Barliman
Member
A few people have asked Peat about bodily facial and torso deformities and he has said it is likely due to high estrogen, especially in early childhood. This recent study seems to add evidence to that hypothesis by showing that crooked bite (a type of facial deformity) is an indication of stress exposure in early life. I find the study interesting because it also mentioned another metric that Peat often talks about but is virtually unknown in the medical world - i.e. the environmental quality during the first 1,000 days since conception have profound impact on both the lifespan and healthspan of the person. So, lower face symmetry can be used as a quick and reliable way to judge systemic health status. I know of a few studies, which showed that survivors of traumatic events who developed PTSD experienced changes in facial structure, and recovery from PTSD coincided with restoration of previous facial structure.
The bad news is that apparently such facial deformity records are no longer being collected in the US since the 1970s, which means that there is no current data for the US population. That is unfortunate, as it is a very reliable and non-invasive way of determining if the population is getting healthier or sicker (on average). Anecdotally, there have been quite a few discussions on this forum, and especially on Reddit about how modern celebrities have weird, gaunt and "fake" faces compared to famous people in the 1960s and earlier. I doubt that this is a coincidence, considering this study and other factoids mentioned by Peat.
Lower face asymmetry as a marker for developmental instability
"...The findings suggest that lower face asymmetries are a marker for environmental stress and cerebral lateralization during early development."
Crooked bite may indicate early life stress, UW study suggests | UW HSNewsBeat
"...Research has repeatedly confirmed that the first 1,000 days after conception strongly influence a person’s life expectancy and susceptibility to chronic diseases. The primary marker used to identify early life stress is low birth weight, which can, for instance, indicate poor nutrition of the mother during pregnancy. But low birth weight is a marker only until birth, about 280 days – far short of a measurement useful for the first thousand days. New research from University of Washington investigators suggests that an asymmetric lower face is a novel marker that also captures early life stresses that occur after birth."
"...“Asymmetries in the skull and teeth have been used for decades by anthropologists to mark environmental stress, but they have only rarely been used in living populations,” said Philippe Hujoel, the corresponding author. “Such lower-face asymmetries can be assessed by looking at the dental bite in the permanent teeth – an exam that can be completed in seconds and with more certainty than a mother’s recall of birth weight and more ease than a search for a birth certificate.”
"...The team had to look back four decades for data because in the 1970’s, he said, dental researchers in charge of designing U.S. surveys began to disregard the value of diagnosing facial asymmetry, and stopped taking those measurements. “From a biological perspective, this decision resulted in an inability to reliably track trends in the U.S.,” Hujoel said. "We don’t have current information on the prevalence of lower-face asymmetries in the U.S. population.”
All these studies miss one very important correlate- the question of injury to the upper cervical spine at birth. These injuries are common, and even if relatively minor tend not to resolve without assistance.
The reason for that is that the chronic asymmetry in proprioceptive tone in the upper neck makes it more difficult to control and stabilise the head.
While this area has in the US been largely the preserve of chiropractors it has been studied in depth by MDs in Germany.
The best book I have encountered on the issue is "Manual Therapy In Children", edited by the German Orthopedic surgeon Heiner Biedermann MD. His coaothors include an impressive array of specialists from multiple other disciplines- including obstetrics, radiology, dentistry, orthodontics, general practice, neurology, rehabilitation medicine, paediatrics.
Most babies who have an injury like this will lie usually with the head to one side (it is less uncomfortable) and will develop significant skull molding as a result. I had the injury myself and only discovered it in my late 40's. 2 years ago I realised the extent of my skull asymmetry- which has a distinct bulge in the left parietal area.
There are 2 chapters on the orthodontic implications as well - these are driven by the skull molding and also the loading implications of the abnormal forward head posture adopted by those who have this injury.
Babies who have this problem are prone to crying a lot, have significant issues with reflux and are often hindered in their motor development. They can be quite a handful, they can be difficult to feed especially on one breast, and this often causes attachment problems (anxious or avoidant attachment).
It is also clear from the Adverse Childhood Events studies that children who have a difficult childhood are much more prone to PTSD than adults who did not.
Biedermann also had some preliminary data to suggest that the risk of getting these birth injuries was related to particular pre-existing deformties of the cervical spine which are heritable.
So there is a very good argument that both these asymmetries and the proneness to stress are all secondary to the birth injury.