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Biomedical subjects

David Fishwick

Publications and source records attributed to David Fishwick.

15 recordsLinked to original sources

Work-related asthma symptoms and attitudes to the workplace.

BACKGROUND: The Health & Safety Executive estimate that between 1500-3000 UK workers develop asthma through potentially avoidable workplace exposures each year. AIMS: To assess the perception of health, safety and the work environment by workers with symptoms suggestive of occupational asthma. METHODS: A total of 97 workers referred to hospital specialists with symptoms suggestive of occupational asthma were studied in order to investigate their attitudes to the workplace, safety and health. A qualitative study design using semi-structured telephone interviews at 2 months and 12 months following enrolment was used at 6 national UK centres with a special interest in occupational asthma. RESULTS: Many workers in the study felt let down by the workplace and management and perceived that a lack of health and safety measures had contributed to the development of their asthma symptoms. Many workers felt that their employers were 'uncaring' and were pursuing or considering medico-legal cases against them. CONCLUSIONS: Workers' perception of risk influences their behaviour in the workplace, and their own health beliefs potentially create barriers to changing this. It is essential to consider workers' perceptions when developing strategies to effect change within the workplace.

Adult↗

Occupational asthma: an assessment of diagnostic agreement between physicians.

OBJECTIVES: To investigate the levels of agreement between expert respiratory physicians when making a diagnosis of occupational asthma. METHODS: 19 cases of possible occupational asthma were identified as part of a larger national observational cohort. A case summary for each case was then circulated to 12 physicians, asking for a percentage likelihood, from the supplied information, that this case represented occupational asthma. The resulting probabilities were then compared between physicians using Spearman's rank correlation and Cohen's kappa coefficients. RESULTS: Agreement between the 12 physicians for all 19 cases was generally good as assessed by Spearman's rank correlation. For all 66 physician-physician interactions, 45 were found to correlate significantly at the 5% level. The agreement assessed by kappa analysis was more variable, with a median kappa value of 0.26, (range -0.2 to +0.76), although 7 of the physicians agreed significantly (p<0.05) with >or=5 of their colleagues. Only in one case did the responses for probability of occupational asthma all exceed the "on balance" 50% threshold, although 12 of the 19 cases had an interquartile range of probabilities not including 50%, implying "on balance" agreement. The median probability values for each physician (all assessing the identical 19 cases) varied from 20% to 70%. Factors associated with a high probability rating were the presence of a positive serial peak expiratory flow Occupation Asthma SYStem (OASYS)-2 chart, and both the presence of bronchial hyper-reactivity and significant change in reactivity between periods of work and rest. CONCLUSIONS: Despite the importance of the diagnosis of occupational asthma and reasonable physician agreement, certain variations in diagnostic assessment were seen between UK expert centres when assessing paper cases of possible occupational asthma. Although this may in part reflect the absence of a normal clinical consultation, a more unified national approach to these patients is required.

Adult↗

Endotoxin exposure, wheezing, and rash in infancy in a New Zealand birth cohort.

BACKGROUND: Wheezing in infancy is common and is associated with small lungs, viral respiratory tract infection, and environmental tobacco smoke exposure. Recently, increased levels of endotoxin in the domestic environment have also been associated with infant wheezing, particularly among infants with a family history of atopic disease. OBJECTIVE: To explore associations between exposure to endotoxin at 3 months of age and reported symptoms of wheezing, rhinitis, itchy scaly rash, and atopy at 15 months in a birth cohort of 881 New Zealand children. METHODS: Using standardized methods, a 1-m(2) site from the bedroom floors of the 3-month-old infants was sampled and analyzed for endotoxin. RESULTS: Wheezing was significantly associated with higher endotoxin levels (odds ratio [OR], 1.54; 95% CI, 1.03-2.30), particularly among infants with a parental history of allergic disease (OR, 1.67; 95% CI, 1.07-2.60). Higher endotoxin concentrations were also strongly associated with recurrent itchy rashes (OR, 1.87; 95% CI, 1.14-3.05), particularly among infants who were atopic (OR, 4.64; 95% CI, 1.56-13.77) or had a parental history of allergic disease (OR, 2.10; 95% CI, 1.22-3.61). CONCLUSION: Domestic endotoxin was associated with reported airway and skin symptoms in this large group of New Zealand infants. The role of endotoxin in the development of respiratory and skin disease in infancy deserves further study. CLINICAL IMPLICATIONS: Reducing domestic endotoxin exposure might reduce infant wheezing and atopic dermatitis, but the long-term benefits of this remain unclear.

Cohort Studies↗

Hand-arm vibration syndrome in South African gold miners.

BACKGROUND: Hand-arm vibration syndrome (HAVS) is associated with the use of hand-held vibrating tools. Affected workers may experience symptoms of tingling, numbness, loss of grip strength and pain. Loss of dexterity may impair everyday activities, and potentially increase the risk of occupational accidents. Although high vibration levels (up to 31 m/s(2)) have been measured in association with rock drills, HAVS has not been scientifically evaluated in the South African mining industry. AIMS: The aim of this study was to determine the prevalence and severity of HAVS in South African gold miners, and to identify the tools responsible. METHODS: A cross-sectional study was conducted in a single South African gold-mine. Participants were randomly selected from mineworkers returning from annual leave, comprising 156 subjects with occupational exposure to vibration, and 140 workers with no exposure. Miners who consented to participate underwent a clinical HAVS assessment following the UK Health and Safety Laboratory protocol. RESULTS: The prevalence of HAVS in vibration-exposed gold miners was 15%, with a mean latent period of 5.6 years. Among the non-exposed comparison group, 5% had signs and symptoms indistinguishable from HAVS. This difference was statistically significant (P < 0.05). All the cases of HAVS gave a history of exposure to rock drills. CONCLUSIONS: The study has diagnosed the first cases of HAVS in the South African mining industry. The prevalence of HAVS was lower than expected, and possible explanations for this may include a survivor population, and lack of vascular symptom reporting due to warm-ambient temperatures.

Adult↗

The perceptions of occupational health in primary care.

AIM: A random sample of general practitioners (GPs), practice nurses (PNs) and practice managers (PMs) in Sheffield and Manchester was recruited into a study to evaluate the perceptions of occupational health (OH) in primary care. METHODS: Qualitative data were collected using focus groups with three groups of primary care sector professionals. Quantitative data were collected nationally from 295 GPs using a postal questionnaire. RESULTS: GPs and PNs had minimal OH training, and 60% of GPs reported constraints in addressing OH matters with patients. The lack of referral routes (63 and 67%, respectively) was also seen as a barrier. OH was regarded as a speciality, and primary care professionals preferred to refer patients with OH problems to specialist centres because they perceived barriers to their dealing with the issues. A total of 74% of GPs surveyed thought that speedier access to secondary care would help them to address OH problems. CONCLUSIONS: This study has identified some of the problems associated with delivering OH through primary care. It also demonstrated a need for greater emphasis on OH education in medical and nurse training, and a need for better advice for GPs, PNs and PMs regarding support services for OH.

Adult↗

Specific IgE to colophony?

BACKGROUND: Colophony (rosin) is a natural product obtained from coniferous trees. It is used in a diverse range of products such as adhesives, ink, paints and soldering fluxes. Some workers exposed to colophony during soldering can develop occupational asthma; at present, no specific IgE test is available to assess sensitization to colophony. METHODS: Serum samples were obtained from exposed symptomatic individuals (n = 7), some with a likely diagnosis of occupational asthma, exposed asymptomatic individuals (n = 10) and unexposed individuals (n = 11). Serum was tested for specific IgE antibodies against a protein extract produced following in vitro challenge of mono-mac-6 cells with colophony extract. RESULTS: Serum from exposed symptomatic individuals showed increased binding of specific IgE antibodies to a range of colophony-cell protein conjugates [29% (2/7) of samples tested when cut-off > 0.1 or 86% (6/7) of samples tested when cut-off > 0%] compared with both the exposed asymptomatic [0% when cut-off > 0.1, or 20% when cut-off > 0% (2/10)] and the non-exposed control populations [0% when cut-off > 0.1, or 27% when cut-off > 0% (3/11)]. CONCLUSIONS: This novel approach for the production of conjugates to assess sensitization to colophony was able to detect specific IgE in colophony-exposed workers with a likely diagnosis of occupational asthma.

Adult↗

Reproducibility and validity of a Yan-style portable citric acid cough challenge.

Although many different methods of measuring cough reflex sensitivity have been published, few are simple enough to use outside of a hospital or laboratory environment. The aim of this study was to develop a simple, quick, and portable cough challenge, assess its reproducibility, and compare its results with those measured by an existing established hospital protocol. Twenty-five volunteers performed cough challenges based on an established hospital dosimeter protocol, and, on a separate occasion, by a protocol inhaling citric acid from DeVilbiss 40 hand-held nebulisers (citric acid concentrations of 10-3000 mM). Reproducibility of the hand-held cough challenge was assessed in 11 volunteers. Cough thresholds were consistently higher by the hand-held method than by the hospital dosimeter method. The geometric mean citric acid concentrations causing two coughs (threshold D2) were 3.14 and 2.77 log mM, respectively (p<0.001). The geometric mean (95% CI) difference between the tests was 0.51 log mM (0.18-0.83) of the average of the two values. Cough D2 thresholds attained by the two techniques did, however, show significant correlation (r=0.95, p<0.0001). The coefficient of repeatability for the hand-held method was 0.40 log mM. Administering citric acid from DeVilbiss 40 hand-held nebulisers offers a rapid, portable, and reproducible cough challenge in healthy volunteers. The results correlate well with an existing Mefar dosimeter challenge, but give two to three times greater cough thresholds.

Anticoagulants↗

Respiratory symptoms, immunology and organism identification in contaminated metalworking fluid workers. What you see is not what you get.

BACKGROUND: Metal working fluids (MWF) constitute a significant respiratory hazard, although symptoms experienced by workers are often poorly investigated and attributed. AIMS: A single possible case of extrinsic allergic alveolitis (EAA) led to a formal workplace investigation. It was clear that other exposed workers were affected. The aim of this study was to accurately quantify the clinical, immunological and microbiological findings in MWF workers following presentation of a sentinel case. METHODS: Eleven of 21 individuals participated; eight were assessed by symptom questionnaire, spirometry and serology and three workers provided blood samples only. The microbes cultured from MWF and air samples were used to determine the presence of precipitating antibodies. RESULTS: Work-related respiratory symptoms were reported in six of eight individuals questioned, two of these complaining of 'flu-like' symptoms. Personal breathing zone measures identified 2.1 x 10(3) to 1.1 x 10(5) colony-forming units/m3 air (CFU/m3). Pseudomonas fluorescens was isolated from air samples. Despite visible 'fungal' contamination of MWF, airborne fungi were detectable in only one sample, at 486 CFU/m3 air. MWF cultured Eurotium sp., Fusarium sp. and Pseudomonas sp. Precipitating IgG antibodies to Pseudomonas sp. were identified in 4/11 and to an extract of the MWF in 3/11. IgG to Pseudomonas was elevated in the two individuals who had the strongest precipitating bands to Pseudomonas sp. CONCLUSIONS: Workplaces with possible EAA must be investigated promptly, thus allowing clinical assessment to be contemporary to exposures and accurate microbiological profiling included to identify the likely cause.

Adult↗

Respiratory symptoms and lung function change in welders: are they associated with workplace exposures?

AIMS: This study investigates whether work-related respiratory symptoms and acute falls in forced expiratory volume in 1 second (FEV1), previously observed in current welders, are related to measured workplace exposures to total fume and metals. METHODS: At four work sites in New Zealand, changes in pulmonary function (and reported respiratory symptoms) were recorded in 49 welding workers (and 26 non-welders) exposed to welding fume. We also determined the personal breathing zone levels of total fume and various metals. RESULTS: Work-related respiratory symptoms were reported by 26.5% of welders and 11.5% of non-welders. These symptoms were related significantly to their personal breathing zone nickel exposure--with an adjusted odds ratio (OR) and 95% confidence interval [CI] of the high exposure group (compared to a low exposure group of 7.0 [1.3-36.6]). There were non-significant associations with total fume exposure (OR = 2.6, 95% CI 0.6-12.2), and exposure index of greater than 10 years (OR=2.8, 95% CI 0.5-15.0). A fall in FEV1 of at least 5% after 15 minutes of work was significantly associated with aluminium exposure (OR=5.8, 95% CI 1.7-20.6). CONCLUSIONS: Nickel exposure from metal inert gas (MIG) and tungsten inert gas (TIG) welding is associated with work-related respiratory symptoms and aluminium exposure from welding is associated with a fall in FEV1 of at least 5 % after 15 minutes of work.

Adolescent↗

An evaluation of occupational health services within the NHS in London.

AIMS: To establish the nature, extent and organization of occupational health service provision for employees within the National Health Service (NHS) in London and to review the systems for monitoring performance. METHODS: Human resources directors and occupational health managers were contacted from a random selection of NHS trusts in the London area and invited to complete an interviewer-led questionnaire. RESULTS: All seventeen trusts interviewed claimed to provide an occupational health service to their employees, with 88% providing this service in-house. The organization of the services varied, although most resided within the human resources function. Only 29% of the trusts could provide a written occupational health policy. Teaching hospital trusts had the most qualified and the highest numbers of medical staff. District/General hospital trusts had the least qualified clinical staff. Although most trusts were able to provide a comprehensive range of services, 87% of occupational health managers felt they could only provide a reactive service. Income was generated from non-NHS sources by 88% of the trusts and all were aware of NHS Plus. There was an indication that some trusts assigned NHS Plus status did not meet the standard of NHS Plus, although the survey took place only 3 months after the launch of NHS Plus. CONCLUSIONS: There was a significant variation in the nature and extent of occupational health services in the NHS trusts. As a consequence, there may be differences in the level of occupational health service available to staff across the NHS in London.

Delivery of Health Care↗

Immunologic response to inhaled endotoxin: changes in peripheral cell surface markers in normal individuals.

Monocyte cell surface CD14 increases following both in vitro challenge with lipopolysaccharide (LPS) and exposure to organic dusts. We investigated 9 volunteers, mean age 39 years (range, 29-53 years). Each inhaled increasing concentrations of lipopolysaccharide (0.5 microg, 5.0 microg, and 20 microg). Monocyte cell surface CD14 (expressed as mean linear fluorescence) was measured before and after using flow cytometry. Upregulation of CD14 (up to 6 hours after LPS exposure) did not differ significantly between LPS (mean, 35.8; standard deviation [SD]; 54.3), n = 7 after 20 l g LPS) in comparison to placebo (39.3 [49.0]; n = 7). Maximum mean (SD) percentage CD14 upregulation up to 6 hours after challenge differed, but not significantly between those experiencing a clinically significant event (58.4 [49.2]) in comparison to those who did not (13.8, [43.2]; P = 0.27). Two individuals with a marked clinical response developed marked CD14 upregulation after exposure to LPS.

Adult↗