Table 3.
Studies reporting breath pH among healthy subjects.
| Reference | Subjects | Central tendency | Range | CV | Comments |
| 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 | NRa | 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 adultsb | Samples de-aerated |
| Corradi et al 2002. [5] | 22 healthy adults with mean age 30 yr, grouped by NQO1 and GSTM1 genotype | Meanc: Group 1 (NQO1wild type and GSTM1null): 7.91 Group 2 (all other genotypes): 8.01 |
Group 1 (NQO1wild 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 | NRd | 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 |
CV = coefficient of variation
NR = not reported
a reports "limits of agreement" using Bland-Altman methods to assess reproducibility
b appears to be reporting the same CV estimate as in Carpagnano 2005a
c breath pH measurement at baseline (before exposure to ozone)
d reports "coefficient of acceptability" as 0.08 pH units