Measurement and socio-demographic variation of social capital in a large population-based survey Tarja Nieminen Æ Tuija Martelin Æ Seppo Koskinen Æ Jussi Simpura Æ Erkki Alanen Æ Tommi Ha ¨rka ¨nen Æ Arpo Aromaa Received: 6 October 2006 / Accepted: 1 March 2007 / Published online: 4 April 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Objectives The main objective of this study was to describe the variation of individual social capital according to socio-demographic factors, and to develop a suitable way to measure social capital for this purpose. The similarity of socio-demographic var- iation between the genders was also assessed. Data and methods The study applied cross- sectional data from the national Finnish Health 2000 survey (n = 8,028) which represents the adult population, aged 30 years and over. Several variables indicating social capital were condensed to dimensions on the basis of factor analysis. Participants were categorized into tertiles in each dimension of social capital by means of factor scores. The multinomial logistic regression model was used to produce the adjusted prevalences for the dimensions of social capital according to socio-demographic categories (age, gender, education, living arrangements, income, and type of region). Results Three dimensions of social capital were distinguished: social support, social participation and networks, and trust and reci- procity. Age had an inverse association with social support as well as participation and networks, and a curvilinear association between age and trust and reciprocity, the oldest age groups showing the highest level of trust. Married persons and those in the highest T. Nieminen (&) Department of Health and Functional Capacity, National Public Health Institute (KTL), Mannerheimintie 166, 00300 Helsinki, Finland e-mail: tarja.nieminen@ktl.fi T. Martelin Á S. Koskinen Á T. Ha ¨rka ¨nen Á A. Aromaa Department of Health and Functional Capacity, National Public Health Institute (KTL), Helsinki, Finland J. Simpura Department of Social Statistics, Statistics Finland, Helsinki, Finland E. Alanen Department of Health and Functional Capacity, National Public Health Institute (KTL), Turku, Finland 123 Soc Indic Res (2008) 85:405–423 DOI 10.1007/s11205-007-9102-x