Although studies have found that few gay men in the United Kingdom use the drug, a recent study suggested that HIV-positive men with large numbers of sexual partners were the group most likely to report using the drug. Several studies have suggested that use of the drug is linked to riskier sexual behaviour and a poorer clinical outcome in HIV-positive patients. Methamphetamine use by gay men in the United States has recently become a major concern. Investigators from the City University of New York also found that the drug was not necessarily a risk factor for unprotected anal sex, and that many men were able to have safer sex whilst using the drug. Crystal methamphetamine is rarely used by younger gay men in New York City during sex, according to research presented to a gay men’s health prevention conference in London.