Cannabis, ENDS, and Tobacco Co-use and Co-exposures Among ECHO Adolescents and Emerging Adults

Analyzing data from 2,786 US adolescents and emerging adults in the ECHO consortium, this study identified four distinct latent classes of tobacco, ENDS, and cannabis use and environmental exposure that vary by developmental stage, underscoring the need for tailored interventions that address both active substance use and environmental co-exposures.

The Gist

Imagine a giant, invisible cloud hovering over the lives of teenagers and young adults. For decades, we knew this cloud was made of cigarette smoke, and we worked hard to clear it out. But recently, the composition of that cloud has changed. Now, it's a swirling mix of cigarette smoke, vape clouds, and cannabis smoke.

This new study is like a weather report for that cloud. It asks a simple but crucial question: Who is getting caught in the storm, and how are they getting wet?

Here is the breakdown of the research in plain English, using some everyday analogies.

🌪️ The Big Picture: The "Mix" is Changing

In the past, if a kid was exposed to smoke, it was usually just from a parent smoking cigarettes. Today, the landscape has shifted.

• The "New Neighbors": More adults (parents) are using cannabis and vaping.
• The "Social Scene": Teens are hanging out with friends who vape and smoke weed.
• The Result: Kids aren't just breathing in one type of smoke; they are breathing in a cocktail of emissions.

The researchers looked at nearly 3,000 young people (ages 11 to 24) across the US to see how they are interacting with these substances. They didn't just ask, "Do you smoke?" They asked, "Do you smoke? Do your friends smoke? Do your parents smoke? Are you breathing it in at home or at parties?"

🔍 The Four "Weather Patterns" (Latent Classes)

Using a fancy statistical tool (think of it as a super-powered sorting machine), the researchers sorted these young people into four distinct groups based on their habits and what they were breathing in.

1. The "Clean Air Club" (53% of kids)

• Who they are: The majority of kids, especially the younger ones (11–13).
• The Vibe: They don't use any of these substances, and they aren't breathing them in either.
• Analogy: They are living in a house with a fresh air filter and no one inside is smoking. They are safe and clear.

2. The "Passive Bystanders" (10% of kids)

• Who they are: Mostly younger kids who don't use the substances themselves but are surrounded by them.
• The Vibe: They aren't the ones lighting up, but their parents or roommates are. They are breathing in the smoke/vapor against their will.
• Analogy: Imagine sitting at a dinner table where everyone else is eating spicy food, and you're the only one who isn't, but you're still getting the spicy fumes in your face. You didn't ask for it, but you're getting exposed.

3. The "Experimenters" (22% of kids)

• Who they are: Mostly middle-to-late teens (14–17).
• The Vibe: They have tried these things a little bit (maybe a puff at a party), but they aren't heavy users. They aren't breathing in huge amounts of smoke either.
• Analogy: These are the kids who dipped their toes in the pool. They've tasted the water, but they aren't swimming laps yet.

4. The "Heavy Mixers" (14% of kids)

• Who they are: Mostly older teens and young adults (18–24).
• The Vibe: This group is the most at risk. They use multiple substances (cannabis, vapes, and maybe tobacco), and they are surrounded by them everywhere they go.
• Analogy: They are in the middle of a foggy forest where everyone is lighting fires. They are actively participating in the fire, and the smoke is thick around them.

📈 The Age Factor: Growing Into the Cloud

The study found a clear pattern as kids get older:

• Younger Kids (11–13): Mostly in the "Clean Air" or "Passive Bystander" groups. Their exposure usually comes from home (parents).
• Older Kids (18–24): They move into the "Experimenter" and "Heavy Mixer" groups. Their exposure shifts from home to social circles (friends, parties, college).

It's like a graduation ceremony for the smoke cloud: as you get older, you move from being a passive victim of your parents' habits to an active participant in your own social habits.

🛡️ Why This Matters (The "So What?")

The researchers are sounding an alarm for three main reasons:

1. The "Double Whammy": Breathing in a mix of cannabis smoke, vape aerosol, and tobacco smoke is worse than breathing in just one. It's like drinking a smoothie made of three different poisons; the damage to your lungs and heart is compounded.
2. The "Parent Trap": Many parents think, "I don't smoke cigarettes, so my kid is safe." But if they are vaping or smoking weed indoors, their kids are still breathing in toxic fumes. The study shows that as adult cannabis use goes up, kids' exposure goes up too.
3. One-Size-Fits-All Doesn't Work: You can't tell a 12-year-old the same thing you tell a 22-year-old.
   • For the 12-year-old: The solution is helping their parents quit or smoke outside.
   • For the 22-year-old: The solution is helping them quit their own habits and avoid friends who are heavy users.

💡 The Takeaway

We spent a century figuring out that cigarette smoke is bad. Now, we are realizing that vape clouds and weed smoke are creating a new, complex cloud of danger.

The study suggests we need to stop looking at these substances in isolation. We need to:

• Update the Rules: Make "smoke-free" zones include vapes and weed, not just cigarettes.
• Talk to Parents: Remind them that "smoke-free" means all smoke, even if it's "just weed."
• Tailor the Message: Give younger kids tools to protect themselves from their parents' habits, and give older kids tools to make better choices for themselves.

In short: The air is getting thicker with new types of smoke. We need to clear the air before the next generation gets stuck in the fog.

Technical Summary

1. Problem Statement and Background

The study addresses a critical gap in public health research regarding the concurrent use of cannabis, electronic nicotine delivery systems (ENDS), and combustible tobacco among youth, alongside their environmental exposures.

• Context: While smoking cessation and reduced environmental tobacco smoke (ETS) exposure have improved over the last three decades, the landscape has shifted with the legalization of recreational cannabis and the proliferation of ENDS.
• The Gap: Existing literature often examines these substances in isolation or focuses on active use rather than co-exposure (passive inhalation of smoke/aerosols). Furthermore, there is a lack of understanding regarding how these use and exposure patterns vary across developmental stages (early adolescence, middle adolescence, and emerging adulthood).
• Hypothesis: The authors posit that co-use and co-exposure are rising and that distinct latent profiles exist that vary by age, necessitating developmentally tailored interventions.

2. Methodology

• Data Source: Secondary data from the Environmental influences on Child Health Outcomes (ECHO) consortium (3rd data release, 2018–2022).
• Sample:
  • Total N: 2,786 adolescents and emerging adults (ages 11–24).
  • Demographics: Early adolescents (11–13; 7.9%), Middle adolescents (14–17; 43.4%), and Late adolescents/Emerging adults (18–24; 48.7%).
  • Cohorts: Aggregated from 19 distinct US-based pediatric cohorts.
• Measures:
  • Substance Use: Assessed via the Youth Risk Behavior Survey (YRBSS) Substance Use module. Variables included lifetime, experimental (past 12-month but not past-month), and current (past-month) use of:
    • Cannabis (smoking, vaping, edibles).
    • ENDS (vaping).
    • Tobacco (cigarettes and other products like cigars/dip, combined into a single variable).
  • Environmental Exposure: Measured via two indicators dichotomized as "No Exposure" vs. "Exposure":
    1. Average daily hours spent near others smoking/vaping.
    2. Number of household members who smoke/vape indoors.
    • Types: Environmental Tobacco Smoke (ETSE), Environmental Nicotine Aerosol Exposure (ENAE), and Environmental Cannabis Smoke Exposure (ECSE).
• Statistical Analysis:
  • Primary Method: Multiple-Group Latent Class Analysis (LCA).
  • Indicators: Six binary/ordinal indicators (Tobacco Use, Cannabis Use, ENDS Use, ETSE, ENAE, ECSE).
  • Model Selection: A 4-class solution was selected based on fit indices (Supplementary Table S5) as the optimal model.
  • Software: RStudio (packages: mglca, poLCA, ggplot2, dplyr).
  • Handling Missing Data: Full-information maximum likelihood (FIML) estimation was used for participants with partial data (<10% missingness), assuming Missing at Random (MAR).

3. Key Contributions

• Simultaneous Assessment: This is the first study to simultaneously model active co-use and environmental co-exposure to tobacco, ENDS, and cannabis within a large, multi-cohort sample of US youth.
• Developmental Granularity: The study explicitly stratifies findings across three distinct developmental stages (Early, Middle, Late adolescence/Emerging Adulthood), revealing how risk profiles shift as youth age.
• Identification of "Polyexposure" in Non-Users: The analysis identified a significant subgroup of youth who do not actively use substances but are heavily exposed to them in their environment (e.g., living with users), a group often overlooked in standard cessation-focused interventions.

4. Key Results

The LCA identified four distinct latent classes:

Latent Class	Prevalence	Characteristics
1. No Use / No Exposure	53%	Minimal use and minimal environmental exposure.
2. No Use / Polyexposure	10%	No active use, but high probability of environmental exposure (ETSE, ENAE, ECSE).
3. Experimental Use / Low Exposure	22%	Low/moderate experimental use (mostly cannabis/ENDS) with low environmental exposure.
4. Polysubstance Use / High Polyexposure	14%	High probability of current use (all three substances) and high environmental exposure.

Developmental Trends:

• Early Adolescence (11–13): Dominated by No Use/No Exposure (75%) and No Use/Polyexposure (22%). Very little active use.
• Middle Adolescence (14–17): Shift begins; Experimental Use/Low Exposure rises to 11%.
• Late Adolescence/Emerging Adults (18–24): Significant shift toward active use.
  • Experimental Use/Low Exposure: 36%.
  • Polysubstance Use/High Polyexposure: 21% (None in early adolescence, 9% in middle, 21% in late).
  • No Use/No Exposure: Drops to 37%.

Substance Specifics:

• Cannabis: Most prevalent substance (34% experimental/current use) and most common source of environmental exposure (20%).
• ENDS: 26% experimental/current use; 19% environmental exposure.
• Tobacco: Lowest prevalence (15% use; 19% exposure).
• Exposure Sources:
  • Younger youth: Exposure primarily driven by household/caregiver use (ETSE).
  • Older youth: Exposure increasingly driven by peer/social contexts (ENAE and ECSE).

5. Significance and Implications

• Public Health Policy: The findings suggest that current smoke-free policies often exclude cannabis and ENDS, leaving youth vulnerable to "polyexposure." The authors argue for amending smoke-free air regulations to encompass all forms of cannabis, nicotine, and tobacco emissions, particularly in multi-unit housing.
• Intervention Strategy:
  • Younger Youth: Interventions should be family-centered, focusing on caregiver cessation and education regarding environmental risks (e.g., cotinine levels in children living with users).
  • Older Youth: Interventions must address peer contexts and harm reduction strategies for social environments.
• Clinical Practice: Pediatric screening should expand beyond asking "Do you smoke?" to include questions about environmental exposure to cannabis and vaping, as these exposures are linked to respiratory and cardiovascular risks (oxidative stress, endothelial dysfunction) even without active use.
• Future Research: The study highlights the need for longitudinal data to establish causality and more granular data on exposure contexts (ventilation, proximity, product type).

Conclusion: The study concludes that the rise in cannabis and ENDS legalization has created a complex landscape of co-use and co-exposure. Prevention strategies must evolve from single-substance approaches to developmentally tailored, multi-substance frameworks that address both active use and involuntary environmental exposure.