Babies born to mothers who did not finish high school, possibly due to socioeconomic stress, are more likely to be born with decreased chromosome protection, according to research published in the Journal of Perinatology.
The ends of chromosomes are capped and protected by molecules called telomeres. Telomeres have been likened to the "plastic tips of shoelaces," and are repeating units of DNA at the ends of chromosomes.
They act as buffers against the loss of protein-coding DNA during cell division.
Shortened telomere length is a feature of cellular aging associated with shorter lifespan in adults, and increased risk for diabetes, obesity and cancer.
While telomere shortening happens naturally with aging, research indicates that psychological and biological stress speed up the process.
Telomeres may indicate future health risks
Previous studies have shown that the length of telomeres in newborns varies, possibly due to genetic ancestry and stress factors, such as the mother smoking, using drugs or lacking nutrition during pregnancy.
A team at the University of Sydney in Australia found that very young children with shorter telomeres were more likely to have increased arterial thickness, an early sign of vascular disease, by the time they were 8 years old.
The current study, led by Dr. Janet Wojcicki, associate professor of pediatrics at the University of California-San Francisco (UCSF), is part of an ongoing longitudinal study tracking several hundred Latino children from the womb to adolescence and beyond. The study is investigating the impact of genetic, hormonal and environmental factors on the children's risk of developing chronic diseases that are prevalent in the community.
The team recruited expectant Latina mothers from Zuckerberg San Francisco General Hospital's prenatal clinics from 2012-13 and took cord blood samples from 54 infants at birth.
Shorter telomeres in certain groups
Telomere length in the newborns' immune cells was analyzed. The researchers then looked at correlations with a range of health and sociodemographic factors, including maternal education level, ethnicity, prenatal body mass index (BMI), maternal and paternal age, the child's sex, gestational age, birth weight and head circumference.
Two factors correlated with cord blood telomere length: male babies' telomeres were 5-6% shorter than those of females; and infants whose mothers had not graduated from high school had telomeres 5-6% shorter than infants of mothers with diplomas.
This contrasts with previous studies that found no gender differences in telomere length. This may be because of the study's focus on genetically similar women of Mexican and Central American origin.
Telomere length linked to socioeconomic factors
Dr. Wojcicki believes this is the first study suggesting that a mother's education affects her child at cellular level from birth and that children whose mothers do not have the chance for a good education may be disadvantaged right from the start.
She says:
"The fact that we found an effect of maternal education on cellular health when infants are essentially still in the womb emphasizes the importance of access to education, particularly for at-risk families. Recently there's been so much focus on quality preschool education, which is wonderful, but if children are already disadvantaged at birth by their mother's education level, then we need to think about providing resources even earlier in the pipeline to mothers and families."
Senior coauthor, Elissa Epel PhD, says that while we know that a woman's educational level impacts her child's health for biological, behavioral and social reasons, these findings may indicate a mechanism for socioeconomic disparities to be passed on to the next generation.
Researchers say that limitations include the small sample size and restriction to a specific group of Latina women, and they recommend further research with more participants to determine the broader clinical significance of shorter telomeres at birth and understand whether this tracks through adulthood.
For coauthor Rebecca Olveda, the result raises the question of whether well-known gender differences in health and mortality risk in adulthood are influenced by biological differences already present at birth.
The authors hope the findings will contribute to breaking the cycle of poverty and chronic disease experienced by immigrant communities in the US.
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