Analysis of gases in exhaled breath is a non-invasive tool that may be helpful in the diagnosis and monitoring of a variety of lung and systemic diseases. Exhaled NO and CO have shown particular promise in this area. It has been suggested that individual characteristics other than the disease (like age and gender) may have an effect on the levels of these gases in exhaled breath. Understanding the effect of such variables is crucial to the study of these gases in various disease states.
To examine if age and/or gender have any effect on the exhaled NO and CO levels in healthy individuals.
We evaluated 59 NO and CO measurements in non-smoking individuals with no respiratory symptoms and no history of lung disease. Exhaled gases were collected for off-line analysis according to American Thoracic Society (ATS) recommendations. NO levels were measured by chemiluminescence. An infrared analyzer was used to measure CO levels.
There was no correlation between exhaled NO and age (R= 0.03, p=0.8). This was also true when the individuals were stratified by age (ANOVA p=0.06).(ppb= parts per billion, ppm= parts per million)The same was true for CO (ANOVA p=0.390).Exhaled NO levels were similar in males and females but CO levels were higher in males.
Age has no significant effect on the levels of exhaled NO and CO in healthy individuals without lung disease. Males tend to have higher CO levels than females.
This needs to be taken into consideration when selecting control groups to study various lung diseases.
AGE GROUP (yrs.)NNO Levels (ppb) Median (25%, 75%)21–30196.9 (6.4, 7.9)31–40206.3 (4.7, 8.0)41–50189.2 (6.4, 10.4)51–6026.4 (4.8, 7.9)AGE GROUP (yrs.)NCO Levels (ppm) Median (25%, 75%)21–30191.2 (0.9, 1.6)31–40201.4 (1.1, 2.1)41–50181.7 (0.9, 2.7)51–6021.2 (0.5, 1.9)NO Levels (ppb) Median (25%,75%)CO Levels (ppm) Median (25%,75%)Male (n=37)6.8 (5.6, 8.7)1.6 (1.1,2.1)Female (n=22)7.9 (6.6, 9.6)1.0 (0.8,1.9)p (t-test)0.080.03
J.M. Duncan, None.