Substance abuse treatment need among older adults in 2020: the impact of the aging baby-boom cohort

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Abstract

Background: There is concern that as the baby boom population ages in the US, there will be a substantial increase in the number of older adults needing treatment for substance abuse problems. To address this concern, projections of future treatment need for older adults (defined as age 50 and older) were made. Methods: Using data from the National Household Survey on Drug Abuse, regression models including predictors of treatment need in 2000 and 2001 were developed. Treatment need was defined as having a DSM-IV alcohol or illicit drug use disorder in the past year. Regression parameters from these models were applied to the projected 2020 population to obtain estimates of the number of older adults needing treatment in 2020. Results: The number of older adults in need of substance abuse treatment is estimated to increase from 1.7 million in 2000 and 2001 to 4.4 million in 2020. This is due to a 50 percent increase in the number of older adults and a 70 percent increase in the rate of treatment need among older adults. Conclusions: The aging baby boom cohort will place increasing demands on the substance abuse treatment system in the next two decades, requiring a shift in focus to address the special needs of an older population of substance abusers. There is also a need to develop improved tools for measuring substance use and abuse among older adults.

Introduction

Historically, alcohol and illicit drug abuse in the United States have been associated with young populations. Rates of problematic use have been shown by many studies to decline with increasing age, starting in the mid- to late 20s (SAMHSA, 2000a, DHHS, 2000). This is primarily due to reduced use of both alcohol and illicit drugs by people as they age. When people are in their 20s and 30s, the reduced use is related to significant shifts in responsibilities, such as a having a regular job, marriage and parenthood (Bachman et al., 1997, Gotham et al., 1997). The continued reductions in prevalence rates at later ages could be related to ‘maturing out’ (Winick, 1962) or to elevated mortality rates among substance abusers (Moos et al., 1994).

Birth cohorts that experience high rates of illicit drug use in youth have subsequently shown higher rates of use and associated problems as they age, relative to other cohorts (SAMHSA, 2000a). Illicit drug use in the US was rare in cohorts immediately preceding the baby-boom cohort, defined as those born from 1946 to 1964. The rate peaked in 1979, when the baby-boom cohort was ages 15–33. During that peak year, approximately 10% of the estimated 25 million current illicit drug users were age 35 or older. In 1995, when the baby-boom cohort was ages 31–49, the percentage of current illicit drug users who were over the age of 34 had increased to 27%. In 1995, 49% of the baby-boom cohort had ever used illicit drugs in their lifetime, compared to only 11% of adults aged 50 and older (SAMHSA, 1996). Rates of heavy alcohol use have also been shown to be higher among baby boomers than in earlier cohorts (DHHS, 2000). In addition to being more likely to be illicit drug and heavy alcohol users than previous cohorts, the baby-boom cohort is larger than earlier cohorts (Koenig et al., 1994). Taken together, these data suggest that the prevalence of problematic substance use among older adults may increase as the baby-boom cohort ages. In 1996, the oldest members of the baby-boom cohort reached age 50. In 1998, only 7% of admissions to publicly-funded substance abuse treatment programs involved patients age 50 or older (SAMHSA, 2000b). The higher rates of problematic substance abuse among the baby- boom cohort will likely lead to an increase in this number. This will require a shift in focus for treatment programs, which have dealt primarily with young populations, in order to address the special needs of an older population of substance abusers.

Information on the size and nature of this potential shift in treatment need is critical to treatment planners and policymakers. The purpose of this paper is to estimate the number of persons with a need for treatment for substance abuse problems in the United States in the year 2020. In 2020, the 50-and-older age group will include all of the surviving baby boomers as well as a post-baby-boom cohort (born 1965–70) that also experienced a high rate of illicit drug use during youth (SAMHSA, 1996).

A variety of methods has been used by researchers to project future disease burden in the United States and other countries. Projections of future prevalence of Alzheimer's disease in the US (Brookmeyer et al., 1998, Brookmeyer and Gray, 2000), diabetes in the Netherlands (Ruwaard et al., 1993), and mental disorders in Japan (Nakamura et al., 1997) have been made. Two early studies made projections of future prevalence of illicit drug use (Richards, 1981) and alcohol abuse and dependence (Williams et al., 1989). Most studies have made projections by first determining rates of incidence or prevalence of the health measure of interest within demographic subgroups, then applying these rates to population projections produced under various assumptions from census data. Adjustments for differential mortality related to the health measure under study have generally been incorporated, when available. Few studies have incorporated data on other (i.e. in addition to demographics) predictors of the outcomes of interest to improve the prevalence rate estimates. A study of future disability among the US elderly assessed the impact of changing levels of education in aging cohorts (Waidmann and Liu, 2000) based on current data showing the correlation between education and disability. Feenstra et al. (2001) included information on past smoking behavior in their model predicting the future prevalence of chronic obstructive pulmonary disease in the Netherlands. A study of future rates of melanoma in Canada discussed the importance of early sun exposure as a predictor, but the authors lamented that there were no data on the prevalence of sun exposure to use in their model (MacNeill et al., 1995).

In contrast with prior attempts to project future US substance abuse burden and most other studies projecting health-related measures, this study incorporates known predictors of substance abuse. Specifically, youths who initiate illicit drug and alcohol use in their early teenage years have been shown to be at greater risk of having substance abuse problems as adults than are youths who never use or who initiate use during their late teenage years (Anthony and Petronis, 1995, Grant and Dawson, 1997, Gfroerer and Epstein, 1999, SAMHSA, 2000a). The goal of this analysis is to take advantage of current data on the patterns of substance use initiation to estimate the prevalence of substance abuse problems in the future.

A previous study that employed a similar methodology estimated that the number of persons aged 50 and older who would need treatment for an illicit drug problem would increase from 147 000 in 1995 to 911 000 in 2020 (Gfroerer and Epstein, 1999). The current study employs some methodological improvements and focuses on a broader population of substance abusers, including those meeting DSM-IV criteria for dependence or abuse of either alcohol or illicit drugs.

Section snippets

Methods

The estimation of substance abuse treatment need among older adults in 2020 involved two steps. First, regression models were run predicting treatment need (defined as dependence on or abuse of either illicit drugs or alcohol) among the older adult population in 2000 and 2001. The purpose of these models was to determine parameter estimates that characterized the relationship between a set of independent variables and treatment need among older adults. Second, the parameters estimated from

Regression models

The Hosmer–Lemeshow tests suggest that there was adequate fit in both the low-risk model (P=0.5928) and the high-risk model (P=0.5462). The maximum re-scaled r-squares were r2=0.03 for the low-risk model and r2=0.08 for the high-risk model. These low r2 values are typical of models with a dichotomous (0/1) outcome measure that has low prevalence, and also reflect the limited number of predictors available in the NHSDA that meet the requirement for this analysis that they be fixed for each

Discussion

These data suggest that the number of adults aged 50 or older who need treatment for a substance abuse problem will increase from approximately 1.7 million in 2000 and 2001 to approximately 4.4 million in 2020. Although this analysis does not distinguish the specific kinds of problems that the estimated 5 million older-adult substance abusers in 2020 will have, it is apparent that the increasing rate of treatment need in this population is driven by an increase in problems associated with the

Acknowledgements

Work by RTI researchers was supported by SAMHSA contract 283-99-0003. Data were collected by RTI under SAMHSA contract 283-98-9008.

References (37)

  • T.L Feenstra et al.

    The impact of aging and smoking on the future burden of chronic obstructive pulmonary disease: a model analysis in the Netherlands

    Am. J. Respir. Crit. Care Med.

    (2001)
  • A Golub et al.

    Variation in youthful risks of progression from alcohol and tobacco to marijuana and to hard drugs across generations

    Am. J. Public Health.

    (2001)
  • H.J Gotham et al.

    Predicting stability and change in frequency of intoxication from the college years to beyond: individual-difference and role transition variables

    J. Abnorm. Psychol.

    (1997)
  • D.W Hosmer et al.

    Applied Logistic Regression

    (1989)
  • H.G Koenig et al.

    Mental health care for older adults in the year 2020: a dangerous and avoided topic

    Gerontologist

    (1994)
  • W Lutz et al.

    First probabilistic population projections for the European Union

  • I.B MacNeill et al.

    Trends in mortality from melanoma in Canada and prediction of future rates

    Stat. Med.

    (1995)
  • R.H Moos et al.

    Mortality rates and predictors of mortality among late- middle-aged and older substance abuse patients

    Alcohol Clin. Exp. Res.

    (1994)
  • Cited by (0)

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