Reference values for respiratory function tests in males: prediction formulas with tobacco smoking parameters

Area of Science:

• Pulmonary Medicine
• Respiratory Physiology
• Biostatistics

Background:

• Accurate prediction equations are crucial for interpreting respiratory function tests.
• Existing formulas may not adequately account for factors like smoking history and age range.

Purpose of the Study:

• To develop and validate new prediction equations for various respiratory function tests.
• To identify key demographic and lifestyle factors influencing respiratory parameters.

Main Methods:

• Multiple regression analysis of data from 263 healthy males aged 20-70 years.
• Measurements included lung volumes, airways resistance, ventilatory capacity, gas distribution, transfer factor, and lung recoil pressures.
• Analysis incorporated age, height, weight, and detailed smoking history (current, ex-smokers, duration, intensity).

Main Results:

• Age, height, weight, and smoking parameters (years, daily grams) significantly correlated with most respiratory function tests.
• Developed basic and extended regression equations, with the latter including non-linear terms and abstinence duration.
• Inclusion of parameters moderately reduced variance (20-69%) in predictions.

Conclusions:

• The developed regression equations provide a more accurate prediction of respiratory function in healthy males.
• Demographic and smoking-related factors are essential predictors for respiratory health assessment.
• These new formulas may offer improved clinical utility compared to previously published equations.