Acetaminophen Linked to Childhood Asthma

[Source: Steven Reinberg, HealthDay Reporter] - Children given acetaminophen during the first year of life to reduce fever are more likely to develop asthma later on, a new study finds.

These children are also more likely to develop rhinoconjunctivitis and eczema when they reach age 6 to 7, according to the report in the Sept. 20 issue of The Lancet.

"If this association is causative, it would suggest that acetaminophen use is a risk factor for asthma and may explain the asthma has become more common," said lead researcher Dr. Richard Beasley, from the Medical Research Institute of New Zealand in Wellington.

Since this study can't definitively say that acetaminophen is a cause of asthma, its use for children shouldn't be changed, Beasley added. "Acetaminophen is the preferred drug for relief of pain and fever in childhood," he said.

Beasley thinks, however, acetaminophen should not be used routinely for childhood fever, but reserved for high fevers. "Acetaminophen is still the preferred agent, but the large amounts of acetaminophen used around the world are unnecessary," he said. "Its use should be limited to treat high fevers."

For the study, Beasley's group collected data on 205,487 children from 31 countries around the world. These children participated in the International Study of Asthma and Allergies in Childhood.

The researchers found that children who were given acetaminophen for fever during the first year of life had a 46 percent increased risk of developing asthma when they were 6 to 7 years old.

In addition, children who were given high doses of acetaminophen within the past year had a more than three times increased risk of asthma. Those who were given medium doses had a 61 percent increased risk of developing the condition, Beasley's team reported.

Acetaminophen use was also associated with an increased risk of severe asthma of about 22 percent to 38 percent, the researchers found.

Moreover, acetaminophen increased the risk of eczema by 18 percent and rhinoconjunctivitis by 32 percent. Among children given high doses of acetaminophen, the risk for eczema almost doubled, and the risk for rhinoconjunctivitis increased by almost threefold, Beasley's group found.

Dr. Norman H. Edelman, vice president for health sciences and professor of medicine at SUNY Stony Brook University in New York, and spokesman for the American Lung Association, said the study adds more evidence to acetaminophen's link to asthma.

"The study is consistent with quite a few others which show that use of acetaminophen associated with an increased in the risk for asthma," Edelman said.

Dr. Geoffrey Chupp, an associate professor of medicine and director of the Yale Asthma Clinic at Yale University School of Medicine, thinks the association between acetaminophen and asthma may be a sign of something else.

"Children who are taking acetaminophen may be getting sick more often and getting more respiratory viruses, and they are getting asthma for other reasons," Chupp said. "It's not actually due to the acetaminophen, but acetaminophen happens to be in the picture, because they get sick all the time."

Another study in the same journal concluded that allergic or not, allergic rhinitis is a predictor of asthma in adulthood.

In the study, researchers collected data on 6,461 patients without asthma. After 8.8 years of follow-up, the researchers found that 3.1 percent of the patients with non-allergenic rhinitis developed asthma, as did 4 percent of the individuals with allergic rhinitis. This compared with only 1.1 percent of the patients without rhinitis who developed asthma.

"This large prospective study provides strong evidence for an increased risk of asthma in adults with allergic rhinitis, and to a lesser extent non-allergic rhinitis... Several clinical trials in asthmatic patients with allergic rhinitis were associated with a reduction in asthma symptoms. However, only interventional studies could be used to conclude that the treatment of allergic rhinitis is effective in reducing the incidence of asthma," the authors concluded.

A third study in the journal found adult asthma has its origins in early childhood.

For the study, researchers from the Arizona Respiratory Center collected data on 849 infants. After 22 years of follow-up, 181 people had asthma. The researchers found that children who had wheezing at age 6 or 7 were four times more likely to develop asthma as adults.

For children whose wheezing persisted, their risk of developing asthma increased 14 times. Other factors in childhood which increased the risk of asthma included low airway function (4.5 times increased risk for asthma) and bronchial responsiveness (7 times increased risk for asthma).

"In over 70 percent of people with current asthma and 63 percent of those with newly diagnosed asthma at age 22 years, episodes of wheezing had happened in the first three years of life or were reported by parents at age 6 years... Our findings support our previous proposition that most forms of asthma have their origins in early life, but we now extend that proposition to asthma diagnosed in early adult life," the authors concluded.