Smoking at home ups kids' lead exposure

Posted: 9/16/2011

From Environmental Health News:

While paint, pipes and gasoline are the commonly considered culprits for lead exposure, researchers show that another preventable source – secondhand smoke – can contribute to children's exposure.

Secondhand tobacco smoke may be an important – and preventable – source of lead exposure in children, report researchers in a recent issue of the American Journal of Public Health. The researchers recommend that homes and other places where children spend a lot of time be smoke-free as a way to prevent children’s exposure to this neurotoxic element.

The study of more than 6,800 children found that blood lead levels in children went up with the number of smokers who live in their household. Levels of those who lived with one smoker were 14 percent higher than those living with no smokers. That doubled to 28 percent if they lived with two or more smokers. Lead levels were also linked to a commonly used tobacco marker: children with higher levels of the marker also had higher blood lead levels.

Children can be exposed to lead from contact with lead paint in older houses or by playing in dusts and soils that were contaminated from leaded gasoline or industrial sources. Children’s blood levels have plummeted in the United States since lead was banned in both paint and gasoline, but blood lead levels in children living in inner-city or low-income areas are still higher compared with other children.

While it is known that cigarette smoke contains lead, secondhand smoke is not generally considered in programs aimed at the prevention of childhood lead exposure. This research shows that secondhand cigarette smoke may be an important source of childhood lead exposure and that promoting smoke-free environments should be part of those programs to reduce children's exposure.

Children are the most susceptible to the health effects of lead. Lead affects the brain and nervous system, leading to changes in behavior and intelligence. Children are more susceptible to these effects because the nervous system is still developing throughout childhood.

The U.S. Centers for Disease Control and Prevention (CDC) considers blood lead levels above 10 micrograms/deciliter to be of concern and recommends that parents of children with these elevated blood lead levels take action to reduce lead exposure in the home. However, many experts believe there is no safe level of lead exposure, especially during childhood.

Researchers from The Johns Hopkins University used data from the National Health and Nutrition Examination Survey (NHANES) from the years 1999-2004. NHANES collects data on health and chemical exposures for about 5,000 U.S. residents every year. In this study, they focused on 6,380 children between 3 and 19 years old who did not smoke. The researchers evaluated whether children’s blood lead levels were related to living with one or more adults who smoked and to levels of the tobacco marker cotinine.  Nicotine is converted to cotinine in the body, and researchers use cotinine as a common chemical measure of tobacco smoke exposure.

The authors statistically adjusted for many social and economic factors, including gender, age, weight, household education and age of the home where the children lived.Exposure to secondhand smoke was associated with increased blood lead levels in children. The researchers report that both living with one or more smokers and higher blood cotinine levels were associated with higher blood lead levels. This relationship was even clearer when the researchers looked only at younger children, perhaps because these children spend more time at home and in close contact with adults who smoke.

Only 24 children had blood lead levels above the CDC's intervention limit of 10 micrograms/deciliter of blood. Among those children, 33 percent lived with at least one smoker, and 8 percent lived with three or more smokers.

Original here.