Women who use high-absorbency tampons run a much greater risk of getting toxic-shock syndrome than users of smaller, less absorbent tampons, according to results of a new study released today.

The new study implicates all high-absorbency tampons in promoting toxic-shock syndrome, and not just the Rely brand, which Procter & Gamble withdrew from the market in September because it had been particularly implicated in studies. However, users of any type of tampons have a greater chance of getting the rare but sometimes fatal illness, the findings show.

The study found that women who used the high-absorbency tampons had a 17 to 30 times higher risk of getting the illness, according to Dr. Michael Osterholm, the Minnesota health department epidemiologist who announced the findings. Those who used the lowest-absorbency products had only two to three times the risk of a women who did not use tampons at all, he said.

Osterholm said the new study also confirms a finding by other researchers that teen-agers have the highest risk of developing toxic-shock syndrome. More than half of the 80 women studied were younger than 19 years old.

The new lead in the investigation of the mysterious disease, which almost exclusively strikes young women who are menstruating, was discovered in a joint study of 80 toxic-shock victims by the Minnesota, Wisconsin and Iowa state health departments

"This [the study's findings], we feel, is by far the next, most important step in solving the toxic-shock puzzle," Osterholm said.

Osterholm said tampon absorbency varies depending on the manufacturer, but those labeled "super" or "superplus" are generally highly absorbent. "All brands have a product which we would consider to be in the high or super-absorbent class," he said.

For the moment, he said, the new information does not change the recommendations that have been made to women by the federal Centers for Disease Control in Atlanta. These are that a woman can virtually eliminate her chances of getting the illness by not using tampons, and can reduce her risk by not using them 24 hours a day during her entire period. If a woman develops fever, vomiting and diarrhea while using a tampon, she should remove it immediately and consult a doctor.

Since late 1979, when doctors in Wisconsin and Minnesota began to notice clusters of toxic-shock syndrome patients, federal disease experts have collected 810 cases of the illness across the country, including 69 deaths.

The scientists did not provide a breakdown on the absorbency of all "super" tampons, but one source not connected with the study said a few tampons labeled super did not fall into the highest absorbency category.

Osterholm added that all manufacturers produce less absorbent tampons, but that the least absorbent ones were Tampax Junior tampons and Tampax Slender Regular tampons.

"There is also some indication of increased risk associated with Rely brand tampons, beyond that predicted by their absorbency," Osterholm said.

Disease experts had discovered last June that tampon use was contributing to a nationwide outbreak of the disease. But the new link to high-absorbency tampons is the first major clue to emerge since the Rely brand was withdrawn.

Osterholm said he and two other epidemiologists, Dr. Jeffrey P. Davis of Wisconsin and Dr. Laverne Wintermeyer of Iowa, used absorbency information supplied by each manufacturer in their investigation, which compared the habits of 80 toxic-shock patients to those of 160 women who did not become ill.

They found that a woman's chances of getting the disease were directly related to the absorbency of the tampon she used. Annually, among all menstruating women in the three states, there were six cases of toxic-shock syndrome per 100,000 women.

Among women who did not use tampons, the disease was far rarer -- less than one case per 100,000, Osterholm said.

The scientists have no idea why super-absorbent tampsons promote the illness. Osterholm said there was no evidence that chemicals contained in the product were responsible, or that they provided a better growth medium for staphylococcus bacteria, the germ thought to produce the illness.

Women who contracted the disease exercised significantly less than those who remained well, and cases of the illness were rarer among those who took birth control pills, the study said. But the reasons these factors influence the disease are unknown.

The disease ordinarily starts with fever, vomiting and diarrhea, often with headache and muscle aches. Within two to three days, a victim's blood pressure can drop dangerously low, producing dizziness or even shock -- blood pressure so low it can cause organ damage. At the same time, the patient develops a sunburn-like rash that later peels.

About 9 percent of cases of toxic-shock syndrome have been fatal. Seriously ill patients often must be treated for days in intensive-care units. There is no cure, although giving a victim antibiotics can prevent recurrences.

A spokesman for the Food and Drug Administration said that in light of the new information, the agency will extend the period for public comment on proposed tampon warning labels until the middle or end of February. He said all tampon manufacturers have agreed voluntarily to include warnings on or in tampon packages, and that the incidence of the disease seems to be decreasing nationally, possibly because of the withdrawal of Rely and consumers' awareness of the hazard.

Representatives of tampon manufacturers said they were examining the study carefully.

"It confirms our own findings that Procter & Gamble's voluntary withdrawal of Rely tampons from the marketplace has in no way caused a major reduction in the risk of toxic-shock syndrome," said Geoffrey Place, the company's vice president of research and development. He added that Procter & Gamble "continues to be committed to a major scientific research program aimed at better understanding this desease."

Asked about the finding that Rely seemed to increase risk of the disease over and above other high-absorbency products, a spokesman for Procter & Gamble said the company had not been informed of this finding at a meeting with the scientists on Monday.

"We don't know what led to the addition of the statement at the last minute, and frankly we don't know what the statement means," he said.

A spokeswoman for Tampax Inc., said, "We haven't really had a chance to look over the study to know how much it involves Tampax." She added that the design of Tampax tampons had not changed in the 44 years they have been produced.