Today's personal project was to review some articles & abstracts in a (peer reviewed) medical journal regarding sourdough (with special interest in celiac disease as well as glycemic index & response). 

I'm sharing the titles & links, as I know there have been other people who had similar curiosities. 

(All articles & abstracts were found at:  PubMed.gov, US National Library of Medicine National Institutes of Health.)

Articles/Abstracts Regarding Sourdough & Celiac Disease:

Title:  Sourdough Fermentation of Wheat Flour does not Prevent the Interaction of Transglutaminase 2 with α2-Gliadin or Gluten
Conclusions (Paragraph 5):  [...] lactic fermentation of wheat flour does not sufficiently prevent TG2 interaction with gluten or decrease available TG2 binding sites on α2-gliadin, compared to unfermented flour. Prolonged fermentation times with L. plantarum (24 h) even increased available TG2 binding sites on α2-gliadin, indicating that lactic fermentation may not be an appropriate method for making celiac safe products.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425136/
2015

Title:  Gluten-free sourdough wheat baked goods appear safe for young celiac patients: a pilot study
Conclusions:  This study showed that a wheat flour-fermented product, having gluten completely degraded, is not toxic for patients with CD. Nevertheless, these foods should not be recommended for patients with celiac disease until a formal trial has been done.
https://www.ncbi.nlm.nih.gov/pubmed/20975578
2010

Title:  Sourdough lactobacilli and celiac disease
(Abstract) https://www.ncbi.nlm.nih.gov/pubmed/17008163
2007

Title:  Sourdough bread made from wheat and nontoxic flours and started with selected lactobacilli is tolerated in celiac sprue patients
Conclusion: These results showed that a bread biotechnology that uses selected lactobacilli, nontoxic flours, and a long fermentation time is a novel tool for decreasing the level of gluten intolerance in humans.
(abstract) https://www.ncbi.nlm.nih.gov/pubmed/14766592 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC348803/
2004
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Articles/Abstracts Regarding Sourdough and Glycemic Index/Glycemic Response:

Title:  Influence of sourdough on in vitro starch digestibility and predicted glycemic indices of gluten-free breads
(Abstract) https://www.ncbi.nlm.nih.gov/pubmed/24492829
2014

Title:  The Acute Impact of Ingestion of Sourdough and Whole-Grain Breads on Blood Glucose, Insulin, and Incretins in Overweight and Obese Men
Conclusion: [...] Despite the variation that these factors produced, the investigation demonstrated that sprouted grain bread attenuated the glycemic response when both portion size and available carbohydrate were controlled for and that, generally, the whole-grain breads did not have what could be interpreted as beneficial, metabolic responses.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317179/
2012

Title:  Sourdough-leavened bread improves postprandial glucose and insulin plasma levels in subjects with impaired glucose tolerance
(Abstract) https://www.ncbi.nlm.nih.gov/pubmed/18317680
Conclusion: [...] Thus, sour-dough bread may potentially be of benefit in subjects with impaired glucose metabolism.
2008

Title:  Use of sourdough lactobacilli and oat fibre to decrease the glycaemic index of white wheat bread
https://www.ncbi.nlm.nih.gov/pubmed/17697425
2007

Title:  The glycaemic index: importance of dietary fibre and other food properties
(Abstract) https://www.ncbi.nlm.nih.gov/pubmed/12749347
2003