective judgment. Since the 1950s, methods to elicit and quantify subjective judgments have been explored but have rarely been applied to the field of environmental exposure assessment. In this phase of the project, seven experts in benzene exposure assessment were selected through a peer nomination process, participated in a 2-day workshop, and were interviewed individually to elicit their judgments about the distributions of residential ambient, residential indoor, and personal air benzene concentrations (6-day integrated average) experienced by both the non-smoking, non-occupationally exposed target and study populations of the US EPA Region V pilot study. Specifically, each expert was asked to characterize, in probabilistic form, the arithmetic means and the 90th percentiles of these distributions. This paper presents the experts' judgments about the concentrations of benzene encountered by the target population. The experts' judgments about levels of benzene in personal air were demonstrative of patterns observed in the judgments about the other distributions. They were in closest agreement about their predictions of the mean; with one exception, their best estimates of the mean fell within 7-11 microg/m(3) although they exhibited striking differences in the degree of uncertainty expressed. Their estimates of the 90th percentile were more varied with the best estimates ranging from 12 to 26 microg/m(3) for all but one expert. However, their predictions of the 90th percentile were far more uncertain. The paper demonstrates that coherent subjective judgments can be elicited from exposure assessment scientists and critically examines the challenges and potential benefits of a subjective judgment approach. The results of the second phase of the project, in which measurements from the NHEXAS field study in Region V are used to calibrate the experts' judgments about the benzene exposures in the study population, will be presented in a second paper.

Performance of electronic flow rate meters used for calibration of air sampling pumps.

Electronic flow rate meters (EFRMs) have been used by industrial hygienists for more than 20 years and are useful because they reduce the time required to calibrate air sampling pumps. This study compared the variability of the traditional bubble burette meter with electronic flow meters and simultaneously compared several EFRMs under different calibration conditions. The flow rates of air sampling pumps were set using a standard bubble burette meter at flow rates of 2 or 50 mL/min using two pressure drops, 2 inches water and 10 inches water. Four airflow rate meters (Bios DryCal, A.P. Buck mini-Buck, MSA Accuflow, and Sensidyne Gilibrator) were concurrently compared at each of the pump flow rate and pressure drop combinations. Results indicated that the standard bubble burette method is more variable than the EFRMs and that the flow rates given by the EFRMs were significantly different (p<0.0001) at both the high and low flow rates. Although the calibrators gave significantly different flow rates, the difference was within the acceptable air sampling pump error of +/- 5%.

A longitudinal investigation of aggregate oral intake of copper.

Four-day composite solid food and beverage duplicate plates and 1-L samples of drinking water were collected from a stratified random sample of 80 individuals as part of the National Human Exposure Assessment Survey in Maryland. The media were obtained from each participant in up to six equally spaced sampling cycles over a year and analyzed for copper by inductively coupled plasma mass spectrometry. Copper concentrations (microg/kg) and consumption rates (kg/d) of solid food, beverage and drinking water were used to derive average daily aggregate oral intake of copper (microg/d). The mean aggregate copper intake of 263 measurements obtained from 68 people was 923.2 +/- 685.6 microg/d (mean +/- SD). Intake through solid food accounted for the majority of aggregate daily intake of copper contributing 87% on average. According to results from mixed model analysis of variance procedures, the mean log-transformed average daily copper intake in each medium except beverage exhibited significant (P < 0.05) variability among sampling cycles. Between-person variability accounted for 50% of the total variance in aggregate copper intake. As measured by the coefficient of variation, distributions of copper intake consisting of one observation per individual were more variable than the distribution consisting of the long-term average intake for each person. These results suggest that estimates of the fraction of a population at risk from chronic copper deficiency or excess copper intake can be overestimated if based upon short-term measures of copper intake. In addition, these results indicate that longitudinal information is required for accurate assessment of aggregate oral intake of copper for an individual.

Fractures of the femoral neck in Australian Aboriginals and Torres Strait Islanders.

The objective was to study patients of Aboriginal and Torres Strait Islander origin who were admitted to Cairns Base Hospital with the diagnosis of femoral neck fracture. An analysis of all 232 admissions with this diagnosis between November 1997 and July 2000 was carried out. Information was gathered from data accumulated on the Clinical Pathways database; other local data was also considered. Patients registered as being of Aboriginal and Torres Strait Islander origin have a lower incidence of these fractures than might be expected on an overall population basis, but similar rates on age-standardised data. The female age profile is substantially older than the female non-indigenous osteoporotic fracture group. Indigenous females develop osteoporotic type fractures of the femoral neck at a later age than do non-indigenous females. This may reflect a genetic difference in bone mineral density or a healthy lifestyle in earlier days. Further research is suggested.

A comparison of four gravimetric fine particle sampling methods.

A study was conducted to compare four gravimetric methods of measuring fine particle (PM2.5) concentrations in air: the BGI, Inc. PQ200 Federal Reference Method PM2.5 (FRM) sampler; the Harvard-Marple Impactor (HI); the BGI, Inc. GK2.05 KTL Respirable/Thoracic Cyclone (KTL); and the AirMetrics MiniVol (MiniVol). Pairs of FRM, HI, and KTL samplers and one MiniVol sampler were collocated and 24-hr integrated PM2.5 samples were collected on 21 days from January 6 through April 9, 2000. The mean and standard deviation of PM2.5 levels from the FRM samplers were 13.6 and 6.8 microg/m3, respectively. Significant systematic bias was found between mean concentrations from the FRM and the MiniVol (1.14 microg/m3, p = 0.0007), the HI and the MiniVol (0.85 microg/m3, p = 0.0048), and the KTL and the MiniVol (1.23 microg/m3, p = 0.0078) according to paired t test analyses. Linear regression on all pairwise combinations of the sampler types was used to evaluate measurements made by the samplers. None of the regression intercepts was significantly different from 0, and only two of the regression slopes were significantly different from 1, that for the FRM and the MiniVol [beta1 = 0.91, 95% CI (0.83-0.99)] and that for the KTL and the MiniVol [beta1 = 0.88, 95% CI (0.78-0.98)]. Regression R2 terms were 0.96 or greater between all pairs of samplers, and regression root mean square error terms (RMSE) were 1.65 microg/m3 or less. These results suggest that the MiniVol will underestimate measurements made by the FRM, the HI, and the KTL by an amount proportional to PM2.5 concentration. Nonetheless, these results indicate that all of the sampler types are comparable if approximately 10% variation on the mean levels and on individual measurement levels is considered acceptable and the actual concentration is within the range of this study (5-35 microg/m3).

Ambient air quality at the site of a former manufactured gas plant.

Prior to the 1950's, manufactured gas was commercially produced from the pyrolysis of coal, coke, and oil at facilities that are termed manufactured gas plants (MGPs). The constituents of residual coal tar present on many MGP sites are an environmental health concern because of their toxicity and the possibility for their off-site migration via water and air. Atmospheric concentrations of five volatile organic compounds (VOCs, e.g., benzene), sixteen polycyclic aromatic hydrocarbons (PAHs, e.g., naphthalene) and particulate matter less than 10 microns in aerodynamic diameter (PM10) were measured at the site of a former MGP. Air samples were obtained before, during, and after excavation of subterranean coal tar at the site. The results of this investigation indicate that subterranean coal tar was not a primary source of VOCs and PAHs in the local atmosphere before or after remediation of the site. However, excavation, treatment, blending, and transfer of the coal tar during remediation generated concentrations of selected aromatic and semi-volatile organic compounds that were substantially greater than typical ambient levels. In addition, these data suggest that blending and mixing of coal tars could lead to exceedance of the U.S. National Ambient Air Quality Standard for PM10, although additional research is required to fully evaluate this possibility. Nuisance odors associated with the site remediation were likely the result of naphthalene and possibly isomers of xylene. Air pollutant concentrations measured adjacent to the excavation area and at the site perimeter during remediation activities were less than the relevant occupational and environmental exposure limits.

Analysis of dietary intake of selected metals in the NHEXAS-Maryland investigation.

As part of a large pilot investigation of multimedia exposure to several classes of environmental contaminants, the National Human Exposure Assessment Survey (NHEXAS)-Maryland study, we collected 388 semiquantitative food checklists and duplicate diet solid food samples, analyzed for arsenic, cadmium, chromium, and lead concentrations, from 80 individuals in Maryland in 1995-1996 in a repeated measures design. Here we explore several methods to infer foods most strongly associated with concentrations of these metals observed in the duplicate diet in our data set. We employed two techniques in which logarithmically transformed metal concentrations in the duplicate diet were regressed on individual food item consumption using algorithms designed to identify the foods most associated with the observed duplicate diet concentrations. We also employed an alternative strategy in which foods to be used as independent variables in regression were selected using data collected in national food consumption and residue surveys, with regression procedures proceeding with the selected foods in a similar manner. The concordance of foods selected as major predictors among these three techniques is noteworthy and is discussed. Finally, the Dietary Exposure Potential Model (DEPM) was used with the Dietary Checklist data to predict duplicate diet concentrations within our sample. A comparison between the predicted values and those observed gave R(2) values of 0.180, 0.206, and 0.076 for As, Cd, and Pb, respectively (p < 0.0001 in all cases). We discuss the significance of these observations and the implications for dietary-exposure-based risk analysis and dietary intake epidemiology.

Longitudinal investigation of dietary exposure to selected pesticides.

Between September 1995 and September 1996, 4-day composite duplicate plate samples (379 solid food samples and 303 beverage samples) were obtained from a stratified random sample of 75 individuals in Maryland and analyzed for the presence of 10 pesticides. Samples were collected in each of six approximately equally spaced cycles as part of a larger pilot investigation of longitudinal exposure to pesticides and other elements. Chlorpyrifos was detected in 38.3% of the solid food samples, malathion in 75.2%, and p,p'-DDE in 21.4%. Other pesticides were detected in less than 10% of the solid food samples. Pesticide residues were not detected in duplicate beverage samples. In solid food samples, the mean concentration of chlorpyrifos was 0.7 (SD 1.7) microg/kg, 1.8 (2.1) for malathion, and 0.2 (0.6) for p,p'-DDE. The detection rate and mean concentration of chlorpyrifos, malathion, and p,p'-DDE varied by a factor of 2-3 among sampling cycles and significantly according to results from several statistical analyses. Co-occurrence of chlorpyrifos and malathion in solid food samples was found relatively frequently and also varied with time. Pesticides were detected in food samples with greatest frequency in spring and summer months and with lowest frequency in winter months. These results support the hypothesis that 4-day average exposure to chlorpyrifos and malathion varies over time for this population mean and for individual members of the population and that correlation between exposures to these two organophosphate pesticides can occur. The measurements of pesticide levels in duplicate plate samples presented here can be used to evaluate and set parameters for dietary exposure models.

Caring about carepaths.

This short paper describes an experiment in the use of clinical pathways for orthopaedic patients at Cairns Base Hospital. We rapidly found they improved the management of cost and quality, and that there were many beneficial side-effects. Our approach was subsequently adopted in other departments. Unfortunately, external support for further developments has not been forthcoming and we argue that this may be an unwise move.

Longitudinal investigation of exposure to arsenic, cadmium, and lead in drinking water.

Arsenic, cadmium, and lead have been associated with various forms of cancer, nephrotoxicity, central nervous system effects, and cardiovascular disease in humans. Drinking water is a well-recognized pathway of exposure to these metals. To improve understanding of the temporal dimension of exposure to As, Cd, and Pb in drinking water, we obtained 381 samples of tap and/or tap/filtered water and self-reported rates of drinking water consumption from 73 members of a stratified random sample in Maryland. Data were collected at approximately 2-month intervals from September 1995 through September 1996. Concentrations of As (range < 0.2-13.8 microg/L) and Pb (< 0.1-13.4 microg/L) were within the ranges reported for the United States, as were the rates of drinking water consumption (median < 0.1-4.1 L/day). Cd was present at a detectable level in only 8.1% of the water samples. Mean log-transformed concentrations and exposures for As and Pb varied significantly among sampling cycles and among respondents, as did rates of drinking water consumption, according to a generalized linear model that accounted for potential correlation among repeated measures from the same respondent. We used the intraclass correlation coefficient of reliability to attribute the total variance observed for each exposure metric to between-person and within-person variability. Between-person variability was estimated to account for 67, 81, and 55% of the total variance in drinking water consumption, As exposure (micrograms per day), and Pb exposure (micrograms per day), respectively. We discuss these results with respect to their implications for future exposure assessment research, quantitative risk assessment, and environmental epidemiology.

Air quality and pediatric emergency room visits for asthma in Atlanta, Georgia, USA.

Pediatric emergency room visits for asthma were studied in relation to air quality indices in a spatio-temporal investigation of approximately 130,000 visits (approximately 6,000 for asthma) to the major emergency care centers in Atlanta, Georgia, during the summers of 1993-1995. Generalized estimating equations, logistic regression, and Bayesian models were fitted to the data. In logistic regression models comparing estimated exposures of asthma cases with those of the nonasthma patients, controlling for temporal and demographic covariates and using residential zip code to link patients to spatially resolved ozone levels, the estimated relative risk per 20 parts per billion (ppb) increase in the maximum 8-hour ozone level was 1.04 (p < 0.05). The estimated relative risk for particulate matter less than or equal to 10 microm in aerodynamic diameter (PM10) was 1.04 per 15 microg/m3 (p < 0.05). Exposure-response trends (p < 0.01) were observed for ozone (>100 ppb vs. <50 ppb: odds ratio = 1.23, p = 0.003) and PM10 (>60 microg/m3 vs. <20 microg/m3: odds ratio = 1.26, p = 0.004). In models with ozone and PM10, both terms became nonsignificant because of collinearity of the variables (r= 0.75). The other analytical approaches yielded consistent findings. This study supports accumulating evidence regarding the relation of air pollution to childhood asthma exacerbation.

Anti-tuberculous therapy for maintaining remission of Crohn's disease.

OBJECTIVES: To evaluate the effects of anti-tuberculous therapy for the maintenance of remission in patients with Crohn's disease. SEARCH STRATEGY: We searched the Inflammatory Bowel Disease Trials Register, the Cochrane Controlled Trials Register and MEDLINE from 1966 to 1998 (supplemented by a manual search of Index Medicus from 1966 to 1994). We also searched for abstracts in Gut, Gastroenterology, and The American Journal of Gastroenterology from 1990 to 1996. Date of most recent search: August 1998. SELECTION CRITERIA: Randomized trials of anti-tuberculous therapy in patients with Crohn's disease. DATA COLLECTION AND ANALYSIS: Data on the number of patients maintaining remission for each treatment group were abstracted. These data were pooled to yield Mantel-Haenszel odds ratios and numbers needed to treat for maintenance of remission in treated versus control groups. MAIN RESULTS: A total of seven randomized trials which included 355 patients were identified. Two trials used anti-tuberculous therapy (clofazimine or clofazimine, rafmpin, ethambutol, and dapsone) in combination with corticosteroids to induce remission. Maintenance therapy consisted of the anti-tuberculous agents without corticosteroids. Control patients received corticosteroids to induce remission but no anti-tuberculous therapy. The analysis of all seven trials yielded an odds ratio for maintenance of remission of 1.36 (95% CI 0.87-2. 13). Removing the two studies that were published as abstracts did not significantly affect this result: the pooled odds ratio was 1.14 (95% CI 0.71-1.83). The two trials reported as abstracts were excluded from subgroup analyses because they did not include any information on adjunct therapy. Subgroup analysis of the two trials which used steroids to induce remission yielded an odds ratio for maintenance of remission of 3.37 (95% CI 1.38-8.24). The number needed to treat was three. However, these two trials included only 89 patients, and the results should be interpreted with caution. The remaining three trials compared the combination of anti-tuberculous therapy and 'standard therapy' with 'standard therapy alone'. The pooled odds ratio was 0.70 (95% CI 0.39-1.25). REVIEWER'S CONCLUSIONS: Anti-tuberculous therapy may be effective in maintaining remission in patients with Crohn's disease when remission has been induced with corticosteroids combined with anti-tuberculous therapy. However, the results which support this conclusion come from a subgroup of only two trials with small numbers of patients and should be interpreted with caution. Use of this therapy cannot be recommended on the basis of this evidence.

Longitudinal investigation of exposure to arsenic, cadmium, chromium and lead via beverage consumption.

Semi-quantitative food checklists and duplicate beverage samples were collected from up to 80 individuals in Maryland in 1995-1996 in as many as six approximately equally spaced sampling cycles as part of a pilot longitudinal exposure investigation. The duplicate beverage samples were homogenized and analyzed for arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) using inductively coupled plasma mass spectrometry (ICP-MS). Metal concentrations (microg/kg) and weights of the duplicate beverage samples (kg/day) were used to derive average daily exposure (microg/day) for each metal. Mixed models and generalized linear models were used to evaluate temporal and population variability of the beverage consumption rates, the log-transformed metal concentrations in the beverage samples, and the associated exposures. The mean number of beverage servings consumed per day was 3.4 (SD 1.9). The temporal variability of the total beverage consumption rates was found to be significant (p = 0.0476). As, Cd, Cr, and Pb were present at quantifiable levels in 93.5, 76.0, 93.5, and 96.7% of the beverage samples, respectively. The mean concentration in the samples was 2.0 (SD 4.4) microg/kg for As, 0.9 (1.6) for Cd, 29.2 (138.5) for Cr, and 2.0 (2.4) for Pb. The mean log-transformed concentrations for As, Cr and Pb and exposure for As varied by as much as a factor of 3 across sampling cycles and were statistically significantly different (p<0.05). Concentrations and exposures of all four metals varied significantly among participants. These findings are discussed with respect to the data collection methods, results from comparable studies, and implications for exposure and risk assessment.

A meta-analysis of antimycobacterial therapy for Crohn's disease.

OBJECTIVE: Various therapies have been studied for the treatment of Crohn's disease, including antimycobacterial therapy. Meta-analysis was used to evaluate the effect of antimycobacterial therapy in patients with Crohn's disease. METHODS: Randomized, controlled trials comparing antimycobacterial therapy with placebo were identified. Key outcome data were abstracted and the results were pooled to yield odds ratios for maintenance of remission in treated versus control groups. RESULTS: A total of eight randomized trials were identified. Six trials were fully published and were included in the primary analysis. Two trials used antimycobacterial therapy in combination with corticosteroids to induce remission in patients with active Crohn's disease, followed by maintenance therapy with antimycobacterial agents. In these trials, control patients received corticosteroids to induce remission but no antimycobacterial therapy. Pooling of these trials yielded an odds ratio of maintenance of remission in treatment versus control of 3.37 (95% confidence interval [CI], 1.38-8.24) in favor of antimycobacterial therapy. The remaining four trials used antimycobacterial therapy combined with standard therapy in patients with Crohn's disease. In these trials, control patients received standard therapy alone. Pooling of these trials yielded an odds ratio of maintenance of remission in treatment versus control of 0.69 (95% CI, 0.39-1.21) in favor of standard therapy. CONCLUSIONS: These results suggest that antimycobacterial therapy is effective in maintaining remission in patients with Crohn's disease after a course of corticosteroids combined with antimycobacterial therapy to induce remission. Treatment of Crohn's disease with antimycobacterial therapy does not seem to be effective without a course of corticosteroids to induce remission. Because of the small number of studies included in this meta-analysis, the results should be interpreted with caution.