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

Design and Methods

Data and Sample

Data for this study came from the public use files of the 2008–2012 National Survey on Drug Use and Health. The annual NSDUH series primarily measures the prevalence and correlates of drug use and health status of the civilian, noninstitutionalized U.S. population aged 12 or older (Inter-university Consortium for Political and Social Research [ICPSR], 2012a). The survey covers substance abuse, treatment history, illegal activities, and arrest record and included questions from the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) that were asked of respondents aged 18 and older. Survey respondents were selected based on multistage area probability sampling methods designed to ensure their representativeness and uniqueness (i.e., nonduplication from year to year). Respondents were interviewed in private at their place of residence using a combination of methods (audio computer-assisted self-interview, computer-assisted personal interview, and computer-assisted self-interview) to increase the validity of reports of substance use and illegal activity (ICPSR, 2012a).

To increase the study's power to detect low frequency events (e.g., DUI arrest), we combined 5 years of the de-identified, public-domain survey data. The data collection methods for the variables examined in this study were the same for all five survey years. The total number of respondents who completed the survey was 55,739 in 2008, 55,772 in 2009, 57,873 in 2010, 58,397 in 2011, and 55,268 in 2012. The number of respondents in the 50–64 age group was 3,317 in 2008, 3,461 in 2009, 3,523 in 2010, 4,219 in 2011, and 3,923 in 2012. The number of respondents in the 65+ age group was 2,008 in 2008, 2,015 in 2009, 2,144 in 2010, 2,486 in 2011, and 2,448 in 2012. This study focused on the 29,634 respondents aged 50+ from 2008 to 2012: 18,443 were 50–64 years of age and 11,191 were 65+ years of age.

Measures

DUI in the Past 12 Months. The NSUDH included four DUI-related questions: (a) "During the past 12 months, have you driven a vehicle while you were under the influence of a combination of alcohol and illegal drugs used together?" (b) "During the past 12 months, have you driven a vehicle while you were under the influence of alcohol/alcohol only?" (c) "During the past 12 months, have you driven a vehicle while you were under the influence of illegal drugs/illegal drugs only?" and (d) "In the past 12 months, were you arrested and booked for driving under the influence of alcohol or drugs?" (ICPSR, 2012b). An affirmative response to any of the earlier questions was considered DUI (1 = yes, 0 = no).

Alcohol Use in Past 12 Months. This was defined as consuming at least one drink of any type of alcoholic beverage (described as a can or bottle of beer, a glass of wine or a wine cooler, a shot of liquor, or a mixed drink with liquor) and excluded the use of only a sip or two from a drink (ICPSR, 2012b). Frequency of alcohol use: Alcohol users reported the total number of days they used alcohol in the past 12 months (1–11, 12–49, 50–99, 100–299, and 300–365 days). Binge alcohol use was defined as drinking ≥5 drinks on the same occasion (i.e., at the same time or within a couple of hours of each other) on at least 1 day in the past 30 days. Heavy alcohol use was defined as drinking ≥5 drinks on the same occasion on each of five or more days in the past 30 days; all heavy alcohol users are, therefore, also binge alcohol users. DSM-IV diagnoses of alcohol dependence and abuse are also presented to describe the sample. Alcohol dependence and abuse were determined only if respondents reported alcohol use on more than 5 days in the past year.

Illicit Drug use in Past 12 Months. This included "marijuana use" (1 = yes, 0 = no) and "illicit drug use other than marijuana" (1 = yes, 0 = no). Because of the small proportion of illicit drug users, frequency of use was not considered, but DSM-IV diagnoses of illicit drug dependence and abuse were presented to describe the sample. Marijuana dependence and abuse were determined only if respondents reported use on more than 5 days in the past year, but the diagnostic criteria for other illicit drugs applied regardless of days of use.

Psychosocial Vulnerabilities in Past 12 Months. This was represented by major depressive episode (MDE) in the past year that met DSM-IV diagnostic criteria (yes = 1, no = 0). To describe the sample, we also present worst month serious psychological distress (SPD), which was measured with the six-item, 4-point Kessler Psychological Distress Scale (K6; 0 = none of the time to 4 = all of the time; Kessler et al., 2003). NSDUH respondents were asked how frequently during the past 30 days they experienced "feeling nervous; feeling hopeless; feeling restless or fidgety; feeling so sad or depressed that nothing could cheer you up; feeling that everything was an effort; and feeling down on yourself, no good, or worthless." A summed score of 13 or higher was considered as having had SPD in the past year. Cronbach's alpha for the K6 among the study sample was 0.91. Of those aged 50–64, 53.76% of those with SPD also had MDE and 29.47% of those 65+ years who had SPD also had MDE.

Poor Decision-making Tendencies. This was measured by lifetime arrest history. Respondents were asked whether or not they had ever been arrested/booked for "breaking the law" in their lifetime (yes = 1, no = 0).

Sociodemographic and Health Status. Sociodemographic factors included age group (individual chronological age is not available in the public use data sets), gender, race/ethnicity, marital status, education, and income. Health status variables included self-ratings of health (on a 5-point scale; 1 = excellent and 5 = poor) and the number of diagnosed chronic illnesses (asthma, cirrhosis of liver, diabetes, high blood pressure, heart disease, stroke, lung cancer, and pancreatitis).

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