A small study of new mothers indicates that not completing high school — a likely marker of socioeconomic stress — may be linked to shorter telomeres in newborns. Telomeres are protective caps at the ends of chromosomes; when shortened, they are a recognized sign of cellular aging and, in adults, are associated with higher risk of conditions such as diabetes, obesity, cancer and reduced lifespan. The long-term consequences of shorter telomeres present at birth remain uncertain.
“To our knowledge, this is the first study suggesting that a mother’s level of education may influence cellular markers in her newborn,” said Janet Wojcicki, PhD, MPH, associate professor of pediatrics at UCSF and lead author of the study published in the Journal of Perinatology. “This finding raises the possibility that children whose mothers have limited educational opportunities may begin life with biological disadvantages.”
The researchers caution that the result is preliminary: the sample was small and drawn from a specific population of Latina women. The work is part of a larger longitudinal study designed to follow several hundred Latino children from pregnancy through adolescence to examine how genetic, hormonal and environmental factors affect risks for chronic diseases that disproportionately affect Latino communities.
“This is an initial step,” said Elissa Epel, PhD, professor of psychiatry and associate director of the Center for Health and Community at UCSF and co-senior author of the study. “Larger studies are needed to confirm this association, clarify the clinical significance of shorter telomeres at birth, and evaluate whether such differences persist into adulthood.”
Telomeres, often compared to the plastic tips on shoelaces, consist of repetitive DNA sequences at chromosome ends that prevent loss of important genetic information during cell division. While telomeres shorten naturally with age, accumulating evidence shows psychological and biological stress can accelerate this shortening process.
Recent research has documented substantial variation in telomere length among newborns. Those differences have been linked to genetic ancestry and in utero stresses such as maternal smoking, substance use or poor nutrition. Only a few studies have explored the health implications of shorter telomeres at birth. One report from earlier research found that shorter telomeres in very young children predicted increased arterial thickness by age eight, an early marker of vascular risk.
Key early finding highlights maternal education
In this segment of the ongoing study, researchers recruited expecting Latina mothers at prenatal clinics at Zuckerberg San Francisco General Hospital between 2012 and 2013, and collected cord blood samples from 54 infants at delivery. Telomere length was measured in newborn immune cells and analyzed against a range of parental, demographic and birth factors, including maternal education, ethnicity, prenatal body mass index (BMI), parental ages, infant sex, gestational age, birth weight and head circumference.
Only two factors showed a clear association with cord blood telomere length: infant sex and maternal education level. Male infants had telomeres about 5–6 percent shorter than female infants. Similarly, infants born to mothers who had not completed high school had telomeres approximately 5–6 percent shorter than those whose mothers had a high school diploma or higher.
“We already understand that a mother’s education strongly influences child health through biological, behavioral and social pathways,” said Epel. “These results provide a potential biological mechanism by which socioeconomic disparities could be transmitted across generations.”
The observation that male infants had shorter telomeres is noteworthy, said study co-author Rebecca Olveda, a UCSF medical student. “This raises questions about whether some of the sex differences observed in adult health and mortality risk begin with biological differences present at birth.”
This sex-related finding differs from prior reports that found no significant difference in newborn telomere length by sex. The authors suggest that studying a relatively genetically homogenous group—women of Mexican and Central American origin—may have made it easier to detect associations that larger, more diverse studies might miss, because varied genetics can obscure certain risk factors.
As research continues, the authors hope these early findings will inform efforts to disrupt cycles of poverty and chronic disease, especially within immigrant communities.
“That maternal education appears to affect cellular markers while the fetus is still in utero highlights the importance of access to education and support for at-risk families,” Wojcicki said. “While expanding quality preschool is vital, our results suggest resources should also reach mothers and families earlier, even before birth.”
Additional co-authors include Mel Heyman, MD, and Deena Elwan from the UCSF Department of Pediatrics, and Jue Lin, PhD, and Elizabeth Blackburn, PhD, from the UCSF Department of Biochemistry and Biophysics.
Funding: The study received major funding from the National Institutes of Health. The authors report no competing financial interests.
Source: Nicholas Weiler – UCSF
Image Source: The image is in the public domain
Original Research: Abstract for “Cord blood telomere length in Latino infants: relation with maternal education and infant sex” by J. M. Wojcicki, R. Olveda, M. B. Heyman, D. Elwan, J. Lin, E. Blackburn and E. Epel in Journal of Perinatology. Published online December 3, 2015. doi:10.1038/jp.2015.178
Abstract
Cord blood telomere length in Latino infants: relation with maternal education and infant sex
Objective:
Telomere length (TL) influences early disease risk and lifelong health. Few studies have examined factors determining TL at birth.
Study Design:
This study examined associations between cord blood TL and parental and birth characteristics that reflect exposure to stress or indicate healthy intrauterine conditions in Latino infants. Associations significant in bivariate analysis were tested in multivariate regression models to identify independent predictors of shorter TL at birth.
Results:
Among 54 infants, two independent predictors emerged. Female infants had longer telomeres by approximately 350 base pairs compared with males (adjusted β for male gender = −369.57; 95% CI −718.21 to −20.92; P = 0.02). Higher maternal education — defined as a high school diploma or greater — was associated with longer telomeres by roughly 500 base pairs (adjusted β for high-school diploma or greater = 505.68; 95% CI 151.69 to 859.68; P < 0.01). Larger head circumference showed a trend toward association with longer telomeres (adjusted β = 7.33; 95% CI −0.52 to 15.18; P = 0.07). After excluding infants exposed to high oxidative stress during pregnancy (including maternal hypertension, preeclampsia, gestational diabetes, low birth weight, or preterm birth; n = 7), increasing birth weight percentile was associated with longer telomeres (adjusted β = 8.04; 95% CI 0.07 to 16.00; P = 0.048).
Conclusion:
Shorter telomere length at birth is associated with male sex, lower maternal education (less than a high school degree), and trends toward lower birth weight and smaller head circumference. Given the role of telomere length in predicting health outcomes, these findings add to the evidence on early-life determinants of telomere biology.