Ronald Bailey analyzes some research on illness and political freedom:
Thornhill and Fincher found that where disease prevalence has been historically high, cultures tend toward collectivist values such as ethnocentrism and conformity—because, they argue, these inward-looking cultural values inhibit the transmission of diseases. The pair examined prevalence data for 22 diseases, looking for correlations with various cultural values, including democratization, property rights, gender equality, and sexual liberalization. Where disease prevalence remains high, they found, autocracy reigns, property rights are weak, women have fewer rights, and sexual behavior is restricted.
The Dish 