What causes disease?
For any "disease" or condition, you could start by considering interactions among environmental and social factors.
» Poor diet, resulting from food choices, "causes" nutritional deficiency or obesity in a population
» Is it "caused" by historical distribution of land use, including (in developing countries) during colonial times?
» Or by the regulatory environment, including crop subsidies, food inspections, etc.?
» What about the role of NGOs, IGOs, aid networks?
» What about infrastructure, such as food distribution networks, transportation, etc.?
» Is the status of women/girls a factor?
» What about mental health issues?
» What is the role of commercial activity?
» What about the healthcare and health insurance system?