Joanna Klein in the New York Times reports on a new study by Lori D’Ortenzio and colleagues examining the lifetime history of rickets in “Old Teeth Tell New Stories About People Who Didn’t Get Enough Sun”
They found that a 24-year-old man who had been buried in Quebec between 1771 and 1860 had suffered four bouts of rickets in his short life: twice before the age of 2, once again around the age of 6, and again, in a somewhat severe episode, around the age of 12. Evidence of this final episode in his third molar correlated with an abnormal curvature in his tailbone that only could have developed around the same time.
“We were able to see inside that tooth, what was housed in there, years ago,” said Dr. Brickley.
They reached this precision because teeth develop at different rates and leave behind concentric circles like tree rings over time. The researchers could look at the abnormalities within those layers to estimate occurrence and severity.
The paper applies a really cool approach that relies upon the failure of dentin to mineralize properly during episodes of rickets. That makes it possible to look for distinct times during the childhood of individuals when they were suffering extreme vitamin D deficiency.
Today, although many individuals do not get the level of vitamin D that would lead to optimal health and development, relatively few suffer altered bone growth to the extent diagnosed as rickets. In skeletal samples of past populations, there are some very extreme cases of rickets. This new approach may help develop a better appreciation of how rickets manifested in past populations, and what the actual challenges were for vitamin D absorption during development.