(Pocket-lint) - The European Commission (EC) has announced it will probe the proposed $2.1 billion takeover of Fitbit by Google. The EC is concerned about the use of Fitbit user data by Google after the transaction closes. 

In an effort for the deal to go through, Google recently announced it wouldn't use any fitness data to target ads - so it couldn't work out when you woke up or exercised, for example and target you with appropriate content. 

Google's previously said: “This deal is about devices, not data. We appreciate the opportunity to work with the European Commission on an approach that safeguards consumers’ expectations that Fitbit device data won’t be used for advertising". 

However, this obviously wasn't good enough for the anti-competitive arm of the EU, which has now launched an in-depth investigation after a preliminary inquiry. 

The Commission's statement says that it is "concerned that the proposed transaction would further entrench Google's market position in the online advertising markets by increasing the already vast amount of data that Google could use for personalisation of the ads it serves and displays."

Executive vice-president Margrethe Vestager, responsible for competition policy, at the EC, said of the move: "The use of wearable devices by European consumers is expected to grow significantly in the coming years. This will go hand in hand with the exponential growth of data generated through these devices. This data provides key insights about the life and the health situation of the users of these devices.

"Our investigation aims to ensure that control by Google over data collected through wearable devices as a result of the transaction does not distort competition."

Writing by Dan Grabham.