Risk Factors for Self-reported Driving Under the Influence of Alcohol and/or Illicit Drugs Among Older Adults

Namkee G. Choi, PhD; Diana M. DiNitto, PhD; C. Nathan Marti, PhD

Disclosures

Gerontologist. 2016;56(2):282-291. 

In This Article

Abstract and Introduction

Abstract

Purpose of the Study: Despite the increasing number of older adults who have a history of substance use, little research has been done on alcohol- and drug-related driving safety among older drivers. This study (a) examined risk factors for older adults' driving under the influence of alcohol and/or drugs (DUI) and (b) discerned differences between those aged 50–64 and those aged 65+.

Design and Methods: Data came from the public use files of the 2008–2012 National Survey on Drug Use and Health for respondents aged 50+ (N = 29,634). Descriptive statistics were used to present sample characteristics by past year substance use and self-reported DUI status for age groups 50–64 and 65+. Age group separate binary logistic regression analysis was used to identify risk factors for DUI.

Results: Of past-year substance users in the 50–64 and the 65+ age groups, 14.54% and 6.19%, respectively, self-reported DUI. Higher frequency alcohol use, binge drinking, marijuana use, and major depressive episode significantly increased the odds of DUI in both age groups. Lifetime arrest history was a predictor in the 65+ age group only.

Implications: Research is needed to improve identification of older drivers at high risk of DUI. Driving safety assessments for older adults can incorporate screening for substance abuse and comorbid mental conditions to identify those at high DUI risk. Older adults who engage in risky substance use should be directed to appropriate services that address substance use and mental health problems concurrently.

Introduction

With the rapid growth of the population aged 65 and older, the number of older adult drivers is projected to double by 2030 from the 2009 figure of 33 million or 15.6% of all licensed drivers (United States Census Bureau, 2012). Although older drivers tend to have the lowest accident rate (4 per 100 drivers) of all age groups, they have one of the highest motor vehicle crash rates per vehicle mile of travel, and older drivers involved in crashes also tended to have more serious injuries requiring more health care resources than younger drivers (Lotfipour, Cisneros, & Chakravarty, 2013). The fatal injury risk from crashes also significantly increases in the 70+ group (Sifrit, Stutts, Martell, & Staplin, 2011). In 2009 alone, almost 1.4 million adults aged 65 or older had motor vehicle accidents, and 3,500 of the 65–74 group and 3,800 of the 75+ group were killed in crashes (United States Census Bureau, 2012).

Studies of driving safety among older adults have focused primarily on age-related declines in cognitive, functional, and visual capacities (Awadzi, Classen, Hall, Duncan, & Garvan, 2008; Thomas, Blomberg, Knodler, Mathew, & Romoser, 2013). Few have considered one of the major sources of preventable accidents—driving under the influence of alcohol and/or drugs. Alcohol and/or other drug involvement in crashes is less prevalent among older adults than among younger adults (Fell, Tippetts, & Voas, 2009). In 2012, drivers aged 65+ were 4.4% of all drivers involved in fatal crashes who had a blood alcohol concentration (BAC) ≥ 0.08g/dl; the proportion of drugged older drivers is estimated to be even lower (National Highway Traffic Safety Administration, 2013). However, studies have shown an increasing rate of substance use disorders among older adults, partly owing to aging baby boomers who are more likely to have a history of substance use and related problems than earlier cohorts (Blazer & Wu, 2009). A study based on the 2005 and 2006 National Survey of Drug Use and Health (NSDUH) found that 36.4% of those aged 65+ and 44.7% of those aged 50–64 used alcohol without abuse or dependence symptoms, but 6.7% of those aged 65+ and 11.2% of those aged 50–64 showed dependence, abuse, or subthreshold dependence symptoms (Blazer & Wu, 2011). A study based on data from the 2005–2008 National Health and Nutrition Examination Survey also found that 14.5% of drinkers aged 65+ consumed alcohol above the National Institute on Alcohol Abuse and Alcoholism's recommended limits (Wilson, Knowles, Huang, & Fink, 2014). When health status was taken into account, 37.4% had engaged in harmful consumption (i.e., exacerbating or complicating existing health problems) and 15.9% had engaged in hazardous consumption (i.e., drinking that posed risks of future harm).

Data from the 2007–2009 NSDUH also show that 9.0% of those aged 50–59 and 2.3% of those aged 60+ used illicit drugs (marijuana being the most common substance—5.9% of the 50–59 group and 1.1% of the 60+ group) (Substance Abuse and Mental Health Services Administration [SAMHSA], 2011). Illicit drug abuse treatment admissions among those 55 years and older have also been increasing. SAMHSA's Treatment Episode Data Set (a compilation of descriptive data on the national flow of admissions to specialty substance abuse treatment providers) for 1998–2008 showed a steady and substantial increase in admissions of those aged 55+ for a primary problem of illicit drug use (marijuana, cocaine, heroin, phencyclidine, hallucinogens, and methamphetamine), whereas alcohol use as the primary substance decreased slightly (Arndt, Clayton, & Schultz, 2011). Illicit drug use is much more common in the 50–59 age group than in the 60+ age group, but the prevalence may rise substantially in the 65+ age group as the younger cohort ages (Blazer & Wu, 2009; Han, Gfroerer, Colliver, & Penne, 2009).

Older adults tend to restrict or stop driving when physical, cognitive, and/or vision impairments begin to affect their driving abilities (Baldock, Mathias, McLean, & Berndt, 2006; Kostyniuk & Molnar, 2008; Stiffler & Wilber, 2013). However, older adults tend to overrate their driving abilities (Freund, Colgrove, Burke, & McLeod, 2005; Okonkwo, Crowe, Wadley, & Ball, 2008; Ross, Dodson, Edwards, Ackerman, & Ball, 2012). Alcohol and drug use may contribute to older drivers' overrating tendency because these substances affect cognitive functioning, especially reasoning and decision-making abilities, despite the fact that these substances negatively affect motor coordination and reaction times, concentration and memory, vision and ability to follow objects with eyes, and discrimination between light intensity and sound that are requisite for safe driving (Mitchell, 1985). Although drinking quantity tends to decline with age, alcohol-induced neurotoxicity in late life is a significant concern even with moderate alcohol consumption (Kapogiannis et al., 2012). Aging- and disease-related physiological changes (e.g., smaller body mass and lower water content) lead to higher and longer-lasting BACs in older adults than in younger adults (Ferreira & Weems, 2008). Older adults who take multiple prescription and nonprescription medications are also at higher risk for dangerous interaction effects of these medications with alcohol and/or illicit drugs.

For older adults, driving is not just a means of getting from one location to another but an essential tool for remaining mobile, socially integrated, and independent (Curl, Stowe, Cooney, & Proulx, 2014; Mezuk & Rebok, 2008; Oxley, 2008). Preserving older adults' mobility by prolonging their safe driving capacities and providing alternative transportation for those who can no longer drive is a necessity for successful aging. Older driver safety involves both vehicle/roadway characteristics and driver health/medical conditions (Staplin & Freund, 2013; Stutts, Martell, & Staplin, 2009). Increases in the number of older drivers combined with increases in the prevalence of substance use among older adults indicate that concerns should extend beyond those typically associated with older adult drivers' health and safety (e.g., physical/functional, cognitive, and sensory impairments) to include substance use. Despite a projected upward trajectory in the number and proportion of older adults who drive under the influence of alcohol and/or drugs (DUI), DUI among older adults has received little research attention compared with DUI among adolescents and young and middle-aged adults. Using multiyear survey data from nationally representative samples, the present study (a) examined DUI risk factors among older adults, focusing on their substance use patterns and psychosocial vulnerabilities and (b) discerned differences between those aged 50–64 and those aged 65+.

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