Overall, asthma prevalence among kids under 18 had been rising for
decades, until it peaked at 9.7% in 2009. Then it held steady until
2013, when it dropped to 8.3% from 9.3% the previous year,
researchers reported online December 28 in the journal Pediatrics.
“International data on asthma prevalence over time shows that trends
appear to be leveling off in many countries, and suggests that the
trend in the United States seems to be following a general pattern,”
said lead study author Dr. Lara Akinbami of the U.S Center for
Disease Control and Prevention’s National Center for Health
Statistics in Hyattsville, Maryland.
Even though the recent decline is statistically meaningful, it’s too
soon to tell whether the decrease from 2012 to 2013 might be the
start of another plateau or the beginning of a meaningful decline in
asthma cases, Akinbami said by email.
In addition to the scant number of years to assess a shift in asthma
trends toward the end of the study period, it’s also possible that
changes in the way U.S. researchers collected survey data on
childhood asthma might have influenced the results.
“It also doesn’t clearly identify which factors underlie changes in
trends,” Akinbami added. “There is likely a complex story on why
asthma prevalence has apparently stopped increasing.”
Part of the complexity stems from variations in rates of asthma
based on age, income, region or race and ethnicity, the study found.
There was no change in asthma prevalence from 2001 to 2013 for white
or Puerto Rican children or for kids living in the Northeast or
Over the same period, prevalence rose for kids aged 10 to 17, poor
children, and residents of the South.
Disparities in asthma between white and black children stopped
increasing, and Puerto Rican kids continued to have the highest
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For low-income children in particular, it’s possible that
environmental risk factors like tobacco exposure, poor housing and
poor indoor air quality, and indoor dust mite and cockroach exposure
may make asthma more likely, said Dr. Avni Joshi of the Mayo Clinic
in Rochester, Minnesota.
“There is a vicious cycle of poverty and obesity which may also
contribute to the risk of development and persistence of asthma,”
Joshi, who wasn’t involved in the study, said by email. “In
addition, children in poor households experience higher psychosocial
stress, which is another risk factor for asthma.”
If there’s a silver lining in the study results, it’s that a plateau
or decrease in asthma suggests that newer medicines and more
aggressive management of the disease may be making a difference,
noted Dr. Todd Mahr of Gundersen Health System in La Crosse,
“It appears that progress is occurring in decreasing the asthma
epidemic,” Mahr, who wasn’t involved in the study, said by email.
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