NASHVILLE -- Calls for health insurance exchanges to strengthen their cybersecurity controls are falling on deaf ears, security experts told health insurers gathered at their trade group's conference last week. The experts said it is becoming increasingly difficult to prevent data breaches as the amount of vulnerable information housed at health plans and networks continues to grow. "We are very concerned at this point," Lee Barrett, executive director of the Electronic Healthcare Network Accreditation Commission, said at the conference hosted...