Health Disparities
The association between total social exposure and incident multimorbidity Ingrid Giesinger* Ingrid Giesinger Emmalin Buajitti Arjumand Siddiqi Peter Smith Rahul G. Krishnan Laura Rosella
Background
The social determinants of health are associated with multiple chronic diseases including multimorbidity, the co-occurrence of two or more conditions. There is a paucity of literature that examines the combined influence of multiple social determinants within an individual i.e., the totality of social exposures. Using comprehensive linked population-representative data, we aimed to evaluate the effect of the totality of social exposures on the incidence of multimorbidity in Ontario, Canada.
Methods
Social exposures were obtained from Ontario respondents aged 18 to 74 to the Canadian Community Health Survey between 2000 to 2011 (females n=56,656; males n=48,611). Totality of social exposure (TSE) was generated through additive and weighted approaches. Additive TSE was generated by summing 12 binary measures of social exposure. Weighted TSE included 15 binary measures of social exposure summed within 5 equally weighted domains (community and social context, material circumstances, economic stability, education and population group). Both additive and weighted TSE measures were categorized into four groups reflecting the spectrum of social disadvantage.
Incident multimorbidity was identified through data linkage to healthcare data (1992 to 2021) using validated algorithms for congestive heart failure, chronic obstructive pulmonary disease, diabetes, lung cancer, myocardial infarction, and stroke. The cumulative incidence function of age to multimorbidity was calculated by each TSE measure. The association between TSE and age to multimorbidity was estimated using cause-specific Cox proportional hazards models. All analyses were sex-stratified.
Results
Totality of social exposure was associated with risk of multimorbidity in both additive and weighted models with a strong social gradient (Figure 1). Those experiencing the most social disadvantage had an over 2-fold increase in the risk of multimorbidity, compared to those with the least social disadvantage (Weighted TSE: AHR females, 2.75; 95%CI 2.73, 2.77; AHR males, 2.23; 95%CI 2.21,2.24).
Conclusions
Our findings highlight the importance of considering the cumulative effect of multiple social determinants of health on multimorbidity.
