Breath acidification in adolescent runners exposed to atmospheric pollution: A prospective, repeated measures observational study

Table 2 Median pre-exercise breath pH values for selected sample characteristics (n = 144 observations from 16 subjects).

Variable	Obs (n)	Median (IQR) (p value)†
Age, yr
14	59	7.56 (7.05–7.87)
15	59	7.70 (7.34–7.86)
16–17	26	7.22 (5.12–7.58)
		(0.01)
BMI, kg/m²
<20	90	7.68 (7.06–7.87)
≥20	54	7.41 (6.05–7.77)
		(0.17)
Sex
Male	86	7.58 (7.05–7.85)
Female	58	7.56 (6.37–7.86)
		(0.71)
Race
White	103	7.60 (7.10–7.87)
Nonwhite	41	7.44 (5.49–7.78)
		(0.13)
Asthma
Yes	13	7.41 (5.00–7.51)
No	131	7.60 (7.05–7.86)
		(0.10)
Allergy
Yes	40	7.51 (7.27–7.82)
No	104	7.60 (6.01–7.86)
		(0.20)
Wheeze or cough in past month
Yes	33	7.51 (7.25–7.78)
No	111	7.59 (6.37–7.86)
		(0.68)
Number of symptoms in past 24 hours*
0	116	7.55 (6.83–7.86)
1	22	7.68 (5.96–7.87)
2 or more	6	7.57 (7.27–7.66)
		(0.58)
Home ETS exposure
Yes	20	7.06 (4.99–7.74)
No	124	7.60 (7.10–7.86)
		(0.009)
Running style
Sprinter	21	6.05 (5.12–7.59)
Distance	123	7.64 (7.10–7.86)
		(0.0004)

* Symptoms included wheeze, cough, scratchy or itchy throat, runny nose, sneezing, and watery eyes.
IQR = interquartile range.
† Nonparametric Wilcoxon rank-sum tests used to examine differences in raw breath pH between groups.

ISSN: 1476-069X