According to a new study from the Sackler Faculty of Medicine at Tel Aviv University (TAU), 70% of children whose parents smoked were found to have nicotine residue in hair samples.

The study was conducted under the leadership of a team of experts headed by Professor Leah (Laura) Rosen of TAU’s School of Public Health. The study was published in the journal Nicotine & Tobacco Research.

The researchers sought to examine whether raising awareness of children’s exposure to nicotine by providing objective feedback might change parents’ behavior and the level of their children’s exposure. Approximately 140 Israeli families headed by parents of children up to age 8 participated in the study; at least one parent of the family is a smoker. The smoking average per household was 15 cigarettes per day. One-third of the respondents reported that they smoke inside the home, and an additional third said that they are in the habit of smoking on the terrace but not inside the home.

Researchers first tested children’s level of exposure via measuring the presence of nicotine in hair, a biomarker that indicates cumulative exposure to tobacco smoke. The researchers took hair samples from the children and tested the nicotine levels of each sample in a laboratory. (The test was for nicotine that had become an integral part of the strand of hair and not just outside precipitate.)

Nicotine residue was found in 70% of the hair of the children tested, and only 29.7% of those children tested did not show nicotine residue in their hair samples. 

The researchers then divided the families into two groups. The first underwent comprehensive instruction about the effects and dangers of exposure to smoking, including feedback and information about the test results. The parents were also given tools to protect their children from exposure to cigarette smoke and a recommendation to keep their home and car smoke-free. The second group received feedback about nicotine levels in the children’s hair after six months, at the end of the study.

Six months after the start of the study, the researchers conducted additional nicotine tests on the children’s hair and found a significant improvement in the data. Among the group that received comprehensive training, the percentage of children whose hair samples contained nicotine decreased from 66% to 53%, whereas in the second group (which did not receive training at the start of the study) the percentage of children whose hair samples contained nicotine decreased from 74% to 49%.

The researchers theorize that the knowledge that the children were tested for tobacco smoke exposure, and that additional testing was planned at six months, resulted in the parents changing their behavior and reducing the children’s exposure.

“To our great dismay, according to the Ministry of Health’s data, approximately 60% of small children in Israel are exposed to secondhand smoke and its harmful effects,” Professor Rosen says. “We believe that conducting nicotine testing — in the hair, urine, or using other testing methods — for every young child in Israel may change parents’ perceptions about exposing their children to tobacco smoke. Changing this perception can also result in changing behavior, exposure levels, and even social norms regarding passive exposure to smoking.”

Other TAU researchers participating in the study included Dr. Vicki Myers, Professor Nurit Guttman, Nili Brown, Professor Mati Berkovitch, and Dr. Michal Bitan. Professor David Zucker of the Hebrew University of Jerusalem and Dr. Anna Rule of Johns Hopkins University in the U.S. also participated in the study.