Effects of vertical and horizontal social capital on oral health

Objectives:

Social capital is an increasingly important concept in public health research. Few studies have distinguished between the effects of different forms of social capital on health. Differences between vertical and horizontal social capital on health have not been explored. This study examined the effects of these different forms of social capital on oral health.

Methods:

The present analysis was based on the Aichi Gerontological Evaluation Study (AGES) Project data. Cross-sectional data were obtained from non-institutionalized elderly aged 65 years or older. Information on social capital, numbers of remaining teeth, oral health behavior, smoking status, physical and mental health and socioeconomic status were obtained by self administered postal questionnaire. We defined vertical social capital as participating in groups which forced hierarchical relations and horizontal social capital as participating in groups of equals. A multilevel logistic regression analysis was conducted to asses the association between vertical and horizontal social capital and self-reported number of remaining teeth with adjustment for individual and community level covariates.

Results:

Complete data were available for 5,560 (48.5%) elderly from 25 districts. Mean age of the subjects was 72.9±6.0. Univariate analysis showed significant beneficial associations between vertical and horizontal social capital and numbers of remaining teeth (odds ratio: OR (95% Confidence Interval) =0.87 (0.77-0.97) and OR=0.56 (0.50-0.63) respectively). After adjusting for individual covariates and community level income, community level horizontal social capital showed beneficial effects on teeth (OR=0.81 (0.68-0.97)). Individual level horizontal social capital also showed beneficial effects on teeth (OR=0.79 (0.69-0.90)). Community and individual level vertical social capital did not show significant association (OR=0.91 (0.76-1.09) and OR=1.04 (0.91-1.19) respectively).

Conclusions:

These results suggest horizontal social capital, not vertical social capital, has beneficial effects on oral health. Public health policy needs to address these social determinants of oral health.

Acknowledgments

This study was supported by funding from the Ministry of Education, Culture, Sports, Science and Technology of Japan (the 21st Century Center of Excellence Program).