Influence of social and psychological isolation and other factors on mortality of elderly people. Request for place in a home for elderly people or a service house / mortality / accessibility of house in respect to stairs / stairs indoors / confinement to bed / need for help with personal care / sight / hearing / difficulties with: using the stairs/ walking/ shopping/ preparing meals/ making the bed/ cleaning the house/ care for heating/ care for laundry/ putting out rubbish bags / assistance / visitors / loneliness / afraid of being alone / help by district nurse / help by neighbours. Background variables: basic characteristics/ residence/ housing situation/ household characteristics