Longevity and Down's Syndrome

In 1992 Dr V P Prasher, Dept of Psychiatry, Queen Elizabeth Psychiatric Hospital, Birmingham, reported as follows: (extract from letter in unidentified journal)

"The average life expectancy of individuals with Down's syndrome has increased from an estimated 9 years in 1929, to 12-15 years in 1947, and 18,3 years in 1961. (Oliver and Holland 1986). Of liveborn Down's syndrome individuals, 44% will survive to the age of 60 years and 13.8% 68 years respectively, compared with 86.4% and 78.4% for the general population (Baird and Sadovnik. 1988). Between the years 1990 and 2010 the number of those with Down's syndrome over the age of 40 years is expected to increase by 75%, but the number with Down's syndrome over 50 years will rise by 200% (Steffalaar and Evanhuis. 1989)

"Virtually all those with Down's syndrome over the age of 40 years have neuropathological changes changes of Alzheimer disease (Mann 1988). However, clinical presentation of dementia is observed in only 36% over the age of 35 years (Lai and Williams 1989)."

He goes on to say ... "I know of one 72-year old man with Down's syndrome who shows no clinical evidence of dementia, and one 71-year old woman with Down's syndrome who has a moderate degree of dementia."

Baird PA, Sadovnik AD. (1988) Life expectancy in Down syndrome adults. Lancet. 1354-1356
Lai F, Williams RS (1989) A prospective study of Alzheimer disease in Down syndrome. Arch.Neurol. 46 849-853
Mann DMA (1988) The pathological association between Down syndrome in Alzheimer disease. Mechanisms of ageing and development $£ 99-136
Oliver C, Holland AJ (1986) Down's syndrome and Alzheimer disease: a review Psychological medicine 16 307-322
Steffelaar JW, Evenhuis HM (1989) Life expectancy, Down syndrome, and dementia Lancet I 492-493