Hand-to-mouth and other hand-to-face touching behavior in a quasi-naturalistic study under controlled conditions.

Data gaps exist in our understanding of hand-to-mouth touching behavior among adults, despite its relevance for accurately characterizing inadvertent ingestion exposures to chemical and pathogenic microbial agents and consequent associated health risks. The present study describes detailed observations of the frequency and nature of hand-to-mouth and other hand-to-face touching behavior among 14 male and female volunteers in a controlled, quasi-naturalistic setting. Participants performed four 15-min tasks: 1) installation of a brass object as part of a short home improvement project, 2) completion of a pen-and-paper survey, 3) engagement in a telephone conversation, and 4) use of headphones to listen to music. Video recordings of the participants performing each task were reviewed and coded for touches to the face with emphasis on specific regions of the face and palmar versus dorsal contacts. During the installation task, only one of the 14 participants was observed touching his face; this was to the nose, on two separate occasions. Summed across the three non-installation tasks, including palmar and dorsal contacts, participants touched their lips, their mouth, and anywhere on their face on average (range) 5.1 (0-19), 0.4 (0-3), and 27.7 (6-49) times, respectively. Facial contacts during these three non-installation tasks were predominantly with the palmar surface of the hand. The implications of these data are contextually specific, as the potential health impacts of face touching behavior among adults might differ based upon toxicity or virulence of hand contaminants of interest.

Potential Exposure and Cancer Risk from Formaldehyde Emissions from Installed Chinese Manufactured Laminate Flooring.

Lumber Liquidators (LL) Chinese-manufactured laminate flooring (CLF) has been installed in >400,000 U.S. homes over the last decade. To characterize potential associated formaldehyde exposures and cancer risks, chamber emissions data were collected from 399 new LL CLF, and from LL CLF installed in 899 homes in which measured aggregate indoor formaldehyde concentrations exceeded 100 µg/m3 from a total of 17,867 homes screened. Data from both sources were combined to characterize LL CLF flooring-associated formaldehyde emissions from new boards and installed boards. New flooring had an average (±SD) emission rate of 61.3 ± 52.1 µg/m2 -hour; >one-year installed boards had ∼threefold lower emission rates. Estimated emission rates for the 899 homes and corresponding data from questionnaires were used as inputs to a single-compartment, steady-state mass-balance model to estimate corresponding residence-specific TWA formaldehyde concentrations and potential resident exposures. Only ∼0.7% of those homes had estimated acute formaldehyde concentrations >100 µg/m3 immediately after LL CLF installation. The TWA daily formaldehyde inhalation exposure within the 899 homes was estimated to be 17 µg/day using California Proposition 65 default methods to extrapolate cancer risk (below the regulation "no significant risk level" of 40 µg/day). Using a U.S. Environmental Protection Agency linear cancer risk model, 50th and 95th percentile values of expected lifetime cancer risk for residents of these homes were estimated to be 0.33 and 1.2 per 100,000 exposed, respectively. Based on more recent data and verified nonlinear cancer risk assessment models, LL CLF formaldehyde emissions pose virtually no cancer risk to affected consumers.

Assessment of Health Risk from Historical Use of Cosmetic Talcum Powder.

This study's objective is to assess the risk of asbestos-related disease being contracted by past users of cosmetic talcum powder.  To our knowledge, no risk assessment studies using exposure data from historical exposures or chamber simulations have been published. We conducted activity-based sampling with cosmetic talcum powder samples from five opened and previously used containers that are believed to have been first manufactured and sold in the 1960s and 1970s.  These samples had been subject to conflicting claims of asbestos content; samples with the highest claimed asbestos content were tested.  The tests were conducted in simulated-bathroom controlled chambers with volunteers who were talc users.  Air sampling filters were prepared by direct preparation techniques and analyzed by phase contrast microscopy (PCM), transmission electron microscopy (TEM) with energy-dispersive x-ray (EDX) spectra, and selective area diffraction (SAED).  TEM analysis for asbestos resulted in no confirmed asbestos fibers and only a single fiber classified as "ambiguous."  Hypothetical treatment of this fiber as if it were asbestos yields a risk of 9.6 × 10-7 (under one in one million) for a lifetime user of this cosmetic talcum powder.  The exposure levels associated with these results range from zero to levels far below those identified in the epidemiology literature as posing a risk for asbestos-related disease, and substantially below published historical environmental background levels.  The approaches used for this study have potential application to exposure evaluations of other talc or asbestos-containing materials and consumer products.

Personal use of hair dyes and risk of bladder cancer: a meta-analysis of epidemiologic data.

OBJECTIVE: We compared, updated, and expanded the analyses of two previous meta-analyses of personal hair dye exposure and bladder cancer, and briefly discussed the biological plausibility of a systemic hazard to human health from exposure to para-phenylenediamine (PPD), a key chemical in hair dyes. METHODS: The meta-analysis included 11 case-control studies and one cohort study. We evaluated heterogeneity across studies and conducted sensitivity and influence analyses. RESULTS: No association was found between any personal use of hair dye and bladder cancer among women (meta-relative risk [mRR] = 1.01, 95% CI: 0.89-1.14), men (mRR = 0.82, 95% CI: 0.60-1.14), or both sexes combined (mRR = 0.97, 95% CI: 0.87-1.08). No statistically significant mRRs were found among the studies that reported data for permanent hair dye use (mRR = 1.06, 95% CI: 0.89-1.27), duration of any hair dye use (mRR = 1.00, 95% CI: 0.85-1.19), duration of permanent hair dye use (mRR = 1.31 95% CI 0.78-2.19), lifetime applications of any hair dye use (mRR = 1.12 (95% CI: 0.72-1.72) or permanent hair dye use (mRR = 1.59, 95% CI 0.69-3.64), or dark color hair dye use (mRR = 0.94, 95% CI: 0.74-1.19). CONCLUSION: The results of this meta-analysis of epidemiologic studies do not indicate a causal association between personal hair dye use and bladder cancer.

A nested case-control study of brain tumors among employees at a petroleum exploration and extraction research facility.

Work-related exposures potentially associated with a cluster of brain tumors at a petroleum exploration and extraction research facility were evaluated in a nested case-control study. Fifteen cases were identified in the original cohort and 150 matched controls were selected. Odds ratios (ORs) for occupational exposure to petroleum, radiation, solvents, magnetic fields, and work activities were near or below 1.0. ORs near 1.5 were observed for: working with computers (OR = 1.47; 95% confidence interval [CI] = 0.30-9.35); work-related travel (OR = 1.48; 95% CI = 0.25-5.95), and travel immunizations (OR = 1.62; 95% CI = 0.23-9.45). Higher ORs were observed for work in administrative and marketing buildings and for achieving a master's or higher degree (OR = 2.0, 95% CI = 0.4-10.7). While some ORs above 1.5 were noted, no work-related chemical and physical exposures were significantly associated with the occurrence of brain tumors among employees at this facility.

Primary brain tumor mortality at a petroleum exploration and extraction research facility.

A cohort mortality study was conducted among 3,779 employees at a petroleum exploration and extraction research facility to evaluate workplace exposures and brain tumor risk. Deaths were identified by searches against the National Death Index, Social Security Administration, and California state mortality files. Work histories were classified by job titles, laboratory activity, and company division. Eleven brain tumor deaths were observed among the cohort (standardized mortality ratio [SMR] 1.8; 95% confidence interval = 0.9-3.2). SMR analyses for scientists, employment in laboratory work, and in the research division were not associated with an increased brain tumor SMR, whereas an increased SMR was observed for administrative and nonresearch employees. Although conclusions are limited by the small study population and lack of specific exposure data, these findings were not consistent with an occupational explanation for the observed brain tumor cluster.

A nested case-control study of prostate cancer and atrazine exposure.

Elevated prostate cancer incidence was found at a plant producing atrazine that had an intensive prostate screening program. This study tested the relationship among atrazine exposure, prostate cancer, and the screening program. Twelve cases and 130 control subjects were selected from the original cohort. Prostate screening and occupational histories were abstracted from company records and atrazine exposures were estimated. Hire date was comparable for cases and control subjects. Nearly half of the control subjects and no cases left before the prostate-specific antigen (PSA) screening program. Cases had more PSA tests than control subjects (odds ratio for > or =1 test, 8.54; 95% confidence interval, 1.69-82.20). There was no association between atrazine exposure and prostate cancer when those with > or =1 test were compared. There was no evidence for an association between atrazine and prostate cancer.