The study could identify no cause of the increased risk, the researchers said.

The study identified 51 new growth areas scattered across 35 states.

The study also identified key areas in which individuals may benefit from additional education and information.

The study didn't identify any likely companies by name, but it showed investors how to do so themselves.

Another recent study identified eight separate risk factors for death among women with heart failure.

The study identified two main problems under deregulation, the officials said.

The study identified a variety of reasons why doctors help their patients die.

The study identified 40 contributors who had given $100,000 or more to the parties.

Another 2011 study identified 632 chemicals used in natural gas operations.

Such studies cannot, therefore, identify the causes of change over time necessarily.