Changes in risk behavior and dynamics of hepatitis C virus infections among young drug users in Amsterdam, the Netherlands.

To elucidate the character and magnitude of the hepatitis C virus (HCV) epidemic among drug users in Amsterdam, 197 young drug users from the period 2000 to 2004 were compared with 215 counterparts from 1985 to 1989. Although injection risk behavior and HCV seroprevalence decreased sharply over time, HCV seroprevalence remains high (44%) among young drug users who have ever injected. Phylogenetic analysis shows that current HCV infections originate from diversification of strains already circulating in the past, but also from the recent introduction of new subtypes. HCV subtypes 1a and 3a remain the most prevalent among drug users in Amsterdam, but other subtypes such as 4d and 2b have entered the population. In conclusion, both the unpopularity of injecting drug use and the success of prevention campaigns are likely to be responsible for the decline in the seroprevalence of HCV and increased median time to seroconversion. Treatment of those infected chronically, in combination with the continuation of prevention programs, might decrease future HCV transmission.

Amount of self-reported illicit drug use compared to quantitative hair test results in community-recruited young drug users in Amsterdam.

AIMS: To assess the dose-effect relationship between self-reported drug intake and the concentration of drugs and/or their metabolites in hair and to examine factors that may mediate this relationship. DESIGN AND SETTING: A cohort study among young drug users (YDU) in Amsterdam, the Netherlands, which began in July 2000. At intake, YDU were asked to report their average drug intake over a 2-month period. A hair sample was taken and then analysed for cocaine, benzoylecgonine (BE), morphine, 6-monoacetylmorphine and methadone. Weighted least-squares regression analysis was used to model hair-test results as a function of reported drug use. PARTICIPANTS: Subjects were 95 YDU (using cocaine, heroin, methadone and/or amphetamines at least 3 days/week) aged 18-30 residing in Amsterdam in 2000-2001. FINDINGS: Of the 95 YDU, one-third were women; mean age was almost 26; 30% had black hair, 33% blond hair and 37% brown hair. Cocaine use was reported by 92%, heroin by 75% and methadone by 64% of participants. All hair samples contained one or more drugs. Crude correlation coefficients between reported drug doses and drug concentrations in hair ranged between 0.45 and 0.59. The multivariate regression analysis showed that, for one or more types of drug, black-haired people, women and non-western European people had relatively high drug concentrations in hair (significant slope effects). The corresponding multivariate correlation coefficients ranged between 0.63 and 0.87. CONCLUSIONS: Hair testing can be used to quantify drug use in epidemiological studies, given that factors such as hair colour and sex are taken into account.

HIV prevalence and risk behaviour in young drug users in Amsterdam.

OBJECTIVES: To assess the HIV prevalence and risk behaviour among regular young drug users (YDU) in Amsterdam. DESIGN: Subjects were 282 YDU (using heroin, cocaine, methadone and/or amphetamines at least 3 days/week) aged 30 years or less who participated in a cross-sectional survey in Amsterdam in 1998. Participants were recruited both directly (41%) through healthcare institutions, and indirectly (59%) by referrals from YDU already enrolled. A comparison sample of YDU from the Amsterdam Cohort Study recruited between 1985 and 1989 was used to describe trends in HIV prevalence and risk behaviour. RESULTS: Mean age was 25 years, 22% were women, 39% had at least once injected drugs, and 22% currently injected in 1998. Cocaine was more often used regularly (70%) than heroin (42%). Of the 282 YDU, 21 (7.4%) were infected with HIV. Among those who had injected drugs, HIV prevalence was 16.2%. Among those who had never injected, the prevalence of HIV infection was 1.8%. A history of injecting declined from 83% in 1985-1989 to 56% in 1998. Compared with 1985-1989, the lack of a recent steady partner appeared to be an important risk factor for a positive HIV status among injectors in 1998, whereas borrowing of used needles/syringes was no longer a risk factor. CONCLUSION: The use of cocaine among YDU is very popular in Amsterdam. A strong decrease in injecting behaviour has taken place, but among those who inject, risk behaviour is still considerable, and HIV infection is still widespread. Preventative activities should be expanded, specifically among YDU.