Characterizing vulnerability to heat and heat illnesses among urban slum dwellers in Ahmedabad, India

India is expected to face increasingly frequent extreme weather events as a consequence of climate change. Extreme heat events may have particularly significant impact since summer temperatures are historically high. Little is known regarding factors that may drive population vulnerability to extreme heat as well as strategies for minimizing heat exposure and susceptibility in this rapidly developing nation. To facilitate public health preparedness for extreme heat, an assessment of factors affecting vulnerability was conducted in summer of 2011 in Ahmedabad, Gujarat, India, a city where seasonal highs have reached 115°F. The study focused on factors that affect heat exposure, susceptibility to heat related illness, and adaptive capacity, all of which are known to feed into vulnerability to heat. Indicators of these factors were identified through literature review and expert opinion, and assessed through a cross-sectional household survey. The survey used randomized cluster-based sampling to identify target households in twelve urban slum populations in Ahmedabad. This population was presumed by local public health authorities to be particularly vulnerable and have greater susceptibility and less resilience to extreme heat exposure. Associations between heat-related morbidity and individual and household demographics, medical history, access to weather warnings and health information, and social connectedness were determined. Multivariate logistic regression was performed with Generalized Estimating Equations to account for clustering effects to test the various associations between outcomes and covariates. Results indicated age, income, preexisting conditions, work location, drinking water sources, access to doctors and information, and social connectedness influence the occurrence of heat-related symptoms and illnesses among slum dwellers. These findings suggest several potentially worthwhile interventions including: working with community health workers to disseminate information and prevent heat illnesses as well as delivering information through television campaigns. Future research studies might include focus groups and evaluations of currently applied adaptive behaviors and future interventions.