Secondhand Smoke Causes 8.45 Million Healthy Life Days Lost in Children: ERS Study

Children lose 8.45 million days of healthy life each year globally due to second hand smoke, according to research presented at the European Respiratory Society Congress in Amsterdam, the Netherlands. Children from low socio-economic regions face the biggest impact of breathing second hand smoke, also known as passive smoking.

The study was presented by Dr Siyu Dai, Assistant Professor in the School of Clinical Medicine at Hangzhou Normal University and an Honorary Research Associate in the Department of Paediatrics at The Chinese University of Hong Kong.

She told the Congress: “Second-hand smoke is a major contributor to preventable illness and death in children and there is no safe exposure level. It is linked to chest infections, cardiovascular disease, and neurodevelopmental problems and makes asthma symptoms worse. Young children are especially susceptible because their bodies and lungs are still developing and they have little control over their own environments.

“Data from the World Health Organization estimate that second-hand smoke exposure causes 1.2 million premature deaths annually, including approximately 65,000 among children under the age of 15. But we know that many more children will suffer illness caused by other people smoking around them, so we wanted to quantify this problem globally and regionally, to provide evidence for more precise tobacco control policies.”

In the first global study to examine the impact of second-hand smoke (SHS) on children under 14 years old, Dr Dai and her colleague Miss Ruiying Jin analysed data from the Global Burden of Disease Study [2], a large international project that tracks deaths and illness from major diseases, injuries, and risk factors across the world.

One of its key measures is the disability-adjusted life year (DALY), which represents the total burden of disease. In simple terms, one DALY equals one year of healthy life lost (whether from dying too early or living with illness or disability).

Looking at data across more than 200 countries and territories, Dr Dai estimated the years lost to second-hand smoke across major disease categories from 1990 to 2021 in children aged 0–14 years. She then compared this to the Socio-demographic Index, which combines information on the economy, education, and fertility rate of countries around the world, as a representation of social and economic development.

She found that in 2021, SHS exposure contributed to 3.79 million DALYs from lower respiratory infections (acute bronchitis, pneumonia), 0.80 million from ear infections, and 3.86 million from chest infections and tuberculosis globally among children.

The researchers found that SHS continues to pose a serious health risk to children worldwide, but is particularly problematic in poorer regions, where the rates of disease burden (measured in DALYs) were much higher.

Regions that score highly on the Socio-demographic Index (SDI) reported age-standardised DALY rates of 7.64 and 10.25 per 100,000 children for lower respiratory infections and respiratory infections/tuberculosis, respectively, compared to low-SDI regions which showed rates of 302.43 and 305.40.

Dr Dai explained: “The impact of second-hand smoke on children’s respiratory health remains severe, but in some parts of the world, children are suffering even more than in others. Children in lower-SDI regions bear a disproportionate share of this preventable health burden. This likely reflects a combination of factors such as lower public awareness about the dangers of second-hand smoke, more overcrowded and poorly ventilated homes, and weaker tobacco control policies. These conditions may lead to higher exposure for children.

“In 2021 alone, exposure to second-hand smoke was linked to nearly 8.45m years of healthy life lost due to respiratory infections and tuberculosis, highlighting a preventable burden that falls most heavily on the least developed areas. Children are losing all these years of healthy life, but this could be prevented if they were protected from other people's smoke,” she added.

Dr Dai plans to carry out further analyses of SHS-related respiratory disease burden based on age, gender, and other factors, to support more precise and targeted interventions in the near future.

Dr Filippos Filippidis, Chair of the European Respiratory Society’s tobacco control committee, based at Imperial College, London, UK, who was not involved in the research said: "Around the world, hundreds of millions of people are still smoking and many are being exposed to second-hand smoke. Sadly, children often suffer the most as their lungs are still developing and they cannot avoid smoking in the home.

"This study quantifies the enormous harm children are suffering from second-hand smoke around the world. It is a wake-up call that we need to do much more to protect children. In particular, we need to create and enforce laws that limit smoking in places where children live or go to school. However, the most efficient approach is to reduce smoking across all age groups, which would substantially limit second-hand smoke exposure for children as well.

"As tobacco companies intensify marketing of emerging products, such as e-cigarettes and heated tobacco, it is also important to explore how these may indirectly affect children's health when they are exposed to second-hand vapours."

Reference:

Children lose 8.45 million days of healthy life due to second hand smoke, European Respiratory Society, Meeting: European Respiratory Society Congress.