Change in lipids before onset of dementia, coronary heart disease, and mortality: A 28‐year follow‐up Whitehall II prospective cohort study

INTRODUCTION The association of lipids with dementia remains a subject of debate. Using data from 7,672 participants of the Whitehall II prospective cohort study, we examined whether timing of exposure, length of follow‐up, or sex modifies this association. METHODS Twelve markers of lipid levels were measured from fasting blood and eight among them a further five times. We performed time‐to‐event as well as trajectory analyses. RESULTS No associations were observed in men; in women most lipids were associated with the risk of dementia, but only for events occurring after the first 20 years of follow‐up. Differences in lipid trajectories in men emerged only in the years immediately before diagnosis whereas in women total cholesterol (TC), LDL‐cholesterol (LDL‐C), non‐HDL‐cholesterol (non‐HDL‐C), TC/HDL‐C, and LDL‐C/HDL‐C were higher in midlife among dementia cases before declining progressively. DISCUSSION Abnormal lipid levels in midlife seem to be associated with a higher risk of dementia in women.