The relationship of congenital heart disease and respiratory infection mortality in patients with Down's syndrome.

Is respiratory infection mortality in Down's syndrome (DS) individuals due mainly to their congenital heart disease (CHD) or to other factors which subject most mentally retarded persons to risk? Detailed clinical and autopsy records of 137 institutionalized DS patients and 480 non-DS controls over 31 years yielded 42 DS subjects and 13 non-DS controls with congenital heart disease. These were compared to 20 DS patients and 20 controls without CHD. The DS and non-DS patients were matched for age, sex and IQ. DS patients had more CHD; controls had more pulmonary oedema. In neither group was there association between heart disease and death from respiratory infection. Nor did pulmonary oedema contribute importantly to such deaths. Such mortality, however, was associated with young age, short institutionalization and bedridden status. We conclude that respiratory infection death in DS individuals is due not primarily to heart disease but to factors which lead to mortality in the general population of retarded people.