Simultaneous use of cannabis and nicotine products is common among young adults, particularly those who vape, according to a new study by researchers at Columbia University Mailman School of Public Health. The research, published in Tobacco Induced Diseases, examined patterns and motivations for cannabis use among young adults in the New York City area.
The study found that both vaped and smoked cannabis use have increased over time, with more participants starting than quitting. Young adults reported using multiple forms of cannabis, including vapes, edibles, and topicals. In 2023, an estimated 61.8 million people—22 percent of Americans aged 12 and older—reported using marijuana at least once in the past year.
"Cannabis use in the U.S. represents a multifaceted and evolving public health challenge that has, for too long, been overlooked," said Katlyn McGraw, PhD, postdoctoral research scientist at Columbia Mailman School. "We aimed to better understand use patterns and potential exposure to cannabis-related contaminants and associated health effects. Our findings show that cannabis use is diverse, complex, and growing -underscoring the need for further investigation."
Researchers analyzed data from the VapeScan longitudinal study involving 372 adults aged 18–50 from the New York City region between 2021 and 2024. Participants were assessed at three intervals: baseline (visit 1), about 12 months later (visit 2), and about 24 months later (visit 3). At each stage, participants provided information on their substance use habits.
By visit two of the study period, nearly six out of ten participants reported using cannabis. The frequency and intensity of usage varied by product type. Notably, self-reported vaped or smoked cannabis use changed between visits: while one-fifth were new users by visit two, only six percent had quit since visit one. Rates of dual cannabis/e-cigarette use were similar among men and women.
"Frequent cannabis use is becoming more widespread and will likely continue to rise with changing social norms, policy liberalization, and the increasing availability and promotion of cannabis products," McGraw noted. "The prevalence of cannabis use among teens and young adults is increasing, as is the variety of products-edibles, concentrates, vapes-adding to the complexity of studying health effects."
Ana Navas-Acien, MD, PhD., Leon Hess Professor at Columbia Mailman School added: "As the third most widely used drug globally, understanding the health implications of cannabis is essential," says Ana Navas-Acien."Our study highlights the importance of assessing cannabis exposure, including potential contaminants, and underscores that cannabis use is multifaceted. Regulatory policies and shifting consumer preferences further complicate efforts to accurately characterize exposure. Strengthening public health education that informs young adults about the compounded risks of cannabis–nicotine co-use is a first step."
Other contributors to this research include Nancy LoIacono; Siyue Gao; William Anderson; Dona Sangapalaarachchi; Vesna Illievski; Justin Liu; Silvia Martins; Tiffany R. Sanchez from Columbia Mailman School; Elizabeth Oelsner; Daichi Shimbo from Columbia University Irving Medical Center.
