How do ethnic and racial variables impact respiratory system physiological function?

From the Guidelines

Ethnic and racial variables significantly impact respiratory system physiological function, with studies showing that individuals of African or Asian ancestry have lower lung function values compared to those of White European ancestry, even after adjusting for body size and socioeconomic factors. These differences are attributed to variations in chest dimensions and thoracic muscle strength, as well as differences in prevalence rates of respiratory conditions, such as asthma, which is more common and often more severe in African Americans and Puerto Ricans compared to other groups 1. Environmental and social determinants of health, including exposure to air pollution, occupational hazards, and access to healthcare, further exacerbate these disparities. Smoking patterns and metabolism of nicotine also vary across ethnic groups, with African Americans typically metabolizing nicotine more slowly, potentially increasing susceptibility to smoking-related respiratory diseases despite lower cigarette consumption. Healthcare providers should consider these ethnic and racial variations when interpreting pulmonary function tests, as using race-specific reference values may be necessary for accurate diagnosis and treatment planning, though this practice remains controversial as it may perpetuate health inequities 1. Some studies suggest that using ethnicity-specific reference equations can eliminate differences in lung function between different ethnic groups, and that adjustment factors, such as a 0.88 correction factor for Asian Americans, may be necessary to account for these differences 1. However, the use of adjustment factors is not as good as using specific race/ethnic equations, and the practice of using 80% predicted as a fixed value for the lower limit of normal may lead to important errors when interpreting lung function in adults 1. Overall, healthcare providers should prioritize the use of race-specific reference values and ethnicity-specific reference equations when interpreting pulmonary function tests to ensure accurate diagnosis and treatment planning. Key considerations include:

• Using reference values based on healthy subjects with the same anthropometric and ethnic characteristics as the patient being tested
• Avoiding extrapolation beyond the size and age of investigated subjects
• Using adjustment factors, such as a 0.88 correction factor for Asian Americans, when necessary
• Considering the potential for health inequities when using race-specific reference values.

From the Research

Ethnic and Racial Variables Impact on Respiratory System Physiological Function

• The impact of ethnic and racial variables on the physiological function of the respiratory system is a complex issue, with various studies suggesting that the use of race-specific reference equations for spirometry may contribute to health disparities 2, 3.
• A study published in the Annals of the American Thoracic Society found that the use of race-specific equations for spirometry interpretation may adversely affect the care of Black patients with advanced respiratory disease, resulting in lower lung allocation scores (LAS) compared to White patients 2.
• Another study published in the American Journal of Respiratory and Critical Care Medicine found that there was no evidence that race/ethnicity-based spirometry reference equations improved the prediction of incident chronic lower respiratory disease (CLRD) events and mortality compared to race/ethnicity-neutral equations 3.
• The etiologies of asthma have been found to vary by race, ethnicity, and social class, with significant disparities in prevalence, mortality, and drug response described 4.
• A study published in the American Journal of Epidemiology found that the associations of age and height with lung function are similar across the three major US race/ethnic groups, suggesting that multiethnic rather than race/ethnic-specific spirometry reference equations may be applicable for the US population 5.
• Researchers have been criticized for failing to define race and ethnicity in studies of lung function, and for assuming inherent (or genetic) differences between racial and ethnic groups rather than examining socioeconomic and environmental factors 6.
• The use of race-specific reference equations for spirometry has been recommended by the American Thoracic Society/European Respiratory Society, but the justification for this recommendation is controversial, with some studies suggesting that it may reinforce disparities and is of unclear clinical benefit 2, 3, 6.