Social networks have a substantial effect on health outcomes, particularly among older people. The Berkman et al. (Social Science and Medicine 2000) framework for explaining the association of social networks with health has formed the basis of research in this area over the last two decades. Most research focuses on measures of network size and the provision of social support by network members. Other dimensions included in the framework, such as network homogeneity, have been neglected. Homophily, the tendency to form network ties with others similar to oneself, is the basis of homogeneity. This study examines the effect on self-rated health (SRH) of homophily in the personal networks of Australians aged 50-90 years who participated in the 2010/2011 national survey of the Social Network and Ageing Project (SNAP). A novel Homophily Indicator was constructed based on up to seven socio-demographic characteristics of each respondent and their friends. Using binary logistic regression, the study found that homophily predicts SRH, net of other network characteristics (friend and family network sizes, density, friends’ number of friends, instrumental and emotional support, group activities, social restriction due to health) and sociodemographic variables (sex, age, education, living standard, ethnicity, partnership, retirement status). Homophily is positively associated with SRH, especially among people aged 50-64, persons in a relationship, and males. This is the first study, to our knowledge, to demonstrate the role of homophily in the health of older people and highlights the need for further research to understand the mechanisms involved.

Heather Booth is Professor of Demography and Director of Research in the School of Demography at the Australian National University.  Her research interests include demographic forecasting methods, longevity and the socio-demography of ageing. Heather is an Associate Investigator with the ARC Centre of Excellence in Population Ageing Research, an Associate Member of Nuffield College Oxford, and was Founding Editor of the Journal of Population Research.                               

Steffen Peters is a Research Assistant in  the School of Demography. He completed his master's degree in Sociology at the University of Rostck, and afterwards worked as a Research Assistant at the Chair of Empirical Social Research and Demography within the university.