Is senile dementia associated with down syndrome : a case-control study.

C. Berr (1), E. Borghi (2), M.O. Rethore (2), J. Lejeune (2), A. Alpérovitch (1).

Abstract Form, XI Scientific Meeting of international epidemiological association, 8-13 august 1987, Helsinki, Finland.


For many years, Down's syndrome (D.S) is known to be one of the best model of premature ageing of the whole organism particulary with brain lesions quite similar to those observed in senile dementia of Alzheimer's type (S.D.A.T.).

Some epidemiological studies have shown that relatives of S.D.A.T. exhibit an excess of both dementing illness and D.S. A possible relationship between those two diseases has been hypothesed. The aim of this study is to test wether there is an excess of senile dementia cases in D.S. relatives or some particular mortality trends in those families.

We conducted by interview of parents a case-control study in families of DS children with trisomy 21 diagnostic proved by a caryotype. A control group was constituted with families of children referred to the salve hospital for benign diseases.

We have currently recruited 132 families of DS children. We obtained reliable data on the medical history on 517 out of 528 grandparents and 764 out of 1056 great-grand parents. Investigation of senile dementia cases was restricted to those who had reached the age of 60 : 365 grandparents and 573 great-grandparents. A total of 25 probable senile dementia with progressive course was found (2.7 %) : 4 in grandparents (1.1 %), 21 in great-grandparents (3.7 %). However, out of 12 Parkinson disease observed in these sample (1.1 %), four cases were associated with dementia.

A total sample size of about 200 DS cases is expected. The proportion of senile dementia observed in these families will be compared to control families.