Studies on Tobacco Exposure and Children

New On February 4, 2014, the U.S. Food and Drug Administration (FDA) issued a press release to launch a new national multi-media educational campaign called "The Real Cost" that aims to reduce the number of U.S. teen smokers. The campaign targets the 10 million 12-17 year olds who have never smoked a cigarette but may be open to it and young adults who are already experimenting with cigarettes and are at risk of becoming regular smokers. Each day, more than 3,200 youth under age 18 in the United States try their first cigarette and more than 700 kids under age 18 become daily smokers. "The Real Cost" campaign dramatizes the health consequences of smoking by graphically showing several health consequences resulting from tobacco use such as tooth loss and skin damage. This campaign kicked off nationwide on February 11th, and is estimated to cost $115 million. Future campaigns will target young adults ages 18-24 and people who influence teens, including parents, family members and peers.

No-smoking policies can change the attitudes and behaviors of children

Adolescents are more likely to smoke if their parents smoke, and a new study points to the strong influence of an older sibling who smokes, too. The study, “Parent and Child Cigarette Use: A Longitudinal, Multigenerational Study,” published in the September 2013 issue of Pediatrics (published online Aug. 5), documents how parents’ long-term smoking habits affect their children’s likelihood of smoking. Data from 214 parents and 314 children ages 11 years and older were analyzed. Eight percent of the children of nonsmoking parents smoked in the last year. Of children of smokers, between 23 percent and 29 percent had smoked in the past year. Rates varied according to how consistently the parents smoked, but even children of “light” smokers who reduced or quit later in adulthood had a higher risk of smoking. Parental smoking at any age, even before the child was born, increased the chances that their children would smoke. Researchers also found that children who had an older sibling who smokes were more than 6 times more likely to smoke than children who do not have a sibling who smokes. An older smoking sibling was 15 times more likely to be present in a household with a heavy-smoking parent compared to nonsmoking parents. The study authors concluded that intervention efforts should target parents who were smokers at any point from adolescence to adulthood, and that prevention efforts should also target the smoking behavior of older siblings.

Laws banning smoking reduce the likelihood that young people will smoke, according to a study done at Purdue University and published July 25, 2012 in the journal Social Forces. "While the bans and policies create a physical obstacle to smoking, they also add a stigma that likely contributes to deterring young people from the habit," according to the researcher, Purdue University's Assistant Professor of Sociology Mike Vuolo who studies youth behavior. "Policies that restrict smoking directly affect young people's behavior, and that may be a key element to curb smoking rates because most adult smokers report starting when they were teenagers," says Vuolo. The study results are based on self-reported cigarette use of people ages 15-24 in the original 15 European Union countries, and the data is from Eurostat (the European Commission's statistics branch) and the World Health Organization. The survey information was collected in the spring of 2002, and there were 7,532 respondents with an average of 450 respondents per country. In 2002, seven of the 15 European countries had restaurant smoking bans. "In countries with restaurant smoking bans, young people were 35 percent less likely to smoke regularly," Vuolo said. Age restrictions to purchase tobacco products do not exist in all countries and were shown to reduce the probability of a young person taking up smoking regularly by 16 percent. Read a news article about the study.

The Center for Disease Control and Prevention (CDC) states smokefree policies reduce smoking among all ages. By challenging the perception of smoking as acceptable adult behavior, smokefree policies can change the attitudes and behaviors of adolescents, resulting in a reduction in tobacco use initiation (Oxford University Press, October 2006). The study "Association Between Household and Workplace Smoking Restrictions and Adolescent Smoking" published in the Journal of the American Medical Association in October 2006, found that adolescents who work in smokefree workplaces are significantly less likely to be smokers than adolescents who work in workplaces with partial smoking restrictions.

Secondhand Smoke Exposure Increases Lead Levels in Children

An study by Johns Hopkins University researchers published in the American Journal of Pediatrics found blood lead levels were 14% and 24% higher in children who lived with 1 or with 2 or more smokers, respectively, than they were in children living with no smokers. Lead exposure presents a signicant health risk to children. Read a February 2, 2013 Healthy Living news article about the study. The news article concludes:

"Researchers recommend, as part of routine medical exams, children should be tested for lead and parents should be given information on how to reduce lead exposure. They also say legislation that promotes smoke-free environments and prohibits smoking in cars and public places where children gather, as well as increasing lead prevention programs that evaluate smoking at home would greatly reduce lead exposure in children."
Read GASP's white paper "Smoking in Cars with Children" which gives supportive background information and lists jurisdictions banning smoking in vehicles when children are present.

Secondhand Smoke Exposure Increases School Absences

In September 2011, a nationwide study published online in Pediatrics concludes that children who live in households where they are exposed to tobacco smoke miss more days of school than do children living in smoke-free homes. These children have higher rates of respiratory illnesses that can be caused by second-hand smoke and details the probable economic costs of their increased school absence, according to the report's investigators at Massachusetts General Hospital (MGH). According to the lead researcher, "among children ages 6 to 11 who live with smokers, one quarter to one third of school absences are due to household smoking." The authors note that one-third of U.S. children live with at least one smoker, and more than half of those aged 3 to 11 have detectable levels of a blood marker for tobacco exposure.

Secondhand smoking has been shown to increase incidence of ear infections and several respiratory conditions, and school absenteeism is an accessible measure of serious illness in children. Of the 3,087 children whose information was analyzed for this study, more than 14 percent lived in a home with at least one person who smoked in the house - 8 percent lived with one household smoker and 6 percent with two or more - which represents 2.6 million children nationwide. Children living with one in-home smoker had an average of 1.06 more days absent, and those living with two or more had 1.54 more days absent than did children living in homes where no one smoked indoors. Since the absentee levels we report are averages, there are probably kids who miss much more school because they live with smokers than our study found. The authors also found that "on a national basis these absences result in $227 million in lost wages and time for caregivers or their employers." Read press release.

Asthma Triggers

An August 2010 study, Influence of indoor factors in dwellings on the development of childhood asthma, published in the 2011 International Journal of Hygiene and Environmental Health, concluded:

"Since exposure to Environmental Tobacco Smoke (ETS) is a likely cause for the onset of asthma in childhood, we conclude that there is a strong need to prevent infants and children from breathing air which is contaminated with tobacco smoke. There is no need for more research. The evidence of an adverse health effect of the exposure to ETS is sufficiently strong to propose such actions."

Increased Blood Pressure

A study published in the January 2011 journal Circulation found that secondhand smoke increases blood pressure in children as young as 4 years old, putting them at risk for a lifetime of cardiovascular problems. The Heidelberg University of Germany study examined 4,000 German children, according to author Dr. Giacomo Simonetti. Children of parents who smoked were 31% more likely to have blood-pressure readings in the top 15% of the entire group, even after adjusting for other risk factors (obesity, parents with high blood pressure). That is significant, because elevated blood pressure in youth can increase an individual's chance of developing serious cardiovascular problems at early ages. "Passive smoking remains a risk factor independent [of] the other risk factors," said Dr. Simonetti. Read a news article about it and the abstract from the study.

Irritative Bladders

At the June 2012 American Urological Association Annual Meeting research was presented from a UMDNJ study showing the association between second-hand cigarette smoke and moderate to severe irritative bladder symptoms in children. Lead researcher Dr. John Barone stated, “Parents should make a concerted effort to reduce their child’s exposure to smoke in confined places, especially in the home and in cars. Quitting smoking is the healthiest option for children.”

Mental Illness and Behavioral Problems

A study published in the January 2013 journal NeuroToxicology found that a pregnant woman's exposure to secondhand smoke may affect her child's risk of behavior problems. Read a March 29, 2013 news article about the study which showed that 25 percent of the children whose mothers were exposed to secondhand smoke showed attention and aggression problems, compared to 16 percent of the children whose mothers were not exposed.

A study published April 2011 in Archives of Pediatrics and Adolescent Medicine found a correlation between secondhand smoke exposure and mental illness in children, including major depressive disorder, generalized anxiety disorder, panic disorder, attention-deficit/hyperactivity disorder, and conduct disorder. Read the study abstract and an April 5, 2011 news article from the Los Angeles Times.

Secondhand Smoke Impact and Biomarker Studies

Read a news article about a University of California study published in the May 2012 Archives of Pediatrics & Adolescent Medicine which measured the blood levels of cotinine, a metabolite of nicotine, to determine the level of second-hand smoke exposure in 496 children aged 1 to 4. Despite only 13% of parents aware that their children were exposed to secondhand smoke, 55% of the children tested positive for exposure. Exposure can occur if children are in and around places not only where people are actively smoking, but also where people have been recently smoking. Exposure to secondhand smoke has been linked to ear infections, impaired lung function, respiratory illnesses, middle ear disease, and asthma in infants and children. Although cotinine is a biomarker for tobacco smoke, the toxicity of SHS is mainly due to toxicants other than nicotine, including oxidant chemicals, nitrosamines, volatile gases, aromatic and heterocyclic amines, and other chemicals. Read an editorial that accompanied the study in which Dr. Winickoff advocates the testing of cotinine when blood tests are done to test for lead to help parents manage their children's level of exposure to secondhand smoke.

Read this Science Daily article on a March 2012 study published in the American Journal of Physiology which found a cancer-causing agent in the gaseous phase of cigarette smoke. "This is critical information with regard to secondhand smoke," said Dr. Rajasekaran (the lead researcher). "We now know that one need not inhale the particulate matter present in secondhand smoke to suffer the consequence of smoking. Exposure to the gaseous substance alone, which you breathe while standing near a smoker, is sufficient to cause harm." The article concludes "This research is the latest finding in the compendium of evidence that supports protecting children from exposure to cigarette smoke. Excessive exposure to cigarette smoke during childhood can facilitate lung cancer development as children grow into adults."

A study published in the January 2011 journal Pediatrics by the University of Rochester Medical Center and MassGeneral Hospital shows significant evidence of tobacco smoke exposure in the blood of children from smokefree apartments who live in non-smokefree multi-unit housing. Read the press release announcing this study. Read the study abstract. Learn more from our webpage on Smokefree Multi-Unit Housing.

A Harvard School of Public Health study, published online in the June 7, 2010 issue of Pediatrics, found that children and adolescents living in non-smoking homes in counties with laws promoting smoke-free public places have significantly lower levels of a common biomarker of secondhand smoke exposure than those living in counties with no smoke-free laws. Read the press release. Read the study abstract.

Smoking During Conception, Pregnancy and Around Infants

A study published January 2013 in the journal Pediatric Infectious Diseases found that infants whose mothers smoked during pregnancy were 50 percent more likely to be hospitalized or to die from a wide number of infectious diseases, compared to babies of mothers who did not smoke. Smoking during pregnancy may weaken an infant's immune system and put them at increased risk for a broad range of infections. Read a news article and the study abstract.

A study published in May 2012 from the University of California San Francisco (UCSF) analyzed nearly 2,500 Latino and African-American children with asthma. The researchers found that children between age 8 and 17 with acute asthma symptoms were far more likely to have had mothers who smoked during pregnancy. Read the article about the study that found a correllation even when the team controlled for elements such as education, socioeconomic level and childhood exposure to tobacco smoke. Read the study abstract from the Journal of Allergy and Clinical Immunology.

In April 2012, another study from UCSF shows the widespread impact of both nicotine and non-nicotine components of tobacco smoke on early embryonic development. Read the article about the study which identified the increased activity of a key gene that keeps embryonic stem cells in an undifferentiated state, impeding the molecular pathways of stem cell differentiation. The scientists were looking for an explanation for known utero smoking exposure risks which include some childhood cancers, preterm and underweight births, respiratory distress, cardiovascular defects, cleft lip and palate, immunodeficiency, SIDS and behavioral and psychological problems later in life.

Nonsmoking women who breathe secondhand tobacco smoke during pregnancy increase their risk of stillbirth, major birth defects, and other harms to their babies, according to a meta-analysis published March 7, 2011 in Pediatrics. Four of the observational studies found a 23% increased risk of stillbirth with tobacco smoke exposure during pregnancy. Seven of the studies found that pregnant women exposed to second hand smoke were also 13% more likely give birth to a child with congenital malformations. Read a Medpage news article.

Infants exposed to secondhand smoke are at an increased risk for SIDS. Read the abstract from a study published in the Tobacco Control Journal about infant mortality as it relates to decreasing exposure to secondhand smoke. Read a publication from an Australian organization, SIDS and Kids, chocked full of information to minimize the risk of SIDS for your infant:

Read this June 2012 article about British researchers found that men who smoke before conception can damage the DNA of their offspring in the womb giving the child a higher risk of disease. Men are encouraged to stop smoking a few months before any planned conception.

Last update: 3/11/14