Olfactory sensitivity in medical laboratory workers occupationally exposed to organic solvent mixtures.

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.

Model study of AREDS antioxidant supplementation of AMD compared to Visudyne: a dominant strategy?

OBJECTIVES: In Ontario, Canada, in a cohort of all people initially aged 50-54 years, modeling whether the Age-Related Eye Disease Study (AREDS) antioxidant supplementation for stage 3 and 4 AMD would decrease the costs of photodynamic treatment with Visudyne. PERSPECTIVE: Third party payer, the Ontario Health Insurance Plan. METHODS: Using reported risk reductions, prevalence data by age and sex from the Beaver Dam studies, and yearly costs: AREDS 182.50 Canadian dollars, potential savings were calculated as the difference or incremental cost between the estimated medical costs for the untreated cohort of 17,000 Canadian dollars for Visudyne treatment of individuals with neovascularization and the same cohort if stage 3 and 4 AMD patients were treated with antioxidants, decreasing progression to neovascularization. Different scenarios were explored for sensitivity analysis of direct cost savings. RESULTS: For the Ontario cohort of approximately 788,000 aged 51-55 years in 2001, for photodynamic therapy of the untreated cohort, modeled costs were 1.7 billion Canadian dollars. AREDS treatment costs would be 513 million Canadian dollars. AREDS would reduce photodynamic therapy costs, a net saving of 431 million Canadian dollars, a saving of 547 Canadian dollars per person in the total cohort, or 6,753 Canadian dollars per stage 3 and 4 patient treated. To explore the sensitivity of this model to AMD incidence rather than prevalence data, Framingham incidence data were incorporated in the model: net savings of 70.3 million Canadian dollars were modeled using Framingham incidence data. CONCLUSION: Under reasonable assumptions, if the case progresses to wet AMD (1) AREDS with Visudyne is less expensive than Visudyne alone in every five-year time period for the cohort that is age 50-54 right now until they become 75-79; thus, the lifetime cost is lower; (2) AREDS with Visudyne yields more QALYs than Visudyne alone in every five-year interval; (3) under all but the most extreme assumptions, the conclusions reached are robust. Even when AREDS costs a little more, it yields more QALYs at a reasonable cost per QALY. Thus, AREDS antioxidant supplementation appears to be a dominant strategy for macular degeneration. Applied to the whole Canadian population, the potential medical cost savings for Visudyne treatment of neovascular AMD are 5.6 billion Canadian dollars in direct costs. These values would be tenfold higher for the USA, because of the currency and population size differences.