I found several questionable areas in this 2014 study that linked the effect of shorter telomere length in children to twin causes of a disadvantaged social environment and genetics. I’ll point out two such areas.
The first questionable area was that the researchers purposely measured telomere length using methods that couldn’t be directly compared with the telomere length measurements found in almost all other telomere studies. They offered up rationale after rationale, but the direct uncomparability with other studies remained.
The largest questionable item was the way the researchers arrived at the concluding sentence:
“We suggest that an individual’s genetic architecture moderates the magnitude and direction of the physiological response to exogenous stressors.”
The researchers deliberately skewed the experimental sampling of 40 9-year old boys. They then asserted that contrasting these two 20-person skewed samples represented something about stress and genetics in a larger population of children.
Researchers can’t validly do this in children’s brain studies, for a comparable example. There’s overwhelming evidence that long-term stress causes a child’s brain to develop differently than an unstressed child’s brain. The brains of children who were stressed for 9 years since birth (and possibly the months before birth), and the brains of unstressed children are two significantly and experimentally different populations. The researchers knew or should have known that this was the situation.
The researchers also split their samples according to maternal depression instead of establishing a control group!
This was an extremely poor choice. Maternal depression is an experimentally proven contributor to epigenetic changes that are detrimental to a developing fetus and onward through infancy and early childhood.
Of course, in general, “an individual’s genetic architecture moderates the magnitude and direction of the physiological response to exogenous stressors.” But the researchers didn’t do the work to find out whether it was the genetic architecture that the 9-year-olds were epigenetically changed into, or the genetic architecture they were conceived with, that stored the damage.
I presume that the additional work on “genetic architecture” wasn’t pursued by the researchers because those types of findings wouldn’t make the race-baiting headlines of the press coverage this study achieved.
Was this study published to further an agenda? If so, did this study also represent a failure of the peer review process? Were the researchers and reviewers even interested in advancing science?
http://www.pnas.org/content/111/16/5944.full “Social disadvantage, genetic sensitivity, and children’s telomere length”