Dementia reduces life expectancy by about 2 years for those diagnosed at age 85, 3 to 4 years for those diagnosed at 80, and up to 13 years with a diagnosis at 65, researchers reported in a study published Jan. 8 in The BMJ.

The average life expectancy of people diagnosed with dementia ranges from 9 years at age 60 to 4.5 years at age 85 for women and from 6.5 to just over 2 years, respectively, in men, finds a systematic review of the latest evidence in The BMJ today.

Life expectancy after a dementia diagnosis varies significantly depending on factors including the age at which the diagnosis is given, a person's gender, and the type of dementia being diagnosed, the researchers found.