Fifteen days before the election, serious gaps remain in the public’s knowledge about the health of the presidential and vice-presidential nominees. The limited information provided by the candidates is a striking departure from recent campaigns, in which many candidates and their doctors were more forthcoming.

In past elections, the decisions of some candidates for the nation’s top elected offices to withhold health information turned out to have a significant impact after the information came to light. This year, the health issue carries extraordinary significance because two of the four nominees have survived potentially fatal medical problems that could recur.

If elected, Senator John McCain of Arizona, 72, the Republican nominee, would be the oldest man to be sworn in to a first term as president and the first cancer survivor to win the office. The scars on his puffy left cheek are cosmetic reminders of the extensive surgery he underwent in 2000 to remove a malignant melanoma.

Last May, his campaign and his doctors released nearly 1,200 pages of medical information, far more than the three other nominees. But the documents were released in a restricted way that leaves questions, even confusion, about his cancer.

A critical question concerns inconsistencies in medical opinions about the severity of his melanoma; if the classification of his melanoma is more severe, it would increase the statistical likelihood of death from a recurrence of the cancer.

Senator Joseph R. Biden Jr. of Delaware, 65, the Democratic vice-presidential nominee, had emergency surgery in 1988 for an aneurysm in an artery in his brain and elective surgery for a second one. His campaign released 49 pages of medical records to The New York Times late last week showing that he was healthy, but the documents did not indicate whether he had had a test in recent years to detect any new aneurysm.

The two other nominees are younger and apparently in good health, but less is known about their medical history. Senator Barack Obama of Illinois, 47, the Democratic presidential nominee, released a one-page, undated letter from his personal physician in May stating that he was in “excellent” health. Late last week, his campaign released the results of standard laboratory tests and electrocardiograms from his checkups in June 2001, November 2004 and January 2007. The findings were normal.

Gov. Sarah Palin of Alaska, 44, Mr. McCain’s running mate, has released no medical information.

There may be no serious problems with the health of any of the nominees. But absent fuller disclosure, there is no way for the electorate to know.

The health of the four nominees is a matter of concern because in the past a number of candidates, and in some cases their doctors and aides, have distorted, kept secret or spoken about the facts only at the last minute when medical events forced the issue. Examples include Senator Thomas F. Eagleton (depression), Senator Paul E. Tsongas (cancer), Senator Bill Bradley (heart rhythm abnormality) and, as a vice-presidential nominee, Dick Cheney (heart disease).

I am a physician who has covered the health of presidential candidates for 36 years. Since 1980, The Times has made it a practice to question nominees for president and other high political offices and, with their permission, their doctors about their health.

The Times has requested such interviews with Mr. Obama since last spring and with Mr. McCain and his doctors since March 2007. None were granted. More recently, The Times sent letters to all four nominees requesting interviews about their health with them and their doctors. None agreed.

The candidates’ health has drawn little attention for most of this long campaign season despite the importance of the issue. But since Mr. McCain selected Ms. Palin as his running mate in August, questions about his health have intensified. In recent weeks, more than 2,700 physicians have signed a petition that ran as an advertisement demanding that Mr. McCain fully release his health records; the petition is sponsored by Brave New Films, the company led by Robert Greenwald, a Hollywood filmmaker who has contributed $2,250 to Democratic candidates and has made a number of anti-McCain videos. Beyond the advertisement, Mr. McCain’s health has become the subject of both speculation and distortion on the Internet and other media.

The following is a summary of the publicly known medical information about all four nominees and the outstanding questions about each.

John McCain

The scars on John McCain’s puffy left cheek are reminders of the extensive surgery he underwent in 2000 to remove a mmelanoma.

The scars on John McCain’s puffy left cheek are reminders of the extensive surgery he underwent in 2000 to remove a malignant melanoma.

Mr. McCain’s difficulty raising his arms and his sometimes awkward gait are remnants of severe, untreated injuries he suffered in Vietnam. Mr. McCain, a Navy pilot, broke both arms and his right knee when his jet was shot down over North Vietnam in 1967. He experienced additional wounds while being tortured during his five and a half years as a prisoner of war. Mr. McCain may eventually need joint replacements, according to his doctor at the Mayo Clinic in Scottsdale, Ariz.

Mr. McCain has released more details about his health than the other three nominees, though he has done so in a phased way and has apparently not agreed to any extensive interviews about his health. A handful of reporters were allowed to view his records during his bid for the 2000 Republican presidential nomination. Another group of reporters were permitted to see newer records last May. By not allowing reporters to interview him or his doctors extensively about his entire medical history, he has made it impossible to get a complete picture of his diagnoses and treatment.

In 1999, early in his first run for the presidency, Mr. McCain allowed a small number of reporters, including me, to review an estimated 1,500 pages of his medical records without photocopying or recording the information.

In doing so, Mr. McCain gave the public its broadest look at the psychological profile of a presidential candidate. He released psychological records about him that were amassed as part of a Navy project to gauge the health of former prisoners of war. Assessments were based on standard psychological tests and what Mr. McCain told his doctors after his release. The records mentioned that in 1968, about eight months after his capture and after some particularly brutal beatings from his North Vietnamese captors, Mr. McCain attempted suicide, trying to hang himself with his shirt.

The records and his doctors, whom I interviewed with the senator’s permission in 1999, said he had never been given a diagnosis of a mental health disorder or treated at the project’s center for a mental health disorder.

The records also showed that a surgeon removed a melanoma from Mr. McCain’s left shoulder in 1993. Melanomas can be a far more deadly form of skin cancer than the more common basal cell and other types.

In early August 2000, just as Mr. McCain’s rival George W. Bush was about to receive the Republican presidential nomination, Dr. John F. Eisold, the attending physician at the United States Capitol, detected two more melanomas, Mr. McCain’s second and third.

One on Mr. McCain’s left arm was determined to be the least risky type, in situ. But the one on his left temple was dangerous.

A few days after detection of the melanomas, Mr. McCain sought care for them at the Mayo Clinic in Scottsdale. Mr. McCain’s campaign said this year that the left-temple melanoma was 2.2 millimeters at its thickest part and graded as Stage IIA on a scale in which Stage IV is the worst. Stage II meant that the melanoma had not spread into the lymph nodes. The number of melanomas is less significant than the thickness measured in the pathology assessment of any one of them.

Mr. McCain underwent extensive surgery on his face and neck for the melanoma on Aug. 19, 2000. Surgeons removed more than 30 lymph nodes, and pathologists then determined that all of them were cancer free.

In March 2007, as Mr. McCain was making his second bid for the Republican nomination, The Times began asking his campaign for permission to speak with the senator and his doctors, citing the history of such interviews.

On May 6, 2008, Jill Hazelbaker, a McCain spokeswoman, denied the requests, writing in an e-mail message that The Times was “not at the top of the list” and including a link to a Times editorial that had criticized Mr. McCain for not disclosing health information and Senator Hillary Rodham Clinton of New York for not disclosing financial records.

On May 23, Mr. McCain allowed a small pool of journalists, including three doctor-reporters, though none from The Times, to spend three hours reviewing a newer set of his Mayo Clinic records. That set, 1,173 pages, included records from 2000 to 2008 but none of the records made available in 1999. Again, the campaign did not allow the journalists to photocopy any documents.

Mr. McCain’s Mayo Clinic doctors answered selected reporters’ questions by telephone, but only for 45 minutes instead of the scheduled two hours. The McCain campaign did not allow New York Times reporters to ask questions in the teleconference.

The clinic doctors said that Mr. McCain was in good health and that no medical reason precluded him from fulfilling all the duties of president.

The doctors said that a fourth melanoma they detected on the left side of his nose in 2002 was also in situ, the least dangerous type. All four melanomas that Mr. McCain experienced were primary, or new, and there was no evidence that any of them had spread, the doctors said.

However, the reporters’ summary cited a report dated Aug. 9, 2000, from two pathologists at the Armed Forces Institute of Pathology in Washington who examined a biopsy of the melanoma taken from Mr. McCain’s left temple a few days earlier.

The Armed Forces pathologists suggested that the left-temple melanoma had spread from another melanoma, known as a metastasis or satellite lesion. “The vertical orientation of this lesion,” the report said, “with only focal epidermal involvement above it is highly suggestive of a metastasis of malignant melanoma and may represent a satellite metastasis of S00-9572-A,” which is the “skin, left temple, lateral” biopsy.

The pool report was by nature unable to provide a complete portrait of Mr. McCain’s recent medical history. It left several questions, including about the number of biopsies and when they were done. On Aug. 18, 2000, Dr. John D. Eckstein, Mr. McCain’s personal physician at the Mayo Clinic in Scottsdale, noted in Mr. McCain’s records that there were two biopsies of the left temple. Dr. Eckstein’s note did not say where and when the biopsies were performed. The Armed Forces report cited one biopsy, so presumably a second was performed in Scottsdale. The Armed Forces pathologists said a melanoma had developed over a skin scar whose origin was unclear.

A skin lesion, not one of the four melanomas, had been removed from Mr. McCain’s left temple in 1996 and interpreted as being benign; some experts have speculated that it might have been misdiagnosed, and thus the origin of the 2000 melanoma.

The Armed Forces pathologists did not speak in the teleconference in May 2008, and questions raised by their report have remained unanswered. The selected reporters did not ask about that report, and the Mayo Clinic doctors did not discuss it. A complete Mayo pathology report was apparently not included in the pool summary.

In interviews, several melanoma experts questioned why the Mayo Clinic doctors had performed such extensive surgery, because the operation was usually reserved for treatment of Stage III melanoma, not Stage IIA.

On Aug. 18, 2000, the day before Mr. McCain’s operation, his surgeon, Dr. Michael L. Hinni, wrote in the records that he planned to do the extensive operation because of the size and location of Mr. McCain’s melanoma. In the teleconference in May 2008, Dr. Hinni explained that because the melanoma was two centimeters across he had to make “a 6-by-6-centimeter island of skin, a fairly sizable wound” to remove it.

If Mr. McCain’s 2000 left-temple melanoma was a metastasis, as the Armed Forces pathologists’ report suggested, it would be classified as Stage III. The reclassification would change his statistical odds for survival at 10 years from about 60 percent to 36 percent, according to a published study.

The greatest risk of recurrence of melanoma is in the first few years after detection. His age, his sex and the presence of the melanoma on his face increase the risk.

The fact that Mr. McCain has had no recurrence for eight years is in his favor. But cancer experts see the 10th anniversary as an important statistical benchmark, and that would not occur until 2010.

In May, his dermatologist at the Mayo Clinic, Dr. Suzanne M. Connolly, said in the teleconference that though there was no way to predict with certainty Mr. McCain’s chance of a recurrence, she judged it to be less than 10 percent. But melanoma is known to be quirkier than most cancers; doctors cite occasional cases in which melanomas come back after 15 or 20 years.

Melanomas can spread to various areas in the body, including the skin and any internal organ. In general, such spreading means the melanoma would not be curable. Treatment would depend in part on what organ or tissues are involved and could include additional surgery, chemotherapy, biologics, vaccines and radiation.

Many such treatments can be debilitating and impair an individual’s physical and mental stamina. If the patient was the president, the location of a recurrence and its treatment could raise the need to invoke the 25th Amendment, elevating the vice president to president, at least temporarily.

On the trail, Mr. McCain has played down concerns about his age by pointing to the vigor of his mother and her twin sister at age 96. Mr. McCain’s father died in 1981 at age 70 after a heart attack.

In the May teleconference, Dr. Eckstein said that he had not detected any memory deficits in Mr. McCain and that the senator had not reported any. Dr. Eckstein did not report whether Mr. McCain had taken any baseline cognitive tests.

Mr. McCain has kidney stones and takes a statin for high cholesterol but has no evidence of significant heart disease, his doctors said.

In making his medical information public, Mr. McCain released his confidentiality in the traditional patient-doctor relationship.

For its part, the Mayo Clinic says it agreed to yield control over all of Mr. McCain’s medical information to his campaign and to refer all questions to the campaign. Pool reporters inspected the records at a hotel near the clinic, which sent the records there under security. In the teleconference, the doctors answered questions by telephone at the clinic with no reporters present.

Dr. Eckstein, Mr. McCain’s doctor, said he understood that the campaign had released all the McCain records to the pool reporters. But a spokeswoman at the Mayo Clinic in Scottsdale, asked if the institution could verify that the campaign had released all the records to the reporters, said she did not know whether the doctors had checked to be sure.

Last week, The Times contacted the McCain campaign to fill in gaps in the medical records. Ms. Hazelbaker, the McCain spokeswoman, wrote in an e-mail message: “As you know, we disclosed over 1,200 pages of Senator McCain’s medical history to Dr. Altman’s colleagues in the press earlier this year. We also arranged a Mayo Clinic briefing with three of Senator McCain’s physicians that Dr. Altman listened to by phone. Additionally, we released a detailed document outlining his most recent physical and lab test results. It was an unprecedented level of disclosure, and Dr. Altman can look at the public document on our Web site if he wishes to do so. It was certainly more significant than the one-page doctor’s note Obama released, though I have little hope The Times will report it that way.”

 
Barack Obama

Barack Obama, who started smoking at least two decades ago, has had trouble quitting. Mr. Obama says he quit last year but has “bummed” cigarettes.

Barack Obama, who started smoking at least two decades ago, has had trouble quitting. Mr. Obama says he quit last year but has “bummed” cigarettes.

On May 29, six days after the McCain campaign’s disclosures about his recent health, Mr. Obama’s campaign released an undated, single-page letter from his doctor in Chicago attesting to Mr. Obama’s “excellent health.”

The six-paragraph letter from Dr. David L. Scheiner said Mr. Obama had no known medical problems that would affect his ability to serve as president. Until the release of test results last week, the letter was the only information that Mr. Obama had made public about his health.

Dr. Scheiner’s assessment was based on regularly examining Mr. Obama since March 23, 1987. Mr. Obama’s last checkup was on Jan. 15, 2007, a day before he created a presidential exploratory committee and more than a year before his campaign released the letter from Dr. Scheiner, a general internist who practices at the University of Chicago Hospitals and the Rush University Medical Center.

The letter was short, the Obama campaign said, because Mr. Obama had not had any serious health problems. The campaign declined to make Dr. Scheiner available for an interview.

Mr. Obama has had a notable medical problem: a difficulty in stopping smoking. It is not known how heavily he smoked. Dr. Scheiner wrote that Mr. Obama began smoking at least two decades ago and had made several efforts to stop. Mr. Obama has used Nicorette gum “with success,” Dr. Scheiner wrote, without defining success.

Nicorette, which contains smaller amounts of nicotine than cigarettes do, is a replacement therapy intended to ease the craving for nicotine and other withdrawal effects of cigarette smoking.

Dr. Scheiner did not say when Mr. Obama had started using Nicorette, how much he had used or for how long he had used it. Reporters have often observed him chewing it.

Mr. Obama said he quit smoking in 2007 when he began his presidential campaign. But he has “bummed” cigarettes since then, he has said.

Also, Dr. Scheiner did not provide a standard measure of smoking risk. It is known as pack years — the number of packs smoked a day multiplied by the number of years a person has smoked. The pack-year number is used to help determine a patient’s risk of developing lung cancer, heart disease and other tobacco-related ailments.

Information about Mr. Obama’s smoking is relevant because studies show that the risk of cancer and other tobacco-related serious diseases declines after an individual stops smoking, but not until then.

According to the newly released documents, in January 2007 Mr. Obama had a total cholesterol level of 173 (HDL 68 and LDL 96) and triglycerides of 44. Those levels were normal.

Sarah Palin

Nothing is known publicly about Sarah Palin’s medical history, aside from the birth of her child last April.

Nothing is known publicly about Sarah Palin’s medical history, aside from the birth of her child last April.

Nothing is known publicly about Ms. Palin’s medical history, aside from the much-discussed circumstances surrounding the birth of her fifth child last April. Ms. Palin has said that her water broke while she was at a conference in Dallas and that she flew to Anchorage, where she gave birth to her son Trig hours after landing.

Last week Maria Comella, a spokeswoman for Ms. Palin, said the governor declined to be interviewed or provide any health records.

Joseph R. Biden Jr.

Joseph R. Biden Jr. in 1988, after he had emergency surgery for an aneurysm in an artery in his brain.

Joseph R. Biden Jr. in 1988, after he had emergency surgery for an aneurysm in an artery in his brain.

In 1988, Mr. Biden was working out on a shoulder press weight machine in the Senate gym when a pain shot through his neck. On the train home to Wilmington, Del., the neck pain returned more severely. His head ached. The right side of his body went numb. A doctor later diagnosed a pinched nerve, and a pain clinic prescribed a neck brace.

Shortly thereafter, on a trip to Rochester, Mr. Biden was alone in his hotel room when he felt a sharp stab in the back of his neck and a lightning flash in his head. The rip of pain was like none he had ever experienced. Nothing Mr. Biden did, including curling up in the fetal position, relieved the pain. He lay unconscious on the floor for five hours, he wrote in his autobiography, “Promises to Keep” (Random House, 2007).

The next morning, he felt somewhat better and flew home. His wife, Jill, summoned from the school where she taught, immediately took him to a hospital. Doctors determined he had a berry-shaped bulge in an artery that was leaking blood into his brain. Such bulges, or aneurysms, can tear at any time. Ruptured aneurysms are fatal in about 50 percent of cases. Up to 20 percent of survivors remain severely disabled. A Roman Catholic priest gave Mr. Biden last rites.

After a harrowing ambulance trip to Walter Reed Army Medical Center in Washington, a team of neurosurgeons put a clip on the artery to stop the bleeding. While recuperating, he suffered a major complication: a blood clot lodged in his lung.

A few weeks later, surgeons operated on a second aneurysm on the opposite side of his brain. Though it had caused no symptoms, it still could have burst as the first one did.

Mr. Biden returned to the Senate after a seven-month absence.

Now, a question arises: Has Mr. Biden developed a new aneurysm over the last two decades that could burst?

Doctors, who long thought that berry aneurysms were a once-in-a-lifetime event, now generally believe that they can recur. About 5 percent or less of patients who have had a berry aneurysm develop new ones at the original site or elsewhere in the brain.

“Over the last two decades,” said Dr. Robert F. Spetzler of the Barrow Neurological Institute in Phoenix, “we have learned much more about aneurysms, and the fact is that when you have had one aneurysm, you are more likely to develop another one. Although the likelihood is very low, it does exist.”

Doctors’ views vary widely on what types of brain imaging tests to recommend to patients who have had a berry aneurysm and when to do them. Some conduct no tests. Others periodically conduct tests like magnetic resonance angiograms.

Mr. Biden has “recovered fully without continued effects” from the aneurysm, Dr. Eisold, the Capitol physician, said in a letter released by the campaign. Dr. Eisold, a specialist in internal medicine, has a longstanding policy not to talk to reporters about his patients, even with their permission.

The Obama-Biden campaign referred me to Dr. Matthew A. Parker, an internist in Washington, who reviewed Mr. Biden’s records and also spoke with Dr. Eisold about them. Dr. Parker said that Dr. Eisold told him that brain imaging tests were not needed now because Mr. Biden had done well for the 20 years after the aneurysm. “It is a nonissue,” Dr. Parker said Dr. Eisold told him.

Dr. Parker, who is associated with George Washington University Hospital and Sibley Memorial Hospital, said he had not treated or met with Mr. Biden and did not have a direct connection to the campaign. Federal Election Commission records show that Dr. Parker contributed the maximum, $2,300, to Mr. Obama’s presidential campaign on March 13, 2008.

The medical records released by the campaign contain a summary of Mr. Biden’s operation and hospital stay in 1988 but no notes from a neurologist or neurosurgeon since then. So it is not known whether Mr. Biden has had recent brain imaging scans or has been evaluated by a neurologist or neurosurgeon recently. Dr. Parker said he did not ask Dr. Eisold when a neurologist or neurosurgeon last examined Mr. Biden.

Four leading neurosurgeons interviewed separately in this country and Europe said that as a vice-presidential nominee, Mr. Biden should have had recent brain imaging studies to detect any new aneurysm, because if one is found he might face more neurosurgery and be out of work for weeks or longer.

“What would I do in this situation?” said Dr. Eugene S. Flamm, the chairman of the department of neurological surgery at Montefiore Medical Center in the Bronx. “I would say, get an M.R.A. and check. You can’t just play the statistics.”

Doctors caring for political leaders and other prominent people often face difficulty in ordering tests that might clarify a situation for such patients but that are not recommended for all patients.

Dr. Parker said, “Some people will say, well, given the high-profile nature of the situation, we should do the test to be sure.” But, he added, “that is not necessarily wise.”

Among the reasons is a desire to avoid anxiety among patients and because doctors may not know what to do about an equivocal finding.

Dr. Parker said that even when he “pressed Dr. Eisold on the very same thing, given the circumstances” with Mr. Biden, Dr. Eisold “was very definitive about” not doing brain scan tests now.

The question of an aneurysm aside, the documents show Mr. Biden to have relatively minor health problems, including chronic sinusitis and allergies. He has an enlarged prostate, but a biopsy showed no evidence of cancer. With the help of a statin, he has normal cholesterol levels: 173 (HDL 47 and LDL 98) and triglycerides of 133.

In Summary

All in all, the gaps and paucity of information leave the electorate with insufficient information to fully judge the health of the nominees. The information that has been released is a retreat from the approach that most campaigns took over the last 10 elections.

In an earlier time, there was a kind of gentlemen’s agreement between officials and the news media that permitted serious health conditions to be played down or kept secret.

Franklin D. Roosevelt was crippled by polio more than a decade before he became president and, by his fourth term, he had developed serious heart disease, but the public was largely shielded from the profound effects. And while much was made of John F. Kennedy’s bad back and the rocking chair that gave him relief, it was only in the years after his assassination that his case of Addison’s disease, a hormonal disorder, became widely known.

What might be called the modern era of disclosure arguably began in 1972, when Mr. Eagleton had to step down as the Democratic vice-presidential nominee because he had not informed his running mate, Senator George McGovern, of his history of depression.

In 1992, Mr. Tsongas, who was seeking the Democratic nomination for president, spoke to me to assure the public that he was free of non-Hodgkins lymphoma, after a bone marrow transplant in 1986. In interviews, his doctors at the Dana-Farber Cancer Institute backed his assertion that he was cancer free. But in fact the cancer had recurred, and Mr. Tsongas eventually withdrew from the race. He died two days before his first term would have ended.

Other candidates who made themselves and their doctors available include the elder George Bush, Bob Dole, Al Gore and John Kerry. A leading example of openness was Ronald Reagan, whose age, 69, had become an issue in the 1980 election. Mr. Reagan authorized his doctors to be interviewed. He also agreed to an interview himself, against the wishes of his aides, answering all my questions, including what would he do if he became senile as president.

“Resign,” he said.