The study finds higher caffeine intake in women over 65 is associated with reduced odds of dementia. MILWAUKEE — A new study suggests a significant relationship between caffeine and dementia prevention, though it stops short of establishing cause and effect. The study, published in The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, found higher caffeine intake in women age 65 and older was associated with reduced odds of developing dementia or cognitive impairment. Among the 6,467 women in the study, self-reported caffeine consumption of more than 261 milligrams of caffeine was associated with a 36 percent reduction in the risk of dementia over 10 years of follow-up.