BDNF serum concentrations in relation to A) age & gender, & B) depression (while controlling for age and gender) as measured by the GDS using general linear models. Concentrations did not show significant relationships with age (F(1,136) = 1.381, p = 0.242), gender (F(1,135)=1.517, p = 0.220), or depression as measured by the Geriatric Depression Scale (F(1, 99) = 1.237, p = 0.269).