Curbs and Caveats

In a flurry of directives, studies and opinions, medical authorities last week confirmed, denied or disputed dangers involving personal health in a variety of areas:

ANTIDIABETICS: FDA WARNING. The

Food and Drug Administration acted in a long-simmering controversy about the safety of oral antidiabetic drugs. The agency announced that these drugs, now prescribed for 1.5 million adult diabetic patients annually, must now carry a strong warning that users face increased risk of dying of heart disease. The FDA's action stemmed from a five-year series of large-scale studies that found that the death rate from heart disease was twice as high among patients on oral antidi-abetics as it was among patients whose conditions were being controlled by injectable insulin. Still, the debate about the drugs continues. Many physicians, among them several leading specialists on diabetes, challenge both the methods and conclusions of the studies, the most recent of which was published in the American Medical Association's Journal earlier this year.

One of those unconvinced by the published research is the A.M.A.'s executive vice president, James Sammons. Last February he sent a letter to state and county medical societies expressing his reservations about the study and urging doctors to use whatever medicines they felt were proper in treating diabetic patients. Against the advice of the A.M.A.'s general counsel, Sammons also allowed the Upjohn Co., the largest manufacturer of oral antidiabetics, to distribute copies of the letter to its salesmen. Some doctors felt this violated the spirit if not the letter of A.M.A. rules against product endorsements by physicians, but Sammons is unpersuaded on this issue too. "I would do it again," he said last week.

AEROSOL: A DEFENSE. Over the past two years, several scientists have become concerned about fluorocarbon propellants, used in aerosol sprays, drifting up through the stratosphere. In their doomsday scenario, these fluorocarbons break down to form chlorine atoms that gradually destroy the ozone shield protecting the earth from an overdose of the sun's ultraviolet rays; this, in turn, increases the risk that humans down on earth will develop skin cancer.

Last week the scenario was dismissed as "utter nonsense" by Richard Scorer, a leading British meteorologist. Scorer argued that the theory was based on an extremely simplified computer model that gives an inaccurate picture of the complicated chemical and meteorological processes of the upper atmosphere. He also maintained that most of the chlorine entering the atmosphere comes from such natural causes as volcanic eruptions and the release of methyl chloride from certain seaweeds. Scorer's views put him in opposition to many scientists, who consider the atmosphere a fragile entity. Scorer believes the atmosphere is "the most robust and dynamic element in the environment." And, he adds, "man's activities have very little impact on it."

MARIJUANA: NEW STUDY. Most U.S. researchers insist that marijuana use poses serious health hazards and have linked the drug with chromosomal and immunological defects, lung damage and interference with speech and memory. But a team of anthropologists from the New York City-based Research Institute for the Study of Man, which spent two years studying marijuana users on the Caribbean island of Jamaica, concluded that although the drug causes inefficiency on the job, even among farm laborers, it does no apparent physical harm. The researchers noted that Jamaicans who smoke ganja, as the powerful, locally grown marijuana is called, take in ten to 25 times as much of the drug's active ingredient as American pot puffers.

In the course of week-long in-hospital examinations of 30 Jamaicans who routinely smoke an average of seven marijuana cigarettes a day, doctors found that they were more likely than nonsmokers to exhibit hypoxia, a decrease of oxygen carried by the blood to the organs and tissues. But their heart rates, liver and lung functioning, coordination and memory were not significantly different from that of nonusers. Critics of the new study feel it did not look long or closely enough to find the genetic and other defects previously shown to be associated with marijuana; they still believe the drug is harmful.

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