Biomedical subjects

Russ Hauser

Publications and source records attributed to Russ Hauser.

At least 19 recordsLinked to original sources

PubMed2024

Phthalates and sex steroid hormones across the perimenopausal period: A longitudinal analysis of the Midlife Women's Health Study.

BACKGROUND: The menopausal transition involves significant sex hormone changes. Environmental chemicals, such as urinary phthalate metabolites, are associated with sex hormone levels in cross-sectional studies. Few studies have assessed longitudinal associations between urinary phthalate metabolite concentrations and sex hormone levels during menopausal transition. METHODS: Pre- and perimenopausal women from the Midlife Women's Health Study (MWHS) (n = 751) contributed data at up to 4 annual study visits. We quantified 9 individual urinary phthalate metabolites and 5 summary measures (e.g., phthalates in plastics (∑Plastic)), using pooled annual urine samples. We measured serum estradiol, testosterone, and progesterone collected at each study visit, unrelated to menstrual cycling. Linear mixed-effects models and hierarchical Bayesian kernel machine regression analyses evaluated adjusted associations between individual and phthalate mixtures with sex steroid hormones longitudinally. RESULTS: We observed associations between increased concentrations of certain phthalate metabolites and lower testosterone and higher sub-ovulatory progesterone levels, e.g., doubling of monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), di-2-ethylhexyl phthalate (∑DEHP) metabolites, ∑Plastic, and ∑Phthalates concentrations were associated with lower testosterone (e.g., for ∑DEHP: -4.51%; 95% CI: -6.72%, -2.26%). For each doubling of MEP, certain DEHP metabolites, and summary measures, we observed higher mean sub-ovulatory progesterone (e.g., ∑AA (metabolites with anti-androgenic activity): 6.88%; 95% CI: 1.94%, 12.1%). Higher levels of the overall time-varying phthalate mixture were associated with lower estradiol and higher progesterone levels, especially for 2nd year exposures. CONCLUSIONS: Phthalates were longitudinally associated with sex hormone levels during the menopausal transition. Future research should assess such associations and potential health impacts during this understudied period.

Humans↗

PubMed2006

Serum PCBs, p,p'-DDE and HCB predict thyroid hormone levels in men.

UNLABELLED: Polychlorinated biphenyls (PCBs) and some organochlorine pesticides, which continue to be measurable in a high proportion of blood samples from the general population, have been found to alter thyroid hormone levels in animals and humans. However, studies of these relationships in adult men are limited and results across studies have been inconsistent. In the present study, we measured serum levels of 57 PCB congeners, dichlorodiphenyldichloroethylene (p,p(')-DDE, a stable metabolite of DDT), and hexachlorobenzene (HCB), as well as free T(4), total T(3), and TSH, in 341 adult men recruited from an infertility clinic from 2000 to 2003. In multivariate linear regression, there were positive associations between p,p(')-DDE and both free T(4) and total T(3), and an inverse association between p,p(')-DDE and TSH. Conversely, for PCBs there was only a suggestive inverse association between PCB 153 and total T(3) when potential confounding variables were considered. However, when results were additionally adjusted for p,p(')-DDE, inverse associations with T(3) were significant for PCB 138, PCB 153, sum of PCBs and three different PCB groupings, and HCB, while the positive associations between p,p(')-DDE and T(3) also remained. In conclusion, serum concentrations of PCBs, p,p(')-DDE, and HCB were associated with circulating thyroid hormone levels in adult men. ABBREVIATIONS: BMI, body mass index; CYP, cytochrome P450; DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane; HCB, hexachlorobenzene; MDL, method detection limit; NHANES, national health and nutrition examination survey: p,p(')-DDE, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene; PCB, polychlorinated biphenyl; T(3), triiodothyronine; T(4), thryoxine; TSH, thyroid stimulating hormone (thyrotrophin); US, United States.

Adult↗

PubMed2006

Relationships between serum hormone levels and semen quality among men from an infertility clinic.

Participation rates in epidemiologic studies on semen quality are generally very low, raising concerns as to the potential for selection bias. Since hormones both initiate and maintain spermatogenesis, they may serve as surrogates of semen quality in epidemiologic studies. For this reason, in the present study, we explored the influence and predictive ability of reproductive and thyroid hormones on semen quality among men who were partners in an infertile couple. Between 1999 and 2003, 388 men were recruited from Massachusetts General Hospital Andrology Laboratory for clinical evaluation of fertility status. Fresh semen samples were assessed for quality (concentration, motility and morphology) and the serum levels of hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), inhibin B, sex hormone-binding globulin (SHBG), testosterone, free androgen index, free T4, total T3, and thyroid-stimulating hormone (TSH), were measured. Multiple logistic regression revealed increased odds for below-reference sperm concentration and morphology in men with increased FSH, and decreased odds for below-reference sperm concentration and motility in men with increased inhibin B. When FSH and inhibin B were divided into quintiles, the relationships with sperm concentration showed evidence of a threshold value. However, the ability of specific FSH (10 IU/L) and/or inhibin B (80 pg/mL) cutoff values to predict semen quality was lower than in previous reports. In multiple linear regression analysis, FSH and LH were inversely associated with sperm concentration, motility, and morphology. Inhibin B and free T4 were positively associated with sperm concentration, while there was a suggestive positive association between testosterone and sperm motility. In conclusion, we have found that FSH, LH, inhibin B, testosterone and free T4 levels are associated with human semen parameters. Additional consideration should be given to the utility of serum hormone levels as a surrogate for semen quality in epidemiologic studies in which the collection of semen is difficult due to logistical and/or volunteer rate constraints.

Adolescent↗

PubMed2006

Utility of urinary 1-naphthol and 2-naphthol levels to assess environmental carbaryl and naphthalene exposure in an epidemiology study.

We recently reported associations between urinary 1-naphthol (1N) levels and several intermediate measures of male reproductive health, namely sperm motility, serum testosterone levels, and sperm DNA damage. However, because 1N is a major urinary metabolite of both naphthalene and the insecticide carbaryl, exposure misclassification stemming from differences in exposure source was probable and interpretation of the results was limited. As naphthalene, but not carbaryl, is also metabolized to 2-naphthol (2N), the relationship of urinary 1N to 2N within an individual may give information about source of 1N. Utilizing data from two previous studies that measured both 1N and 2N in urine of men exposed to either carbaryl or naphthalene, the present study employed several methods to differentiate urinary 1N arising from exposures to carbaryl and naphthalene among men in the reproductive health study. When re-evaluating the reproductive health data, techniques for identifying 1N source involved exploring interaction terms, stratifying the data set based on 1N/2N ratios, and performing an exposure calibration using a linear 1N to 2N relationship from a study of workers exposed to naphthalene in jet fuel. Despite some inconsistencies between the methods used to distinguish 1N source, we found that 1N from carbaryl exposure is likely responsible for the previously observed association between 1N and sperm motility, whereas 1N from naphthalene exposure is likely accountable for the association between 1N and sperm DNA damage. We demonstrate that studies of health effects associated with carbaryl should utilize a 1N/2N ratio to identify subgroups in which carbaryl is the primary source of 1N. Conversely, studies of naphthalene-related outcomes may utilize 2N levels to estimate exposure.

Adult↗

PubMed2006

Thyroid hormones in relation to urinary metabolites of non-persistent insecticides in men of reproductive age.

Human exposure to contemporary-use insecticides is widespread, but effects of exposure on human endocrine function have gone largely untested to date. Samples of urine and blood were collected concurrently from 322 adult men between the years 2000 and 2003. Urine samples were analyzed for 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, and 1-napththol (1N), a metabolite of carbaryl and naphthalene. Serum samples were analyzed for free T(4), total T(3), and thyroid stimulating hormone (TSH). There was an association between TCPY and TSH, where an interquartile range (IQR) increase in TCPY was associated with a 9% (95% confidence interval 0-18%) increase in TSH. There was also a suggestive inverse association between TCPY and free T(4). There were no associations between 1N and thyroid hormones. Environmental exposure to chlorpyrifos, chlorpyrifos-methyl, or its metabolite TCPY may be associated with altered thyroid function in human males.

Adult↗

PubMed2006

The environment and male fertility: recent research on emerging chemicals and semen quality.

Scientific and public concern about the potential risk of environmental chemicals to male reproductive health has been heightened by reports of downward trends in semen quality, as well as increased rates of developmental urogenital tract anomalies and testicular cancer. Of particular concern is whether some contemporary-use environmental chemicals alter semen quality. Specific toxicants of interest include phthalates and pesticides, as well as polychlorinated biphenyls (PCBs). The human data on the relationship of semen quality with phthalate and pesticide exposure are limited and do not currently allow for a definitive conclusion on whether adult exposure, at background environmental levels, alters semen quality. However, the epidemiologic data support an inverse association of PCBs with reduced semen quality, specifically reduced sperm motility. The associations found were generally consistent across studies despite a range of PCB levels. In addition to the chemicals discussed, there are additional classes of chemicals that require further study on their relation with human semen quality.

Age Factors↗

PubMed2006

Exposure to nonpersistent insecticides and male reproductive hormones.

BACKGROUND: Urinary metabolites of several nonpersistent insecticides have been measured in a high percentage of men in the general population, suggesting widespread environmental exposures to these compounds. The present study explored the association of urinary concentrations of 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, and 1-naphthol (1N), a metabolite of carbaryl and naphthalene, with serum reproductive hormone levels in adult men. METHODS: Subjects (n = 268) were the male partners in couples presenting to a Massachusetts infertility clinic in years 2000 through 2003. TCPY and 1N were measured in a spot urine sample from each subject and adjusted for dilution using specific gravity. Reproductive hormones (follicle-stimulating hormone, leuteinizing hormone, inhibin B, testosterone, and sex hormone-binding globulin) were measured in serum collected from subjects during the same clinic visit. RESULTS: Multiple linear regression models showed an inverse association between TCPY and testosterone concentration. An interquartile range (IQR) increase in TCPY was associated with a decline of 25 ng/dL (95% confidence interval = -40 to -10) in testosterone concentration. The association appeared to be dose-dependent when exposure was divided into quintiles. The highest TCPY quintile was associated with a testosterone decline of 83 ng/dL (-128 to -39) compared with the lowest TCPY quintile. We also found inverse associations between TCPY and free androgen index and between 1N and testosterone, and suggestive inverse associations between TCPY and leuteinizing hormone and between 1N and free androgen index. CONCLUSION: In adult men, TCPY and 1N were associated with reduced testosterone levels. On a population level, these reductions are of potential public health importance because of widespread exposure to these nonpersistent insecticides.

Adult↗

PubMed2006

Altered semen quality in relation to urinary concentrations of phthalate monoester and oxidative metabolites.

BACKGROUND: Phthalates are multifunctional chemicals used in a variety of consumer, medical, and personal care products. Previously, we reported dose-response associations of decreased semen quality with urinary concentrations of monobutyl phthalate (MBP) and monobenzyl (MBzP) phthalate, which are metabolites of dibutyl phthalate and butylbenzyl phthalate, respectively. The present study extends our work in a larger sample of men and includes measurements of di(2-ethylhexyl) phthalate (DEHP) oxidative metabolites. METHODS: Between January 2000 and May 2004, we recruited 463 male partners of subfertile couples who presented for semen analysis to the Massachusetts General Hospital. Semen parameters were dichotomized based on World Health Organization reference values for sperm concentration (<20 million/mL) and motility (<50% motile) and the Tygerberg Kruger Strict criteria for morphology (<4% normal). The comparison group was men with all 3 semen parameters above the reference values. In a single spot urine sample from each man, phthalate metabolites were measured using solid-phase extraction coupled to high-performance liquid chromatography isotope-dilution tandem mass spectrometry. RESULTS: There were dose-response relationships of MBP with low sperm concentration (odds ratio per quartile adjusted for age, abstinence time, and smoking status = 1.00, 3.1, 2.5, 3.3; P for trend = 0.04) and motility (1.0, 1.5, 1.5, 1.8; P for trend = 0.04). There was suggestive evidence of an association between the highest MBzP quartile and low sperm concentration (1.00, 1.1, 1.1, 1.9; P for trend = 0.13). There were no relationships of monoethyl phthalate, monomethyl phthalate, and the DEHP metabolites with these semen parameters. CONCLUSION: The present study confirms previous results on the relationship of altered semen quality with exposure to MBP at general population levels. We did not find associations between semen parameters and 3 DEHP metabolites.

Adult↗

PubMed2006

Exposure to phthalates in neonatal intensive care unit infants: urinary concentrations of monoesters and oxidative metabolites.

OBJECTIVE: We previously demonstrated that among 54 infants in neonatal intensive care units, exposure to polyvinyl chloride plastic medical devices containing the plasticizer di(2-ethylhexyl) phthalate (DEHP) is associated with urinary concentrations of mono(2-ethylhexyl) phthalate (MEHP) , a DEHP metabolite. In this follow-up report, we studied the neonates' exposure to DEHP-containing devices in relation to urinary concentrations of two other DEHP metabolites, and to urinary concentrations of metabolites of dibutyl phthalate (DBP) and benzylbutyl phthalate (BzBP) , phthalates found in construction materials and personal care products. MEASUREMENTS: A priori, we classified the intensiveness of these 54 infants' exposure to DEHP-containing medical products. We measured three metabolites of DEHP in infants' urine: MEHP and two of its oxidative metabolites, mono(2-ethyl-5-hydroxylhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) . We also measured monobutyl phthalate (MBP) , a metabolite of DBP, and monobenzyl phthalate (MBzP), a metabolite of BzBP. RESULTS: Intensiveness of DEHP-containing product use was monotonically associated with all three DEHP metabolites. Urinary concentrations of MEHHP and MEOHP among infants in the high-DEHP-intensiveness group were 13-14 times the concentrations among infants in the low-intensiveness group (p</= 0.007). Concentrations of MBP were somewhat higher in the medium- and high-DEHP-intensiveness group; MBzP did not vary by product use group. Incorporating all phthalate data into a structural equation model confirmed the specific monotonic association between intensiveness of product use and biologic measures of DEHP. CONCLUSION: Inclusion of the oxidative metabolites MEHHP and MEOHP strengthened the association between intensiveness of product use and biologic indices of DEHP exposure over that observed with MEHP alone.

Age Factors↗

PubMed2005

Longitudinal assessment of PCBs and chlorinated pesticides in pregnant women from Western Canada.

BACKGROUND: Maternal exposures to organochlorines prior to pregnancy are considered a risk to neonatal welfare, specifically in relation to neurocognitive functions. There is growing interest in the evaluation of maternal blood testing as a marker for fetal exposure as well as the variable geographic distribution of these priority chemicals. METHODS: Three hundred and twenty-three women in the second trimester of pregnancy entered the study at a prenatal clinic providing genetic counselling information. Subjects who had an indication for genetic amniocentesis based on late maternal age were eligible to participate. Two hundred and thirty-eight completed an environmental questionnaire. A sample of amniotic fluid was taken for karyotype analysis in 323 women and blood samples during pregnancy (209), at birth (105) and from the umbilical cord (97) and breast milk (47) were also collected. These samples were tested for 29 PCB congeners and organochlorine pesticides. RESULTS: The concentrations of PCB 153 in these media were relatively low in relation to other studies. Sigma PCBs measurements in samples taken during the second trimester of pregnancy, at birth and in the umbilical cord were strongly correlated. Specific measurements of PCB 153 and PCB 180 among those subjects with completed sampling of blood samples from mothers and cord samples were significantly correlated. The concentrations of PCBs and pesticides did not differ in relation to prior spontaneous abortion history. There were no organochlorines present in the amniotic fluid at the current level of quantification. CONCLUSION: Pregnant women from the Western Canada region of Calgary, Alberta are exposed to relatively low concentrations of organochlorines. Measurement of maternal blood during the second trimester of pregnancy can reliably estimate the fetal exposure to PCBs. This estimate is reliable for Group 2 and 3 PCBs as well as PCB 153 and PCB 180. The amniotic fluid does not contain measurable concentrations of pesticides and PCBs under the conditions of the levels of quantification.

Adult↗

PubMed2005

Predictors of serum dioxin levels among adolescent boys in Chapaevsk, Russia: a cross-sectional pilot study.

BACKGROUND: Toxicological studies and limited human studies have demonstrated associations between exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) and adverse developmental and reproductive health effects. Given that children may be particularly susceptible to reproductive and developmental effects of organochlorines, and the paucity of information available regarding childhood exposures to dioxins in particular, we undertook a pilot study to describe the distribution of, and identify potential predictors of exposure to, dioxin-like compounds and dioxins among adolescent boys in Chapaevsk, Russia. The pilot study was also designed to guide the development of a large prospective cohort study on the relationship of exposure to PCDDs, PCDFs, and PCBs with growth and pubertal development in peri-pubertal Chapaevsk boys. METHODS: 221 boys age 14 to 17 participated in the pilot study. Each of the boys, with his mother, was asked to complete a nurse-administered detailed questionnaire on medical history, diet, and lifestyle. The diet questions were used to measure the current and lifetime consumption of locally grown or raised foods. Blood samples from 30 of these boys were sent to the Centers for Disease Control and Prevention (CDC) for analysis of dioxins, furans and PCBs. RESULTS: The median (25th, 75th percentile) concentrations for total PCDDs, PCDFs and coplanar PCBs were 95.8 pg/g lipids (40.9, 144), 33.9 pg/g lipids (20.4, 61.8), and 120 pg/g lipids (77.6, 157), respectively. For WHO-TEQs, the median (25th, 75th percentile) for total PCDDs, PCDFs, and coplanar PCBs were 0.29 (0.1, 9.14), 7.98 (5.27, 12.3), and 7.39 (4.51, 11.9), respectively. Although TCDD was largely non-detectable, two boys had high TCDD levels (17.9 and 21.7 pg/g lipid). Higher serum levels of sum of dioxin-like compounds and sum of dioxin TEQs were positively associated with increased age, consumption of fish, local meats other than chicken, PCB 118, and inversely with weeks of gestation. CONCLUSION: The total TEQs among Chapaevsk adolescents were higher than most values previously reported in non-occupationally exposed populations of comparable or even older ages. Dietary consumption of local foods, as well as age and weeks of gestation, predicted dioxin exposure in this population.

Adolescent↗

PubMed2005

Does the potential for selection bias in semen quality studies depend on study design? Experience from a study conducted within an infertility clinic.

BACKGROUND: The low participation rates in human semen quality studies raises concern for the potential of differential participation based on semen quality (or a surrogate). To explore the potential for differential participation, we compared semen analysis results from study subjects with those of non-study subjects. METHODS: We obtained semen analysis results from 235 study subjects and retrospectively obtained results from a subset of 235 infertility clinic patients that were not study subjects but met the same eligibility criteria. The study was conducted at the Massachusetts General Hospital Infertility Clinic. All semen samples (study subjects and non-study subjects) were analysed for sperm concentration and motility by computer-aided semen analysis (CASA), and morphology was assessed using strict criteria. Semen analysis parameters for the non-study subjects were compared with the semen analysis results from study subjects. RESULTS: For all semen characteristics (sperm concentration, total sperm count, sperm motility and morphology), there were only marginal (non-significant) differences between study subjects and non-study subjects. CONCLUSIONS: Among men from an infertility clinic, we found no strong evidence of differential participation based on semen quality. This is reassuring since the potential for selection bias is of concern in semen quality studies. However, the potential for selection bias in other study designs remains unclear.

Ambulatory Care Facilities↗

PubMed2005

Laceration injuries among workers at meat packing plants.

BACKGROUND: Employees in meat packing experience one of the highest occupational laceration injury rates in the US. METHOD: A retrospective study was conducted using OSHA 200 injury and illness logs and First Reports of Injury from two large US meat packing plants from 1998 to 2000. The total workers observed during the study period ranged between 2,449 and 2,682 per year. RESULTS: Laceration injury incidence rates in Plant 1 were 14.0 injuries per 200,000 person hours (per 100 workers per year) in 1998, 11.5 in 1999, and 8.3 in 2000, whereas in Plant 2 the overall incidence rate was 3.7 in 1998, 4.8 in 1999, and 3.0 in 2000. Laceration injury rates in Plant 2 were close to the expected OSHA recordable laceration injury rate in 1999 (3.0 per 100 workers per year), but Plant 1 was considerably higher. Plant 1 had a kill support department, and removed animal hides whereas Plant 2 did not. Handheld non-powered tools were the most common contact objects whereas the slaughter department had the highest number of injuries. Finger injuries from a handheld non-powered tool were the most frequent. CONCLUSIONS: Findings confirm the high rate of injury from laceration in this industry and indicate hazard varies across time into shift, task being performed, and type of tool being used.

Accidents, Occupational↗

PubMed2005

Obesity and cardiovascular disease risk factors in firefighters: a prospective cohort study.

OBJECTIVE: Obesity, despite being a significant determinant of fitness for duty, is reaching epidemic levels in the workplace. Firefighters' fitness is important to their health and to public safety. RESEARCH METHODS AND PROCEDURES: We examined the distribution of BMI and its association with major cardiovascular disease (CVD) risk factors in Massachusetts firefighters who underwent baseline (1996) and annual medical examinations through a statewide medical surveillance program over 5 years of follow-up. We also evaluated firefighters' weight change over time. RESULTS: The mean BMI among 332 firefighters increased from 29 at baseline to 30 at the follow-up examination (2001), and the prevalence of obesity increased from 35% to 40%, respectively (p < 0.0001). In addition, the proportion of firefighters with extreme obesity increased 4-fold at follow-up (from 0.6% to 2.4%, p < 0.0001). Obese firefighters were more likely to have hypertension (p = 0.03) and low high-density lipoprotein-cholesterol (p = 0.01) at follow-up. Firefighters with extreme obesity had an average of 2.1 CVD risk factors (excluding obesity) in contrast to 1.5 CVD risk factors for normal-weight firefighters (p = 0.02). Finally, on average, normal-weight firefighters gained 1.1 pounds, whereas firefighters with BMI > or = 35 gained 1.9 pounds per year of active duty over 5 years of follow-up. DISCUSSION: Obesity is a major concern among firefighters and shows worsening trends over time. Periodic medical evaluations coupled with exercise and dietary guidelines are needed to address this problem, which threatens firefighters' health and may jeopardize public safety.

Adult↗

PubMed2005

Temporal variability of urinary levels of nonpersistent insecticides in adult men.

Widespread application of contemporary-use insecticides results in low-level exposure for a majority of the population through a variety of pathways. Urinary insecticide biomarkers account for all exposure pathways, but failure to account for temporal within-subject variability of urinary levels can lead to exposure misclassification. To examine temporal variability in urinary markers of contemporary-use insecticides, nine repeated urine samples were collected over 3 months from 10 men participating in an ongoing study of male reproductive health. These 90 samples were analyzed for urinary metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPY)) and carbaryl (1-naphthol (1N)). Volume- based (unadjusted), as well as creatinine (CRE)- and specific gravity (SG)-adjusted concentrations were measured. TCPY had low reliability with an intraclass correlation coefficient between 0.15 and 0.21, while 1N was moderately reliable with an intraclass correlation coefficient between 0.55 and 0.61. When the 10 men were divided into tertiles based on 3-month geometric mean TCPY and 1N levels, a single urine sample performed adequately in classifying a subject into the highest or lowest exposure tertiles. Sensitivity and specificity ranged from 0.44 to 0.84 for TCPY and from 0.56 to 0.89 for 1N. Some differences in the results between unadjusted metabolite concentrations and concentrations adjusted for CRE and SG were observed. Questionnaires were used to assess diet in the 24 h preceding the collection of each urine sample. In mixed-effects models, TCPY was significantly associated with season as well as with consuming grapes and cheese, while 1N levels were associated with consuming strawberries. In conclusion, although a single sample adequately predicted longer-term average exposure, a second sample collected at least 1 month following the first sample would reduce exposure measurement error.

Adult↗

PubMed2005

Exposure to fuel-oil ash and welding emissions during the overhaul of an oil-fired boiler.

The health effects of exposure to vanadium in fuel-oil ash are not well described at levels ranging from 10 to 500 microg/m(3). As part of a larger occupational epidemiologic study that assessed these effects during the overhaul of a large oil-fired boiler, this study was designed to quantify boilermakers' exposures to fuel-oil ash particles, metals, and welding gases, and to identify determinants of these exposures. Personal exposure measurements were conducted on 18 boilermakers and 11 utility workers (referents) before and during a 3-week overhaul. Ash particles < 10 microm in diameter (PM(10), mg/m(3)) were sampled over full work shifts using a one-stage personal size selective sampler containing a polytetrafluoroethylene filter. Filters were digested using the Parr bomb method and analyzed for the metals vanadium (V), nickel (Ni), iron (Fe), chromium (Cr), cadmium (Cd), lead (Pb), manganese (Mn), and arsenic (As) by inductively coupled plasma mass spectrometry. Nitrogen dioxide (NO(2)) was measured with an Ogawa passive badge-type sampler and ozone (O(3)) with a personal active pump sampler.Time-weighted average (TWA) exposures were significantly higher (p < 0.05) for boilermakers than for utility workers for PM(10) (geometric mean: 0.47 vs. 0.13 mg/m(3)), V (8.9 vs. 1.4 microg/m(3)), Ni (7.4 vs. 1.8 microg/m(3)) and Fe (56.2 vs. 11.2 microg/m(3)). Exposures were affected by overhaul time periods, tasks, and work locations. No significant increases were found for O(3) or NO(2) for boilermakers or utility workers regardless of overhaul period or task group. Fuel-oil ash was a major contributor to boilermakers' exposure to PM(10) and metals. Vanadium concentrations sometimes exceeded the 2003 American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value.

Adult↗

PubMed2005

Estimation of personal exposures to particulate matter and metals in boiler overhaul work.

OBJECTIVE: We sought to develop an algorithm and estimate unmeasured exposures to particulate matter (PM) and metals in an epidemiologic study of boilermakers. METHODS: The algorithm was based on limited measurements and workers' task and time activity patterns. Half of the measurements were used to develop exposure estimates for unmeasured person days. The other half was used for method validation. RESULTS: The validation demonstrated good approximations of actual exposures with differences less than 5% for PM and vanadium (V). Average estimated exposures to PM (mg/m3) and V (microg/m3) were significantly higher for workers doing boiler repair than utility work (0.36 vs. 0.09 for PM and 5.99 vs. 0.38 for V). CONCLUSIONS: This algorithm provided reasonably accurate exposure indices for our epidemiologic study in this population. It also is likely applicable to similar exposure scenarios in other studies.

Air Pollutants, Occupational↗

PubMed2005

Evidence of interaction between polychlorinated biphenyls and phthalates in relation to human sperm motility.

Previously, we reported evidence of inverse associations between exposure to some polychlorinated biphenyls (PCBs) and some phthalate monoesters in relation to semen parameters, specifically sperm motility. Because humans are exposed to both phthalates and PCBs and because experimental studies suggest that PCBs may interact with glucuronidative enzymes that are responsible for phthalate metabolism, we explored the potential interaction between phthalates and PCBs in relation to human semen quality. We studied 303 men who were partners in subfertile couples seeking infertility diagnosis from the andrology laboratory at Massachusetts General Hospital. Semen parameters were dichotomized based on World Health Organization reference values, and phthalate and PCB levels were dichotomized at their respective medians. After adjusting for age and abstinence time, for below reference sperm motility there was a greater than additive interaction between monobenzyl phthalate and PCB-153 [relative excess risk due to interaction (RERI) = 1.40; 95% confidence interval (CI), 0.41-3.22], sum of PCBs (RERI = 1.24; 95% CI, 0.15-2.94), and cytochrome P450 (CYP450)-inducing PCBs (RERI = 1.30; 95% CI, 0.21-3.06). For below-reference sperm motility, there was also a greater than additive interaction between monobutyl phthalate (MBP) and PCB-153 (RERI = 1.42; 95% CI, 0.09-3.76) and CYP450-inducing PCBs (RERI = 1.87; 95% CI, 0.56-4.52) and a suggestive interaction between MBP and sum of PCBs (RERI = 1.35; 95% CI, -0.11 to 3.48). In conclusion, because there are important risk assessment and public health implications of interactions between these two ubiquitous classes of compounds, further studies need to be conducted to confirm these results and identify potential mechanisms of interactions.

Adult↗