People with greater lean muscle mass in middle age had reduced incidence of heart attacks and stroke. Those with the most muscle volume were 81% less likely to have a heart attack or stroke.

Retinal imaging is showing promise as a non-invasive method for early detection of Alzheimer's disease. The imaging characterizes light scatter changes in the retina and correlated with memory scores.

Supercentenarians (people over 110 years old) have an excess amount of cytotoxic CD4 T-cells, immune cells that can kill other cells. This likely increases their immunity to diseases and infections.

Circadian rhythm disruption plus chronic stress can lead to metabolic diseases like obesity and type 2 diabetes. Shift work, jet lag, or repeated inadequate sleep can disrupt the hormones associated with circadian rhythm.