May 12, 2010

Roman Volcanoes

A colleague in Iceland told me that the recent eruption of the Eyjafjallajokull volcano created a problem for livestock farmers. Their animals were eating plants and drinking water covered by the fine ash, which was high in fluoride. Excessive ingestion of fluoride leads to dental fluorosis as well as skeletal fluorosis. Fluoride is a regular byproduct of volcanic activity, so it stands to reason that fluorosis was actually a common problem particularly in the late 1st century Italy, following the eruption of Vesuvius. I don't actually know how soon people began farming the land around Pompeii and Herculaneum or how far the ash cloud spread. But fluorosis should be a relatively easy thing to spot in ancient skeletal remains, even if it can get confused with DISH (diffuse idiopathic skeletal hyperostosis). As far as I can tell, there is one publication on dental fluorosis in ancient Italy, on some skeletons from Herculaneum, in a letter to the editor of the Lancet in 1995 (Torino et al., vol. 345, p. 1306). Excluding the table, the entire thing reads:

Dental fluorosis in ancient Herculaneum

"Sir - Excavations of the arches surrounding the beach of Herculaneum (the ancient Roman town buried with Pompeii by the eruption of Vesuvius in AD 79) revealed whole skeletons of some hundreds of victims. The ancient Herculaneans enjoyed an excellent and very cariogenic alimentation, chiefly based on fish and meat with large amounts of honey. However, only 49 (3-8%) of 1275 teeth from 41 adults and 12 children were carious. This percentage is very low for both modern and ancient populations, in which values were between 8-5%, as in classic Magna Graecia/ and 11 -4%, as in Roman Britain. In fact, in the Herculaneum skeletons we showed in a high proportion of individuals (14 of 48, 29.2%) enamel hypoplasia due to alterated amelogenesis, which is often caused by starvation or other types of stress but is also common in well nourished people subject to chronic fluorosis. These data strongly suggested the presence of some cases of dental fluorosis. To elucidate this hypothesis, we examined thin sections of permanent teeth enamel (first molar) from 8 individuals found in the Herculaneum arches site and from a present-day patient from Pisa without evidence of fluorosis, as control. Enamel was analysed by energy dispersion system (EDS) with an SEM (Jeol) 6400 connected to a microanalysis system (EDS) (Noran-Tracor) with a detection of Z-MAX 30. The following results were obtained (table). Enamel fluorine concentrations were greater than 10-fold higher than normal (1500-3600 parts per million [ppm]) were recorded in 6 individuals (table). However, in an adolescent girl and an adult woman, fluorine was not detectable. Furthermore, the absence of fluorine in the soil excluded any contamination.

Together with the finding of very few caries and the high frequency of enamel hypoplasia, these results clearly demonstrate the presence of endemic dental fluorosis. These findings are lent support by the strong concentration of fluorine in the water-bearing stratum of Herculaneum (3-8 mg/mL), with a calculated intake of 11-4-19-0 mg a day per person at the time of the volcanic eruption. Members of the Roman aristocracy had villas in Herculaneum, so perhaps some of our subjects were visitors to the region."

I stumbled upon this idea while brainstorming ways that immigrants to Rome might be less healthy than locals (other than lack of immunity to endemic diseases). If people stuck around after the eruption of Vesuvius in 79 AD, then decided to journey north to Rome, they might have come with skeletal or dental fluorosis from ingesting too much fluoride. I doubt dental fluorosis results in poor health outcomes, but I suspect skeletal fluorosis would at the very least make someone more susceptible to development of osteoarthritis. If only I had graduate students, I could make one of them research fluorosis in late 1st century AD Italy for a thesis or dissertation!

And this is why I had to stop myself from following up every citation that piqued my interest while dissertating... what should have been a simple clarification of how immigrants tie into the epidemiology of the Roman population has turned into two hours' worth of reading about fluorosis.

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