Asymmetric lower jaw may indicate early life stress

Wednesday, June 21, 2017



A new study from the University of Washington has made the claim that an asymmetric lower jaw may be a marker of early life stress.

The first 1,000 days after conception have a strong influence on a person’s life expectancy and immune system. The typical marker for identifying early life stress is a low birth weight. This is only a useful marker for the first 280 days following conception however. According to this study, an asymmetric lower face can be used as an indicator for environmental stresses that occur after birth.

For the paper, researchers looked at data from a National Health Examination Survey which gathered data on 12–17 year olds between 1966 and 1970. They had to rely on data this old because dental researchers stopped measuring facial asymmetry in the 1970s.

An asymmetric bite can be defined as the teeth biting backward or forward on one side of the face and normally on the other side. The study found that backward-biting asymmetries differed randomly between the left and right side of the face, which according to researchers, indicated early life stress.

For decades, anthropologists have used asymmetries in the skull and teeth as markers for environmental stress and degenerative diseases. This has rarely been applied to living populations. The study notes that more research is required to identify whether these asymmetries are indicative of chronic diseases. This study appeared in the American Journal of Human Biology.