According to a study done over 12 to 14 years in the U.S. and summarized in a BBC article, smoking in mid-life increases one's chances of developing dementia. High blood pressure and diabetes also significantly increases one's chances of developing dementia. Similarly, another study done in the U.S. and summarized in a Reuters article determined that high cholesterol in study participants at ages 40 to 45 greatly increased those people's chances of developing Alzheimer's Disease or vascular dementia within 30 years. Researchers pointed out that changing behaviors and addressing risk factors, to help keep a healthy heart, seem to be important for people's brain health through their lives.