Twenty years of SHIELD: decreasing incidence of occupational asthma in the West Midlands, UK?

INTRODUCTION: Since 2000 a decline in the incidence of occupational asthma (OA) has been reported in the UK and Europe. We aimed to describe and account for trends in the incidence of OA in the West Midlands, UK using annual notification data from the SHIELD voluntary surveillance scheme over the period 1991-2011. METHODS: All notifications to the SHIELD database between January 1991 and December 2011 were identified, along with patients' demographic data, occupations, causative agents and confirmatory tests. Annual notifications were scaled to give an annual count per million workers, giving a measure of incidence, and also standardised against those of bakers' asthma. Non-parametric analyses were undertaken between annual incidence and time (years) for common causative agents using (1) a negative binomial regression univariate model and (2) a logistic regression model calculating annual reporting ORs. A step-change analysis was used to examine time points at which there were marked reductions in incidence. RESULTS: A decrease in annual incidence of OA was observed over the study period (incident rate ratio=0.945; 95% CI 0.933 to 0.957; p<0.0001), an effect that was lost after standardising for bakers' asthma. Decreases in incidence were seen for most common causative agents, with only cleaning product-related OA increasing over 21 years. Marked fall in incidence was seen in 2004 for isocyanates, and in 1995 for latex. Most notifications came from a regional specialist occupational lung disease unit, with notifications from other sites falling from 16 cases/million workers/annum in 1995 to 0 in 2004. CONCLUSIONS: Reporter fatigue and increasing under-recognition of OA are both factors which contribute to the apparent fall in incidence of OA in the West Midlands. There is a future need for interventions that enable health professionals to identify potential cases of OA in the workplace and in healthcare settings.

Agents and trends in health care workers' occupational asthma.

BACKGROUND: There is a disproportionately high number of cases of work-related asthma occurring in health care occupations due to agents such as glutaraldehyde, latex and cleaning products. AIMS: To understand the causes and measure trends over time of occupational asthma (OA) in health care workers (HCWs). METHODS: We reviewed OA notifications from the Midland Thoracic Society's Surveillance Scheme of Occupational Asthma (SHIELD) database in the West Midlands, UK, from 1991 to 2011 and gathered data on occupation, causative agent and annual number of notifications. RESULTS: There were 182 cases of OA in HCWs (median annual notifications = 7; interquartile range [IQR] = 5-11), representing 5-19% of annual SHIELD notifications. The modal annual notification was 20 (in 1996); notifications have declined since then, in line with total SHIELD notifications. The majority of cases (136; 75%) occurred in nursing, operating theatre, endoscopy and radiology staff. The most frequently implicated agents were glutaraldehyde (n = 69), latex (n = 47) and cleaning products (n = 27), accounting for 79% of the 182 cases. Cleaning product-related OA was an emerging cause with 22 cases after 2001 and only 5 cases between 1991 and 2000. CONCLUSIONS: Control measures within the UK National Health Service have seen a decline in OA in HCWs due to latex and glutaraldehyde, though OA remains a problem amongst HCWs exposed to cleaning products. Continuing efforts are required to limit the number of cases in this employment sector.

Audit of the recording of occupational asthma in primary care.

BACKGROUND: Occupational asthma (OA) remains common; 1 in 10 cases of adult-onset asthma is due to work. Health outcomes are better with early diagnosis, but there is considerable delay, largely due to lack of enquiry about work effect in primary care. National guidelines (2008) recommend asking two screening questions, which together have a high sensitivity in identifying OA. AIMS: To audit how working-age asthmatics are currently screened for OA in a local primary care population. METHODS: An audit of the electronic patient records of working-age asthmatics, from four Birmingham primary care practices was undertaken. Practice-level data (list size, gender, prevalence of asthma and OA and socio-economic status) and patient-level data (gender, age, onset, occupation and work-effect enquiry and lung function) were collected. RESULTS: The total practice population was 27,295 of which 17,564 (64%) were of working age. The audit sample was 396 of whom 49% were male. The prevalence of asthma in working-age adults was 12% (8-15%) and the prevalence of OA in working-age asthmatics was 0.3% (0-0.8%). Occupation was recorded in only 55/396 (14%) cases with very few (2) documented within the asthma-review template. Occupation was only recorded in 13/55 adult-onset asthmatics in high-risk occupations. Of 396, 9 (2%) had any work-effect enquiry and 4 patients had work-effect enquiry at diagnosis in those with traceable notes (n = 117). CONCLUSIONS: The prevalence of OA was low, suggesting under-diagnosis plus under-reporting in primary care. Occupation and work-effect enquiry is lacking despite guidelines for identifying OA. Existing electronic templates for recording asthma review could be modified to include these elements.

Diagnostic tests for tuberculous pleural effusion.

The investigation of pleural effusion has been greatly assisted by advancements in pleural fluid analysis. In the case of tuberculous pleural effusion, diagnosis traditionally requires the demonstration of acid fast bacilli in the pleural space using microbiological or histological techniques. In recent years, there has been progress in pleural fluid analysis in suspected tuberculous effusions, with particular interest in adenosine deaminase and interferon-γ. These individual tests are quite sensitive and specific; however, data are sparse on the benefits that multiple-parameter testing may have when analysed in combination. We reviewed the literature to investigate the evidence for multiple-parameter testing, both biochemical and clinical, in the evaluation of tuberculous effusion.

A systematic approach to the investigation and diagnosis of a unilateral pleural effusion.

Fluid in the pleural space is a common sequela of a wide range of diseases which may be pulmonary, pleural or extrapulmonary. As the differential diagnosis is wide, a systematic approach to investigation and diagnosis is recommended. This review highlights the important features and recommendations for the investigation of a unilateral pleural effusion, a common condition encountered by the general physician. The aim of this study was to assist with a speedy diagnosis of the underlying pathology, using appropriate investigative techniques, while minimising the use of invasive procedures.

Guidelines on the diagnosis and treatment of pulmonary non-tuberculous mycobacteria infection.

While the prevalence of Mycobacterium tuberculosis continues to decline in the developed world, the same cannot be said for non-tuberculous mycobacteria (NTM). These organisms are increasing in incidence and prevalence throughout the world. This is probably because of a combination of increased exposure, improved diagnostic methods and an increase in the prevalence of risk factors that predispose individuals to infection. Considerable confusion can arise in determining in the wide range of species whether an isolated NTM is in fact a contaminant or a pathogenic organism when isolated in sputum or bronchoalveolar lavage. This confusion combined with increasing requests for advice on the treatment of disease has led to the development of guidelines to assist the clinician in diagnosing and treating infection accurately.