Chemical exposure and lung function in fragrance industry employees
Student thesis: Doctoral Thesis
Introduction: Production employees within the UK fragrance industry are exposed to large quantities of chemical substances and mixtures over working shifts. Occupational respiratory exposure within this industry is managed in line with relevant legislation and guidelines. There is a lack, however, of published literature studying the effects of respiratory exposure to chemicals on fragrance production employees. A multi-site cross-sectional study was conducted using employees from the UK fragrance industry. The primary aim was to answer the research question: In fragrance industry employees, is occupational respiratory exposure to chemicals linked to a statistically significant change in lung function as measured using spirometry? The secondary aim was to use the data acquired to develop a weighted questionnaire that is predictive for potential lung function problems, for use as a preplacement occupational health tool within the fragrance industry. Methods: A cross-sectional study was designed, using an exposed group (fragrance production and associated functions, n = 60) and a control group (non-exposed fragrance industry employees, e.g. office staff, n = 52). 5 UK companies took part, giving a total of 112 participants. This was calculated as sufficient to achieve 80% power and 5% significance. Spirometric measurements (FEV1, FVC and PEF*) were taken pre-shift and postshift.Information was provided by participants for information on potential confounding factors (smoking, personal or family history of respiratory problems, body mass index). Post-shift measurements were compared between groups, using analysis of covariance (ANCOVA) to adjust for the baseline pre-shift measurements. A pilot questionnaire was developed. The weightings for each of the questions contained within the questionnaire were found by performing simple and multiple linear regression on the spirometric and demographic data. The unstandardised coefficient (B) was used as a measure of effect size in order to calculate a weighted score for each question response. * FEV1 = forced expiratory volume in 1 second; FVC = forced vital capacity; PEF = peak expiratory flow Results: Adjusted mean difference in post-shift measurements between groups (exposed vs. control) for each outcome measure was NOT observed to be statistically significant. Adjusted p-values for FEV1, FVC and PEF were 0.722, 0.883, and 0.676, respectively. Internal validation checks showed that the weighted questionnaire scores correlated with FEV1 measurements, with a high score correlating with a reduced FEV1 performance. Further validation is necessary to determine a threshold score corresponding to FEV1 of <80 predicted, the lower limit of normal for FEV1 performance. Conclusions: The present study showed no significant effects of occupational respiratory exposure on the spirometric performance of the study population. On first inspection the present findings support the suggestion that protective measures in place in the fragrance industry are sufficient in minimising occupational risk to respiratory health. Further validation of airway hypersensitivity measurement methods used in spirometry and the questions asked in the questionnaire is vital in order to determine a threshold score corresponding to FEV1 of <80%predicted, the lower limit of normal for FEV1 performance. The pre-placement occupational health questionnaire has potential to be employed as a predictive tool for potential lung functionality in fragrance industry employees, subject to further development. Subsequent external validation in future studies will be required before the questionnaire can be released for widespread use. In conclusion, this work is the first step in a novel area of research, and the industry would benefit from the follow-up or expansion of this research.
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