Drug and Alcohol Dependence 78 (2005) 253–261 Early onset inhalant use and risk for opiate initiation by young adulthood  Carla L. Storr a , Ryan Westergaard b , James C. Anthony c,∗ a Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N Broadway 8th FL, Baltimore, MD 21205 USA b Department of Medicine, University of Colorado Health Sciences Center, 4200 E. Ninth Avenue, #B177, Denver, CO 80262, USA c Department of Epidemiology, Michigan State University, West Fee Hall B601, East Lansing, MI 48824 USA Received 19 June 2004; received in revised form 5 November 2004; accepted 17 November 2004 Abstract In this study, we estimate a hypothesized link from early onset inhalant use to later use of opiates by young adulthood, with data from an epidemiological sample of 2311 first graders who entered an urban mid-Atlantic public school system in 1985 or 1986 (49.8% male; 67.1% ethnic minority), and who were studied longitudinally to young adulthood. An estimated 9% had initiated inhalant use before the age of 14 and at follow-up in young adulthood an estimated 3% (n =66) of the sample had tried opiates at least once. Youth who used inhalants prior to age 14 were twice as likely to initiate opiate use, as compared to those who had never tried (relative risk 2.2; 95% CI = 1.4, 3.3). Statistical adjustment for other covariates attenuated but did not dissolve this relationship. These findings help confirm previously reported evidence that the use of inhalants might be an early marker of vulnerability for future involvement with illegal drugs such as heroin, but an exploratory analysis suggests that there may be no direct inhalants–opiate link once a general early onset susceptibility trait is taken into account. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Inhalants; Heroin; Epidemiology; Longitudinal; Adolescent; Solvents 1. Introduction The purpose of this study was to estimate the strength of a suspected association between inhalant use before age 14 and subsequent occurrence of opiate use by early adulthood, with a focus on heroin and opium, the two opiate compounds used most frequently by young people in the world. This linkage has been suggested in prior cross-sectional investigations, but has rarely been approached longitudinally. Internationally, inhalant drug use is an important public health problem among children and adolescents, although it often receives less public attention than illegal drug use. In Europe, estimates of cumulative lifetime inhalant use by  A table listing previous studies of the associations between inhalant and opiate abuse can be found by accessing the online version of this paper. Please see Appendix A for more information. ∗ Corresponding author. Tel.: +1 517 353 8623x100; fax: +1 517 432 1130. E-mail address: janthony@msu.edu (J.C. Anthony). 15–16 year olds vary greatly by country, ranging from 3% to a high of 20% in the United Kingdom (EMCDDA, 2003). Apparently, among youths in the European countries, the use of inhalants is not as popular as the use of cannabis. However, inhalants are used more often than other illegal drugs. School surveys of adolescents in seven countries of Latin America found that an estimated 5% of the youths in this region of the world have tried inhalants, which is comparable to the frequency of cannabis smoking and other illegal drug use in that region (Dormitzer et al., 2004). In the United States, recent national household survey data indicate inhalant drugs are used by an estimated 9% of 12–17 year olds, but only one-third as many non-Hispanic African heritage youths had tried inhalant drugs (SAMHSA, 2003). Of course, this value is averaged over all youths age 12–17 years, and indeed the occurrence of inhalants is not equal for all segments or subgroups of the population. In addition, the history of inhalant use accumulates across the adolescent and young adult years. For example, based upon national survey 0376-8716/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.drugalcdep.2004.11.005