Cocaine, crack, methamphetamine laws, methamphetamine, rural, substance abuse.

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1 RESEARCH REPORT doi: /j x Longitudinal changes in methamphetamine and cocaine use in untreated rural stimulant users: racial differences and the impact of methamphetamine legislation Tyrone F. Borders 1, Brenda M. Booth 2,3, Xiaotong Han 2, Patricia Wright 2, Carl Leukefeld 4, Russel S. Falck 5 & Robert G. Carlson 5 Department of Health Policy and Management, University of Arkansas for Medical Sciences, Little Rock, AR, USA, 1 Division of Health Services Research, Department of Psychiatry, University of Arkansas for Medical Sciences, Little Rock,AR, USA, 2 VA HSR & D Center for Mental Healthcare Outcomes and Research, Little Rock, AR, USA, 3 Department of Behavioral Science, University of Kentucky, Lexington, KY, USA 4 and Center for Interventions, Treatment, and Addictions Research, Wright State University, Dayton, OH, USA 5 ABSTRACT Aims To examine how race and methamphetamine legislation are associated with changes in cocaine and methamphetamine use among untreated rural stimulant users. Design A longitudinal study of stimulant users identified through respondent-driven sampling. Setting Rural areas of three US states. Participants Participants at baseline were current users of methamphetamine and/or cocaine. Measures Self-reports of methamphetamine, crack cocaine and powder cocaine use were assessed at 6-month intervals over a 2-year period. Generalized estimating equations were performed to account for correlations between the repeated measurements. Findings Compared to whites, African Americans were much more likely to use crack cocaine, equally likely to use powder cocaine and much less likely to use methamphetamine. Both whites and African Americans reduced their consumption of methamphetamine and both forms of cocaine over 2 years. Exposure to laws restricting the purchase of over-the-counter cold medications containing methamphetamine precursors was not associated with methamphetamine use, but associated with a slight rise in powder and crack cocaine use. Conclusions The study yielded disconcerting as well as promising findings regarding the natural history of stimulant use in rural areas. Of some concern is that methamphetamine precursor laws were correlated with increased cocaine consumption, diminishing their net public health benefits. However, despite its insurgence in rural areas of the United States, very few African Americans have initiated methamphetamine use. Regardless of race, many stimulant users stopped using cocaine and methamphetamine without formal substance abuse treatment over 24 months. Keywords Cocaine, crack, methamphetamine laws, methamphetamine, rural, substance abuse. Correspondence to: Tyrone F. Borders, Department of Health Policy and Management, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, 4301 W. Markham Street, #820, Little Rock, AR , USA. tfborders@uams.edu Submitted 1 June 2007; initial review completed 18 September 2007; final version accepted 9 January 2008 INTRODUCTION Cocaine and amphetamine are among the more commonly used illicit drugs [1]. Global cocaine consumption has declined slightly in recent years, but continues to be used by an estimated 13.4 million people aged years [2,3]. Among the estimated 25 million people using amphetamine-type stimulants, the most commonly abused substance is methamphetamine [2]. Methamphetamine use is exploding in parts of Europe, South Africa and Mexico, and continues to be widespread in areas of Asia and the United States [1,2]. Within the United States, both cocaine and methamphetamine consumption have become substantial public health problems in rural and small towns [4 7]. A nationally representative survey showed that cocaine use is particularly high among younger adults, men and African Americans [8]. Other studies suggest that methamphetamine is used primarily by white males [9 12], but recent growth in its availability has generated concern about

2 Longitudinal methamphetamine and cocaine use 801 whether African Americans are choosing increasingly to try methamphetamine [13]. To combat methamphetamine use, the US government has enacted a number of laws limiting the trade of methamphetamine precursor agents, namely ephedrine and pseudoephedrine [14]. A 1989 law mandated that legal distributors of bulk quantities of precursor chemicals be licensed by the Drug Enforcement Administration [14 16]. Subsequent laws in 1995 and 1997 regulated the mass purchase of tablets and capsules containing ephedrine and pseudoephedrine [14,17,18]. Studies have examined the effects of the latter laws, which targeted primarily large-scale producers, on methamphetaminerelated hospital admissions and arrests, finding that they had only short-term impacts [14,19]. More recently, the number of smaller-scale laboratories has exploded, prompting a number of state governments to enact regulations in which restricted individual consumers purchase of over-the-counter cold and sinus medications containing pseudoephedrine, ephedrine and phenylpropanolamine. These laws vary by state, but generally limit the number of pills that an individual can purchase and restrict sales to people 18 years of age or older. To our knowledge, no research has examined whether these state laws are associated with reductions in methamphetamine consumption. This study used data from a longitudinal, communitybased cohort of untreated stimulant users residing in rural areas to: (i) examine overall changes in methamphetamine, powder cocaine and crack cocaine use over a 2-year interval; (ii) test for racial differences (African American versus white) in methamphetamine and cocaine use, particularly whether African American cocaine users initiated methamphetamine use; and (iii) determine if the enactment of state laws restricting the purchase of methamphetamine precursors was followed by reductions in methamphetamine use. METHODS Study design and sample Data are from the Rural Stimulant Study (RSS), a large natural history study conducted among stimulant users residing in selected rural counties in eastern Arkansas, western Kentucky, and western Ohio [4,13,20 23]. County eligibility criteria included being within a manageable driving distance from the relevant home university of the researchers, evidence of cocaine or methamphetamine use and being rural. Rural was defined according to the US Office of Management and Budget definition of a non-metropolitan area, or a county with or fewer people [24]. The counties represent a range of social and demographic characteristics, particularly racial diversity. The three Arkansas counties, which are located adjacent to the Mississippi River, were 49 57% African American compared to 1 8% in Ohio and 0 2% in Kentucky. Baseline participant eligibility criteria were broad and included: (i) age 18 years or older and residence in the selected geographic areas; (ii) self-reported crack, powder cocaine or methamphetamine use by any route of administration within the past 30 days; (iii) no formal drug abuse treatment within the past 30 days; and (iv) a verifiable address where the participant could be reached for follow-up. Because the sampling methodology has been described in detail elsewhere, we only highlight it here [4,22,23]. Respondent-driven sampling (RDS), a variant of snowball sampling [25 27], was used to identify and recruit stimulant users for the study. This type of non-probabilistic sampling is virtually essential for recruiting hidden populations, such as illicit drug users. Theoretically, RDS can generate a sample that is much more representative of the hidden populations than other sampling methods. The baseline interviews were 2 3 hours in length and were conducted face to face in project site offices by trained interviewers between October 2002 and September Urinalysis was also conducted at each follow-up interview to help increase the veracity of selfreported drug use [28 30]. The study sites had identical recruitment, interviewing and measurement methods. This research was approved by the institutional review boards of the investigators universities. To study the natural history of stimulant users and determine exactly what happens without the benefit of treatment, we excluded from the current analyses 132 participants who reporting receiving formal substance abuse treatment at any point after entry into the study. Because we were interested in differences between African Americans and whites, we also excluded 19 individuals of other race/ethnicity from the sample. These exclusions, coupled with a small number of people who had missing data for the dependent variables at baseline, yielded a final sample size of 559 participants for analyses. Of these 559 people, 431 (77%) completed the 24-month follow-up interview. Additional analyses of attrition showed that males and whites were slightly less likely to complete the follow-up interviews. Measures The Substance Abuse and Health Services Utilization Assessment (SAHSUA) was used to collect the quantitative variables [31]. The SAHSUA contains either whole or in part the Addiction Severity Index (ASI) [32 34], measures of the frequency and intensity of stimulant and other drug use, alcohol use as measured using Armor and

3 802 Tyrone F. Borders et al. colleague s quantity frequency index and items measuring socio-demographics, health beliefs and the utilization of drug abuse treatment. Reasonable test retest reliability for the SAHSUA has been demonstrated among urban crack users [31]. The three primary dependent variables were selfreports of any (yes/no) past 6-month methamphetamine, powder cocaine and crack cocaine use as well as selfreports of the counts of the number of days in the past 30 days using methamphetamine, powder cocaine and crack cocaine. The main independent variables were race (African American or white), time (which was treated as a linear variable ranging from 1 to 5 to represent the baseline to 24-month follow-up interviews) and the length of exposure to the methamphetamine laws. Because the purpose of the original study was not to examine the effects of methamphetamine laws, it did not include questions regarding their impact on methamphetamine use or availability. Rather, information about the state laws, which went into effect in Arkansas and Kentucky in March and June 2005, was obtained from a secondary source [35]. The Arkansas and Kentucky laws are similar as they limit the dosage or number of pills sold over a 30-day period, require a current identification card for purchase and restrict sales to people 18 years of age and older. The Arkansas law also requires that products be sold by a licensed pharmacist or technician, while the Kentucky law restricts storage to behind a pharmacy counter or in a locked cabinet. Depending on the timing of the follow-up interviews, Arkansas and Kentucky participants were exposed to the laws at some point between their 6- and 18-month interview dates, whereas Ohio participants were not exposed to any law during the study (such laws have since been implemented in Ohio). We computed the number of days of exposure to the methamphetamine law by calculating the number of days between the law implementation date and the follow-up interview date. To facilitate easier interpretation of the results, we recoded the variable as a continuous measure of the number of months of exposure to the law (the number of days exposed/30). People who resided in Ohio were given a 0 for exposure. We included as covariates additional demographic (age and gender) and socio-economic factors (marital status, whether the participant had any children and educational attainment) that could affect stimulant use. Because they are used commonly in combination with stimulants, we also adjusted for past 30-day use (no use, 1 19 days of use and 20 days of use) of alcohol and marijuana. In addition, we adjusted for ASI employment, family/social, legal and psychiatric composite scores, as greater severity of problems in these areas could be correlated with stimulant use [32]. The ASI composite scores range between 0 (not severe) and 1 (very severe). Finally, to control for drug markets, which may have differed between states, we included covariates representing the state of residence. Similarly, to account for time trends in drug use which may have differed between earlier and later recruits, we included covariates representing the year of entry into the study. Statistical analysis Proportions for past 6-month drug use and means for the number of days using a drug in the past 30 days were calculated at baseline and each follow-up period. To determine whether the independent variables were associated with drug use over time, generalized estimating equations (GEE) were conducted using the PROC GENMOD commands in SAS/STAT version 9.1. GEE is an extension to generalized linear models (GLM) that use quasi-likelihood estimation. It is employed frequently in longitudinal analyses that have correlated data such as repeated measures from the same subject [36 38]. A benefit of GEE is that it allows for the inclusion of all possible data in the analyses, rather than excluding participants who did not have information for any of the four follow-up interviews [36]. RESULTS Descriptive statistics Table 1 describes characteristics of the analytical sample at the baseline interview. Table 2 describes longitudinal changes in methamphetamine and cocaine use. At baseline, 48% of participants reported methamphetamine and 87% reported cocaine (powder or crack) use in the past 6 months. Crack cocaine was used more commonly compared to powder cocaine (65% versus 57%). Stimulant use declined markedly over time, with 60% using powder or crack cocaine and 19% using methamphetamine at the 24-month interview. The proportion using both methamphetamine and cocaine also declined steadily over time from 35% at baseline to 10% at the 24-month follow-up. Approximately 33% abstained from both drugs 2 years after entering the study. In addition to past 6-month use, Table 2 displays the mean number of days in the past 30 days using methamphetamine, powder cocaine and crack cocaine. Similar to trends for past 6-month use, the number of days in the past 30 days using each drug declined from baseline to the 24-month follow-up. Figure 1 illustrates racial differences in the trajectories of drug use. At baseline, powder cocaine was used more commonly by whites than African Americans (63% versus 44%). In contrast, crack cocaine was used much more frequently by African Americans than whites (81% versus 57%). A very small percentage of African Americans (13%), compared to 65% of whites, reported

4 Longitudinal methamphetamine and cocaine use 803 Table 1 Descriptive statistics at baseline (n = 559). Variable Demographics (%) Race African American White Age, mean (SD) (10.54) Gender (%) Male Female Social factors Education (%) <High school High school College/technical Marital status (%) Married/have partner Single Number of children (%) None Other substance use Alcohol use in past 30 days (%) None days days Marijuana use in past 30 days (%) None days days ASI scores (mean, SD) Employment 0.68 (0.30) Family/social 0.15 (0.20) Legal 0.15 (0.20) Psychiatric 0.19 (0.22) State of residence (%) Arkansas Kentucky Ohio Year entered study (%) ASI: Addiction Severity Index; SD: standard deviation. methamphetamine use at baseline. Regardless of race, drug use was much lower at the 24-month follow-up compared to baseline, although there was a slight increase in whites use of powder and crack cocaine between the 18- and 24-month interviews. We did not separate the route of drug administration for each drug (smoke, swallow, sniff/snort or inject) because the dependent variables largely distinguish the usual route. However, we provide here some statistics describing the usual route for each drug at the baseline interview. Most crack cocaine users reported smoking (96%), whereas most powder cocaine users reported snorting (86%). The majority of methamphetamine users (60%) reported smoking as the usual route, followed by snorting (22%) and injecting (16%). Methamphetamine, powder and crack cocaine use over time Table 3 displays adjusted odds ratios (OR) and 95% confidence intervals (CI) from the GEE analyses. African Americans had substantially lower odds of using methamphetamine than whites (OR 0.03, 95% CI ). Time was significant (OR 0.61, 95% CI ), indicating that the likelihood of using methamphetamine declined over the study period. The number of months exposed to a methamphetamine precursor law was not associated with methamphetamine use. Of the covariates, no demographic or social factors were significant, but higher ASI employment and legal composite scores were associated with greater odds of methamphetamine use. Drinking alcohol on 20 or more days, relative to no alcohol in the past 30 days, and using marijuana on 20 or more days, relative to no marijuana in the past 30 days, were associated with higher odds of methamphetamine use. Regarding powder cocaine, we found no racial differences, but time was significant (OR 0.73, 95% CI ), indicating that use declined over 2 years. While exposure to the methamphetamine laws was unrelated to methamphetamine use, months of exposure to the methamphetamine law was associated with a 9% increase in the odds of powder cocaine use (OR 1.09, 95% CI ). Of the covariates, older age and higher ASI legal composite scores were associated with higher odds of powder cocaine use. Drinking alcohol on 20 or more days in the past month (compared to not drinking) and using marijuana on 1 19 days or 20 or more days in the past month (compared to not using marijuana) were associated with greater odds of powder cocaine use. African Americans were more likely to use crack cocaine than whites (OR 3.93, 95% CI ). The associations between time (OR 0.72, 95% CI ) and exposure to methamphetamine laws (OR 1.07, 95% CI ) with crack cocaine use were similar to those for powder cocaine. Of the demographic and social factors, age was associated with higher odds of crack use, while being male and having at least a high school education were associated with lower odds of crack use. Higher ASI employment, family/social and legal composite scores were associated positively with the likelihood of using crack. Drinking alcohol on 1 19 days or 20 more days (relative to no alcohol in the past 30 days) and using marijuana on 1 19 days or 20 or more days (relative to no use in the past 30 days) were associated with higher odds of crack use.

5 804 Tyrone F. Borders et al. Table 2 Longitudinal methamphetamine and cocaine use. Variable Baseline n = months n = months n = months n = months n = 431 % using in past 6 months Meth Cocaine (powder or crack) Powder cocaine use Crack cocaine use Both cocaine and meth No cocaine or meth No. of days using in past 30 days Mean (SD) Meth 3.35 (6.61) 2.20 (5.64) 1.67 (5.00) 0.98 (3.61) 0.85 (3.62) Powder cocaine 4.02 (7.27) 1.81 (4.90) 1.77 (5.14) 1.51 (4.86) 1.28 (4.33) Crack cocaine 7.13 (9.64) 4.50 (8.58) 4.32 (8.49) 5.21 (9.42) 4.18 (8.53) SD: standard deviation % Using Powder-Afr. Amer. Powder-Whites Crack-Afr. Amer. Crack-Whites Meth-Afr. Amer. Meth-Whites Baseline 6 months 12 months Interview 18 months 24 months Figure 1 Longitudinal methamphetamine, powder cocaine, and crack cocaine use by race (% using in past 6 months) The results of the analyses of the number of days in the past month using each drug are very similar to those for any past 6-month drug use, thus reinforcing the robustness of the models. In Table 4, the estimated negative binomial regression coefficient for African Americans (b =-2.831, P < ) indicates that African Americans used methamphetamine on fewer days than whites (specifically, the expected number of days using methamphetamine for African Americans is the exponentiation of , or 0.06, times that for whites). African Americans had more days using powder cocaine (b = 1.111, P < ) and crack (b = 0.935, P < ) in the past 30 days. The number of days using each drug declined over time, as indicated by the negative coefficients for time (P < ). Exposure to the methamphetamine laws was unassociated with days using methamphetamine, but associated with more days using powder (b = 0.110, P < ) and crack (b = 0.073, P < ) cocaine in the past 30 days. DISCUSSION Drug abuse is a substantial public health problem in the United States, but very little research has investigated stimulant use among rural residents [4 7,39,40]. In particular, the burgeoning availability of methamphetamine in rural communities has spawned questions about whether African American cocaine users have begun to adopt methamphetamine, which historically has been a drug of choice among whites [9 12]. In this longitudinal study of known stimulant users, very few African Americans used methamphetamine over a 2-year period. Similar to national estimates of racial differences in the prevalence of cocaine use [8], we found that African Americans and whites were equally likely to use powder cocaine, but that crack use was much more common among African Americans. Other qualitative research conducted among our study sample suggests that many African Americans prefer cocaine over

6 Longitudinal methamphetamine and cocaine use 805 Table 3 Model of past 6 month methamphetamine, powder cocaine, and crack cocaine use. Meth Powder cocaine Crack cocaine Variable (reference group) OR 95% CI OR 95% CI OR 95% CI Main variables of interest African American (ref. white) 0.03* * Time 0.61* * * Months exposed to meth law * * Demographic/social factors Age * * Male (ref. female) * Married/partner (ref. single) Have children (ref. no children) Educational status High school (ref. < high school) * College/tech. (ref. < high school) * ASI scores Employment score 1.67* * Family/social score * Legal score 2.31* * * Psychiatric score Alcohol in past 30 days 1 19 days (ref. 0 days) * days (ref. 0 days) 1.88* * * Marijuana in past 30 days 1 19 days (ref. 0 days) * * days (ref. 0 days) 1.76* * * *P < Results are from generalized estimating equations with a binary distribution for the dependent variable and adjusted for state of residence and year of entry into the study. Months exposed to meth law: no. of days exposed to law at the interview date/30. ASI: Addiction Severity Index; OR: odds ratio; CI: confidence interval. methamphetamine because they fear the psychological and physiological effects of methamphetamine and have limited access to methamphetamine distributors, many of whom are white [13]. Almost a third of participants who were assessed at the 24-month follow-up remitted from stimulant use, despite not receiving formal substance abuse treatment, although this may be a slightly inflated estimate if a higher proportion of participants lost over the follow-up period did not remit. One explanation for the decline in stimulant use is spontaneous or natural remission. A small number of studies have shown that many people remit from alcohol [41 43] and drug use [44 47] without formal treatment. We can also not rule out the possibility that simply participating in the study served as a de facto intervention which motivated some people to reduce their consumption [48]. The enactment of state level restrictions of the purchase of over-the-counter sinus and cold medications containing methamphetamine precursor agents could partially explain reductions in methamphetamine use, but our results refute this explanation. A small percentage of known users were still able to gain access to the drug either from distributors continuing to operate small, personal laboratories or from alternative supply chains, such as foreign producers. In fact, some estimates indicate that the majority of the methamphetamine distributed currently in the United States is imported from Mexico [49]. Although we found no evidence of an association between the precursor agent restrictions and methamphetamine consumption among people who already made the decision to use methamphetamine, it is possible that the restrictions help prevent the initiation of methamphetamine consumption among non-users. Moreover, these laws may yield other benefits not examined in the current study. For example, methamphetamine laboratories are also an important public health problem in and of themselves, as they contain hazardous chemicals which place producers as well as law enforcement and emergency personnel at substantial risk of injury or death from inhalation, fire and explosion [50,51]. Other data indicate that the number of methamphetamine laboratory incidents declined in the year after enactment of the methamphetamine law in Arkansas, but there was no such change in Kentucky [52]. Surprisingly, we found that methamphetamine legislation was associated with a slight but significant rise in powder and crack cocaine consumption. While we do not

7 806 Tyrone F. Borders et al. Table 4 Model of days using methamphetamine, powder, and crack cocaine in past 30 days.* Meth Powder cocaine Crack cocaine Variable (reference group) b P-value b P-value b P-value Main variables of interest African American (ref. white) Time Months exposed to meth law Demographic/social factors Age Male (ref. female) Married/partner (ref. single) Have children (ref. no children) Educational status High school (ref. < high school) College/tech. (ref. < high school) ASI scores Employment score Family/social score Legal score Psychiatric score Alcohol in past 30 days 1 19 days (ref. 0 days) days (ref. 0 days) Marijuana in past 30 days 1 19 days (ref. 0 days) days (ref. 0 days) *Results are from generalized estimating equations with a negative binomial distribution for the dependent variable and adjusted for state of residence and year of entry into the study. Months exposed to meth law: no. of days exposed to law at the interview date/30. ASI: Addiction Severity Index. have information about important market factors such as the supply and price of each stimulant where the study was conducted, it is plausible that the methamphetamine legislation reduced the supply of methamphetamine and, in turn, contributed to increased demand for cocaine. Some stimulant users could have switched from methamphetamine to cocaine, but we hypothesize that much of the increase in cocaine use is attributable to people who had a history of using both cocaine and methamphetamine. However, given the observational design of this study, we must caution against concluding that the enactment of methamphetamine laws caused known stimulant users to consume more cocaine. In addition to the main variables of interest, several other factors emerged as significant correlates of stimulant use. Participants of all ages were equally likely to use methamphetamine. However, while older participants were less likely to use powder cocaine, they were more likely to use crack. We doubt that older people mature out of using powder cocaine, but that these age-related differences reflect differences in drug preferences between younger and older cohorts. Although no cause effect relationships can be inferred, the positive association between poor employment and legal scores from the ASI and stimulant use underscore the possibility that continued drug use leads to employment and legal problems. Finally, the findings mirror those from national surveys which have demonstrated the concomitant use of alcohol and marijuana with cocaine [53,54] and provide new evidence of a similar concomitant association with methamphetamine. A major strength of the proposed study is that it was carried out in three different rural regions of the United States, thereby increasing the generalizability of the findings. We recognize, however, that this does not guarantee that results will be applicable to other urban or rural areas of the United States or abroad. A strength and limitation of the study is that it used RDS for recruitment. Although non-random sampling raises concerns about generalizability and bias, we have evidence from our Ohio data that RDS yielded a sample which is fairly representative of the underlying population of interest and have reason to believe the same for our Arkansas and Kentucky samples. CONCLUSION In summary, we found that laws restricting the purchase of over-the-counter cold medications containing methamphetamine precursors were associated with increased

8 Longitudinal methamphetamine and cocaine use 807 cocaine consumption. However, despite the recent surge in methamphetamine in rural areas of the United States, very few African American cocaine users have begun to use methamphetamine. Many rural stimulant users, regardless of race, stopped using cocaine and methamphetamine without formal treatment over the course of 2 years, a change that could result in increased quality of life through better health, decreased criminal justice involvement and greater opportunities for employment. Future research should examine whether stimulant users substitute cocaine and methamphetamine for other drugs or alcohol over time. Finally, we recommend the conduct of additional research to identify the intrapersonal, family and geographic factors that facilitate remission from drug use and distinguish those who are unable to abstain without formal treatment. Acknowledgements We would like to thank Reid Landes PhD for statistical consultation and Shanti Tripathi MS for assistance with data management. This research was supported by National Institute on Drug Abuse grant R01 DA15363 to Brenda M. Booth and grant R01 DA14340 to Harvey A. Siegal, who died on 22 December Robert Carlson is now principal investigator of R01 DA The views expressed in this article do not necessarily reflect those of the National Institute on Drug Abuse, the Department of Veterans Affairs or the relevant universities. References 1. Rawson R. A., Condon T. P. Why do we need an Addiction supplement focused on methamphetamine? Addiction 2007; 102(Suppl. 1): United Nations Office of Drugs and Crime (UNODC) World Drug Report. Vienna: UNODC; United Nations Office of Drugs and Crime (UNODC) World Drug Report. Vienna: UNODC; Booth B. M., Leukefeld C., Falck R. S., Wang J., Carlson R. 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