Cannabis use associated with increased asthma prevalence
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Key takeaways:
- Asthma prevalence increased with the number of days of cannabis use in the previous 30 days.
- Odds for current asthma increased with blunt use compared with overall cannabis use.
Individuals who used cannabis in the previous 30 days were more likely to have current asthma, with a dose-response relationship between frequency of use and odds for asthma, according to a study published in Preventive Medicine.
However, no causal relationship should be inferred from this data, Renee D. Goodwin, PhD, MPH, a distinguished professor in the Graduate School of Public Health and Policy at the City University of New York, and colleagues wrote.
“Cigarette smoking is a risk factor for asthma and a trigger for asthma exacerbation. Public health programs such as education, prevention and available treatments have made much progress in lowering the prevalence of cigarette smoking,” Goodwin told Healio.
“With the rapid increase in cannabis use and exposure to secondhand cannabis smoke, we are interested in understanding whether cannabis use may be associated with asthma, and there is little to no information on this in the epidemiologic literature in the general population,” she said.
Study design, results
The researchers used data from 32,893 respondents aged 12 years and older in the 2020 National Survey on Drug Use and Health public-use data file. Overall, 7.4% (n = 2,611) of the sample had current asthma.
Current asthma prevalence also included 9.8% of those who reported any cannabis use in the previous 30 days (n = 432) and 7.1% of those who did not (n = 2,179). The odds ratio for current asthma among respondents reporting cannabis use was 1.43 (95% CI, 1.16-1.78) compared with those who did not report cannabis use.
“Current asthma is significantly more common among individuals who report any past 30-day cannabis use, relative to those who do not,” Goodwin said.
After adjusting for sociodemographic variables alone (adjusted OR = 1.38; 95% CI, 1.11-1.73) and for sociodemographic variables with cigarette use (aOR = 1.35; 95% CI, 1.07-1.69), this association remained significant.
“We found a dose-response relationship where greater frequency of cannabis use was associated with even greater likelihood of asthma,” Goodwin said. “The relationship was even stronger with blunt use, a hollowed-out cigar with cannabis in it, and asthma.”
The odds ratio for current asthma increased to 1.73 (95% CI, 1.29-2.31) for respondents who reported between 20 and 30 days of cannabis use in the previous 30 days.
Adjustments also found that these associations were not significant for respondents who reported fewer than 20 days of use in the previous 30 days, indicating a positive dose-response between the number of days of cannabis use and prevalence of current asthma (P < .0001), the researchers wrote.
The odds ratio for current asthma with blunt use in the previous 30 days was 1.66 (95% CI, 1.25-2.21) compared with a lack of blunt use.
Adjustments for sociodemographic variables (aOR = 1.61; 95% CI, 1.2-2.16) and cigarette use (aOR = 1.54; 95% CI, 1.14-2.09) also found significant associations between current asthma and blunt use.
These odds ratios increased with 6 to 19 days of blunt use (OR = 1.85; 95% CI, 1.07-3.21) and 20 to 30 days of blunt use (OR = 2.2; 95% CI, 1.35-3.6) in the previous 30 days, compared with no blunt use.
Combined with these findings, the lack of association between current asthma and fewer than 5 days of blunt use in the previous 30 days indicated a dose-response relationship between the number of days of use and the prevalence of current asthma (P < .0001), the researchers wrote.
Although the study indicated dose-response relationships between cannabis use and likelihood for current asthma, it did not explore age or sequence of asthma onset or cannabis use, so causal relationships should not be inferred, Goodwin and colleagues wrote.
These relationships may be due to unmeasured confounding, or cannabis use may lead to increased asthma persistence and exacerbation, the researchers wrote. Conversely, poorer asthma management may be associated with cannabis use.
Conclusions, next steps
Having conducted research on cigarette smoking, secondhand smoke and adult-onset and child-onset asthma for 20 years, Goodwin said that these findings were not surprising.
“What is surprising is the way that cannabis is now being marketed as a ‘healing’ or ‘wellness’ product without regulation by the FDA and that packaging, where legal, has no information on the potential risks associated with continued smoking of cannabis or the frequency,” Goodwin said.
The same could be said for cigarette packaging, she added, although at least cigarette packaging includes warnings and cigarettes are not advertised as health care products for all, though they once were.
“Physicians used to appear in ads recommending patients smoking cigarettes, and history appears to repeat itself here, without any data or warning of potential secondary health consequences,” she said. “That surprises me.”
Goodwin and colleagues also cautioned that empirical data about possible connections between asthma and cannabis use are limited and that the public remains uninformed about the potential impact that cannabis may have on asthma onset and control.
The researchers called for additional studies that would address the limitations of current studies of the relationship between asthma and cannabis and examine how asthma and cannabis use may be linked.
In the meanwhile, Goodwin said, patient communication matters.
“Screen patients in a sensitive and caring way about cannabis use, as you would for cigarette use and other potential triggers for asthma exacerbation and inform them that frequent use may compromise effective asthma management,” she said.
Goodwin and her colleagues are continuing their research as well.
“We are working on understanding the pathways underlying the observed link between cannabis use and asthma in order to provide more public education,” she said.
For more information:
Renee D. Goodwin, PhD, MPH, can be reached at rdg66@cumc.columbia.edu.