The Contextual Effects of Violence and Poverty on Cardiometabolic Risk Biomarkers
Poverty and violence within cities frequently concentrate in the same places and evidence suggests these exposures have deleterious consequences on health. The 2007 homicide increase in both rich and poor Mexican municipalities and the available biomarkers in a public panel study offer a unique opportunity to test each contextual effect in isolation on an innovative health outcome. Using an ecological framework, the main hypothesis of the dissertation is that, in urban environments, exposure to higher levels of contextual violence works as a stressor that wears down the body by increasing the levels of cardiovascular risk. This effect was hypothesized to be independent from poverty but with significant interactions and with heterogeneous effects among subpopulations. Multilevel cross-sectional and longitudinal analyses were conducted treating the data as a natural experiment using the homicide rate increase as treatment. The outcomes were two indices and single biomarkers that reflect cardiovascular risk in three waves of data corresponding to the years 2002, 2006, and 2012. Results showed that three complementary statistical approaches provided evidence indicating that exposure to cumulative violence at the municipality level yielded higher cardiovascular risk when controlling for individual covariates like victimization and household expenditure. The significant threshold for homicide rates was 35 and the differences between exposed and unexposed municipalities was between 1.5% & 8.3%, while the threshold for changes in the homicide rates between 2006 and 2012 was 10, with an effect size of 7%. Poverty and violence were not correlated in Mexico during the homicide rate spike, so the effects were independent. Unexpectedly, they did not show interaction effects: affluent and violent municipalities were the most stressful contexts. These effects were higher in women, in individuals in the two lowest socioeconomic quintiles and had significant impact in cohorts younger than 40 years old. The dissertation expands the ecosocial approach by exploring independent effects that shape multiple stressful contexts. It demonstrates that violence is a public health concern in Mexico that has indirect effects in the whole population, which not only worsens the obesity epidemic, but also demands a new perspective on assessing the burden of violence on everyday life.