Growth factors in recurrent aphthous stomatitis

Background: Over 100 million Americans experience recurrent aphthous stomatitis (RAS) at some point in life. To develop better drugs for RAS, it is critical to identify its cause. We noted that peak age prevalence for RAS and certain growth factors coincide. Thus, we hypothesized that high levels of IGF-1 or related factors are the primary source of immune activation and impaired wound healing in RAS patients. In this study we determined if serum levels of IGF-1 (and IGF-1-related factors) are associated with RAS. Methods: We analyzed data from 1,480 NHANES III participants aged 20-40 who had surplus sera collected after an overnight fast. Participants who had used tobacco in the prior 5 days, had a history of diabetes or lupus, had cotinine levels 6 ng/ml or higher, or glycemia 110 mg/dl or higher were excluded. We compared levels of IGF-1, IGF-BP3, leptin and insulin in participants with a positive vs. negative history of RAS in the prior 12 months. For analyses we used logistic regression in SAS/SUDAAN to account for the complex sampling design. Results: The odds of a positive RAS history were 1.31 times higher for every 100 ng/ml increase in serum IGF-1. This association persisted after adjustment for age, race, medications, BMI, insulin, leptin, glycemia, and income (OR=1.30, 95% CI=1.06-1.60). Leptin, IGF-BP3 and insulin levels did not differ by RAS status. Conclusion: Participants with a positive RAS history had elevated IGF-1 levels compared to controls. Further studies are needed to determine the role of IGF-1 in RAS etiology.