July 14, 2017
A new study led by researchers at the UNC Gillings School of Global Public Health has determined reference parameters for measuring lung capacity in non-Mexican American Hispanics. Accurate reference values for such measures are important for diagnosing common chronic lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) and predicting mortality.
Reference measures previously had been established for Mexican-Americans but not for other Hispanic/Latino populations living in the U.S.
The study, published June 14 in the American Journal of Respiratory and Critical Care Medicine, was led by researchers affiliated with the UNC Gillings School of Global Public Health’s biostatistics department, including lead author Lisa LaVange, PhD, former Professor of the Practice; Sonia Davis, DrPH, Professor of the Practice; Rebecca Wilson, doctoral student; and Ai (Andy) Ni, PhD, 2015 alumnus.
In 2006, the UNC Gillings School’s Collaborative Studies Coordinating Center (CSCC), based in the School’s Department of Biostatistics, was awarded a 6.5-year, $22 million grant from the National Heart, Lung and Blood Institute to coordinate a nationwide health study of Hispanics in the United States. LaVange was the original principal investigator for the grant.
Researchers aimed to recruit 16,000 Hispanic adults self-identifying as having Puerto Rican, Cuban, Dominican, Mexican, Central or South American background who could help them identify prevalence of and risk factors for a variety of diseases and conditions – from heart disease to dental cavities.
Renewed continuously since that time, the grant has recruited 16,415 participants who live in Bronx, Chicago, Miami and San Diego and is by far the most comprehensive health assessment study conducted among Hispanics/Latinos in the U.S.
In the current study, researchers employed spirometry, a common medical office test used to assess how well participants’ lungs work by measuring how much air is inhaled and exhaled and how quickly one exhales, to examine differences between people of various Hispanic/Latino ethnicities.
They found that nonsmoking men and women of Dominican and Puerto Rican backgrounds, who had no respiratory symptoms or disease, performed substantially worse on the spirometric tests. The findings suggest that taking into consideration a Hispanic/Latino person’s geographical background may provide more accurate diagnoses of lung impairment in this population.
“Because these types of reference equations play an important role in diagnosing lung disease during pulmonary examinations,” LaVange said, “people with Puerto Rican or Dominican background may be misdiagnosed, unless an adjustment is made to the Mexican-based reference equations currently in use. Because we found lower levels of lung function among healthy Hispanics of Puerto Rican and Dominican background living in the U.S. compared to those of Mexican background, over-diagnosis in these population subgroups may result. A Puerto Rican living in the Bronx, for example, may appear to have lung function values lower than normal values based on the Mexican-American equations, but actually be in the normal range when compared to equations based on the HCHS/SOL Puerto Rican cohort of participants (recruited in Chicago and the Bronx).”
“We are grateful for the dedication of the CSCC staff and students to the successful implementation of important public health research studies such as HCHS/SOL,” Davis said.
“The rich data collected in the HCHS/SOL study and the important findings based upon these data will have significant long-term impact for the understanding of Hispanic/Latino health,” said Jianwen Cai, PhD, Cary C. Boshamer Distinguished Professor and principal investigator for the HCHS/SOL project. “Many investigators from the Gillings School actively have been involved in HCHS/SOL and have made important contributions to this landmark study.”
Co-authors of the study are from Hankinson Consulting Inc., in Athens, Ga., University of Arizona at Tucson, Columbia University Medical Center, Albert Einstein College of Medicine, Northwestern University and San Diego State University.