Biomedical subjects

D I McBride

Publications and source records attributed to D I McBride.

7 recordsLinked to original sources

PubMed2004

Assessing individual employee risk factors for occupational asthma in primary aluminium smelting.

AIMS: To assess the significance of individual risk factors in the development of occupational asthma of aluminium smelting (OAAS). METHODS: A matched case-control study nested in a cohort of 545 workers employed in areas with moderate to high levels of smelting dust and fume. The cohort comprised those who had their first pre-employment medical examination between 1 July 1982 and 1 July 1995; follow up was until 31 December 2000. Forty five cases diagnosed with OAAS and four controls per case were matched for the same year of pre-employment and age within +/-5 years. The pre-employment medical questionnaires were examined, blinded as to case-control status, and information obtained on demographics and details of allergic symptoms, respiratory risk factors, respiratory symptoms, and spirometry. Data from the subsequent medical notes yielded subsequent history of hay fever, family history of asthma, full work history, date of termination or diagnosis, and tobacco smoking history at the end-point. RESULTS: There was a significant positive association between hay fever diagnosed either at or during employment and OAAS (adjusted OR 3.58, 95% CI 1.57 to 8.21). A higher forced expiratory ratio (FEV1/FVC%) at employment reduced the risk of developing OAAS (adjusted OR 0.93, 95% CI 0.88 to 0.99). The risk of OAAS was more than three times higher in individuals with an FER of 70.0-74.9% than in individuals with an FER > or =80.0% (adjusted OR 3.46, 95% CI 1.01 to 11.89). CONCLUSIONS: Individuals with hay fever may be more susceptible to occupational asthma when exposed to airborne irritants in aluminium smelting. The pathological basis may be reduced nasal filtration and increased bronchial hyperresponsiveness.

Adult↗

PubMed2001

Audiometric notch as a sign of noise induced hearing loss.

OBJECTIVES: To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch. METHODS: The study sample had exposure to both continuous and impulse noise and was drawn from a population of electrical transmission workers. Audiograms, taken as part of a hearing conservation programme, were read by three clinicians experienced in the assessment of NIHL. Working independently and using their clinical judgment, they were asked to identify localised increases in the threshold of hearing (audiometric notches) which they would attribute to noise, had a suitable history of exposure been elicited. Prevalent cases of NIHL were identified by the presence of a notch in either ear. Risk factors for NIHL were assessed by a questionnaire which sought information about exposure to air blast circuit breaker noise; firearms; explosions, and continuous noise. The odds of exposure to these factors in those with and without hearing loss were calculated, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression. RESULTS: Of the 648 questionnaires sent out 357 were returned, a response rate of 55%. Of these, at least two out of the three assessors identified 175 (49%) people with a notch at any audiometric frequency. There was no association between these cases and the NIHL risk factors identified by the questionnaire, but a further frequency specific analysis showed a small proportion of people (15 (4%)) with notches at 4 kHz who had the expected associations with exposure to noise and a significant OR for firearms of 4.25 (95% CI 1.28 to 14.1). The much larger proportion of people with 6 kHz notches (110 (31%)) did not show these associations. CONCLUSIONS: To diagnose NIHL it is important to elicit a detailed and accurate history of exposure to noise: although the notch at 4 kHz is a well established clinical sign and may be valuable in confirming the diagnosis, the 6 kHz notch is variable and of limited importance.

Audiometry↗

PubMed2000

Air blast circuit breaker noise and hearing loss: a multifactorial model for risk assessment.

The assessment of the risk to hearing from impulse noise exposure may be a problem for the occupational physician because existing legislative and international noise exposure standards deal primarily with continuous noise, and are not valid in excess of the peak exposure limit of 200 pa (140 dB). Noise exposure in excess of this level, for example that due to firearms, is frequently perceived as harmful, but this is not necessarily the case, as impulse noise standards do, in fact, allow exposure with a maximum in the order of 6.3 kPa (170 dB). To illustrate this, a cross-sectional group of electrical transmission workers have been studied who were exposed to significant levels of impulse noise from air blast circuit breakers and firearms. Important hearing loss factors have been identified by means of a specially designed questionnaire. Using the Health & Safety Executive definition, the risk of hearing loss was determined by calculating prevalence odds ratios (ORs) for exposure to these factors. The OR for those with fewer than eight unprotected air blast circuit breaker exposures was 2.27 (95% confidence interval (CI), 1.01-5.08), whilst for those with more than eight exposures the OR was 2.10 (95% CI, 0.97-4.54). For firearm exposure, ORs of 1.61 (95% CI, 0.95-2.74) were noted in the medium exposure group and 2.05 (95% CI, 1.08-3.86) in the high exposure group. When all the factors were included in the model, the most significant factor was age. The study gives support to the impulse noise exposure criteria, confirming the borderline risk from air blast circuit breaker noise exposure and the relative safety of moderate gunfire exposure.

Adult↗

PubMed2000

The incidence, nature, and severity of injuries in New Zealand civil aviation.

BACKGROUND: Strategies to improve aviation safety can be directed at the pre-crash, in-crash, or post-crash phases of aircraft crashes. For resources to be made available for in-crash interventions, and for these to be well designed, it is necessary in the first instance to have a detailed understanding of the injuries sustained in crashes. The purpose of this study was to describe the incidence, nature, and severity of injuries sustained in aircraft crashes and other related events in civil aviation in New Zealand. METHODS: National injury databases were searched for fatalities and hospitalizations sustained in aircraft crashes and related events, and cases were linked with Civil Aviation Authority accident records to identify the aircraft involved. Rates were based on estimates of total hours flown by active pilots. RESULTS: There were 104 fatalities identified for the period 1988-1992, giving a rate of 2.57 per 100,000 flight hours. There were 120 hospitalizations identified for the period 1988-1993, giving a rate of 2.45 per 100,000 flight hours. Most fatalities involved injury to multiple body regions, with at least one injury being sufficient in itself to cause death in 48% of cases. For hospitalizations, the lower extremities (23%), spine (20%), and head and face (18%) were the body regions most commonly injured, with fractures being predominant. While the majority of fatalities and hospitalizations occurred in fixed- and rotary-wing aircraft, the highest rates were for microlight and home-built aircraft. CONCLUSIONS: Different patterns of injury were evident for fixed- and rotary-wing aircraft. Reasons for these are suggested. Future research will seek to determine the relative risk associated with potentially modifiable risk factors.

Abbreviated Injury Scale↗

PubMed1997

Occupational exposure to magnetic fields in relation to mortality from brain cancer among electricity generation and transmission workers.

OBJECTIVE: To investigate whether the risks of mortality from brain cancer are related to occupational exposure to magnetic fields. METHODS: A total of 112 cases of primary brain cancer (1972-91) were identified from a cohort of 84,018 male and female employees of the (then) Central Electricity Generating Board and its privatised successor companies. Individual cumulative occupational exposures to magnetic fields were estimated by linking available computerised job history data with magnetic field measurements collected over 675 person-workshifts. Estimated exposure histories of the case workers were compared with those of 654 control workers drawn from the cohort (nested case-control study), by means of conditional logistic regression. RESULTS: For exposure assessments based on arithmetic means, the risk of mortality from brain cancer for subjects with an estimated cumulative exposure to magnetic fields of 5.4-13.4 microT.y v subjects with lower exposures (0.0-5.3 microT.y) was 1.04 (95% confidence interval (95% CI) 0.60 to 1.80). The corresponding relative risk in subjects with higher exposures (> or = 13.5 microT.y) was 0.95 (95% CI 0.54 to 1.69). There was no indication of a positive trend for cumulative exposure and risk of mortality from brain cancer either when the analysis used exposure assessments based on geometric means or when the analysis was restricted to exposures received within five years of the case diagnosis (or corresponding period for controls). CONCLUSIONS: Although the exposure categorisation was based solely on recent observations, the study findings do not support the hypothesis that the risk of brain cancer is associated with occupational exposure to magnetic fields.

Brain Neoplasms↗

PubMed1988

Basal cell carcinoma mimicking rhinophyma. Case report and literature review.

An 82-year-old man presented with rapid enlargement of a long-standing rhinophyma. Following an uncomplicated excision of rhinophyma, histologic examination showed that the enlargement was entirely due to basal cell carcinoma. Radiotherapy was administered, and the nose has now healed satisfactorily. There are few reports of an association between rhinophyma and basal cell carcinoma; but it is claimed that it occurs more frequently than is expected by chance. The evidence for this is reviewed. Previous reports were anecdotal or contained biases that prevent generalization of the results and, in addition, a statistical analysis was incorrect. There is insufficient evidence to claim an association between basal cell carcinoma and rhinophyma.

Aged↗

PubMed1988

Understanding Latin abbreviations: a survey.

A questionnaire was sent to general practitioner principals and trainees and to retail pharmacists in the west of Scotland to ascertain how well they translated 20 Latin abbreviations. The results showed that pharmacists had a high level of understanding, but that general practitioner principals and trainees misunderstood some of the less commonly used terms. Misunderstanding was more likely among trainee general practitioners than principals.

Abbreviations as Topic↗