The association between the rural-urban continuum, social capital, and nutritional risk in community-dwelling older adults in Canada: an analysis of baseline data from the Canadian Longitudinal Study on Aging

Abstract

Background: High nutritional risk poses a significant threat to the health of older adults. Currently, most research in Canada focuses on nutritional risk in hospital or institutional settings, with little emphasis placed on community-dwelling older adults. Social capital, an increasingly popular concept in the social determinants of health literature, may offer key insights into the mechanisms by which the rural-urban continuum is associated with nutritional risk. Objectives: (1) Estimate the prevalence of high nutritional risk among community-dwelling older adults in Canada, and how it varies by sociodemographic characteristics; (2) Determine if there is an association between the rural-urban continuum and high nutritional risk among community- dwelling older adults in Canada; (3) Determine if social capital acts as a mediator and/or an effect modifier of the relationship between the rural-urban continuum and nutritional risk Methods: This study was a secondary analysis of baseline data from the Canadian Longitudinal Study on Aging (CLSA). The CLSA provided measures for nutritional risk [a modified version of the Seniors in the Community Risk Evaluation for Eating and Nutrition (SCREEN-II-AB) nutrition screening tool] and the rural-urban continuum (Statistics Canada’s Population Centre and Rural Area Classification). Composite measures of structural and cognitive social capital were created by mapping variables in the CLSA to the Adapted Social Capital Assessment Tool. Simple and multiple logistic regression were used to estimate crude and adjusted associations between the rural-urban continuum and nutritional risk, with adjustment for potential confounders including age, sex, ethnicity, income, education, years lived in the current community, household size, access to food outlets, and province. The role of social capital in explaining the relationship between the rural-urban continuum and nutritional risk was determined using two approaches: (i) assessing the presence of multiplicative interaction (via an interaction term in the logistic regression model) and additive interaction (relative excess risk due to interaction) and (ii) the product of coefficients technique to assess the presence of mediation. Results: The prevalence of high nutritional risk in community-dwelling older adults was 33.4%. Residents of an urban core had significantly increased odds of high nutritional risk relative to rural residents in both the crude and adjusted models, with an adjusted OR [99% CI] of 1.35 [1.10-1.64]. None of the other categories of the rural-urban continuum were significant in the multivariable model. There was no evidence to suggest that structural social capital acts as an effect modifier or as a mediator. In contrast, the relative indirect effect of urban core on nutritional risk via cognitive social capital was -0.07 (99% CI: [-0.12, -0.02]), providing evidence of mediation. Implications: In light of Canada’s rapidly aging population and the increased hospitalization costs associated with malnutrition, reducing and preventing high nutritional risk in community-dwelling older adults is a key public health priority. This project expanded the discussion of nutritional risk into the broader social determinants of health literature. Identifying the factors associated with nutritional risk is an essential step in developing effective interventions for this population.