Scientists at the Johns Hopkins School of Hygiene and Public Health believe they have found evidence that distributing sterile needles to drug addicts could help to stem the AIDS epidemic.
A study in Baltimore of people who inject illegal drugs has found that addicts who happen to have diabetes are less than half as likely to contract the AIDS virus than are addicts who don't have the disease.
Dr. Kenrad Nelson, an epidemiologist, said that there is only one likely explanation for the difference: Diabetes enables addicts to buy clean needles at any pharmacy, making it less probable that they will share dirty needles when injecting heroin or cocaine.
In Maryland, it is against the law for people to buy or possess hypodermic needles without a prescription. This forces many addicts, in Dr. Nelson's view, to use needles already used by other addicts.
"When we tell drug users not to share needles and then make it illegal for them to carry a needle, then what option do they have?" said Dr. Nelson, whose findings appear in last week's Journal of the American Medical Association.
Hopkins scientists compared infection rates of 2,880 addicts who did not have diabetes and 41 who did have the illness. Twenty-four percent of the non-diabetics were infected with the human immunodeficiency virus that causes acquired immune deficiency syndrome, while 9.8 percent of the diabetics carried HIV.
The results were based on blood tests taken in 1988 and 1989.
While HIV transmission has declined greatly among homosexuals, it remains high among intravenous drug users -- a trend that has spurred many public health authorities to suggest that clean needles be made available to addicts.
In August, the National Commission on AIDS recommended that drug addicts be given legal access to needles.
However, state and city leaders said they could not move ahead with such a program because of opposition from law enforcement officials and the lack of studies proving that it would work.