This 2014 UK human study found:
“Type 2 diabetes is characterized by disruption of stress-related processes across multiple biological systems and increased exposure to life stress.”
HOWEVER, the stress effects weren’t conclusively shown to be either a cause or consequence of type 2 diabetes. Correlation wasn’t causation.
Looking around for clues as to what went wrong, I found this data sample of cortisol in a small table that comprised the total amount of information in the supplementary material:
“Geometric means, adjusted for education, marital status, BMI, smoking status, use of statins, and time of day.”
It’s hubris for the researchers to state that they improved data measurements by averaging them after adjusting for all of the above six factors.
Maybe the problem was elsewhere, maybe in the study design. Wherever the problems were, they guaranteed that the researchers would NEVER find cause and effect.
But maybe that’s the point?
There appeared to be other agendas that ensured studies like these failed to make a contribution toward advancing science. The researchers inevitably used buzzwords such as “allostatic load” and cited the need for further studies (money). Everybody was okay with that, including the reviewer, and everybody kept their safe jobs.
Such studies also had limiting effects on how we “do something” about real problems because the researchers wouldn’t produce findings that weren’t politically correct.
http://www.pnas.org/content/111/44/15693.full “Disruption of multisystem responses to stress in type 2 diabetes: Investigating the dynamics of allostatic load”