IGF1 and major depressive disorder: A further transverse study has also reported an association between free IGF-I, IGFBP3, and cognitive impairment among community-living elderly subjects, after adjusting for numerous potential confounders (age, sex, education, cerebrovascular disease, ischemic heart disease, congestive heart failure, hypertension, diabetes, depression, Parkinson’s disease, thyroid disease, smoking status, alcohol abuse, BMI, and number of medications) (Landi et al. 2007).