More adults, especially women, are smoking these days and their secondhand smoke may be contributing to the asthma epidemic among children in the United States, results of a study suggest.

“This is the first study to suggest, and provide evidence consistent with the hypothesis that the parallel increase in smoking, especially among women who are primary caregivers, may explain the increase in asthma in children via increased exposure to ETS (environmental tobacco smoke) over time,” Dr. Renee D. Goodwin, of Columbia University in New York City, told Reuters Health.

“It is conceivable that greater efforts to protect children from exposure to secondhand smoke, from birth onwards, may be effective in starting to prevent asthma in children and ultimately decrease the direction of this epidemic,” she added.

There has been a 3-fold increase in the prevalence of childhood asthma over the past 30 years, for unknown reasons, particularly in industrialized nations, studies show. Currently, more than 15 million children experience daily secondhand tobacco exposure at home and almost 5 million children in the US under the age of 18 are known to have asthma.

Goodwin investigated whether increased cigarette smoking, particularly among women, after World War II may have indirectly contributed to the increasing asthma epidemic among children.

The researcher examined data on 4,500 children who were involved in the National Health Interview Survey and compared it with data from the American Lung Association on cigarette use in the United States from 1900 to 2003.

As suspected, Goodwin found that rates of cigarette use during the past century increased along with rates of childhood asthma.

For example, for each consecutive year from 1980 to 1995, there was an estimated 5 percent annual increase in the overall prevalence of asthma among children, and this increase was particularly evident among 5- to 10-year olds, Goodwin notes in the Annals of Allergy, Asthma & Immunology.

Likewise, in 2003, an estimated 400 billion cigarettes were consumed, a substantial increase from the estimated 2.5 billion cigarettes that were smoked in 1900. Cigarette smoking reached its peak around 1981 with 640 million cigarettes smoked annually.

Although cigarette consumption in the US had declined in the past 10 years, “the consequences and health effects of the drastic increase in cigarette consumption in the mid-1980s are thought to be still affecting adults and children in the United States,” Goodwin writes.

And “while new laws are increasingly implemented to protect workers from smoke in the workplace, diners in restaurants and even bar patrons, from the dangers from secondhand smoke, no such measures have been taken that directly aim to protect children, who are most vulnerable,” she contends.

In light of this, “educational programs aimed at high risk groups for smoking may be beneficial,” Goodwin added, “as it is likely that many are unaware of the impact of ETS on child respiratory health.”

SOURCE: Annals of Allergy, Asthma & Immunology, May 2007.