IGF1 and periodontal disorder: Higher levels of IGFBP-2 were found in GCF at disease sites.42 Smoking, one of the major risk factors of periodontal disease, did not seem to be a major confounder of the reported clinical associations between IGF-1, IGFBP-3, or IGF-1/IGFBP-3 ratios and specific disease entities when gender and age were matched.36