Neuropsychological function and past exposure to metallic mercury in female dental workers

Abstract

The aim of this study was to see if dental personnel with previous exposure to metallic mercury have later developed disturbances in cognitive function. Ninety-one female participants who had been selected from a previous health survey of dental personnel were investigated neuropsychologically within the following domains: motor function, short-term memory, working memory, executive function, mental flexibility, and visual and verbal long-term memory. The scores were mainly within normal ranges. Relationships between an exposure score, the duration of employment before 1990, and previously measured mercury in urine as independent variables and the neuropsychological findings as dependent variables, were analyzed by multiple linear regression controlling for age, general ability, length of education, alcohol consumption, and previous head injuries. The only relationship that was statistically significant in the hypothesized direction was between the previously measured urine mercury values and visual long-term memory, where the urine values explained 30% of the variability. As the study had a low statistical power and also some other methodological limitations, the results have to be interpreted with caution. Even so, we think it is right to conclude that neuropsychological findings indicative of subsequent cognitive injuries are difficult to find in groups of otherwise healthy dental personnel with previous occupational exposure to mercury.

Chronic exposure to low mercury chloride concentration induces object recognition and aversive memories deficits in rats

“…Recently, Hu et al (2012) observed that administration of mercury‐contaminated rice to 3 weeks old rats disturbed the spatial learning and memory in Morris water maze. Considering mercury effects for humans, only a few studies reported effects of exposure to mercury in adulthood on cognitive functions; the most of them investigate consequences of uncontrolled exposure to this metal in humans (Smith et al, 1983; Sletvold et al, 2012); or during a short exposition in rats (Hu et al, 2012).…”

Neurotoxic effects of mercury exposure for dental workers - A literature review

“…2012 [29] To find late developed disturbances in cognitive function of dental personnel with previous exposure to metallic mercury.…”

“…This review includes 13 studies about possible CNS effects of chronic exposure to mercury [17][18][19][20][21][22][23][24][25][26][27][28][29] and 2 studies about possible CNS effects on offspring of female dental professionals exposed to mercury during pregnancy [30,31]. All the papers compare a group of dental workers exposed to mercury proved by blood and/or urine tests with a control group.…”

“…The same association was done by Aydin, et al [24] and established a positive relationship with increased scores of anxiety and psychoticism using SCL-90-R test in a group of 43 dental workers. Sletvold, et al [29] discovered a statistically significant relationship between measured urine mercury level and visual long-term memory based on evaluation of 91 female dental workers by questionnaire and neuropsychological tests.…”

Mulige senskader hos tannhelsepersonell etter kvikksølveksponering

“…Hos de i utgangspunktet friske personene som ble undersøkt, fant vi ingen sammenheng mellom kognitiv funksjon og antatt grad av tidligere kvikksølveksponering (9). Det var imidlertid en svak sammenheng mellom visse forstyrrelser ved visuell hukommelse og kvikksølvnivåer i urin hos 28 individer der dette var målt (10).…”