WASHINGTON (AP) — Barack Obama's doctor said Thursday the presidential candidate was in excellent health at the time of his last checkup 16 months ago, but he has a family history of cancer and a big, obvious risk — a smoking habit that he's trying, again, to break.

In a one-page letter released by the campaign, Obama's longtime physician, Chicago internist Dr. David L. Scheiner, said he was summarizing 21 years of medical records, during which the Democrat suffered only minor problems such as upper respiratory infections.