Daily health headlines: New study explores link between obesity and colon cancer, questions about the benefits of vitamin D, and more top stories. Source

A Pennsylvania man is expected to make a full recovery after a chainsaw got stuck in his neck. KDKA’s Lynn Hayes Freeland reports. Source

A review of 50 years of research suggests the benefits of mammograms have been overstated, and the risks understated. Norah O’Donnell reports. Source

General Motors CEO Mary Barra repeatedly apologized to families whose loved ones had been killed or injured in crashes related to a faulty ignition switch. She tried to distance herself from the actions of previous management, which she blamed for a culture centered on cost and lack of communication between departments. Jeff Glor reports. Source

A ribbon-cutting ceremony at Walter Reed National Military Center in Bethesda, Md., marked the grand opening of a state-of-the-art Warrior and Family Center, a facility offering recreation and relaxation for active duty serviced members, wounded warriors, their families and their caregivers. Source

Measles outbreaks in New York City and Orange County, Calif., are raising concerns about a disease that had been virtually eliminated in the United States. CBS News chief medical correspondent Dr. Jon LaPook explains why it’s spreading and how to protect your family. Source

Before open enrollment closed at midnight Monday night, 7.1 million signed up for private insurance coverage via the Affordable Care Act marketplaces, President Obama announced. Source

All new: A lover is shot dead – will cell phone video clear or convict? Troy Roberts reports Saturday, April 5 at 10 p.m. ET/PT on CBS. Source

Researchers at Harvard Medical School and Brigham and Women’s Hospital looked at decades of studies on mammography and found the benefits are often overestimated and the harms underestimated. Danielle Nottingham reports on the newest data in the ongoing debate. Source

Flash Points: CBS News Homeland Security Correspondent Bob Orr and CBS News Senior National Security Analyst Juan Zarate discuss a still-classified report from the Senate Intelligence Committee that allegedly shows the CIA for years misled Congress about its now-defunct detention interrogation program. Source