Dr. Lee R. Mandel reviewed Kennedy's White House medical records as well as correspondence from his physicians and concluded Kennedy had the most complex medical history of any U.S. president with his medical conditions, back pain, medications and hormones.
"To all appearances, Kennedy was the picture of health and vitality. In actuality, he had the most complex health history of anyone to occupy the White House. In an era of less media scrutiny, he was able to conceal the true nature of his complex medical problems throughout his presidency," Mandel wrote in an article in Annals of Internal Medicine.
Unbeknownst to the public, Kennedy was diagnosed with Addison's disease -- in September 1947 -- a rare endocrine disorder in which the adrenal glands do not produce enough of the hormone cortisol. Later, when he was a senator, he was found to have hypothyroidism -- something not uncommon with those with Addison's disease.
During the 1960 campaign for the presidency, Kennedy's physician denied the Addison's diagnosis and deflected further probes with a carefully-worded statement to the media.
Kennedy's doctor, Dr. Janet Travell, said Kennedy did "not now nor has he ever had an ailment described classically as Addison's disease, which is a tuberculose [sic] destruction of the adrenal gland."
In fact, Addison's disease has an autoimmune cause in nearly 80 percent of cases and tuberculosis accounts for only 10 percent, the journal article said. However, this narrow definition of Addison disease was successful in deflecting further probes, the article said.
Today, with newly available evidence, researchers can plausibly conclude that Kennedy had a rare unifying autoimmune endocrine disorder called polyendocrine syndrome type II, or APS II, which is characterized by the coexistence of hypothyroidism and Addison's disease, among other conditions, the article said.
Francis Graham Lee, a professor of political science at Saint Joseph's University in Philadelphia, said despite Kennedy's medical problems, he conveyed an image of youth and vigor and that might be his lasting legacy,
"The assassination of President John F. Kennedy on Nov. 22, 1963, in Dallas, is one of the defining events of 20th century America. But although the assassination occurred 50 years ago, Kennedy's presidency "lives on in many of the choices the American populace has made in the voting booth for the office of the chief executive," Lee said.
Lee said Kennedy's lasting legacy for his and subsequent presidencies was "image" after a series of senior-citizen presidencies.
Kennedy's youthful victory paved the way for younger and less experienced candidates, such as Democrats Bill Clinton and Barack Obama, and Republican candidate George W. Bush, to run for and win the highest office.
"Kennedy's image still resonates," Lee added.