Baby teeth may one day help identify kids at risk for mental disorders
later in life
Like the rings of a tree, teeth contain growth lines that may reveal
clues about childhood experiences.

Date:
November 10, 2021
Source:
University of Bristol
Summary:
The thickness of growth marks in primary (or 'baby') teeth may
help identify children at risk for depression and other mental
health disorders later in life, according to a ground-breaking
investigation.



FULL STORY ==========================================================================
The team analysed 70 primary teeth collected from 70 children enrolled in
the Children of the 90s study (also known as the Avon Longitudinal Study
of Parents and Children) based at the University of Bristol. Parents
donated primary teeth (specifically, the pointed teeth on each side of
the front of the mouth known as canines) that naturally fell out of the
mouths of children aged 5 to 7.


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The results of this study could one day lead to the development of
a much- needed tool for identifying children who have been exposed to early-life adversity, which is a risk factor for psychological problems, allowing them to be monitored and guided towards preventive treatments,
if necessary.

The origin of this study traces back several years, when senior author
Erin C.

Dunn, ScD, MPH, learned about work in the field of anthropology that
could help solve a longstanding problem in her own research. Dunn is
a social and psychiatric epidemiologist and an investigator in MGH's Psychiatric and Neurodevelopmental Genetics Unit. She studies the effects
of childhood adversity, which research suggests is responsible for up to one-third of all mental health disorders. Dunn is particularly interested
in the timing of these adverse events and in uncovering whether there are sensitive periods during child development when exposure to adversity is particularly harmful. Yet Dunn notes that she and other scientists lack effective tools for measuring exposure to childhood adversity. Asking
people (or their parents) about painful experiences in their early years
is one method, but that's vulnerable to poor recall or reluctance to
share difficult memories. "That's a hindrance for this field," says Dunn.

However, Dunn was intrigued to learn that anthropologists have long
studied the teeth of people from past eras to learn about their
lives. "Teeth create a permanent record of different kinds of life experiences," she says. Exposure to sources of physical stress, such
as poor nutrition or disease, can affect the formation of dental enamel
and result in pronounced growth lines within teeth, called stress lines,
which are similar to the rings in a tree that mark its age. Just as the thickness of tree growth rings can vary based on the climate surrounding
the tree as it forms, tooth growth lines can also vary based on the
environment and experiences a child has in utero and shortly thereafter,
the time when teeth are forming. Thicker stress lines are thought to
indicate more stressful life conditions.

Dunn developed a hypothesis that the width of one variety in particular,
called the neonatal line (NNL), might serve as an indicator of whether an infant's mother experienced high levels of psychological stress during pregnancy (when teeth are already forming) and in the early period
following birth.

To test this hypothesis, Dunn and two co-lead authors -- postdoctoral
research fellow Rebecca V. Mountain, PhD, and data analyst Yiwen Zhu, MS,
who were both in the Psychiatric and Neurodevelopmental Genetics Unit at
the time of the study -- led a team that analysed the teeth. The width of
the NNL was measured using microscopes. Mothers completed questionnaires
during and shortly after pregnancy that asked about four factors that
are known to affect child development: stressful events in the prenatal
period, maternal history of psychological problems, neighbourhood quality (whether the poverty level was high or it was unsafe, for instance),
and level of social support.

Several clear patterns emerged. Children whose mothers had lifetime
histories of severe depression or other psychiatric problems, as well as mothers who experienced depression or anxiety at 32 weeks of pregnancy,
were more likely than other kids to have thicker NNLs. Meanwhile,
children of mothers who received significant social support shortly after pregnancy tended to have thinner NNLs. These trends remained intact after
the researchers controlled for other factors that are known to influence
NNL width, including iron supplementation during pregnancy, gestational
age (the time between conception and birth) and maternal obesity.

No one is certain what causes the NNL to form, says Dunn, but it's
possible that a mother experiencing anxiety or depression may produce
more cortisol, the "stress hormone," which interferes with the cells
that create enamel. Systemic inflammation is another candidate, says
Dunn, who hopes to study how the NNL forms. And if the findings of this research can be replicated in a larger study, she believes that the NNL
and other tooth growth marks could be used in the future to identify
children who have been exposed to early life adversity.

"Then we can connect those kids to interventions," says Dunn, "so we can prevent the onset of mental health disorders, and do that as early on in
the lifespan as we possibly can." Dunn is also an associate professor
of Psychiatry at Harvard Medical School.

Mountain is now a postdoctoral research fellow at Maine Medical Center
Research Institute. Zhu is now a doctoral student at the Harvard T.H. Chan School of Public Health.

========================================================================== Story Source: Materials provided by University_of_Bristol. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Rebecca V. Mountain, Yiwen Zhu, Olivia R. Pickett, Alexandre
A. Lussier,
Jill M. Goldstein, Joshua L. Roffman, Felicitas B. Bidlack, Erin
C. Dunn.

Association of Maternal Stress and Social Support During Pregnancy
With Growth Marks in Children's Primary Tooth Enamel. JAMA Network
Open, 2021; 4 (11): e2129129 DOI: 10.1001/jamanetworkopen.2021.29129 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211110104603.htm

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