New reference values for forced spirometry in white adults in Brazil

Area of Science:

• Pulmonary Function Testing
• Respiratory Physiology
• Public Health

Background:

• Spirometric reference equations are crucial for diagnosing lung diseases.
• Previous reference values for Brazilian adults may not reflect current population characteristics.
• Establishing updated equations ensures accurate interpretation of lung function tests.

Purpose of the Study:

• To establish current spirometric reference equations for healthy, never-smoking Brazilian adults.
• To compare these new predicted values with previously established equations from 1992.

Main Methods:

• Spirometry was performed on 270 men and 373 women across eight Brazilian cities.
• Participants' ages ranged from 20 to 86 years.
• Examinations adhered to Brazilian Thoracic Society recommendations, with lower limits determined by the fifth percentile of residuals.

Main Results:

• Linear regression best fitted Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1/FVC, and FEV1/FEV6.
• Log equations provided the best fit for flow rates.
• New reference values for FEV1 and FVC were higher than those from 1992, with greater height correlating to lower FEV1/FVC and FEV1/FEV6 ratios.

Conclusions:

• Updated spirometric reference equations for white Brazilians have been established.
• The new predicted values are higher than those from 1992, potentially due to technical advancements.
• These findings necessitate a revision of current diagnostic thresholds for lung function in Brazil.