Vaping was linked to an older “biological age” in a US survey

Smoking cigarettes is well known to speed up the wear and tear of aging and to raise the risk of heart disease. E-cigarettes, which heat a nicotine liquid into a vapour instead of burning tobacco, are much newer, so much less is known about their long-term effects. A team at the Boston University School of Public Health asked a simple question: do people who vape look biologically older than people who don't?

What they did

The team used the National Health and Nutrition Examination Survey (NHANES), a long-running US survey that interviews and examines a sample of people chosen to represent the whole country. They took two rounds from before the COVID-19 pandemic, 2015–2016 and 2017–2018, and included 8,595 adults aged 20 to 79.

• Vaping: “current” meant any use in the past 30 days (417 people), “former” meant ever used but not recently (1,253), and the rest had never used e-cigarettes (6,925).
• Biological age: they used PhenoAge, a score that combines nine routine blood measures (such as the white blood cell count and the liver enzyme alkaline phosphatase) with a person's age into an estimated age that tracks the risk of disease and death. The key number was the gap between PhenoAge and actual age: positive means “older than your years”.
• Fair comparison: the analysis took into account cigarette smoking, sex, ethnicity, education, body weight, alcohol, use of cigars or smokeless tobacco, and exposure to second-hand smoke.

What they found

• Current vapers: their biological age was about 1.2 years older than that of never-users, after the adjustments.
• Former vapers: about 0.7 years older.
• Cigarette smokers, for comparison: current smokers were about 1.5 years older than people who had never been regular smokers. Former smokers were not significantly different from never-smokers.
• Not just smokers in disguise. More than half of current vapers also smoked cigarettes. But when the team looked only at people who had never been regular smokers, the link with vaping remained and was stronger. It also held in people aged 50 or younger, who made up most of the vapers.

What to keep in mind

• A snapshot, not a film. The authors point out that the survey measured everyone once, so it can't show whether vaping came before the older-looking blood tests, or the other way round. They call for long-term studies.
• Links, not causes. This is an observational study. Vapers differed from non-vapers in many ways (they were younger, more often male, and drank more often); the adjustments help but can't rule out other differences.
• Self-reported habits. Vaping and smoking were reported by participants, and the authors say some tobacco use may have been missed. How often people vaped varied too little to test whether more vaping meant a bigger gap.
• One measure of aging. PhenoAge is only one of many “biological age” scores, and the authors suggest checking the result with others.
• About a year. The differences are averages across groups, about one year of “biological age”, and say little about any one person.

Why it matters

E-cigarettes are often seen as a lower-risk alternative to smoking, and many people use both. This study is among the first to look at vaping and a measure of biological aging in a large, nationally representative sample. The link it found was a little smaller than that for current smoking but still there in people who had never smoked regularly. The pattern for cigarettes, with no clear difference for former smokers, is consistent with the idea that stopping may help, although a survey like this can't prove it. Long-term studies that follow vapers over years are needed before anyone can say whether vaping itself speeds up aging.