Sometimes I write stuff here not because I know things, but rather, because I would like to know more, and I think the audience of this blog may help me find the material I need to become more knowledgeable on some topic. Having a blog is a privilege, in the sense that the one-to-many communication it establishes between the writer and the readers allows the owner to sometimes have access to the (all together vast) knowledge of his or her readers. Thanks to you, dear reader, to your comments, reactions, and suggestions expressed in the comments thread, I learn more on topics I do not have an expertise on. I cherish this one-to-many communcation means and I am grateful to you for it. 
Of course, in order to have access to one's readers' knowledge, one need first of all to be humble and expose one's ignorance. On this one count I claim I am as good as any and better than most. I never hide the fact that I am an ignorant on several topics, and I am not ashamed of it. That is a very good asset! As I tell my students often, "Ask questions! You will sound ignorant for five minutes, but if you don't you will stay ignorant for the rest of your life!"

So, today it just occurred to me to think, while I was taking a shower, at the possibility that the large amount of data that is available on the web, in research articles, in medical studies, and other sources, makes possible to construct very precise predictors for the chance of developing specific diseases. What I am thinking at is some personal tool - an app, if you want - that collects automatically data on your lifestyle, on what you eat, where you live, what exercise do you make, what air you breathe, and tons of other data, like your blood exams, genetic information from your genome mapping if available. Such an app might then use a multivariate analysis tool to produce a prediction of your chance of developing, e.g., diabetes or cancer. It could advise you to perform specific medical tests, or even automatically decide to test your blood or other bodily functions (in case it is a wearable device).

Is anything like this already available, or in development ? I can't help thinking that in the future such a tool, made more powerful and precise, will become universally available, or even mandatory. An advanced instrument might not only use data about you, but also employ data sources in the environment, automatically connecting to sensors that report temperature and humidity readings, particulate composition in the air, and data from devices of other owners around you. In the future, epidemiology might be entirely controllable. What do you think ? I will be happy to get inputs from you on this topic, links to available material, etcetera.