Is pesticide exposure a cause of obstructive airways disease?

A systematic review was performed to identify any associations between pesticide exposure and the occurrence (both prevalence and incidence) of airways disease (asthma and chronic obstructive pulmonary disease) and wheezing symptoms. PubMed, MEDLINE, Embase, Scopus, CINAHL, Google Scholar and the Cochrane Database of Systematic Reviews were searched between September 2010 and October 2010 for papers with the inclusion criteria of English language, published after 1990, peer-reviewed and nondietary exposure. From a total of 4390 papers identified, 42 were included after initial assessment of content. After evaluating the included studies for quality, those considered to be at high risk of bias were excluded, leaving a total of 23 relevant papers. Results suggest that exposure to pesticides may be associated with prevalent asthma, but methodological issues, such as cross-sectional/case-control design, measurements of exposure and limited adjustment for confounders, limit the strength of the evidence base in this area. The association between pesticide exposure and asthma appears to be more evident and consistent in children than in adults. Exposure to pesticides may be associated with COPD; however, the strength of evidence for an association with COPD is weaker than for asthma. As the exposure metrics within each health end-point varied across studies, no meta-analyses were carried out.

The 'take home' burden of workplace sensitizers: flour contamination in bakers' families.

BACKGROUND: Exposure to flour/flour constituents is a leading cause of occupational asthma. Paternal occupational exposure to flour has been associated with increased likelihood of childhood asthma, raising the possibility of para-occupational exposure whereby family members are exposed to sensitizers 'taken home' on contaminated skin/clothing. OBJECTIVE: To establish whether workplace contamination of skin/clothing with wheat flour allergen (WFA) and fungal α-amylase (FAA) is associated with increased levels of these allergens in bakers' homes. METHODS: Bakeries in north-east Scotland were invited to participate. Control subjects were recruited from University of Aberdeen staff and students. Exposure assessment was carried out in bakeries, bakers' cars and the homes of bakers and controls using surface wipe and vacuum sampling; samples were analyzed for total protein, FAA and WFA. RESULTS: 164 wipe samples and 49 vacuum samples were collected from 38 bakers (from 5 bakeries) and 10 controls. Compared to non-bakers, bakers had higher median levels of WFA and FAA in house vacuum samples; the difference was statistically significant for WFA/total protein (515.8×10(-6) vs. 163.7×10(-6), p=0.031), FAA/total protein ratios (1.45×10(-6) vs. 0.04×10(-6), p<0.001) and FAA loading (median 1.2 pg/cm(2) vs. 0.1 pg/cm(2), p<0.001) with workplace exposure-home contamination relationships between bakers with higher and lower workplace contamination. We found positive correlations between WFA contamination of the bakers' foreheads and cars (r(s)0.57, p=0.028), foreheads and houses (r(s)0.46, p=0.025), shoes and houses (r(s)0.45, p=0.029); and between FAA contamination of shoes and houses (r(s)0.46, p=0.023), and cars and houses (r(s)0.70, p=0.008). There was no evidence of bakers using work-sourced flour for domestic baking. CONCLUSIONS: This work demonstrates pathways for 'take home' exposure of occupationally sourced flour. Taken with our previous work, showing that bakers' children are more likely to have asthma, this supports the need for further investigation to establish whether 'take home' of occupationally sourced flour is widespread with health consequences.

Side-by-side comparison of an open-chamber (TM 300) and a closed-chamber (Vapometer™) transepidermal water loss meter.

BACKGROUND: The measurement of transepidermal water loss (TEWL) is used to monitor changes in the stratum corneum's permeability to water vapor. This measurement is widely used in the cosmetics industry and in dermatology research. However, only limited work has been undertaken to assess the comparability of results from different TEWL meters over an extended range of measurements. METHODS: This study compared the results of TEWL measurements between two commonly used open-chamber and closed-chamber TEWL devices. Five hundred and forty measurements were taken in 17 participants on the dorsum and palm of both hands on two different days and the order of the devices was randomized. RESULTS: The results showed that the open TEWL meter's capacity for measuring high values of TEWL was restricted, and that the closed-chamber TEWL meter was less sensitive to differences in the lower range of measurements. CONCLUSION: Both devices have their strengths for different applications, but their results cannot be directly compared. We were unable to find a statistical model that would allow us to transform the measurements made on one device for a comparison with the results generated by the other device.

A case-control study of Parkinson's disease and tobacco use: gene-tobacco interactions.

A case-control study of genetic, environmental, and occupational risk factors for Parkinson's disease (PD) was carried out in five European countries (Italy, Malta, Romania, Scotland, and Sweden) to explore the possible contribution of interactions among host and environmental factors in sporadic PD. Whereas smoking habits confirmed its negative association with PD, a possible modulatory role of genetic polymorphisms was investigated to obtain further mechanistic insights. We recruited 767 cases of PD and 1989 age-matched and gender-matched controls. Participants completed an interviewer-administered questionnaire including the history of smoking habits. The polymorphisms of genes involved either in metabolism of compounds contained in tobacco smoke (CYP2D6, CYP1B1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, SOD2, EPHX and NAT2) or in dopaminergic neurotransmission (MAOA, MAOB, DAT1 and DRD2) were characterized by PCR based methods on genomic DNA. We found evidence of statistically significant gene-tobacco interaction for GSTM1, NAT2, and GSTP1, the negative association between tobacco smoking and PD being significantly enhanced in subjects expressing GSTM1-1 activity, in NAT2 fast acetylators, and in those with the GSTP1*B*C haplotype. Owing to the retrospective design of the study, these results require confirmation.

Hearing symptoms and audiometry in professional divers and offshore workers.

AIMS: The aims are to compare hearing loss between professional divers and offshore workers and to study whether hearing loss symptoms reflected physical disorder. A secondary objective was to study total threshold shift assessment as a method of detecting noise-induced hearing loss (NIHL). METHODS: Participants (151 divers and 120 offshore workers) completed a questionnaire for symptoms and screening audiometry. Audiograms were assessed for total threshold shift at 1, 2, 3, 4 and 6 kHz and the prevalence of referral (within population 5th centile) or warning levels (within population 20th centile) of hearing loss. Audiograms were assessed for an NIHL pattern at four levels by two occupational physicians. RESULTS: Hearing loss symptoms were commoner in divers at all levels of hearing loss regardless of differences between groups on audiometry. Hearing loss in offshore workers was within the population age-adjusted norm. Thirteen per cent of divers were within the 5th percentile for threshold shift for the population norm in contrast to 4% of offshore workers and this was predominantly left sided (OR 3.16, 95% CI 1.13-8.93). This difference was lost after adjustment for history of regular exposure to explosion or gunfire. Divers were more likely to have a pattern of severe NIHL on the left (OR 4.61, 95% CI 1.39-15.39, P < 0.05). Approximately 50% of participants with severe NIHL did not have a referral level of hearing loss. CONCLUSIONS: Divers suffer more NIHL than a control population. Current guidance on the assessment of total threshold shift for the detection of significant NIHL was inadequate in the sample studied.

Solvent exposure and cognitive ability at age 67: a follow-up study of the 1947 Scottish Mental Survey.

OBJECTIVES: Organic solvent exposure may be associated with cognitive impairment in later life although the evidence for this association is inconsistent. This study sought to examine the association between organic solvent exposure and cognitive function in later life. METHODS: A prospective longitudinal study set in Aberdeen, Scotland examined 336 men and women born in 1936 who participated in the 1947 Scottish Mental Survey. Cognitive function at age 67 years was measured using the Trail Making Test B (TMT B), the Digit Symbol (DS) test, and the Auditory Verbal Learning Test (AVLT). Occupational hygienists reviewed occupational histories, blind to cognitive function, and estimated lifetime solvent exposures. Multiple regression analyses were employed to explore the association between solvent exposure and cognitive performance after adjustment for confounders. RESULTS: After adjusting for childhood IQ, smoking, alcohol and sex, the solvent exposed group took on average almost 10 s longer than the unexposed group to complete the TMT B, a highly significant difference. For the DS test, after adjusting for childhood IQ, smoking and gender, the exposed group scored on average two points lower than the unexposed group, which was again highly significant. There was no evidence of an effect for cumulative solvent exposure on the TMT B or DS test. For the AVLT there were no significant differences associated with exposure. CONCLUSIONS: This study of subjects with generally low exposures, found no clear evidence of an association between solvent exposure and cognitive function.

Sharps injuries among medical students.

BACKGROUND: Medical students may be at risk of sharps injuries for several reasons. These exposures can transmit a range of blood-borne pathogens including hepatitis B, hepatitis C and human immunodeficiency virus. AIMS: To evaluate medical students' knowledge regarding the prevention and management of sharps injuries and their experience of such exposures in the calendar year 2007. METHODS: A cross-sectional, web-based, survey of fourth and fifth year medical students enrolled at the University of Aberdeen in Scotland. All students were at the mid-point of their year of study. An invitation e-mail and two electronic reminders were sent, on specified days, to the study population. These contained a summary of the study and the link to the anonymous questionnaire. RESULTS: Of the 395 medical students e-mailed, 238 (60%) responded. When compared with fourth year medical students, final year students had higher mean knowledge scores for sharps injury management (P < 0.01). Of total, 18% reported resheathing used needles and 31% reported disposing of sharps for others, indicating poor compliance with standard precautions. In the event of an injury, 29% stated that they would scrub the wound. Only 44% were familiar with policies for reporting exposures. In all, 11% of students had experienced at least one contaminated sharps injury in 2007 and, of those, 40% had reported the most recent incident. CONCLUSIONS: Medical students are at risk of sharps injuries and their knowledge regarding the prevention and management of these exposures is limited: training on these issues should be increased.

Benchmarking self-reported practice regarding Scottish Executive guidance on hepatitis C-infected health care workers.

BACKGROUND: The 2002 Scottish Executive guidance 'hepatitis C-infected health care workers' advised NHS Scotland occupational health departments regarding screening health care workers (HCW) who perform or who may perform exposure-prone procedures (EPPs) for hepatitis C virus (HCV) infection. In 2004, 2 years following the launch of the guidance, there was anecdotal evidence of challenges to implementation and clinical and ethical concerns regarding the screening process. AIM: To benchmark the implementation of the Executive guidance on hepatitis C-infected HCW in NHS Scotland. METHODS: Lead occupational health practitioners in 15 Scottish NHS Boards completed a questionnaire and provided relevant local policies. RESULTS: All 15 NHS Boards responded: 87% (n = 13) had implemented the guidance with partial implementation in the remaining boards. While 87% required identified and validated samples (IVS), no consistent method was reported for how results from an IVS were recorded. There was also no consensus as to the duration a result was considered valid or consistency in charging for tests required by other employers. Across Scotland, some employee groups were being screened over and above those recommended within the guidance. Overall, there was agreement on the value of a standardized NHS hepatitis C status certificate and the importance of explicit screening criteria and identifying EPP workers. CONCLUSION: The survey confirms the challenges in implementing the guidance on managing HCV-infected HCW within NHS Scotland. These include lack of clarity regarding who, when and how frequently a HCW should be screened and how the results of such tests should be recorded.

The impact of educational interventions on primary health care workers' knowledge of occupational exposure to blood or body fluids.

AIM: To assess the impact of educational interventions on primary health care workers' knowledge of management of occupational exposure to blood or body fluids. METHODS: Cluster-randomized trial of educational interventions in two National Health Service board areas in Scotland. Medical and dental practices were randomized to four groups; Group A, a control group of practices where staff received no intervention, Group B practices where staff received a flow chart regarding the management of blood and body fluid exposures, Group C received an e-mail alert containing the flow chart and Group D practices received an oral presentation of information in the flow chart. Staff knowledge was assessed on one occasion, following the educational intervention, using an anonymous postal questionnaire. RESULTS: Two hundred and fifteen medical and dental practices were approached and 114 practices participated (response rate 53%). A total of 1120 individual questionnaires were returned. Face to face training was the most effective intervention with four of five outcome measures showing better than expected knowledge. Seventy-seven percent of staff identified themselves as at risk of exposure to blood and body fluids. Twenty-one percent of staff believed they were not at risk of exposure to blood-borne viruses although potentially exposed and 16% of exposed staff had not been immunized against hepatitis B. Of the 856 'at risk' staff, 48% had not received training regarding blood-borne viruses. CONCLUSIONS: We found greater knowledge regarding management of exposures to blood and body fluids following face to face training than other educational interventions. There is a need for education of at risk primary health care workers.

Occupational titles as risk factors for Parkinson's disease.

BACKGROUND: Job title or employment sector may be associated with Parkinson's disease (PD). METHODS: In a case-control study, in four European centres, lifetime occupational histories were coded using modified International Standard Industrial Classification (ISIC) and Dictionary of Occupational Titles (DOT). We employed multiple logistic regression analyses adjusting for age, gender, smoking and family history of PD. RESULTS: A total of 649 cases and 1587 controls were recruited. Scottish data showed a non-significant increased risk for agriculture (DOT: OR 1.32, 95% CI 0.81-2.16; ISIC: OR 1.30, 95% CI 0.84-2.02) and reduced risk for 'transport and communication' (ISIC: OR 0.60, 95% CI 0.37-0.97). Subsequent four-centre analyses showed reduced risk for processing occupations (DOT: OR 0.69, 95% CI 0.5-0.95). An association with pesticide exposure, found using detailed exposure assessment, was not apparent using job classification. CONCLUSIONS: In contrast to retrospective exposure assessment, job or industrial sector is a weak indicator of toxic exposures such that true associations may be missed.

A life-course approach to the aetiology of late-onset dementias.

Substantial progress has been made in the understanding of the neurobiology of dementias, but comprehensive causal models are not available. Genetic and environmental factors probably interact to determine vulnerability to the dementias. The life-course approach to age-related diseases, when systematically applied to the dementias, provides opportunities to identify the nature and timing of environmental contributions. We discuss the relevance of the fetal origins of adult disease hypothesis to the dementias. Associations between the dementias (most often described as Alzheimer's disease) and ischaemic heart disease, obesity, hypertension, hyperlipidaemia, and non-insulin-dependent diabetes mellitus are set against associations between dementias and childhood intelligence, low educational attainments, low socioeconomic status, occupation, and lifetime dietary history. Biological mechanisms that explain how fetal development might influence the risk of adult disease may be relevant to many age-related diseases including the dementias and, possibly, to the biology of ageing.

Parkinson's disease and pesticide exposures.

INTRODUCTION: Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder in which loss of dopaminergic neurons in the basal ganglia leads to tremor, bradykinesia, rigidity and postural instability. METHODS: Literature search using Medline with keywords 'Parkinson's disease' and 'pesticides', limited to English, was undertaken, supplemented by articles from the author's files. RESULTS: Many studies have found an association between pesticides and PD, but no one agent has been consistently identified. Those implicated include organochlorine insecticides, maneb and paraquat. One meta-analysis of pesticide exposure and PD found an almost doubling of risk in those exposed. Associations with specific agents may be confounded by exposure to other pesticides, making it difficult to identify the causative agent. CONCLUSIONS: The available evidence indicates that pesticides are associated with PD, but further research is needed to identify long-term biomarkers of exposure, improve methods for estimating pesticide-exposure and undertake prospective cohort studies of pesticide-exposed workers.

Dog noise as a risk factor for hearing loss among police dog handlers.

AIM: To determine the sources of noise exposure among police dog handlers and to examine whether these levels might lead to noise-induced hearing loss. METHODS: We conducted a cross-sectional study at four Royal Air Force bases using a noise survey, a postal questionnaire and medical record review. The noise survey was conducted following task analysis. We surveyed police dog handlers and a comparison group of police who had never been dog handlers, using a postal questionnaire on noise exposures and confounders. Audiometric and otological data were extracted from medical records. RESULTS: The noise survey revealed significant exposures due to dogs, travelling in vans and aircraft noise during foot patrol. The overall response rate to the questionnaire was 56% (29 police dog handlers, 24 police officers). Five subjects (9.4%) had age-corrected hearing loss exceeding 10 dB, averaged over the 4 and 6 kHz frequencies, affecting the left ear only, but there were no differences between dog handlers and controls. CONCLUSION: Although the measured noise exposures of police dog handlers did not exceed current legal limits, the noise levels at times are such that the proposed Physical Agents (Noise) Directive has implications for employers who use dogs for security purposes.

Exposure assessment for a population-based case-control study combining a job-exposure matrix with interview data.

OBJECTIVES: A system that combines the ease of use of a job-exposure matrix while taking into account job-specific data is needed. This study aimed to produce a detailed method for combining interview data with expert assessments for a large population-based case-control study of Parkinson's disease. METHOD: An interview-administered core questionnaire with a series of questions that triggers substance-specific questionnaires to gather information on key parameters is administered. Using a job-exposure matrix to generate base estimates, assessors can modify this estimate of exposure intensity using worker-specific data such as the use of control measures, reports of substance-specific acute symptoms, and the quantity of material being processed. Detailed guidance for making adjustments to exposure estimates for these modifiers is presented. RESULTS: The method has been partially validated through the use of a comparison of estimates for a separate cohort with previously validated exposure reconstructions. Agreement was high, with a Spearman's rho of 0.89 (P < 0.01). The results from a quality assurance system employed as part of the methodology show a high degree of repeatability in generated exposure values both over time (Spearman's rho 0.98, P < 0.01) and between different assessors (Spearman's rho 0.88, P < 0.01). CONCLUSIONS: The method provides detailed quantitative exposure indices for occupational epidemiology. It has particular strengths both in terms of ease and speed of use. It is hoped that it will provide a useful structure for future epidemiologic work.

A rapid method of screening for N-acetyltransferase (NAT2) phenotype by use of the WAVE DNA fragment analysis system.

N-Acetyltransferase 2 (NAT2) is involved in Phase II biotransformation of a variety of toxicants. Polymorphisms in the NAT2 gene result in a slow acetylator phenotype, which has been associated with various cancers and neurodegenerative diseases. To date most studies investigating NAT2 genotype/phenotype have adopted an RFLP approach, which is both expensive and time-consuming. Using the Wave DNA fragment analysis system, we have developed a fast and robust method of identifying two polymorphisms (C282T and T341C) of the NAT2 gene which allows identification of the most common slow acetylator alleles found in Caucasian populations: NAT2*5, NAT2*6, NAT2*7, and NAT2*14. This was done by comparing phenotype status in 126 samples genotyped by RFLP analysis and also by Wave analysis for the polymorphisms C282Tand T341C. All 126 samples analyzed by both RFLP and Wave analysis gave consistent phenotype results and 100% correlation was achieved between the two methods.