evidence: Daily or weekly use of poppers over a number of years is associated with a substantial increase in the risk of cancers caused by viruses in men who have sex with men (MSM) without HIV, but only in the 50-70 age group, a study published in the journal AIDS shows. Heavy use of poppers was not associated with an increased risk of these cancers in men with HIV. [...] Poppers, or nitrite inhalants, are used frequently by men who have sex with men during sex as a stimulant and to make anal intercourse easier. Animal models have shown poppers to cause transient immunosuppression, but numerous epidemiological studies have disproved claims that poppers were linked to immunosuppression in gay men with HIV or to the development of Kaposi’s sarcoma, the most common AIDS-defining cancer. [...] The greater the use of poppers over the first five years after enrolment, the higher the risk of virus-associated cancers in men without HIV aged 50-70 (incidence rate ratio 1.011 per day per year of heavy use averaged over five years, 95% CI 1.002-1.020, p = .014), implying a substantially increased risk in very heavy users of poppers.