July 10, 2019

expert reaction to conference abstract looking at insulin nasal spray and cognitive function

An abstract, being presented at the Society for the Study of Ingestive Behaviour conference, reports that insulin delivered as a nasal spray can improve brain and cognitive function in adolescents with obesity.

Prof Masud Husain, Professor of Neurology & Cognitive Sciences, University of Oxford, said:

“I don’t think this is worth covering.  The results are very preliminary and the sample size far too small to make anything of this.”

Dr Vladimir Litvak, Senior Lecturer in Imaging Neuroscience, UCL, said:

“The key sentences in the Results section of the abstract are not very clear and I would not conclude from them that insulin improves cognitive performance, which is the key message of the press release.

“One thing they say is that there was a negative correlation between BMI and performance in two cognitive tasks and that there was no such correlation after insulin.  This is not equivalent to saying that the performance was significantly improved by insulin or that the effect size is clinically meaningful.  Normally, if there is a significant effect people would just say it and not formulate their main result in terms of presence or absence of some correlation.

“The next two sentences are even more confusing.  They say that for one of the areas of interest they tested there was an increase in connectivity but they do not say that this increase was correlated with behavioral improvement.  They then say that for other areas they tested there are no effects and also no correlation to improvement.  This second sentence would make more sense if there was a correlation for the first area, but they didn’t say that.

“So based on the abstract alone I would suggest to be cautious.  Perhaps the press release was based on their full results which had additional information.”

Prof Derek Hill, Professor of Medical Imaging Sciences, UCL, said:

“The authors of this research are investigating whether taking the drug insulin via a nasal spray can improve the functioning of the brain in overweight young people.  They report that the more overweight the young person, the worse they did on the memory tests prior to taking the insulin.  But that this difference disappeared after they took the inhaled insulin.  Furthermore the brain scanning results suggested an associated change in the brain’s ‘functional connectivity’.

“But the study is very small – only 11 individuals were studied.  As the authors themselves mention, the results must be considered extremely preliminary.  It is quite possible that, with so few people studied, this ‘positive’ result could have arisen by pure chance.  To have 95% confidence in these results using the memory tests and brain scanning methods, it is likely that 100 or more individuals would need to be studied rather than just 11.  And to better understand any link between insulin and brain function in overweight people, and whether there might be any possibility of using insulin as a treatment for obesity, there is a need to carry out larger, longer term research, to see how these brain functions change as the obesity evolves.”

Abstract title: ‘Effects of intranasal insulin on brain connectivity and cognition in overweight/obese adolescents’ by Tuki N Attuquayefio et al.

This is a conference abstract from the Society for the Study of Ingestive Behaviour conference, and was embargoed until 22:00 UK time on Tuesday 9 July 2019.

There is no paper as this is not published work.

Declared interests

Prof Masud Husain: “I don’t have any conflict of interest.”

Prof Derek Hill: “No conflict of interest.”

None others received.