The vast majority of children who took part in a study had traces of second-hand smoke in their bodies even though nearly three-quarters of their parents reported they were not exposed to it at home.

The research has provided a snapshot of the hidden impact of tobacco that potentially exists in the age cohort. 

The study involved taking urine samples from 174 children aged nine to 11 from five public schools.

Although nearly three in four parents (72.4%) reported that their children were not exposed to tobacco smoke at home, the urine samples revealed that 95.4% of the children were exposed to nicotine and 98.3% were exposed to NNK (nicotine-derived nitrosamino ketone), a known lung carcinogen derived from the addictive nicotine.

“Since almost all children were exposed to tobacco smoke, the exposure does not occur only at home, but certainly also in transit – by walking or in cars – or during other social activities where adults smoke in the presence of children,” said lead researcher Dr Noel Aquilina from the University of Malta’s Department of Chemistry.

Researcher Noel Aquilina

The study, he said, shed light on the need to better monitor children’s exposure to NNK in order to aid legislation to curb the exposure of schoolchildren to potent carcinogens in their early development years.

Children tend to flush carcinogens from their bodies slowly compared to adults.

According to Maltese legislation, smoking is not allowed in public indoor spaces.

It is also prohibited to smoke in private cars carrying children under 16.

But there are no restrictions on smoking at home, outdoors or in the presence of children.

Aquilina explained that, over the years, many studies have looked into the impact of second-hand smoke on adults.

Those that examined the impact of children often relied on parents’ questionnaire data.

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Indisputable facts

This study, titled ‘Second-hand smoke exposure in school children in Malta assessed through urinary biomarkers’, was the fifth in the world that checked for the level of second-hand smoke exposure in children by looking for smoking-derived carcinogens in their urine.

The facts were indisputable.

Published in the internationally peer-reviewed journal Environmental Research, the paper was co-authored by Stephen Montefort and Peter Fsadni from the Department of Medicine, Faculty of Medicine and Surgery. 

It was a spin-off of a European project called Schools Indoor Pollution and Health Observatory Network in Europe carried out between October 2011 and February 2012.

As part of the study, parents were given a questionnaire about their children’s exposure to second-hand smoke.

In parallel, the 174 students were asked to provide a morning urine sample that was analysed by a team from the University of California in San Francisco in collaboration with Aquilina.

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The samples were stored and could not be analysed in 2012 since, at the time, the analytical procedure was not available.

The San Francisco team have now analysed the data for three biomarkers to verify the level of the children’s exposure to second-hand smoke and provide a snapshot of the situation on the ground.

The biomarkers were NNAL, a potent carcinogen created by the body on absorbing NNK, as well as Cotinine (COT) and 3HC, both primary indicators of inhaling nicotine.

Biomarker results showed that out of all the schoolchildren, 4.6% were defined as not exposed while 95.4% were exposed to second-hand smoke.

While 23% of the children surveyed were exposed to very low levels of second-hand smoke, the majority, 70.7%, were exposed to significant levels.

Three children (1.7%) could be classified as active smokers from their biomarker levels. These biomarker tests are very sensitive even to low levels of secondhand smoke.

A total of 16.4% reported that someone smoked at home.

From the children reporting smoking at home, 11% had a clinical confirmation of a history of asthma and their measured carcinogen levels were double compared to the schoolchildren considered non-asthmatic.

“This is extremely worrying in view of their respiratory health and other medical conditions that these children might develop primarily lung cancer, but not only, as they grow older,” Aquilina said.