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1.  Development of a Computer-Based Survey Instrument for Organophosphate and N-Methyl-Carbamate Exposure Assessment among Agricultural Pesticide Handlers 
Annals of Occupational Hygiene  2010;54(6):640-650.
Background: Assessment of occupational pesticide exposures based on self-reported information can be challenging, particularly with immigrant farm worker populations for whom specialized methods are needed to address language and cultural barriers and account for limited literacy. An audio computer-assisted self-interview (A-CASI) survey instrument was developed to collect information about organophosphate (OP) and N-methyl-carbamate (CB) exposures and other personal characteristics among male agricultural pesticide handlers for an ongoing cholinesterase biomonitoring study in Washington State.
Objectives: To assess the feasibility of collecting data using the A-CASI instrument and evaluate reliability for a subset of survey items.
Methods: The survey consisted of 64 items administered in Spanish or English on a touch-screen tablet computer. Participants listened to digitally recorded questions on headphones and selected responses on the screen, most of which were displayed as images or icons to facilitate participation of low literacy respondents. From 2006–2008, a total of 195 participants completed the survey during the OP/CB application seasons on at least one occasion. Percent agreement and kappa coefficients were calculated to evaluate test–retest reliability for selected characteristics among 45 participants who completed the survey on two separate occasions within the same year.
Results: Almost all participants self-identified as Hispanic or Latino (98%), and 97% completed the survey in Spanish. Most participants completed the survey in a half-hour or less, with minimal assistance from on-site research staff. Analyses of test–retest reliability showed substantial agreement for most demographic, work history, and health characteristics and at least moderate agreement for most variables related to personal protective equipment use during pesticide applications.
Conclusions: This A-CASI survey instrument is a novel method that has been used successfully to collect information about OP/CB exposures and other personal characteristics among Spanish-speaking agricultural pesticide handlers.
PMCID: PMC2918489  PMID: 20413416
agriculture; audio computer-assisted self-interview (A-CASI); exposure assessment; pesticides; survey instrument
2.  Occupational determinants of serum cholinesterase inhibition among organophosphate-exposed agricultural pesticide handlers in Washington State 
To identify potential risk factors for serum cholinesterase (BuChE) inhibition among agricultural pesticide handlers exposed to organophosphate (OP) and N-methyl-carbamate (CB) insecticides.
We conducted a longitudinal study among 154 agricultural pesticide handlers who participated in the Washington State cholinesterase monitoring program in 2006 and 2007. BuChE inhibition was analyzed in relation to reported exposures before and after adjustment for potential confounders using linear regression. Odds ratios estimating the risk of ‘BuChE depression’ (>20% from baseline) were also calculated for selected exposures based on unconditional logistic regression analyses.
An overall decrease in mean BuChE activity was observed among study participants at the time of follow-up testing during the OP/CB spray season relative to pre-season baseline levels (mean decrease of 5.6%, P < 0.001). Score for estimated cumulative exposure to OP/CB insecticides in the past 30 days was a significant predictor of BuChE inhibition (β = −1.74, P < 0.001). Several specific work practices and workplace conditions were associated with greater BuChE inhibition, including mixing/loading pesticides and cleaning spray equipment. Factors that were protective against BuChE inhibition included full-face respirator use, wearing chemical-resistant boots, and storing personal protective equipment in a locker at work.
Despite existing regulations, agricultural pesticide handlers continue to be exposed to OP/CB insecticides at levels resulting in BuChE inhibition. These findings suggest that modifying certain work practices could potentially reduce BuChE inhibition. Replication from other studies will be valuable.
PMCID: PMC2908529  PMID: 19819864
cholinesterases; organophosphates; pesticides; agricultural workers; occupational exposure
3.  Perceptions of Environmental and Occupational Health Hazards Among Agricultural Workers in Washington State 
The purpose of this study is to describe perceptions of environmental and occupational health issues among agricultural workers. Interviews were conducted with 389 agricultural workers in the Yakima Valley in central Washington State in the summers of 2004 and 2005. Undergraduate students from the community conducted interviews in Spanish or English. Environmental and occupational health issues were ranked by frequency of concern, and differences by demographic characteristics were evaluated using multivariate analyses. In both 2004 and 2005, agricultural workers expressed high levels of concern about working in hot weather, agricultural injuries, pesticides, and pediatric asthma. Perceptions of environmental and occupational health issues among agricultural workers differed by certain demographic characteristics, particularly age and ethnicity. Consideration should be given to these issues when designing research studies, creating educational materials, and developing interventions related to environmental and occupational hazards among agricultural workers.
PMCID: PMC2882378  PMID: 19715263
4.  Pleural plaques related to “take-home” exposure to asbestos: An international case series 
While a large number of studies indicate the risks of high-level exposures to asbestos in the workplace setting, a relatively small number of studies describe the risk of pleural disease related to “take-home” asbestos brought into the household by workers exposed to asbestos. Consequently, the risk of pleural disease in family members of asbestos-exposed workers is likely underappreciated.
Case presentations:
Two families of siblings, one in Israel and one in the US, were evaluated because of their significant exposures to asbestos brought into the home by family members with heavy occupational exposures. Two of the four children of an asbestos cement debagger in Petach Tikvah, Israel and two children of a pipe lagger in a naval shipyard near Seattle, Washington, manifested benign pleural disease without parenchymal disease, despite having no occupational exposure to asbestos.
These cases illustrate that “take-home” asbestos exposure may lead to pleural disease at higher rates than commonly realized.
Relevance to clinical practice:
Providers should recognize that due to the potential for “take-home” exposures, asbestos-related disease in a patient may be a marker for disease in household contacts. Patients with family members heavily exposed to asbestos should be strongly encouraged to quit smoking in an effort to reduce any further carcinogenic exposures. Additionally, workplace control and regulation of asbestos use should be emphasized to protect both workers and their families.
PMCID: PMC2840547  PMID: 20428401
take-home; household; asbestos; pleural plaques; case series; environmental; nonoccupational
5.  Serum Cholinesterase Inhibition in Relation to Paraoxonase-1 (PON1) Status among Organophosphate-Exposed Agricultural Pesticide Handlers 
Environmental Health Perspectives  2009;117(9):1402-1408.
Animal studies have demonstrated that low paraoxonase-1 (PON1) status (i.e., low catalytic efficiency and/or low plasma PON1 activity) is associated with neurotoxic effects after exposure to several organophosphate (OP) insecticides. However, few human studies have investigated associations between PON1 status and intermediate end points, such as serum cholinesterase [butyrylcholinesterase (BuChE)] inhibition, among OP-exposed individuals.
We evaluated the relation between plasma PON1 status and BuChE inhibition among OP-exposed agricultural pesticide handlers.
Agricultural pesticide handlers in Washington State were recruited during the 2006 and 2007 spray seasons when they were seen for follow-up ChE testing by collaborating medical providers as part of a statewide monitoring program. Blood samples were collected from 163 participants and tested for PON1 status based on plasma PON1 activity [arylesterase (AREase)] and PON1 Q192R genotype. We evaluated percent change in BuChE activity from baseline level in relation to PON1 status.
We observed significantly greater BuChE inhibition among QQ homozygotes relative to RR homozygotes (p = 0.036). Lower levels of plasma PON1 activity were significantly associated with greater BuChE inhibition (p = 0.004). These associations remained after adjustment for year, days since baseline test, age, and OP exposure in the last 30 days.
We found that both low PON1 catalytic efficiency (i.e., the Q192 alloform) and low plasma PON1 activity were associated with BuChE inhibition among OP-exposed agricultural pesticide handlers. Corroborative findings from future studies with prospective collection of blood samples for PON1 testing, more sensitive markers of OP-related effects, and larger sample sizes are needed.
PMCID: PMC2737017  PMID: 19750105
agriculture; cholinesterase; farmworkers; gene-environment interaction; organophosphates; paraoxonase; pesticides

Results 1-5 (5)