Another Reason to Quit ; Secondhand Smoke Also Linked to Increased Cavities in Kids
Smokers aren't the only ones harmed by tobacco smoke. Secondhand tobacco smoke is responsible for up to 40,000 deaths a year from heart and blood vessel disease, and 3,000 lung cancer deaths. Research has shown that constant exposure to secondhand smoke d
But what about the children of smokers? Their problems with secondhand smoke start in the womb. Babies born to mothers who smoke while pregnant are at risk for premature birth and low birth weight. Exposure to tobacco smoke in the womb and during early childhood can also impair lung function throughout childhood, increasing the risk of developing asthma and pneumonia. Secondhand smoke also affects the immune system, inhibiting the body's ability to fight off infections and making those children who breathe in smoke more susceptible to illnesses such as colds and earaches.
There is another reason for smoking parents and caregivers not to light up. A study in the Journal of the American Medical Association found that children living in environments with high levels of secondhand smoke have a much higher rate of tooth decay than children who do not grow up around smokers. Annual treatment costs for childhood tooth decay are an estimated $4.5 billion, making tooth decay the most common chronic childhood disease in the United States.
For the past 50 years, childhood tooth decay has substantially declined, probably as a result of more effective toothpastes and powders and the increased levels of fluoride in drinking water. But one group has not been served well from this overall progress. Little headway has been made in reducing cavities in children living in poverty, who ordinarily have less access to dental care and seem to be more vulnerable to dental decay.
The authors of this study did not want to only test for poverty, but wanted to identify risk factors for tooth decay in this group of children that could be modified and controlled for. They found a relationship between secondhand smoke and childhood cavities that persisted even after they had controlled for the variable of family income, as well as many others including age, sex, race, geographic region, frequency of visits to the dentist and blood lead levels.
The study, based on data from the Third National Health and Nutrition Examination Survey (NHANES III) done between 1988 and 1994, performed dental examinations on about 3,500 children aged 4 to 11 years old, and measured their blood levels of cotinine, a chemical by-product of nicotine that is consistent with exposure to secondhand smoke.
The study found that children had an increased risk of tooth decay if they had high levels of cotinine in their blood. About 32 percent of the children with cotinine levels consistent with exposure to secondhand smoke had decayed surfaces on their deciduous or baby teeth, compared with 18 percent of children with lower levels of cotinine. In other words, children regularly exposed to secondhand smoke were almost twice as likely to have cavities as children who were not.
The study concluded that one-quarter of these children would not have developed cavities in their baby teeth if the secondhand smoke were eliminated. However, the study did not find a similar association between exposure to secondhand smoke and cavities in permanent teeth; the researchers suggested that because younger children spent more time with their parents, their deciduous or baby teeth were more exposed to a smoking environment.
According to Dr. David Avery, Ralph E. McDonald Professor and director of Pediatric Dentistry at Indiana University School of Dentistry, there are several possible explanations why secondhand smoke might make children more susceptible to the development of cavities.
Avery thinks there is a particularly vulnerable time for a large number of children when they may be more at risk for acquiring the organisms that produce tooth decay. Certain bacteria, called Streptococcus mutans, produce an acid that dissolves the surface structure of teeth, and nicotine has been shown to promote the growth of these tooth decay-producing bacteria. Mothers who smoke and then kiss their babies have been shown to transmit this type of bacteria to their children.
Avery also notes that the enamel in baby teeth is much thinner than in permanent teeth and that there are some structural differences on a molecular level. " The fact that the enamel is thinner," he says," would certainly suggest that if the environment is right for tooth decay to occur, then the primary tooth would be more susceptible." Furthermore, research has shown that children born to mothers who smoke have thinner tooth enamel.
In addition, children's saliva is different from adult's because their immune systems are less mature, and saliva has protective components that play an important role in resisting dental decay in adults. Studies have also shown that passive smoke elevates levels of cotinine in the saliva, and that in turn lowers the levels of the immune components, removing a normal protective property of the saliva.
Salivary flow rate in children is lower, too, so a child will have a drier mouth and less of the protective flushing ability of saliva that works to neutralize acids that are produced and to physically remove debris from tooth surfaces. Many young children also respond to
secondhand smoke by developing various respiratory conditions that may cause mouth breathing, further decreasing salivary flow and causing a dry mouth.
The federal Centers for Disease Control and Prevention has reported that even though smoking levels in the United States have declined, more than 50 percent of children in this country are exposed to secondhand smoke. There is much in dental literature that correlates the use of tobacco with oral diseases. This study is yet another piece of scientific evidence that secondhand smoke poses a serious health hazard for young children.