Maternal exposure to biomass smoke and carbon monoxide in relation to adverse pregnancy outcome in two high altitude cities of Peru.

BACKGROUND: Exposure to pollution from biomass fuel has been associated with low birthweight in some studies. Few studies have included exposure-response analyses. METHOD: We conducted a case-control study of biomass fuel use and reproductive outcome at high altitude in Peru. Cases (n=101) were full term births who were SGA (birth weight <10th percentile for gestational age). Controls (n=101) had a birthweight ≥10th percentile, and were matched to cases on birth week and residence. Biomass fuel use during pregnancy was determined by questionnaire. Carbon monoxide (CO) in the kitchen was measured in a subgroup (n=72). Logistic regression was used to estimate the effects of biofuel and CO on the risk of SGA, controlling for maternal education and parity. RESULTS: Among cases, 30%, 27% and 44% used gas, gas+biomass, and biomass, respectively, while the figures for controls were 39%, 33%, and 29%. The adjusted odds ratio (OR) for biomass fuel alone compared with gas alone was 4.5 (95% CI: 1.3, 15.5, p=0.02), while the OR for biomass+gas vs. gas alone was 2.1 (0.80-5.5) (p=0.13). Among the subgroup with measured CO, the mean 48-h kitchen CO levels were 4.8, 2.2 and 0.4ppm for biofuel only, biofuel+gas, and gas respectively. ORs by increasing tertile of CO level were 1.0, 1.16, and 3.53 (test for trend, p=0.02). The exposure-response trend corresponds well with one other study with analogous data. CONCLUSION: Despite limited sample size, our data suggest that maternal exposure to biomass smoke and CO, at high altitude, is associated with SGA among term births.

Organochlorine chemicals and neurodegeneration among elderly subjects in Costa Rica.

BACKGROUND: We previously screened 400 elderly Costa Ricans for neurodegenerative disease. Those reporting occupational pesticide exposure (18%) had an increased Parkinson׳s disease (PD) risk (OR 2.57, 95% CI 0.91-7.26), and worse cognition (Mini-Mental States Exam (MMSE) 24.5 versus 25.9 points, p=0.01). We subsequently measured long-lasting organochlorine pesticides (ß-HCH, DDE, DDT, and dieldrin) in a sub-sample (n=89). Dieldrin and ß-HCH have been linked to PD, and DDE to Alzheimer׳s disease. METHODS: We ran regression models for MMSE and tremor-at-rest to assess associations with pesticides in 89 subjects. RESULTS: The percent of ß-HCH, DDE, DDT (parent compound for DDE), and dieldrin above their limit of detection (LOD) were 100%, 93%, 75%, and 57%, respectively. Tremor-at-rest was found in 21 subjects, and the mean MMSE was 25. Those who reported occupational pesticide exposure (n=36) had more detectable dieldrin samples (p=0.005), and higher mean levels of dieldrin (p=0.01), than those not reporting exposure. Other pesticides did not differ between those with and without self-reported occupational exposure. There was a positive but non-significant trend of higher risk for tremor-at-rest with higher dieldrin (p=0.10 for linear trend). Neither DDE nor DDT showed a relationship with MMSE. However, after excluding two outliers with the lowest MMSE scores, higher DDT levels showed some modest association with lower MMSE (p=0.09 for linear trend). CONCLUSIONS: Our data are limited by small sample size. However, dieldrin was high in our population, has been previously linked to PD, and could be partly responsible for the excess PD risk seen in our population.

Occupational pesticide exposure and screening tests for neurodegenerative disease among an elderly population in Costa Rica.

BACKGROUND: Pesticides have been associated with Parkinson's disease (PD) in many studies, and with Alzheimer's disease (AD) in a few. METHODS: We conducted screening tests for neurologic disease and occupational pesticide use in a population-based sample of 400 elderly subjects at two government-run clinics in Costa Rica; 361 subjects who failed the initial screen were given both the mini-mental states exam (MMSE) and a modified version of a 10-item united Parkinson's disease rating motor subscale (UPDRS). Among subjects who failed either test, 144 were then examined by a neurologist. RESULTS: Past occupational pesticide exposure was reported by 18% of subjects. Exposed subjects performed worse on the MMSE than the non-exposed (mean 24.5 versus 25.9, p=0.01, adjusted for age, sex, and education). The exposed had significantly elevated risks of abnormal scores on two UPDRS items, tremor-at-rest (OR 2.58, 1.28-5.23), and finger-tapping (OR=2.94, 95% CI 1.03-8.41). Thirty-three (23%) of those examined by the neurologist were diagnosed with possible/probable PD, 3-4 times the expected based on international data; 85% of these cases had not been previously diagnosed. Among subjects who took the UPDRS, the exposed had an increased risk of PD (OR=2.57, 95% CI 0.91-7.26). No excess risk was found for a diagnosis of AD or mild cognitive impairment. CONCLUSIONS: Elderly subjects with past occupational pesticide exposure performed significantly worse on screening tests for dementia and PD, and had an increased risk of an eventual PD diagnosis. Screening may be particularly appropriate among elderly subjects with past pesticide exposure.

Risk assessment for PFOA and kidney cancer based on a pooled analysis of two studies.

INTRODUCTION: Perfluorooctanoic acid (PFOA) has been associated with kidney cancer in human studies. METHODS: We conducted a pooled analysis of two large studies of PFOA and renal cell carcinoma (RCC, the most common type of kidney cancer); one from the National Cancer Institute (NCI) (324 cases and controls), and a second from the C8 Science Panel (103 cases and 511 controls). Serum PFOA levels were estimated a median of 8 years before diagnosis. Analyses were conducted via conditional logistic regression. Lifetime risk of kidney cancer per unit serum PFOA concentration and per unit dose were calculated. RESULTS: The 25th, 50th and 75th percentiles of serum PFOA levels were 4.8, 7.3, and 23.9 ng/ml for the pooled analysis. The preferred model for the pooled datawas a two-piece linear spline model (knot at 12.5 ng/ml serum PFOA); the log odds of RCC increased 0.1349 per 1 ng/ml increase in serum PFOA up to the knot (eg, an OR of 2.02 (1.45-2.80) from the median to the knot), and was flat thereafter. The estimated lifetime excess risk (cancer slope factor) with an exposure of 1 ng/ml was 0.0018, similar to the excess risk of 0.0026 recently reported by CalEPA based on different methods. Assuming a serum half-life of 2.3 years and a distribution volume of 170 ml/kg for PFOA, our results are equivalent to 0.0128 per ng/kg/d of PFOA intake. To limit excess lifetime kidney cancer risk to 1/1,000,000, our data suggest a limit of 0.0015 ng/L (0.0015 ppt) for PFOA in drinking water, similar to CalEPA's proposed Public Health Goal and the new US EPA Drinking Water Health Advisory. CONCLUSIONS: Our results correspond reasonably well with cancer slope factors developed by other investigators using published summary data, and suggest drinking water limits similar to new recommendations by the US EPA.

Differences in treatment-based beliefs and coping between African American and white men with prostate cancer.

The purpose of the study was to explore racial differences related to treatment-based beliefs (trust in physician, physician bias, access to care, and self-efficacy) and coping (religious coping and social support). The study was conducted in a 33-county area located in southwest Georgia (SWGA). Men living in SWGA and newly diagnosed with prostate cancer were invited to participate in the study. Men were also required to be 75 years of age or younger at the beginning of the study and free of dementia. In collaboration with the Georgia Cancer Registry, potentially eligible participants were identified through pathology reports. Participants completed three interviews during a 12-month period post-diagnosis. The 320 participants in this analysis ranged in age from 44 to 75 years with a mean age of 63 years, and 42% were African American. After controlling for confounders, African American participants were more likely to report physician bias, financial problems with access to care, and use of religious coping strategies. These results, based on a largely rural patient population, support those of other studies noting differences in perception of care, access to care, and coping strategies between African American and white men with prostate cancer.

Association between maternal exposure to particulate matter (PM2.5) and adverse pregnancy outcomes in Lima, Peru.

The literature shows associations between maternal exposures to PM2.5 and adverse pregnancy outcomes. There are few data from Latin America. We have examined PM2.5 and pregnancy outcomes in Lima. The study included 123,034 births from 2012 to 2016, at three public hospitals. We used estimated daily PM2.5 from a newly created model developed using ground measurements, satellite data, and a chemical transport model. Exposure was assigned based on district of residence (n = 39). Linear and logistic regression analyzes were used to estimate the associations between air pollution exposure and pregnancy outcomes. Increased exposure to PM2.5 during the entire pregnancy and in the first trimester was inversely associated with birth weight. We found a decrease of 8.13 g (-14.0; -1.84) overall and 18.6 g (-24.4, -12.8) in the first trimester, for an interquartile range (IQR) increase (9.2 µg/m3) in PM2.5. PM2.5 exposure was positively associated with low birth weight at term (TLBW) during entire pregnancy (OR: 1.11; 95% CI: 1.03-1.20), and at the first (OR: 1.11; 95% CI: 1.03-1.20), second (OR: 1.09; 95% CI: 1.01-1.17), and third trimester (OR: 1.10; 95% CI: 1.02-1.18) per IQR (9.2 µg/m3) increase. Higher exposure to PM2.5 was also associated with increased risk of small for gestational age (SGA). There were no statistically significant associations between PM2.5 exposure and preterm births (PTB). Exposure to higher concentrations of PM2.5 in Lima may decrease birth weight and increase the frequency of TLBW and SGA. Our study was inconsistent with the literature in finding no associations with preterm birth.

Time-series analysis of ambient PM2.5 and cardiorespiratory emergency room visits in Lima, Peru during 2010-2016.

INTRODUCTION: There have been no time-series studies of air pollution in Peru. Here we evaluate the effect of ambient PM2.5 on emergency room (ER) visits in Lima. METHODS: We estimated daily PM2.5 levels at a 1 km2 resolution during 2010-2016 using ground measurements, satellite data, and chemical transport model simulations. Population-weighted average daily PM2.5 levels were calculated for each district in Lima (n = 40), and assigned to patients based on residence. ER visits for respiratory and circulatory diseases were gathered from nine large public hospitals. Poisson regression was used to estimate the rate ratio for daily ER visits with change in daily PM2.5, controlling for meteorology, time trends, and district. RESULTS: For each interquartile range (IQR) increase in PM2.5, respiratory disease ER visits increased 4% (95% CI: 0-5%), stroke visits 10% (3-18%), and ischemic heart disease visits (adults, 18-64 years) 11% (-1, 24%). Districts with higher poverty showed significantly stronger associations of PM2.5 and respiratory disease ER visits than districts with lower poverty. Effects were diminished 24-42% using Lima-wide instead of district-specific PM2.5 levels. CONCLUSIONS: Short-term exposure to ambient PM2.5 is associated with increases in ER visits in Lima for respiratory diseases and stroke, and among middle-aged adults, ischemic heart disease.

Adjustment for temporal confounders in a reanalysis of a case-control study of beryllium and lung cancer.

OBJECTIVES: To evaluate potential confounding of the association between beryllium and lung cancer in a reanalysis of data from a published case-control study of workers at a beryllium processing facility. METHODS: The association of cumulative and average beryllium exposure with lung cancer among 142 cases and five age-match controls per case was reanalysed using conditional logistic regression. Adjustment was made independently for potential confounders of hire age and birth year. Alternative adjustments to avoid taking the logarithm of zero were explored. RESULTS: Adjustment for either birth cohort or hire age (two highly correlated factors) attenuated lung cancer risk associated with cumulative exposure; however, lung cancer risk was significantly associated with average exposure using a 10-year lag following adjustment. Stratification of analyses by birth cohort found greater lung cancer risk from cumulative and average exposure for workers born before 1900 than for workers born later. The magnitude of the association between lung cancer and average exposure was not reduced by modifying the method used to take the log of exposure. CONCLUSION: In this reanalysis, average, but not cumulative, beryllium exposure was related to lung cancer risk after adjustment for birth cohort. Confounding by birth cohort is likely related to differences in smoking patterns for workers born before 1900 and the tendency for workers hired during the World War II era to have been older at hire.

Challenges and Opportunities for Occupational Epidemiology in the Twenty-first Century.

PURPOSE OF REVIEW: There are many opportunities and challenges for conducting occupational epidemiologic studies today. In this paper, we summarize the discussion of a symposium held at the Epidemiology in Occupational Health (EPICOH) conference, Chicago 2014, on challenges for occupational epidemiology in the twenty-first century. RECENT FINDINGS: The increasing number of publications and attendance at our conferences suggests that worldwide interest in occupational epidemiology has been growing. There are clearly abundant opportunities for new research in occupational epidemiology. Areas ripe for further work include developing improved methods for exposure assessment, statistical analysis, studying migrant workers and other vulnerable populations, the use of biomarkers, and new hazards. Several major challenges are also discussed such as the rapidly changing nature and location of work, lack of funding, and political/legal conflicts. As long as work exists there will be occupational diseases that demand our attention, and a need for epidemiologic studies designed to characterize these risks and to support the development of preventive strategies. Despite the challenges and given the important past contribution in this field, we are optimistic about the importance and continued vitality of the research field of occupational epidemiology.

Lung cancer incidence among patients with beryllium disease: a cohort mortality study.

We have conducted a cohort mortality study on 689 patients with beryllium disease who were included in a case registry. An earlier mortality study on 421 of these patients was limited to males and resulted in a determination of a nonsignificant twofold lung cancer excess based on only seven lung cancer deaths. We have extended this earlier study by including females and by adding 13 years of follow-up. Comparison of the 689 beryllium disease patients with the U.S. population resulted in a lung cancer standardized mortality ratio (SMR) of 2.00 (95% confidence interval = 1.33-2.89) based on 28 observed lung cancer deaths. Adjustment for smoking did not change these results. All causes of mortality were also significantly elevated (SMR = 2.19), largely because of the very high rate of deaths due to pneumoconioses (primarily beryllium disease) (SMR = 34.23; 158 deaths). No other causes of death were significantly elevated. The excess of lung cancer was consistent for both sexes and did not appear to increase with duration of exposure to beryllium or with time elapsed since first exposure to this element. The case registry included those with acute beryllium disease, which resembles a chemical pneumonitis, and those with chronic beryllium disease, which resembles other pneumoconioses. The lung cancer excess was more pronounced among those with acute disease (SMR = 2.32) than among those with chronic disease (SMR = 1.57).

Cancer, heart disease, and diabetes in workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

BACKGROUND: In 1997, the International Agency for Research on Cancer classified 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a group 1 human carcinogen, based largely on four highly exposed industrial cohorts that showed an excess of all cancers combined. In this study, we extended the follow-up period for the largest of these cohorts by 6 years and developed a job-exposure matrix. METHODS: We did cohort mortality analyses involving 5132 chemical workers at 12 U.S. plants by use of life table techniques (U.S. population referent) and Cox regression (internal referent). We conducted exposure-response analyses for 69% of the cohort with adequate work history data and adequate plant data on TCDD contamination. All P values are two-sided. RESULTS: The standardized mortality ratio (SMR) for all cancers combined was 1.13 (95% confidence interval = 1.02-1.25). We found statistically significant positive linear trends in SMRs with increasing exposure for all cancers combined and for lung cancer. The SMR for all cancers combined for the highest exposure group was 1.60 (95% confidence interval = 1.15-1.82). SMRs for heart disease showed a weak increasing trend with higher exposure (P = .14). Diabetes (any mention on the death certificate) showed a negative exposure-response trend. Internal analyses with Cox regression found statistically significant trends for cancer (15-year lag time) and heart disease (no lag). CONCLUSIONS: Our analyses suggest that high TCDD exposure results in an excess of all cancers combined, without any marked specificity. However, excess cancer was limited to the highest exposed workers, with exposures that were likely to have been 100-1000 times higher than those experienced by the general population and similar to the TCDD levels used in animal studies.

Seasonal variation of aryl hydrocarbon hydroxylase activity in human lymphocytes.

A seasonal variation was observed when aryl hydrocarbon hydroxylase (AHH) activity was measured in the cultured lymphocytes of 977 donors over a period of 2 1/2 years. The variation was strongest in AHH activity induced by 3-methylcholanthrene and was less apparent for AHH activity in lymphocytes grown without any inducer. The period of the seasonal variation is 1 year, and maximal induced AHH activity occurs during late summer and early fall with minimal activity 6 months later. Based on the average of all individuals tested during the highest and lowest weeks, induced AHH activity can be as much as 10-fold higher during the peak season. It is not possible to tell from these experiments whether the seasonal variation is tissue specific, occurring only in lymphocytes, or characteristic of microsomal oxidases in other tissues as well.

Absence of seasonal variation in antipyrine metabolism.

The induced activity of aryl hydrocarbon hydroxylase (AHH), measured by the metabolism of benzo[a]pyrene to fluorescent products in cultured human lymphocytes, shows a strong seasonal variation. The in vivo metabolism of antipyrine, which is also catalyzed by microsomal cytochrome P-450-dependent monooxygenases, has been reported to be correlated with AHH inducibility in human lymphocytes. To determine whether antipyrine metabolism also showed seasonal changes, we measured antipyrine half-life (t 1/2) in 10 nonsmokers and eight smokers at the two times of the year that correspond to the high and low peaks of inducible AHH activity as measured in lymphocytes. The mean antipyrine t 1/2 determined in all 18 subjects in summer was almost identical to that found in winter (mean +/- SEM = 10.90 +/- 0.65 and 10.96 +/- 0.78 hr). AHH activity in cultured human lymphocytes from the nonsmoking subjects was determined in control and 3-methylcholanthrene-induced cells to obtained inducibility ratios of 4.2 +/- 0.56 (SEM) in the summer and 1.4 +/- 0.14 (SEM) in winter. These results indicate that the seasonal variation in AHH inducibility in human lymphocytes is not reflected by a corresponding seasonal variation in antipyrine metabolism in vivo.

Problems in assessing the relative predictive value of internal markers versus external exposure in chronic disease epidemiology.

Epidemiology traditionally has relied on measures of "external" exposure in determining the association between exposure and disease. Recently, there has been increasing reliance on internal markers reflecting internal dose and/or early stages of disease. In the context of observational studies of chronic disease in which there is a known exposure-disease association, the question arises whether the external exposure or the internal marker is a better predictor of eventual disease outcome. Here we describe some simple approaches to evaluate the relative predictive value of the internal marker (or biomarker, defined in the most general sense) versus the exposure, as well as their limitations. The problems of assessing the predictive value of internal markers for chronic disease are illustrated via two examples: (a) carcinogens, cytogenetic outcomes, and cancer; and (b) asbestos, asbestosis, and lung cancer. We conclude that it is unlikely that observational epidemiology will allow a full assessment of the predictive value of cytogenetic outcomes versus exposure for cancer in humans exposed to known carcinogens in the near future, although animal studies could provide important complementary information. For asbestos, data to date indicate that the presence or absence of asbestosis is a better predictor of lung cancer in an exposed population than is the level of exposure to asbestos itself. In general, the most useful markers for predicting chronic disease are ones which persist over time.

Cancer incidence in the National Health and Nutrition Survey I. Follow-up data: diabetes, cholesterol, pulse and physical activity.

We examined cancer incidence among 14,407 men and women who were enrolled in the National Health and Nutrition Survey I in the early 1970s and then followed through 1987. We studied 657 male and 593 female cancer cases, using Cox regression. Analyses were conducted for all cancers, lung, colorectal, breast, and prostate cancer. Analyses focused on diabetes, cholesterol, pulse, and physical activity, four risk factors with limited or inconsistent prior evidence. All four risk factors were modestly associated with all cancers for men but not for women. For diabetic men, the rate ratio for all cancers was 1.38 [95% confidence interval (CI) = 1.00-1.91]; the elevated risk was particularly evident for colorectal and prostate cancer. Slight inverse trends of cancer risk with cholesterol were apparent for men but not for women and were diminished compared to prior analyses of these data with less follow-up. Males with the lowest quartile of cholesterol versus the highest had a rate ratio of 1.21 (CI = 0.98-1.51) for all cancers. A modest positive trend between pulse and all cancers was seen for males [rate ratio of 1.27 (CI = 1.04-1.57)] for the highest versus the lowest quartile). The rate ratio for men with the least amount of nonrecreational physical activity was 1.29 (CI = 0.99-1.69). There is some evidence in these data that findings for cholesterol and nonrecreational physical activity could be artifacts of the early effects of disease because they diminished when cases were restricted to those with longer follow-up.

Empirical Bayes adjustments for multiple results in hypothesis-generating or surveillance studies.

Traditional methods of adjustment for multiple comparisons (e.g., Bonferroni adjustments) have fallen into disuse in epidemiological studies. However, alternative kinds of adjustment for data with multiple comparisons may sometimes be advisable. When a large number of comparisons are made, and when there is a high cost to investigating false positive leads, empirical or semi-Bayes adjustments may help in the selection of the most promising leads. Here we offer an example of such adjustments in a large surveillance data set of occupation and cancer in Nordic countries, in which we used empirical Bayes (EB) adjustments to evaluate standardized incidence ratios (SIRs) for cancer and occupation among craftsmen and laborers. For men, there were 642 SIRs, of which 138 (21%) had a P < 0.05 (13% positive with SIR > 1.0 and 8% negative with SIR < or = 1.0) when testing the null hypothesis of no cancer/occupation association; some of these were probably due to confounding by nonoccupational risk factors (e.g., smoking). After EB adjustments, there were 95 (15%) SIRs with P < 0.05 (10% positive and 5% negative). For women, there were 373 SIRs, of which 37 (10%) had P < 0.05 before adjustment (6% positive and 4% negative) and 13 (3%) had P < 0.05 after adjustment (2% positive and 1% negative). Several known associations were confirmed after EB adjustment (e.g., pleural cancer among plumbers, original SIR 3.2 (95% confidence interval, 2.5-4.1), adjusted SIR 2.0 (95% confidence interval, 1.6-2.4). EB can produce more accurate estimates of relative risk by shrinking imprecise outliers toward the mean, which may reduce the number of false positives otherwise flagged for further investigation. For example, liver cancer among chimney sweepers was reduced from an original SIR of 2.2 (range, 1.1-4.4) to an adjusted SIR of 1.1 (range, 0.9-1.4). A potentially important future application for EB is studies of gene-environment-disease interactions, in which hundreds of polymorphisms may be evaluated with dozens of environmental risk factors in large cohort studies, producing thousands of associations.

Cytogenetic effects of formaldehyde exposure in students of mortuary science.

The effect of low-level exposure to formaldehyde on oral, nasal, and lymphoycte biological markers was studied prospectively in a group of 29 mortician students who were about to take a course in embalming. During the 85-day study period, the subjects performed an average of 6.9 embalmings and had average cumulative formaldehyde exposures of 14.8 ppm-h, with an average air concentration of 1.4 ppm during embalming. Since the average time spent embalming was 125 min, formaldehyde exposures calculated as an 8-h time-weighted average were 0.33 ppm on days when embalmings were done, which was less than the Occupational Safety and Health Administration permissible exposure limit of 0.75 ppm. Epithelial cells from the buccal area of the mouth showed a 12-fold increase in micronucleus frequency during the study period, from 0.046 +/- 0.17/1000 cells preexposure to 0.60 +/- 1.27/1000 cells at the end of the course (P < 0.05). Nasal epithelial micronuclei increased 22%, from 0.41 +/- 0.52/1000 cells to 0.50 +/- 0.67/1000 cells (P = 0.26). In blood cells, the frequency of micronucleated lymphocytes increased 28%, from 4.95 +/- 1.72/1000 cells to 6.36 +/- 2.03/1000 cells (P < 0.05), while sister chromatid exchanges decreased 7.5% (P < 0.05). A dose-response relationship was observed between cumulative exposure to formaldehyde and increases in buccal micronuclei in the 22 male subjects but not in the 7 female subjects. We conclude that low-level exposure to formaldehyde is associated with cytogenetic changes in epithelial cells of the mouth and in blood lymphocytes. These cytogenetic effects may be useful as markers of biologically effective dose.

Effect of travel and rest on performance of professional basketball players.

We have studied 8,495 regular season games in the National Basketball Association over eight seasons (1987-1988 through 1994-1995) to analyze the effects of travel and rest on performance. We found that more time between games improved performance, an effect that was constant over time and statistically significant. More than 1 day between games increased the home team's score by 1.1 points and the visitor's by 1.6 points. Peak performance occurred with 3 days between games. The negative effects of little time between games may be due to lack of time for physical recovery, rather than any effects of circadian rhythm (jet lag). We found few consistent effects of distance traveled or direction of travel. We did find a suggestion of circadian rhythm effects in a subanalysis of games on either coast in which the visitor traveled across the country, while the home team did not travel (n = 101). In these games, the visiting team did four points better (p = 0.07) when they traveled west to east rather than east to west, almost nullifying the home-court advantage. This effect, like similar findings for Monday Night Football games, may be due to West Coast visitors playing night games at an earlier time according to their "internal clock". An incidental finding in our study was that the home-court advantage decreased over 8 years, from about six points to three points (due to relatively lower field-goal percentages and fewer free throws by the home team).

Risk assessment for heart disease and workplace ETS exposure among nonsmokers.

In 1994 the U.S. Occupational Health and Safety Administration (OSHA) published a study of risk assessment for heart disease and lung cancer resulting from workplace exposure to environmental tobacco smoke (ETS) among nonsmokers. This assessment is currently being revised. The present article considers different possible approaches to a risk assessment for heart disease among nonsmokers resulting from workplace ETS exposure, reviews the approach taken by OSHA in 1994, and suggests some modifications to that approach. Since 1994 the literature supporting an association between ETS exposure and heart disease among never smokers (sometimes including long-term former smokers) has been strengthened by new studies, including some studies that have specifically considered workplace exposure. A number of these studies are appropriate for inclusion in a meta-analysis, whereas a few may not be due to methodological problems or problems in exposure definition. A meta-analysis of eight relative risks (either rate ratios or odds ratios) for heart disease resulting from workplace ETS exposure, based on one reasonable selection of appropriate studies, yields a combined relative risk of 1.21 (95% confidence interval [CI], 1.04-1.41). This relative risk, which is similar to that used by OSHA in 1994, yields an excess risk of death from heart disease by age 70 of 7 per 1000 (95% CI 0.001-0.013) resulting from ETS exposure in the workplace. This excess risk exceeds OSHA's usual threshold for regulation of 1 per 1000. Approximately 1,710 excess ischemic heart disease deaths per year would be expected among nonsmoking U.S. workers 35-69 years of age exposed to workplace ETS.

Thyroid hormones and cytogenetic outcomes in backpack sprayers using ethylenebis(dithiocarbamate) (EBDC) fungicides in Mexico.

Ethylenebis(dithiocarbamate) (EBDC) fungicides are used heavily in the United States. EBDCs (e.g., mancozeb, maneb) are metabolized to ethylene thiourea (ETU). The EPA classifies ETU as a carcinogen, based on thyroid and other cancers in rodents, and has restricted the use of EBDCs, while requiring workers to use protective equipment. There are no data on the potential carcinogenicity of EBDCs in humans, and there is only one study on human genotoxicity. ETU is known to cause decreases of thyroxine (T4) and increases in thyroid-stimulating hormone (TSH) in rodents. We have studied cytogenetic outcomes and serum thyroid hormone levels among 49 heavily exposed workers without protective equipment spraying EBDC on tomatoes in Mexico. We also studied 14 lightly exposed landowners and 31 nonexposed controls. Urinary ETU was used to compare exposure between groups. We found an increase in TSH (p = 0.05) among applicators compared to controls, but no decrease in thyroid hormone (T4). We found increases in sister chromatid exchange (p = 0.03) and in chromosome translocations (chromosome aberrations that persist through cell division) for applicators compared to controls (p = 0.05). However, the subset of reciprocal translocations showed a lesser increase (p = 0.24). Our data suggest that EBDCs affect the thyroid gland and the lymphocyte genome among heavily exposed workers. However, our data are limited to subclinical outcomes, are of borderline statistical significance, and should be interpreted with caution.