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Olfactory sensitivity in medical laboratory workers occupationally exposed to organic solvent mixtures
1 Department of Epidemiology & Biostatistics, Kresge Building, University of Western Ontario, London, Ontario, Canada N6A 5C1
2 Group for the Advocacy and Advancement of Medical and Dental Education at the University of Western Ontario (GAMES), University of Western Ontario, London, Ontario, Canada N6G 4X8
Correspondence to: Elaine M. Zibrowski, c/o GAMES, Suite 227, 100 Collip Circle, London, Ontario, Canada N6G 4X8; e-mail: elaine.zibrowski{at}schulich.uwo.ca
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Abstract |
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Background Published epidemiological information relating the effects of occupational exposure to organic solvents (OS) to olfaction is limited.
Aims The objectives of this pilot study were to measure the chemosensory abilities of medical laboratory employees occupationally exposed to OS mixtures, to compare these with control workers employed within the same occupational setting and to correlate chemosensory performance with OS exposure history and with employees' hedonic (pleasantness) perceptions about workplace OS odors.
Methods Twenty-four medical laboratory employees (OS-exposed technicians plus control workers minimally exposed to OS) completed a health-related questionnaire, a test of pyridine odor detection threshold, along with a gustatory detection threshold test involving aqueous quinine solutions. Estimates of cumulative hours of OS exposure (CSI) were calculated from self-reports.
Results OS-exposed laboratory technicians detected weaker concentrations of pyridine odor. Positive correlations were detected between CSI estimates to both pyridine detection and the degree that participants reported that OS odors were present in the workplace. However, no association was detected between pyridine detection and how unpleasant workplace OS odors were perceived. The OS-exposed participants were able to detect weaker concentrations of quinine. Compared to controls, OS-exposed workers complained more of experiencing several symptoms while working, including headaches, nasal irritation and mild cognitive impairment.
Conclusions The results of this cross-sectional pilot study indicated that, compared to controls, medical laboratory technicians exposed to low-level OS mixtures displayed evidence of elevated olfactory sensitivity (hyperosmia) to pyridine odor. The relation of this study's results to chemical intolerance warrants further investigation.
Keywords Chemosensory; occupational exposure; olfaction; pyridine; solvents
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Introduction |
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Published epidemiological information relating the effects of occupational organic solvent (OS) exposure to olfaction (OLF; smell) is limited. The few studies in this area have primarily utilized a qualitative, microencapsulated test as their main OLF outcome. The findings of these have been mixed [1–4]. A study was located which utilized a quantitative test of OLF sensitivity [5]. Here, OS-exposed printers were found to have a slightly lower smell threshold.
Even less information exists regarding the potential effects of OS on gustation (taste) [6]. Two studies were located which reported that OS-exposed employees complained more of experiencing symptoms of taste loss and ‘funny tastes in their mouth’ [5,7].
The aim of this pilot study was to further explore the potential association between occupational OS exposure and the chemosensory abilities of medical laboratory workers.
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Methods |
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Fifteen, OS-exposed medical laboratory technicians (3 men, 12 women) and nine control workers (two men, seven women), minimally exposed to OS in the same laboratories, participated in this pilot study (80% participation rate; original participant pool of 120 workers).
For current and past employment, estimates of cumulative OS exposure (CSI) were calculated from self-reports [hours/day x days of employment]. Participants completed a questionnaire probing areas including prevalence of symptoms and the presence/perception of workplace OS odors.
Chemosensory sensitivity was estimated using descending staircase tests of detection threshold. Twenty-five concentrations of pyridine (has a shellfish-like odor) and 17 aqueous solutions of quinine sulfate (bitter tastant) were used as stimuli. For both tests, the detection threshold was defined as the weakest stimulus correctly detected three times in a row. The weaker score obtained between the two nares was the diagnostic value.
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Results |
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Associations between continuous variables were explored with Pearson's product moment correlations (PPMC, r); Spearman's rho (
) correlations were used to estimate relationships between continuous and ordinal variables or continuous and dichotomous variables. Crude relative odds ratios (OR) of workplace symptoms were calculated. Ninety-five percent confidence intervals (CI) were calculated around group differences, OR and PPMC. The mean age of the participants was 37.5 ± 8.6 years (range 23–59). No significant differences were observed in terms of group demographics.
The technicians reported that they were occupationally exposed to an average of three OS (most commonly reported were xylene, ethyl alcohol, acetone and methanol). Technicians reported more hours of OS exposure (see Table 1). Although industrial hygiene data were not available, laboratory administrators indicated that OS exposure levels were below the short-term and time-weighted 40-h work week limits.
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The CSI estimates were associated with the degree that participants reported OS odors were present in the workplace (
= 0.49), how aversive these were perceived to be while working ( = 0.40) and the use of personal protective equipment ( = 0.45).
Chemosensory detection threshold tests and workplace symptoms
Exposed participants detected weaker concentrations (higher steps) of pyridine (Table 2). An association was detected between CSI and pyridine detection [r = 0.3; 95% CI (–0.12 to 0.63)]. The degree that participants' reported OS odors permeated the workplace also correlated with this test ( = 0.32). However, pyridine detection failed to correlate with the degree to which participants' perceived these smells as being aversive ( = 0.07).
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OS-exposed technicians detected weaker concentrations of quinine (Table 2) and this was weakly associated with CSI [r = 0.16, 95% CI (–0.26 to 0.53)] and the perceived aversiveness of workplace OS odors (
= 0.15).
Compared to controls, exposed participants complained more of ‘ever’ experiencing several symptoms while working (Table 3). An association between CSI and prevalence of workplace headache was detected ( = 0.36).
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionConflicts of interestReferences |
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The results of this cross-sectional pilot study indicated that, compared to controls, medical laboratory technicians exposed to low-level OS mixtures displayed evidence of hyperosmia to pyridine odor. Moreover, pyridine detection was positively associated with two indices of occupational OS exposure, CSI estimates and employees' appraisals of the presence of workplace OS odors.
As this study involved volunteers, potential bias due to self-selection needs to be addressed. We do not feel that self-selection was a factor as the relationship between OS and the chemical senses has not received a lot of attention. It is unlikely that participants would be more or less likely to volunteer based on prior information, and none of the participants reported having any experience with chemosensory testing.
The headache and cognitive symptoms reported in this pilot study by exposed workers are similar to those reported elsewhere [5,7,8]. These complaints in conjunction with increased OLF sensitivity raise the question of the relevance of this study's findings to chemical intolerance (ChI). ChI involves an unpleasant sensation and the experience of one or more somatic/cognitive/affective symptoms in response to low-level chemical exposure [9]. Sensitization of OLF-limbic areas, similar to kindling, has been proposed as its underlying neural mechanism [10]. Electrocorticographic recordings have shown that repeated OS presentation results in gradual enhancement/sensitization of field potentials in the rat OLF brain [11]. Increased avoidance behaviors correlate with these changes.
Despite the fact that OS exposure was positively associated with how unpleasant employees perceived workplace OS odors to be, no relation was detected between these appraisals and the pyridine detection threshold. Hence, the relevance of this pilot's results to ChI requires further exploration. As we utilized a single stimulus, it would be interesting to explore OLF sensitivity across a range of compounds, including the OS an individual predominantly works with. While there were no obvious differences between the groups in their behavioral reactions to pyridine, these were not specifically examined. Given that pyridine is a trigeminal irritant, the influence of nasal pungency and/or other irritant effects needs to be examined.
To our knowledge, this pilot study involved the first psychophysical exploration of bitter taste detection in OS-exposed workers. As the chemical senses are strongly linked, the ability of the technicians to detect weaker concentrations of quinine may be a reflection of enhanced OLF sensitivity. Nevertheless, it would be interesting to see whether similar results extend to the other taste modalities as the relation between OS and gustation has received little attention.
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Conflicts of interest |
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TopAbstractIntroductionMethodsResultsDiscussionConflicts of interestReferences |
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None declared.
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Acknowledgements |
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This research was partially funded by a Doctoral Research Fellowship awarded to E.M.Z. by the Canadian Institute for Health Research. The study's protocol was reviewed and approved by the University of Western Ontario's Ethics Committee for Research Involving Human Subjects. The authors thank the study's participants and the Monell Chemical Senses Center for their assistance with the threshold tests used in this study.
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References |
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- Schwartz B, Ford DP, Bolla KI, Agnew J, Rothman N, Bleecker ML. Solvent-associated decrements in olfactory function in paint manufacturing workers. Am J Ind Med 1990;18:697–706.[Web of Science][Medline]
- LoSasso GL, Rapport LJ, Axelrod BN, Whitman RD. Neurocognitive sequelae of exposure to organic solvents and (Meth)Acrylates among nail-studio technicians. Neuropsychiatry Neuropsychol Behav Neurol 2002;15:44–55.[Medline]
- Sandmark B, Broms I, Lofgren L, Ohlson C-G. Olfactory function in painters exposed to organic solvents. Scand J Work Environ Health 1989;15:60–63.[Medline]
- Schwartz BS, Doty RL, Monroe C, Frye R, Barker S. Olfactory function in chemical workers exposed to acrylate and methacrylate vapors. Am J Public Health 1989;79:613–618.
[Abstract/Free Full Text] - Baelum J, Andersen I, Molhave L. Acute and subacute symptoms among workers in the printing industry. Br J Ind Med 1982;39:70–75.[Medline]
- Schiffman SS, Nagle T. Effect of environmental pollutants on taste and smell. Otolaryngol Head Neck Surg 1992;106:693–700.[Web of Science][Medline]
- Parkinson DK, Bromet EJ, Cohen S et al. Health effects of long-term exposure among women in blue-collar occupations. Am J Ind Med 1990;17:661–675.[Medline]
- Orbaek P, Nise G. Neurasthenic complaints and psychometric function of toluene-exposed rotogravure printers. Am J Ind Med 1989;16:67–77.[Medline]
- Bell IR, Baldwin CM, Schwartz GE. Illness from low levels of environmental chemicals: relevance to chronic fatigue syndrome and fibromyalgia. Am J Med 1998;105:74S–82S.[CrossRef][Medline]
- Bell IR, Miller CS, Schwartz GE. An olfactory-limbic model of multiple chemical sensitivity syndrome: possible relationship to kindling and affective spectrum disorders. Biol Psychiatry 1992;32:218–242.[CrossRef][Web of Science][Medline]
- Vanderwolf CH, Zibrowski EM. Pyriform cortex ß-waves: odor-specific sensitization following repeated olfactory stimulation. Brain Res 2001;892:301–308.[CrossRef][Medline]
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