The purpose of this study was to resolve a critical gap in depression literature through assessment of the temporal relationship between depression and low LDL.
A systematic review and meta-analysis was conducted to investigate the overall cross-sectional association between serum LDL and depression. Inconsistent findings suggest that more work must be done to clarify the link between LDL and depression.
Next, Cox regression was used to explore the association between LDL and the subsequent onset of depressive symptoms within a subset of the Women’s Health Initiative cohort and evaluate the potential for effect modification by lipid-lowering medication use. This study provides evidence toward an association between low LDL and the subsequent onset of depressive symptoms, with increased risk confined to LDL below 100 mg/dL. Elevated risk was not associated with lipid-lowering medication use.
The final study examined the differences in the magnitude and direction of change in serum LDL levels among individuals experiencing new-onset depression, and examines the potential for physical activity, energy intake, and total body weight to mediate the depression-LDL relationship. This study provides no evidence of an association between depression and subsequent serum LDL changes.
Altogether, this data suggests that LDL that is below 100 mg/dL without the use of lipid-lowering medication may predispose individuals to a greater risk of depression, and also suggests that low LDL is not likely a state brought about by physiological or behavioral changes following the onset of depression.