Another study into mobile health reveals that insomnia may be caused by using a mobile phone late in the evening. 

A sample size of 71 would be ok for an A-level project but not one that tries to offer the holy grail of news by finding a real link to health, or lack of it.  There are many other stresses in life and receiving a call at snooze time just adds to the load.  

Calls between 10pm and 9am used to be bad news, but with mobile email interfering with down time there is little time to rest for any of us.