Table 3 Studies reporting breath pH among healthy subjects.

Children:

Carpagnano et al 2004. [23]

15 healthy children with mean age 7 yr

Mean (SE): 7.85 (0.02)

NR; estimated 7.6 – 8.2 from Figure 1A

CV = 0.04% from 6 adult controls

Samples de-aerated

Carraro et al 2005 [31]

10 healthy children with mean age 10 yr

Median (IQR): 7.85 (7.80 – 7.90)

NR; estimated 7.7 – 8.0 from Fig 2

NR

Samples de-aerated

MacGregor et al 2005 [32]

47 healthy control children of mean age 16 yr

Median: 5.90

5.00–7.30

NR

Samples not de-aerated

Nicolaou et al 2006 [30]

562 8-year old children from unselected population-based birth cohort

Median (IQR): 7.77 (7.59–7.87)

Range for normal subjects not reported. For all subjects (including 54 asthmatics and 562 normals): 4.40–8.29

NR

Bimodal distribution that "could not be normalized"; samples de-aerated

Rosias et al 2004 [33]

9 control children with mean age 9 yr

Median (SEM): 8.11 (0.07) de-aerated

6.64 (0.05) non-de-aerated

NR

NR

pH reported both before and after de-aeration

Adults:

Borrill et al 2005 [34]

12 healthy adults with mean age 26 yr

Mean (95%CI): 7.61 (7.52 – 7.70)

NR

NR^a

Samples de-aerated

Carpagnano et al 2005a [24]

15 healthy adults with mean age 35 yr

Mean (SD): 7.85 (0.14)

NR; estimated 7.6–8.2 from Fig IC

CV = 0.4% in 10 healthy adults

Samples de-aerated

Carpagnano et al 2005b [17]

7 healthy adults with mean age 42 yr

Mean (SEM): 7.9 (0.1)

NR; Estimated 7.8–8.2 from Fig 3C

CV = 0.4% in 10 healthy adults^b

Samples de-aerated

Corradi et al 2002. [5]

22 healthy adults with mean age 30 yr, grouped by NQO1 and GSTM1 genotype

Mean^c: Group 1 (NQO1 wild type and GSTM1 null): 7.91

Group 2 (all other genotypes): 8.01

Group 1 (NQO1 wild type and GSTM1 null): 7.70 – 8.08

Group 2 (all other genotypes): 7.80–8.11

NR

Samples apparently de-aerated following procedures in Hunt 2001

Gessner et al 2003 [35]

12 healthy adults with mean age 57

Mean (SD): 7.46 (0.48)

NR

NR

Samples de-aerated

Hunt et al 2000 [25]

19 healthy subjects with mean age 20.5

Mean (SE): 7.65 (0.20)

NR; estimated 4.6 – 8.5 from Fig 1

CV = 3.3% from 6 normals and 3 asthmatics; CV in normals not reported

Samples de-aerated

Kostikas et al 2002 [18]

10 healthy adult controls with mean age 34 yr

Mean (95%CI): 7.57 (7.51–7.60)

NR; estimated 7.4 – 7.75 from Fig 1A

NR

Samples de-aerated

Niimi et al 2004 [36]

16 healthy adults with mean age 43 yr

Mean (SD): 8.26 (0.20)

NR; estimated 7.8 – 8.6 from Fig 1

NR

Samples de-aerated

Ojoo et al 2005 [37]

15 healthy adults with mean age 39 yr

Median (IQR): 6.08 (5.58–6.64)

NR; estimated 5.6 – 6.7 from Fig 2

NR

Samples not de-aerated

Paget-Brown et al 2006 [29]

404 healthy children and adults from 0 to >71 yr of age

Mean: 7.85

Median (IQR): 8.0 (7.8 – 8.1);

In 11 to 20 yr olds (n = 163):

Median (IQR): 8.0(7.8–8.1)

Mean (SD): 7.8 (0.7)

4.5–8.4

NR

Samples de-aerated

Tate et al 2002 [38]

12 healthy adults with mean age 33 yr

Mean (SD): 6.15 (0.16)

NR; estimated 5.8 – 6.5 from Fig. 1

NR^d

Samples not de-aerated

Vaughan et al 2003 [22]

76 healthy adults with mean age 21 yr

Mean (SD): 7.70 (0.49)

NR

Mean CV = 4.5%;

by subject, CV = 0.9 – 20%

Samples de-aerated