Higher levels of HDL-C—known as the "good cholesterol"—have been shown to correlate with heightened risk for Alzheimer's disease. A new study might explain why. Once women reach the menopause transition, it's a matter of the quality, rather than quantity, of the total cholesterol carried by HDL particles circulating in a woman's bloodstream, and that quality declines over time, according to a research team. HDL particles vary in their size, composition and level of functioning. The team measured these features in the blood of 503 women from the Study of Women's Health Across the Nation (SWAN) HDL ancillary study. The researchers...