Background:
This study addresses gaps in our understanding about the validity and utility of using salivary adiponectin to index serum adiponectin levels. Matched blood and saliva samples were collected on a single occasion from healthy adults (n=99; age 18-36 years, 53% male). Serum and saliva was assayed for adiponectin and inflammatory cytokines (IL-1β, IL-6, IL-8, TNFα), and saliva was also assayed for markers of blood contamination (transferrin), total protein (salivary flow rate) and matrix metalloproteinase-8 (MMP-8). We examined the extent to which salivary adiponectin was associated with serum adiponectin, and the influence of potential confounders on the serum-saliva correlation, including age, sex, body mass index, and markers of inflammation, oral health, salivary blood contamination, and flow rate. Findings revealed a modest serum-saliva association for adiponectin, and strong positive associations between salivary adiponectin and salivary levels of inflammatory cytokines, MMP-8, transferrin, and total protein. By contrast, salivary adiponectin was not related to serum levels of inflammatory activity. The magnitude of the serum-saliva association was strengthened when controlling for total protein in saliva, blood leakage into oral fluid, salivary inflammatory cytokines, and MMP-8. The pattern of findings extends our understanding of salivary adiponectin and its potential use as an index of circulating adiponectin levels.