Barbara Bush Cause of Death: What is Chronic Obstructive Pulmonary Disease?

Barbara Bush, former first lady, died Tuesday at her home in Texas at the age of 92.

"A former first lady of the United States of America and relentless proponent of family literacy, Barbara Pierce Bush passed away Tuesday, April 17, 2018, at the age of 92," read a statement from the office of former President George H.W. Bush.

Her son, and former President, George W. Bush also released a statement.

"My dear mother has passed on at age 92. Laura, Barbara, Jenna, and I are sad, but our souls are settled because we know hers was," he said. "Barbara Bush was a fabulous First Lady and a woman unlike any other who brought levity, love, and literacy to millions."

The man who defeated her husband George H.W. Bush in the 1992 presidential election, Bill Clinton, also released a joint statement with his wife Hillary.

Bill and Hillary Clinton statement on Barbara Bush recalls how close George HW and Bill Clinton had become during their post-presidencies.

— Jim Acosta (@Acosta) April 18, 2018

Barbara Bush had suffered from Chronic Obstructive Pulmonary Disease (COPD) and congestive heart failure before her death, according to CNN.

On Sunday, a spokesperson for the family said that she had been hospitalized several times and had opted to stop seeking medical treatment.

"Following a recent series of hospitalizations, and after consulting her family and doctors, Mrs. Bush, now age 92, has decided not to seek additional medical treatment and will instead focus on comfort care," the statement put out by the family's spokesperson, Jim McGrath, read.

COPD affects a person's lungs and makes it hard to breathe. Symptoms include "a cough that produces a lot of mucus, shortness of breath, especially with physical activity, wheezing and chest tightness," according to the U.S. National Library of Medicine. Symptoms typically become worse over time.

Congestive heart failure is a condition where a person's heart has trouble pumping blood, according to the Mayo Clinic. Barbara Bush also suffered from Grave's Disease, an autoimmune disorder that causes an overactive thyroid gland, according to the U.S. National Library of Medicine.

Barbara Bush had been in and out the hospital before her death, according to The New York Times. She and her husband were both hospitalized last year, missing the inauguration of President Donald Trump. Barbara Bush was hospitalized for bronchitis.

Barbara Bush married George H.W. Bush in 1945. Together they had six children including former President George W. Bush and former Florida Governor Jeb Bush.

While her husband was vice president to Ronald Reagan, she took up the cause of fighting illiteracy, a cause she continued as first lady. She founded the nonprofit Barbara Bush Foundation for Family Literacy in 1989.