“Cigarette smoking is an avoidable health risk, and its seeds are in childhood,” said David Jacobs, Jr., lead study author and Mayo Professor of Public Health in the Division of Epidemiology and Community Health at the University of Minnesota in Minneapolis in a news release.
The study, published in the Journal of the American Heart Association, drew on information from more than 6,600 people, 57% of whom were female, from the United States, Australia and Finland.
It looked at their experiences of smoking between the ages of 6 to 19, during their 20s and their 40s. The study said the prevalence of smoking during adolescence and adulthood was similar among US, Finnish and Australian participants in the study.
The new research has the longest follow-up of any study focused on smoking at an early age, the authors said.
Between 250 million to 270 million people in developed countries around the world smoke daily and smoking is thought to account for six million deaths per year among adults over 30, the study said. In the US, 87% of daily smokers started before age 18 and 95% started before age 21.
The younger people were when they started smoking, the more likely they were to be smoking daily in their 20s and less likely to have quit by their 40s, the research found.
- For those who first tried smoking at ages 18-19, just 8% still smoked daily in their 20s.
- For those who first tried smoking at ages 15-17, 33% were still smoking daily in their 20s.
- For those who first tried smoking at ages 13-14, 48% were still smoking daily in their 20s.
- For those who first tried smoking at ages 6-12, 50% were still smoking daily in their 20s.
Even children who only experimented with smoking a few cigarettes were more likely to end up smoking daily as an adult, the study found.
The study said it wasn’t clear why smokers with an early and more intense smoking history tended to smoke more as adults and have more trouble quitting, but they suggested it was the early exposure to nicotine.
“It has been suggested that nicotine addiction is stronger when smoking initiation occurs earlier in childhood,” the study said, although no age cut off point has been identified, it added.
“This is a very important study, both because it has data from multiple countries and because it has been able to follow individuals into middle age, a critical observation,” said Rose Marie Robertson, the deputy chief science and medical officer for the American Heart Association, who wasn’t involved in the study.
“It re-emphasizes the importance of keeping tobacco products out of the hands of children before age 21 to prevent long-term addiction.”
According to the US Food and Drug Administration, 27.5% of US high school students were current users of e-cigarettes in 2019 — up from 20.8% in 2018 and 11.7% in 2017.
“Vaping products had not been introduced at the time these study participants were teens, but it is plausible that the findings may relate to vaping as well, since both addiction to nicotine and the adverse effects of nicotine on the developing brain in youth are relevant to these nicotine delivery devices as well,” Robertson said.