Definitely (down the road). And not just health-specific things. There's all kinds of data that can serve as a (proxy) signal for health. e.g. physical activity is correlated with weather: http://rd.springer.com/article/10.1186/1479-5868-3-21 and it's suggested that your diet can be affected by a bunch of different things: http://eab.sagepub.com/content/39/1/106.abstract