Daniel Notterman from Penn State and his team have found that children who grew up in stressful situations had telomeres that were 40 percent shorter than those who did not. Telomeres are the nucleotide sequences at the ends of chromatids which protect information in the chromosome during replication. The results of the study were published today in the Proceedings of the National Academy of Sciences.

Notterman’s research used participants of Princeton’s Fragile Families and Child Wellbeing Study. The current paper examined 40 nine-year-old African-American boys. The children have been in that study since birth, giving Notterman’s team the unique opportunity to have full records of the boys’ family situation throughout their entire lives. 

Many factors were considered when determining what constitutes a “disadvantaged” household. A combination of household income, family stability, maternal education, maternal mental health, and the strictness of parenting were all used. DNA samples from each of the 40 boys were collected and analyzed and compared about their home environment.

The study found that the boys from the most disadvantaged households had shorter telomeres. The results also showed a relationship between the environment and telomere length due to genetic variants that affect how the powerful neurotransmitters serotonin and dopamine are regulated. Even those with the highest predisposition for genetic sensitivity were very much shown to be a product of their environments. The most sensitive individuals who lived in stressful circumstances had the shortest telomeres, while the most sensitive individuals who lived in nurturing environments had the longest. 

The participants of this study are now 15 years old and DNA samples have been taken once again to see how things have changed over the last 6 years. Though the sample size is admittedly small, the data fit the theory incredibly well. It is also important to note that although the correlation is incredibly strong, there is not yet enough information to definitively draw a causal relation. It is hoped that a similar study can be done with a larger sample size and also further investigate the individual genes involved.