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Table 5 Spirometry results with PFT pattern classification based upon new-onset respiratory symptoms (N = 220)

From: Respiratory symptoms and lung function 8–10 months after community exposure to chlorine gas: a public health intervention and cross-sectional analysis

 

Mean NHANES % predicted (std)

Below LLN and symptoms N = 110 (%)

Below LLN and no symptoms N = 110 (%)

Adjusted prevalence ratio*** (95% CI)

p-value

Median

   

FEV1

72.1 (21.5)

75 (68.2)

51 (46.4)

1.73 (1.11, 2.69)

0.015*

74.0

FVC

81.7 (23.6)

61(55.5)

49 (44.6)

1.66 (1.0, 2.77)

0.051

80.0

FEV1/FVC ratio %

82.4 (0.09)

15 (13.6)

9 (8.2)

2.25 (0.542, 9.34)

0.264

84.3

FEF25-75%

95.1 (39.1)

16 (14.6)

9 (8.2)

1.60 (0.50, 5.16)

0.431

93.2

Any abnormal parameter

 

82 (74.5)

64 (59.1)

1.62 (1.10, 2.39)

0.015*

Air-Flow pattern results**

Normal

28

45

 

Obstructive§

12

8

        Mild

3

0

        Moderate

4

3

        Severe

5

3

        Very severe

0

2

        Restrictive§§

46

34

        FEV1<LLN§§§

24

23

  1. *Statistically significant at α = 0.05.
  2. **Normal = FEV1 and FVC ≥ LLN and FEV1/FVC ratio ≥ LLN.
  3. §Obstructive Spirometry Pattern = FEV1/FVC ratio < LLN.
  4. Mild: FEV1% predicted > 80% ,Moderate: 50% < FEV1 < 80% predicted, Severe: 30%< FEV1 <50% predicted, Very Severe: <30% predicted [39, 42].
  5. §§Restrictive Spirometry Pattern = FEV1, FVC, and FEV1/FVC Ratio > LLN.
  6. ***Covariate adjustment for age, sex, race, smoking and educational status.
  7. Adjusted prevalence ratios (PR), 95% confidence intervals, and Chi-square p-values for the association between report of respiratory symptoms and spirometry parameters below LLN.