# Medications and the Risk of Motor Vehicle Crashes in Older Adults

> **NIH NIH R01** · BROWN UNIVERSITY · 2021 · $442,653

## Abstract

PROJECT SUMMARY
Despite the common belief that prescription drug use is a leading cause of motor vehicle crashes, data are
scarce and controversy remains about the effects of medications on crashes in older adults aged ≥65 years.
Unlike other determinants of crashes (e.g., medical conditions), medications are one of few modifiable potential
determinants of the 6,800 crash-related deaths and 191,000 crash-related non-fatal injuries that occur annually
among older adults. In particular, psychoactive drugs are commonly used among older drivers, but may interfere
with safe driving. As more adults continue to drive into older age, there is an urgent need to understand the
effects of medications and distinguish them from the effects of contemporaneous age-related medical conditions,
impairments, and physiological changes. The overall objective of this proposal is to examine the causal effects
of medications on crashes in older drivers, and the extent to which these medications disproportionately affect
crash risk across subgroups [e.g., Alzheimer's disease and related dementias (ADRD), polypharmacy] and by
medication adherence status. The central hypothesis is that sedating psychoactive medications (opioids,
nonbenzodiazepine hypnotics, antidepressants, and antipsychotics) will increase crash risk while central
nervous system (CNS)-activating drugs (cholinesterase inhibitors, CNS simulants) and others (non-steroidal anti-
inflammatory drugs) will decrease the risk, and that these effects will be greatest among individuals with ADRD
and those who are adherent to their medications. This hypothesis will be tested by pursuing three specific aims:
1) Estimate the effect of initiating sedating psychoactive, CNS-activating, and other medications, including dose,
on crashes in older adults; 2) Quantify the effect of initiating sedating psychoactive, CNS-activating, and other
medications on crashes across important subgroups of older adults, including those with ADRD; polypharmacy;
multimorbidity; and sleep, psychiatric, neurological, and musculoskeletal disorders; and 3) Evaluate the effect of
non-adherence to sedating psychoactive, CNS-activating, and other medications, each separately compared to
adherence, on crash risk. To accomplish the three aims, our team will develop a unique database that combines
data on older drivers' licensing and crash histories; Medicare health insurance and drug claims; and data on
important determinants of medication use and crashes (e.g., access to transportation alternatives). This
approach is innovative because it is the first to compile high-quality U.S. data on all three domains necessary to
study the effect of medications on crashes—1) medical conditions (covariates); 2) medication use (exposure);
and 3) crashes (outcome)—in a dataset that is large enough to precisely estimate effects using causal inference
methods while accounting for differential driving frequency between drivers. The proposed research is significant
be...

## Key facts

- **NIH application ID:** 10260401
- **Project number:** 5R01AG065722-02
- **Recipient organization:** BROWN UNIVERSITY
- **Principal Investigator:** Andrew Reis Zullo
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $442,653
- **Award type:** 5
- **Project period:** 2020-09-15 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10260401

## Citation

> US National Institutes of Health, RePORTER application 10260401, Medications and the Risk of Motor Vehicle Crashes in Older Adults (5R01AG065722-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10260401. Licensed CC0.

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