Changes in pro-inflammatory cytokine levels and late-life depression: A two year population based longitudinal study.

•A 2 year longitudinal study was conducted investigating cytokine levels and late-life depression.•Depression at baseline was associated with higher contemporaneous cytokine levels.•Incident depression was associated with increases in cytokine levels during follow-up.•Incident depression was not predicted by cytokine levels at baseline.•Depression may precede and lead inflammatory processes in late-life.•Inferences can only be tentative, and future studies measuring central inflammation are needed.