For Latinos, Ancestry Drives Asthma Development

Among Latinos, a Native American heritage was linked to a lower rate of asthma development, while an African lineage resulted in an increased asthma risk, researchers at University of California San Francisco (UCSF) found.

While environmental factors are often discussed in regards to asthma development and treatment, the study published in the Journal of Allergy and Clinical Immunology highlights genetics’ role among different ethnic groups, a UCSF statement pointed out.

In the largest study comparing genetic variation and asthma among Latinos, UCSF researchers analyzed the ancestry of 5493 Latinos for African, European, and Native American lineage. From there, researchers determined whether asthma and lung infection prevalence was tied to their ethnicity.

Considering several factors such as air pollution and socioeconomic status, the investigators discovered for every 20 percent increase in African American ancestry(OR = 1.40, 95% CI: 1.14-1.72, P = .001), Puerto Ricans were 40 percent more likely to develop asthma. Conversely, Mexicans and other Latinos has a 43 percent decrease in asthma risk for every 20 percent increase in their Native American ancestry (OR = 0.72, 95% CI: 0.66-0.78, P = 8.0 × 10−15).

“Among children with asthma, African ancestry was associated with lower lung function, including both pre- and post-bronchodilator measures of FEV1 (−77 ± 19 mL; P = 5.8 × 10−5 and −83 ± 19 mL; P = 1.1 x 10−5, respectively) and forced vital capacity (−100 ± 21 mL; P = 2.7 × 10−6 and −107 ± 22 mL; P = 1.0 x 10−6, respectively),” the researchers also reported.

“Differences in the proportions of genetic ancestry can partially explain disparities in asthma susceptibility and lung function among Latinos,” the authors wrote.

In diagnosing asthma, lung specialists often use tests to determine how much air a person can exhale and inhale before and after using an inhaler. Based on their findings, the study’s senior scientist, Esteban Burchard, MD, a professor of bioengineering at UCSF’s School of Pharmacy, believes ethnicity should also be considered when predicting asthma prevalence and severity.

“The current method for predicting lung function in Puerto Ricans relies on reference equations derived from Mexicans or Whites,” Burchard pointed out. “We need to develop a new reference standard to predict normal lung function in Puerto Ricans, who have the highest asthma risk.”