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.

Insufficient sleep was linked to increased heart disease risk and quicker signs of biological aging. Those who slept less than 5 hours per night were twice as likely to have shortened telomeres.