The sociology of health and illness requires a global approach of analysis because the influence of societal factors varies throughout the world. Diseases are examined and compared based on the traditional medicine, economics, religion, and culture that is specific to each region. For example, HIV/AIDS serves as a common basis of comparison among regions. While it is extremely problematic in certain areas, in others it has affected a relatively small percentage of the population. Sociological factors can help to explain why these discrepancies exist.