Women who have experienced high levels of trauma in childhood, such as abuse by a parent, are biologically older at the epigenetic cellular level in adulthood than women of the same age who have not experienced such adversity, according to a new study by UC San Francisco.
Epigenetic "clocks" measure biological age, by examining methylation patterns at certain sites in the DNA of blood cells. An individual may be 40 years old and have cells that look more like those of someone who is 50 years old; conversely, a 40-year-old may have cells that look like those of someone 30 years old. Being epigenetically older than your chronological age, based on these measures, is associated with developing diseases, such as heart disease and cancer, at a younger age and with a shorter life span.
In the study, published Jan. 10 in Developmental Psychobiology, 183 premenopausal women completed blood draws so that their biological ages could be calculated using epigenetic clocks. All the women were non-smokers and had no major diseases. The women were asked about the number of traumatic events that they had experienced before the age of 12, which are called adverse childhood experiences (ACEs). They also reported the age at which they began menstruating.
The level of trauma the women had experienced in childhood was associated with the age of their epigenetic clocks. The study also found that it was specifically abuse in early life that resulted in older epigenetic aging in adulthood, whereas physical neglect did not show the same relationship. Other studies have similarly found that not all ACEs have similar effects - physical, sexual or emotional abuse may have more severe effects than neglect.
A secondary finding was that the earlier a woman had started menstruation during puberty, the older her epigenetic clock was. Early life adversity has been speculated to result in earlier puberty, but this particular study found no association between childhood trauma and age at menarche.
"Trauma in childhood appears to age immune cells at a more rapid pace," said lead author Elissa J. Hamlat, PhD, a postdoctoral scholar at the UCSF Department of Psychiatry and Behavioral Sciences, and Center for Health and Community (CHC). "This could be one reason why individuals who experience more adversity in early life are more likely to have serious mental and physical health problems as adults."
The link between ACES and health conditions, such as asthma, diabetes, heart disease, and Alzheimer's, has made screening for ACEs by primary care physicians a priority for the California Surgeon General Nadine Burke Harris, MD.
"Early-life adversity may lead to premature aging decades before chronic disease develops," Hamlat, "These were healthy young and middle-aged women, who had yet to develop significant health conditions."
Targeting the mechanisms by which childhood circumstances increase risk for severe health problems in adulthood can lead to the earlier identification and treatment of those most likely to develop physical and mental illness.
Elissa Epel, PhD, professor in Psychiatry and Behavioral Sciences and CHC, the senior author of the study, warns that the current pandemic, due to the sharp increases in isolation, financial and parenting stress, and domestic violence, has increased exposure to traumatic stressors for children.
Intervention with children who have experienced early adversity may protect children from developing mental health problems later, and some studies show family-based prevention programs may buffer against accelerated epigenetic aging in children from risky environments.
"It is important to focus on prevention, most critically, but also intervention," Epel said.
