WASHINGTON (AP) - Exposure to Agent Orange in Vietnam may lead to high blood pressure in some veterans, but the evidence is limited and only suggestive, the Institute of Medicine said Friday.

The IOM, an arm of the National Academy of Sciences, has been studying the effects of the herbicide Agent Orange on veterans since the early 1990s, and is issuing its seventh update.

Two recent studies of Vietnam veterans who handled Agent Orange and other defoliants indicated that these veterans have higher rates of high blood pressure, the report said.

Hypertension affects more than 70 million American adults and is a major risk factor for heart attack and stroke.

The new findings were consistent with other studies that looked at the health effects of herbicides. However, a new environmental study and an earlier study of workers in a herbicide manufacturing plant did not find evidence of an association between herbicide or dioxin exposure and increased high blood pressure.

Because of the inconsistent results the institute said the evidence is suggestive of, but insufficient to conclude with certainty, that exposure to the herbicide leads to high blood pressure.

The new update also said there is suggestive but limited evidence that AL amyloidosis is associated with herbicide exposure.

A rare condition that affects one person in 100,000, AL amyloidosis is characterized by the accumulation of protein deposits in and around organs.

The committee said AL amyloidosis shares many biological and pathological similarities with multiple myeloma and certain B-cell lymphomas, which have previously been found to be associated with exposure to herbicides.