The dynamics of the relationship between diabetes incidence and low income: Longitudinal results from Canada's National Population Health Survey

This paper sheds light on the dynamic relationship between people's experiences of low income and the development of type 2 diabetes (T2DM) by moving beyond the static perspective provided by cross-sectional studies to a long-term approach informed by longitudinal analyses. Methods: We analyzed data from the Canadian National Population Health Survey (NPHS) conducted by Statistics Canada from 1994 to 2007. The longitudinal sample is composed of 17,276 respondents (8046 males, 9230 females) 12 years of age or older. We further developed an algorithm to distinguish T2DM from other types of diabetes. Proportional hazard models with time-varying predictors were used to explore the dynamics of the relationship between low income and T2DM. Results: The results suggest that living in low income and experiencing persistent low income are significant precursors of developing T2DM. Being in low income in the previous cycle of T2DM onset was associated with 77% higher risk of T2DM (hazard ratio 1.77; 95% CI: 1.48-2.12). The association between low income and diabetes incidence remains significant after adjusting for age, sex, health behaviors, and psychological distress (hazard ratio 1.24: 95% CI: 1.02-1.52). Conclusion: This study contributes to the under-developed research examining longitudinally the relationship between socioeconomic status and diabetes incidence. Employing this long-term approach, this study calls attention to the primary effect of socioeconomic position on diabetes incidence that cannot be explained entirely by behavioral factors. Findings draw attention to the need to address the role played in T2DM by the inequitable distribution of the social determinants of health. Crown Copyright (C) 2012 Published by Elsevier Ireland Ltd. All rights reserved.