There is one study in older adults titled: Association Between Aspects of Oral Health–Related Quality of Life and Body Mass Index in Community-Dwelling Older Adults. it was published in Journal of American Geriatrics society, 2007.
PMID: 17727644
it has assessed the association between multiple ordinals of obesity and oral health related quality of life.
Dear Shahrukh, The WHO's Study on global AGEing and adult health (SAGE) Wave 1 has all the data you would need to look at: general oral health, loss of all teeth, self-reported and measured height and weight, and the WHOQOL instrument. These data are available for China, Ghana, India, Mexico, Russia and South Africa. The Ghanaian team has recently submitted an analysis of QoL and edentulism, the manuscript is under review.
Otherwise, these colleagues have published on edentulism:
yes, I have several presentations I could share with you. I would recommend that you expand your focus and start looking at insulin resistance index as it relates to obesity - there is a paper already available on that on this web site or in Google Scholar