  Objective: Ubiquitous internet access is reshaping the way we live, but it is
accompanied by unprecedented challenges in preventing chronic diseases that are
usually planted by long exposure to unhealthy lifestyles. This paper proposes
leveraging online shopping behaviors as a proxy for personal lifestyle choices
to improve chronic disease prevention literacy, targeted for times when
e-commerce user experience has been assimilated into most people's everyday
lives.
  Methods: Longitudinal query logs and purchase records from 15 million online
shoppers were accessed, constructing a broad spectrum of lifestyle features
covering various product categories and buyer personas. Using the
lifestyle-related information preceding online shoppers' first purchases of
specific prescription drugs, we could determine associations between their past
lifestyle choices and whether they suffered from a particular chronic disease.
  Results: Novel lifestyle risk factors were discovered in two
exemplars--depression and type 2 diabetes, most of which showed reasonable
consistency with existing healthcare knowledge. Further, such empirical
findings could be adopted to locate online shoppers at higher risk of these
chronic diseases with decent accuracy [i.e., (area under the receiver operating
characteristic curve) AUC=0.68 for depression and AUC=0.70 for type 2
diabetes], closely matching the performance of screening surveys benchmarked
against medical diagnosis.
  Conclusions: Mining online shopping behaviors can point medical experts to a
series of lifestyle issues associated with chronic diseases that are less
explored to date. Hopefully, unobtrusive chronic disease surveillance via
e-commerce sites can grant consenting individuals a privilege to be connected
more readily with the medical profession and sophistication.
