Moderate-to-vigorous physical activity in childhood may protect 60% of 13-year-olds from smoking their first tobacco cigarette

Teenagers may be less likely to start tobacco smoking if they take part in moderate-to-vigorous physical activity (MVPA) from childhood, a new study by the University of Eastern Finland in collaboration with the universities of Bristol and Exeter has shown. The results are published in Behaviour Research and Therapy.

The study is the largest and the longest follow-up of accelerometer-based MVPA and smoking behaviour in young people in the world. 2,503 children from the University of Bristol’s Children of the 90s cohort were followed up from age 11 until 24 years. The incidence of smoking at ages 13, 15, and 24 years was 1.5%, 13.5%, and 26.6%, respectively.

According to the research, 6 out of 1,000 children who take part in MVPA at age 11 had begun tobacco smoking by 13-years-old, while the prevalence of smoking in the whole age group was 15 out of 1,000. In other words, the risk of starting tobacco smoking may be prevented in 60% of 13-year-olds who would have taken their first tobacco puff because of childhood participation in MVPA.

Continuous exposure to MVPA from childhood through young adulthood cumulatively lowered the risk of beginning and continuing tobacco smoking from ages 13 years to age 24 years in 8 out of 1,000 children when the prevalence of smoking was 266 out of 1,000 young adults.

Also, teenagers who were non-smokers at ages 13 and 15 years spent an extra 15 minutes a day in MVPA by age 24 years when compared with those who had a history of smoking at ages 13 and 15 years.

Childhood and teenage tobacco smoking is a strong preventable risk factor for early damage to the structure and function of the heart in mid-twenties. Physical activity intervention studies have reported reduced smoking rates among adults. However, physical activity studies in preventing smoking in children and adolescents have been inconclusive due to short study durations, small population sizes, and lack of accelerometer-measured physical activity data.

At baseline, the children spent six hours per day inactive, six hours per day engaging in light physical activity, and approximately 55 minutes per day in MVPA. At follow-up in young adulthood, nine hours per day were spent sedentary, three hours per day in light physical activity, and approximately 50 minutes per day in MVPA. The children’s fasting blood samples were also repeatedly measured for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, glucose, insulin, and high-sensitivity C-reactive protein. Blood pressure, heart rate, socio-economic status, family history of cardiovascular disease, as well as dual-energy X-ray absorptiometry measured fat mass and lean mass were accounted for in the analyses.

Professor Andrew Agbaje, Associate Professor of Clinical Epidemiology and Child Health at the University of Eastern Finland and lead author of the paper, said:

“The MVPA-smoking preventive potential had a strong causal consistency across all tested statistical models but the effect diminished by young adulthood. This requires supportive legislation to prevent tobacco smoking and/or nicotine use initiation from mid-teens through young adulthood.”

Increased time spent inactive during growth from childhood to young adulthood has been established as an independent risk factor for worsening insulin resistance, obesity, hypertension, inflammation, elevated cholesterol level, excess liver fat, and premature vascular and cardiac damage. However, increased childhood sedentariness was not associated with the risk of tobacco smoking.

Professor Agbaje explained:

“Stopping smoking in adulthood is good but late since a residual long-term risk of heart disease for the next thirty years still exists. Preventing childhood smoking initiation is critical to lifelong health and these findings may be extrapolated to vaping and electronic cigarette use in teenagers since the same active ingredient in both smoke and smokeless tobacco is nicotine.”

“The World Health Organization’s Freedom from nicotine and tobacco: guide for schools and Nicotine- and tobacco-free schools toolkit publications, recommends a ban on smoking on school campuses as well as prohibiting the sale and advertising of tobacco products near school campuses to protect children’s health. Parents, caregivers, and adults must show example to the young generation by living a tobacco and nicotine free life.”