The size of your head could determine if you'll be diagnosed with dementia later in life. The study participants were taken from The Nun Study, which started in 1991 and includes 678 Catholic nuns from seven cities across the US. Scientists believe a larger head circumference, which also indicates a bigger brain, provides a 'cognitive reserve' of extra brain cells and connections. When brain cells become damaged with age, a larger brain is able to withstand it easier than a smaller brain. Prenatal factors such as a mother's nutrition, weight and history of substance abuse may influence head size, and exposure to environmental toxins like lead may stall growth.

Source: Daily Mail January 02, 2026 17:45 UTC