The need for race-specific reference equations for pulmonary diffusing capacity for nitric oxide

Area of Science:

• Pulmonary Medicine
• Physiology
• Racial Health Disparities

Background:

• Limited reference equations exist for pulmonary diffusing capacity for nitric oxide (DLNO) in healthy adults across different races.
• Pilot data collection is crucial to establish the necessity of race-specific DLNO reference equations.

Purpose of the Study:

• To collect pilot data demonstrating the need for race-specific reference equations for DLNO.
• To investigate racial differences in DLNO and DLCO in healthy adults.

Main Methods:

• Recruited 59 healthy African American (Black) adults (27 males, 32 females) for pulmonary function tests.
• Developed multiple linear regression equations for DLNO, VA, and DLCO using a 5-6 second breath-hold.
• Used a matched white reference sample for comparison in developing DLNO reference equations.

Main Results:

• Race, sex, age, and height explained 71% of the variance in DLNO and DLCO.
• Race accounted for approximately 5-10% of the total variance in diffusing capacity.
• Black adults exhibited significantly lower DLNO (12.4 mL/min/mmHg) and DLCO (3.9 mL/min/mmHg) compared to white adults, partly due to lower alveolar volume (VA).

Conclusions:

• Pilot data reveal statistically significant, though small, racial differences in DLNO and DLCO.
• Future reference equations for DLNO and DLCO must incorporate racial variations.
• Failure to account for racial differences risks misdiagnosing lung disease in Black adults using white-specific reference equations.