[Role of the social support network which influences age of death and physical function of elderly people: study of trends in and outside of Japan and future problems].

Concerning associations between the social support network and physical health of the elderly, longitudinal studies have been conducted using various measurement indexes. The studies indicated that the support network influences on physical function and life expectancy. In this study we compared research papers from Japan and elsewhere that appeared after 1980, from the viewpoint of 1) social support effects, and 2) social network effects, to examine potential problems in the future. The main knowledge obtained was that the receipt of emotional support, wide network size, and participation in social activities reduced the risk of early death and decrease in physical function of elderly people. Sex differences were indicated, and in many cases, the effects were more remarkable in men than women. In addition the positive influence of receiving help from a support network, a major subject of conventional research, the effects of offering help to others and negative findings were also examined. It has been indicated that participation in volunteer groups and offer of support to other people can prevent decrease in physical function or early death. As negative effects, improper instrumental support rather disturbs the mental and physical independence of elderly people. As future issues, it is necessary to focus on both positive/negative and receipt/offer effects of support network, and to clarify how to provide example which best match the life of elderly people by comparing sexes and regions. It is also important to actually apply the knowledge gained from observational studies to prevent the elderly from becoming a condition requiring care, and to develop intervention studies which can increase the social contacts of elderly people at the same time as conducting health education and medical treatment.