A nearly finished six-year University of Utah study does not show a dramatically high incidence of leukemia or thyroid disease in southern Utah in the 1950s and early 1960s.

But the principal investigator stresses that it's too early to tell if the study will find a link between the diseases and radiation exposure from open-air nuclear tests.Walter Stevens, interim dean of the U. School of Medicine, talked with reporters Thursday after an article about the study appeared in the Los Angeles Times.

In that article, Stevens said, "Any large-scale effect should be apparent by now . . . . In fact, I don't see a major hazard. I don't see anything I would be overly worried about."

But in talking with Salt Lake reporters, he emphasized: "It's too early to draw any conclusions about connections between radiation and disease."

He said researchers have calculated estimates of the individual exposure levels for 1,177 people who lived in Utah between 1952 and 1967 and died of leukemia and about 5,600 similarly situated people who didn't get the disease.

Records of The Church of Jesus Christ of Latter-day Saints were used to track where the subjects - all Mormons and all deceased - lived during the study years.

Now epidemiologists are weeding out other variables to see if there's a correlation between exposure level and disease, he said.

By Nov. 18, the researchers will send a preliminary draft report of the leukemia results and separate thyroid disorder research to the National Cancer Institute, which is funding the $7 million study. The scientists will complete their final report by March 30.

When contacted Thursday evening, Steve Erickson, a spokesman for the Downwinders advocacy group for purported victims of nuclear tests, had not seen the Los Angeles Times article or heard Stevens' remarks.

But he said he would probably question the conclusions, because the study employed reconstructions of radiation exposure levels, the validity of which Downwinders doubts. He also said he understood that a number of people had refused to cooperate with the thyroid studies.

The open-air tests have already been the subject of a lawsuit against the federal government by nearly 1,200 people who maintained that exposure caused them or their relatives sickness and death. In 1982, a federal judge ruled that the government had failed to warn residents of radiation hazards. But the ruling was overturned on appeal, and the U.S. Supreme Court upheld the reversal on governmental immunity grounds.

Stevens said the latest study results don't necessarily refute the 1979 findings of U. epidemiologist Joseph L. Lyon of a higher-than-expected number of leukemia deaths in southern Utah.

"What we're trying to do is establish a rational basis for saying that radiation was related to what he found."

Previous studies have not established that link because sufficient data weren't available. Stevens said he believes the latest fallout information provided by the Department of Energy is reliable, even though reporters suggested DOE has a vested interest in downplaying exposure levels.

He said he knows some of the scientists who've helped DOE reconstruct the fallout patterns, has seen their work and is "convinced that they're extremely honest people."

Stevens denied any political motive behind Lyon's being replaced as lead investigator for the latest study. He said the change was made at the request of an NCI review committee in 1985. "They told me that they felt that we needed to have more assistance in managing the program."

Stevens was brought in to manage the massive study, which has involved about 60 researchers over the past six years. He in turn brought in two scientists from the University of Southern California, Duncan Thomas and Susan Preston Martin, to direct the epidemiological analysis, and they work with Lyon.

The leukemia and thyroid disease studies have used various kinds of data, Stevens said.