Health apps are capturing increasing amounts of information about us. And it’s a lot more than medical history. We’re often asked to enter our names, address, real-time location, height, weight, date of birth, and other demographic information into the app.

A recent study raises some serious concerns about how all of that information is being used.

The way that a developer will use the information collected by the app is usually spelled out in a Privacy Policy. To get a better sense of how information use is being disclosed, researchers from the University of Cologne in Germany and Boston Childrens Hospital looked at the 300 most popular apps in iTunes and Google Play (600 apps total).

An impressive 70% of apps lacked a privacy policy; slightly more iOS apps had privacy apps than Android apps (38% vs. 23%, p<0.001). And of the apps that did have a privacy policy, nearly two thirds described the developer or topics unrelated to the app itself. For the privacy policies that were found, most were written at a very high reading level.

A limitation here is that the researchers didn’t look specifically at what types of information these apps are collecting. That said, most apps can collect at least some information about us – even if we don’t specifically enter more information. And we should be able to quickly assess how that information could be used.

The study indexed apps for evaluation in May 2013 so hopefully things have changed for the better since then. However, it’s an important reminder that a privacy policy – particularly for apps that we enter personal information into – is something that we should all be looking for.