Immunomodulation by nitrite inhalants may predispose abusers to AIDS and Kaposi's sarcoma

Use of poppers (nitrite inhalants) among young men who have sex with men with HIV: A clinic-based qualitative study

Nitrite inhalants (poppers) are associated with HIV transmission and commonly used among young men who have sex with men (YMSM), a group at increased risk for HIV. Significant research gaps exist in understanding the context in which YMSM use poppers. Qualitative interviews were conducted with 15 YMSM (22-31 years) with HIV to better understand the context in which poppers are used and their impacts on HIV care outcomes, such as care retention and antiretroviral adherence. The Social Ecological Model was applied to understand intrapersonal, interpersonal, community, and system level influences on popper use. Factors influencing popper use included: ubiquity of popper use in sexual settings, introduction to poppers by casual sexual partners, patient-HIV provider communication surrounding poppers, neighborhood, substance use and HIV care systems, and the legal status of poppers. Implications for clinical care, public health, policy, and future research are discussed.

Long-term nitrite inhalant exposure and cancer risk in MSM

OBJECTIVES

Nitrite inhalants (poppers) are commonly used recreational drugs among MSM and were previously associated with elevated rates of high-risk sexual behavior, HIV and human herpesvirus type 8 (HHV-8) seroconversion, and transient immunosuppressive effects in experimental models. Whether long-term popper use is associated with cancer risk among MSM in the HAART era is unclear.

DESIGN

Prospective cohort study of cancer risk in 3223 HIV-infected and uninfected MSM in the Multicenter AIDS Cohort Study from 1996-2010.

METHODS

Poisson regression models were used to examine the association between heavy popper use (defined as daily or weekly use for at least 1 year) and risk of individual cancers or composite category of virus-associated cancers.

RESULTS

Among all participants, heavy popper use was not associated with increased risk of any individual cancers. Among HIV-uninfected men aged 50-70, heavy popper use was associated with increased risk of virus-associated cancer with causes linked to human papillomavirus, HHV-8, and Epstein-Barr virus in models adjusted for demographics, number of sexual partners, immunological parameters (CD4 cell counts or CD4/CD8 ratios), and hepatitis B and C viruses [incidence rate ratio (IRR), 95% confidence interval (CI) 3.24, 1.05-9.96], or sexually transmitted infections (IRR 3.03, 95% CI, 1.01-9.09), as was cumulative use over a 5-year period (IRR 1.012, 95% CI 1.003-1.021; P = 0.007). There was no significant association between heavy popper use and virus-associated cancer in HIV-infected men.

CONCLUSIONS

Long-term heavy popper use is associated with elevated risk of some virus-associated cancers with causes related to human papillomavirus, HHV-8, and Epstein-Barr virus infections in older HIV-uninfected MSM independent of sexual behavior and immunological parameters.

A systematic review of evidence to inform HIV prevention interventions among men who have sex with men in Europe

An estimated 42% of all newly diagnosed HIV cases in Europe in 2013 were transmitted during sex between men. This review was performed to identify and describe studies evaluating the efficacy and effectiveness of HIV prevention interventions among men who have sex with men (MSM), in relation to implementation data from European settings. A systematic search was performed individually for 24 interventions.Data were extracted from studies including efficacy or implementation data from European settings,appraised for efficacy, implementation and plausibility, and assigned a grade (1-4) according to the Highest Attainable Standard of Evidence (HASTE)framework. Four interventions (condom use, peer outreach,peer-led groups, and using universal coverage of antiretroviral treatment and treatment as prevention)were assigned the highest HASTE grade, 1. Another four interventions were assigned 2a for probable recommendation, including voluntary counseling and testing for HIV, using condom-compatible lubricant,using post-exposure prophylaxis, and individual counselling for MSM living with HIV. In addition, seven interventions were assigned a grade of 2b, for possible recommendation. Encouragingly, 15 interventions were graded to be strongly, probably or possibly recommended.In the relatively resource-rich European setting, there is an opportunity to provide global leadership with regard to the regional scale-up of comprehensive HIV prevention interventions for MSM.

Associations between duration of illicit drug use and health conditions: results from the 2005-2007 national surveys on drug use and health

PURPOSE

To estimate and compare prevalence rates of lifetime health conditions by inferred duration of illicit drug use among the general U.S. adult population and to investigate associations between duration of use of each specific illicit drug (marijuana, cocaine, heroin, hallucinogens, or inhalant) and each lifetime health condition after controlling for potential confounding factors.

METHODS

Data from respondents aged 35 to 49 (N = 29,195) from the 2005-2007 National Surveys on Drug Use and Health (NSDUH) were analyzed.

RESULTS

The prevalence rates of a broad range of health conditions by duration of use of specific illicit drug among persons 35 to 49 years of age in the United States were estimated and compared. After adjustment for potential confounding factors, the results of 20 multivariate logistic regression models indicated positive associations between duration of marijuana use and anxiety, depression, sexually transmitted disease (STD), bronchitis, and lung cancer; between duration of cocaine use and anxiety and pancreatitis; between duration of heroin use and anxiety, hepatitis, and tuberculosis; between duration of hallucinogen use and tinnitus and STD; and between duration of inhalant use and anxiety, depression, HIV/AIDS, STD, tuberculosis, bronchitis, asthma, sinusitis, and tinnitus.

CONCLUSIONS

This study provides initial analyses on the relationships between illicit drug use and health conditions based on a large nationally representative sample. These results can help prepare for treating health problems among former and continuing illicit drug users.

Paradoxical ozone associations could be due to methyl nitrite from combustion of methyl ethers or esters in engine fuels

We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.

Inhalant use and disorders among adults in the United States

OBJECTIVE

To examine the patterns of adult inhalant use and correlates of inhalant use disorder.

METHOD

We drew study data from the 2002 and 2003 National Surveys on Drug Use and Health (NSDUH). We used logistic regression to identify the characteristics associated both with inhalant use and inhalant use disorder.

RESULTS

One in 10 of all adults had used an inhalant at least once in their lives, and 0.5% used one in the past year. Among all past year inhalant users, 8% met the criteria for an inhalant use disorder (i.e., 6.6% for abuse and 1.1% for dependence) within that period. We found an increased prevalence of past year inhalant use among young adults aged 18-25 years, Asians, past year alcohol abusers and dependents, lifetime drug users, white women, and men reporting symptoms of serious mental illness. Inhalant-using adults who met the criteria for an inhalant use disorder were predominantly adults aged 35-49 years and were less educated, had received recent professional treatment for emotional or psychological problems, used inhalants weekly, and had a coexisting alcohol use disorder.

CONCLUSION

The patterns and consequences of adult inhalant use differ from those of adolescents. Compared with adolescent inhalant users, adult users tend not to initiate inhalant use until adulthood, use inhalants less frequently, use fewer inhalants, and are less likely to engage in criminal activities.

Use of nitrite inhalants ("poppers") among American youth

PURPOSE

We examined the patterns and correlates of nitrite inhalant use among adolescents aged 12 to 17 years.

METHODS

Study data were drawn from the 2000 and 2001 National Household Surveys on Drug Abuse. Logistic regression was used to identify the characteristics associated with nitrite inhalant use.

RESULTS

Among adolescents aged 12 to 17 years, 1.5% reported any lifetime use of nitrite inhalants. The prevalence of lifetime nitrite inhalant use increased to 12% and 14% among adolescents who were dependent on alcohol and any drug in the past year, respectively. Many nitrite inhalant users used at least three other types of inhalants (68%) and also met the criteria for alcohol (33%) and drug (35%) abuse or dependence. Increased odds of nitrite inhalant use were associated with residing in nonmetropolitan areas, recent utilization of mental health services, delinquent behaviors, past year alcohol and drug abuse and dependence, and multi-drug use.

CONCLUSIONS

Adolescents who had used nitrite inhalants at least once in their lifetime tend to engage in delinquent activities and report co-occurring multiple drug abuse and mental health problems in the past year.

Sexual Risk, Nitrite Inhalant Use, and Lack of Circumcision Associated With HIV Seroconversion in Men Who Have Sex With Men in the United States

Men who have sex with men (MSM) continue to account for the largest number of new HIV infections in the United States, but limited data exist on independent risk factors for infection beyond the early 1990s. The HIV Network for Prevention Trials Vaccine Preparedness Study enrolled 3257 MSM in 6 US cities from 1995 to 1997. HIV seroincidence was 1.55 per 100 person-years (95% confidence interval: 1.23-1.95) over 18 months of follow-up. On multi-variable analysis using time-dependent covariates, independent risk factors for HIV seroconversion were increased number of reported HIV-negative male sex partners (adjusted odds ratio (AOR) = 1.14 per partner, population attributable risk (PAR) = 28%), nitrite inhalant use (AOR = 2.2, PAR = 28%), unprotected receptive anal sex with an HIV unknown serostatus partner (AOR = 2.7, PAR = 15%) or HIV-positive partner (AOR = 3.4, PAR = 12%), protected receptive anal sex with an HIV-positive partner (AOR = 2.2, PAR = 11%), lack of circumcision (AOR = 2.0, PAR = 10%), and receptive oral sex to ejaculation with an HIV-positive partner (AOR = 3.8, PAR = 7%). Having a large number of male sex partners, nitrite inhalant use, and engaging in receptive anal sex explained the majority of infections in this cohort and should be targeted in prevention strategies for MSM.

Acute exposure to the abused inhalant, isobutyl nitrite, reduced T cell responsiveness and spleen cellularity

Isobutyl nitrite is an inhalant abused principally by male homosexuals. We have reported that subchronic inhalation exposure (45 min/day for 14 days) to 900 ppm isobutyl nitrite was immunosuppressive. In the present study, the effects of acute exposure to the inhalant were examined. Mice were exposed in an inhalation chamber to 900 ppm isobutyl nitrite for 45 min. One day later, spleen cellularity was reduced by 39% without selectively depleting CD4(+) or CD8(+) cells. The numbers of peripheral blood leukocytes and peritoneal cells were also reduced. Following acute inhalation exposure, T cell proliferative responses stimulated with allogeneic cells or anti-CD3 and anti-CD28 antibodies were inhibited, while mitogen-induced responses were not affected. Purified T cells exposed to the inhalant also had compromised responses, suggesting a direct effect on T cells. However, the cumulative effects of multiple exposures were necessary to inhibit T-dependent antibody responses or T cell or macrophage cytotoxicity.

Racial/ethnic and educational differences in the estimated odds of recent nitrite use among adult household residents in the United States: an illustration of matching and conditional logistic regression

This article compares estimates of the relative odds of nitrite use obtained from weighted unconditional logistic regression with estimates obtained from conditional logistic regression after post-stratification and matching of cases with controls by neighborhood of residence. We illustrate these methods by comparing the odds associated with nitrite use among adults of four racial/ethnic groups, with and without a high school education. We used aggregated data from the 1994-B through 1996 National Household Survey on Drug Abuse (NHSDA). Difference between the methods and implications for analysis and inference are discussed.