The exact cause of asthma isn't known. Researchers think some genetic and environmental factors interact to cause asthma, most often early in life. These factors include:
If asthma or atopy runs in your family, exposure to irritants (for example, tobacco smoke) might make your airways more reactive to substances in the air.
Some factors might be more likely to cause asthma in certain people than in others. Researchers continue to explore what causes asthma.
One theory researchers have for what causes asthma is called the hygiene hypothesis. They believe that our Western lifestyle—with its emphasis on hygiene and sanitation—has resulted in changes in our living conditions and an overall decline in infections in early childhood.
Many young children no longer have the same types of environmental exposures and infections as children did in the past. This affects the way that young children's immune systems develop during very early childhood, and it may increase their risk for atopy and asthma. This is especially true for children who have close family members with one or both of these conditions.
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Asthma, visit www.clinicaltrials.gov.
Visit Children and Clinical Studies to hear experts, parents, and children talk about their experiences with clinical research.
May 8, 2013
NIH statement on Asthma Month 2013
For Asthma Awareness Month 2013, the National Institutes of Health stands with the international community to renew our dedication to improving the quality of life for the estimated 300 million people living with asthma worldwide. To most effectively manage asthma, we need to address the disproportionate impact of the disease on minorities and families at or below the poverty line. NIH is committed to reducing asthma disparities and improving asthma control for all who live with the disease.
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.