The Shift Toward Race-Neutral Spirometry

In occupational health, spirometry is a vital tool used to protect and monitor workers in job roles that may put respiratory health at risk, due to exposure to various workplace respiratory hazards. It is commonly used to:

• Establish baseline lung function

• Monitor changes over time

• Determine eligibility for specific job roles

• Support evaluations for work-related disability compensation

Measured values obtained from spirometry are compared to predicted values which are estimated lung function values expected in a healthy person of the same age, birth sex, height and historically ethnicity. This comparison helps determine whether a worker’s lung function is within the normal range. The predicted values are calculated using reference equations, which are based on collection of large datasets from healthy, non-smoking individuals.

The traditional use of race in spirometry

It has been widely accepted that there are four main factors which can influence lung function: age, birth sex, height and ethnicity. While the first three have clear physiological links (e.g. taller people have larger lung volumes), the accuracy of using self-reported race and ethnicity in lung function has long been debated. Historically, race-based adjustments in spirometry stemmed from observed differences in lung function across populations, but the reasons behind the differences are complex and not often only biological. The origins of using race-based adjustments in spirometry are based on historical practices rooted in increasing racial inequality. The aim of including ethnicity was to improve interpretation accuracy for all ethnic groups.

The creation of GLI Global

In response to growing concerns, the American Thoracic Society (ATS) who work in collaboration with European Respiratory Society (ERS) released a recommendation in April 2023 advocating for a race-neutral approach to spirometry interpretation. The aim of the recommendation was to provide an update on the 2022 new race-neutral equation which was published by the Global Lung Function Initiative (GLI). 

GLI is a taskforce under the European Respiratory Society, which collects and analyses global spirometry data to improve interpretation worldwide. In 2012, GLI published a race-specific reference equation based on data from 74,187 healthy, non-smoking individuals across 26 countries. This equation covered ages 3–95 years and included five ethnic categories: Caucasian, African American, North-East Asian, South-East Asian, and Other/Mixed. 

At the time, this was seen as an improvement over previous equations, such as the European Coal and Steel Community (ECSC) equation, which only offered "Caucasian" and "non-Caucasian" categories. However, concerns arose as this involved reducing predicted values for non-Caucasian individuals by 10% which lacked robust scientific backing and risked reinforcing racial bias. 

The GLI Global 2022 equation was created using the same dataset as the GLI 2012 equation, but averaged across all ethnic categories, assigning them equal weight. This new, race-neutral model aims to eliminate the use of self-reported race and ethnicity as a variable in spirometry interpretation and to reflect the natural variability in lung function across populations.

Why Move to a Race-Neutral Approach? 

The shift away from a race-specific reference equation is supported by emerging evidence that differences in lung function are better explained by social and environmental factors, rather than genetic or anatomical differences across racial groups. 

These social determinants include: 

• Childhood exposure to pollutants

• Nutrition and access to healthcare

• Housing conditions 

• Education and socioeconomic status

Using race-specific equations without considering these factors can misclassify disease severity and exacerbate health inequalities. Race-neutral models seek to provide a more equitable approach, especially in underrepresented and historically marginalised populations. 

Reviewing the Evidence: GLI 2012 vs. GLI Global 2022 

Several studies have compared the outcomes of the race-specific GLI 2012 equation with the race-neutral GLI Global 2022 equation. Most show that overall predictions of respiratory outcomes remain similar however disease classifications and severity may change. The overall findings are:

•  Caucasian individuals may see slightly lower predicted values. 

• Black and some Asian individuals may see increased predicted values

For example, a retrospective study by Kanj et al. assessed over 109,000 spirometry tests, and the key information observed was GLI Global 2022 changed interpretation of 7.6% of tests overall and found:

• Mean FEV₁ and FVC values increased for White and North-East Asian individuals

• Mean FEV₁ Values decreased for South-East Asian and Black individuals, indicating potentially more frequent detection of respiratory impairment.

A study by Moffat et al, identified some individuals may observe a change disease classification as highlighted in figure 1. This highlights that changing to GLI Global 2022 may lead to earlier diagnosis for other ethnic groups and aligns with efforts to reduce racial bias. There is some concern of whether GLI Global 2022 may underestimate diagnosis in White individuals. Guidot et al did find more classification of restrictive disease in White individuals using GLI-2012, however the authors acknowledge that because a FVC classification has changed it would translate to a change in diagnosis, white individuals may go from having restriction to being above the lower limit of normal (LLN), there may be a pathological reduction in lung function that may be  labelled as healthy, it is important to note further testing and investigations are needed to confirm findings on spirometry.

These changes can have downstream effects in occupational health as well as other healthcare sectors, such as earlier detection of disease, higher disability payments, or reduced eligibility from certain occupational roles — particularly among non-white workers.

Applying race-neutral spirometry in practice

Therefore, implementation must be handled with care and contextual understanding.

In the UK the ARTP recommend for previous spirometry data to be recalculated for longitudinal monitoring, however measured values will remain the same.  

Occupational health professionals must evaluate changes to ensure fair and evidence-based decision-making. Where GLI Global is not yet available, the ATS recommends using the GLI “Other” category — a less precise average of previous ethnic categories. It is recommend checking with the manufacturer of the spirometer or software to check whether the equation is available. A Harvard public health author acknowledged the adoption of race-neutral equations means more workers from non-Caucasian backgrounds may now be flagged as having impaired lung function, which may result in greater access to compensation but could also lead to ineligibility for safety-critical roles, depending on local regulations. Therefore, implementation must be handled with care and contextual understanding. Occupational health professionals must evaluate changes to ensure fair and evidence-based decision-making. 

Occupational health practitioners interpreting spirometry should: 

• Not select a worker’s ethnicity for spirometry interpretation

• Use GLI Global, and where it is not available use GLI-other

• If possible, recalculate past data or longitudinal monitoring on trend reports

• Use other clinical observations and further testing to aid spirometry test results

• Where appropriate inform and explain to workers of the change in reference equations