Modern medicine and plumbing have greatly extended humans' average life-expectancy. However, a study of teeth from ancient English burial sites suggests we might have overestimated this effect by failing to realize how common it was for people in previous centuries to reach an advanced age.

Christine Cave, a PhD student at the Australian National University, developed a new method for determining age of death by looking at teeth wear, after recognizing the problem with current estimates of ancient life expectancies. “When you are determining the age of children you use developmental points like tooth eruption or the fusion of bones that all happen at a certain age," she explained. "Once people are fully grown it becomes increasingly difficult to determine their age from skeletal remains, which is why most studies just have a highest age category of 40 plus or 45 plus.”

However, there is plenty of reason to believe many people in ancient times lived longer. Cave told IFLScience studies of surviving hunter-gatherer populations with little access to modern technology have revealed the presence of numerous older people. Literate ancient societies, such as ancient Rome, record some long lives.

To address archaeology’s blindspot on the elderly, Cave measured the wear on teeth from Anglo-Saxon cemeteries in Essex, Kent, and Hampshire. Since everyone in those societies ate a relatively similar diet, the most worn teeth should belong to the oldest citizens. In previous work, Cave helped devise a method to match tooth wear at one of these cemeteries to known ages.

Combining these two projects, Cave has published a paper in the Journal of Anthropological Archeology that provides estimates of the ages of those buried at the three cemeteries, many of whom turn out to have lived well past 45. Cave's findings fit with those made using other methods in other societies. "For people living traditional lives without modern medicine or markets the most common age of death is about 70, and that is remarkably similar across all different cultures," she said. 

However, Cave clarified to IFLScience this is true only for those who survived childhood. Infant mortality was so high prior to vaccines and clean water supplies that the average life expectancy at birth was still decades lower than today.

Cave's findings show it is not just the very young who had a bad time in England from 475-625 AD, however. The respect with which an individual was held can be seen from the items with which they were buried. High-status men were interred with weapons, and the quality of these generally rose with age. On the other hand, Cave said, "Women were buried with jewelry, like brooches, beads, and pins,” and this seldom happened for older women, who appear to have no longer been much valued.