Air Pollution by Hydrothermal Volcanism and Human Pulmonary Function
Table 1
Description of the study populations (study and reference groups) (mean ± SE for continuous variables or n (%) for categorical variables).
Reference group (Ponta Delgada, )
Study group (Ribeira Quente, )
P valuea
General characteristics
Age (years)
41.3 ± 12.7
39.8 ± 11.2
45.1 ± 15.3
0.001
Age, >41b
234 (46.3)
152 (42.3)
82 (56.1)
0.005
Gender, male
207 (40.9)
155 (43.1)
52 (35.6)
0.117
BMI (kg/m2)
26.1 ± 4.4
25.7 ± 3.9
27.1 ± 5.4
0.006
BMI, >26c
213 (42.2)
141 (39.3)
72 (49.3)
0.041
Smoking status
Smoker
163 (32.2)
135 (37.6)
28 (19.1)
<0.001
Previous smoker
91 (18)
69 (19.2)
22 (15)
0.271
Easy fatigue, yes
116 (23)
40 (11.1)
76 (52)
<0.001
Asthma, yes
43 (8.5)
29 (8)
14 (9.6)
0.581
Occupation
White collar
135 (26.7)
122 (34)
13 (8.9)
<0.001
Blue collar
256 (50.7)
233 (65)
23 (15.8)
<0.001
Other
114 (22.6)
4 (1)
110 (75.3)
<0.001
Study
FEV1 predictedd
88.5 ± 20.4
92.5 ± 16.6
78.6 ± 25.2
0.001
FVC predicted
96.6 ± 19.2
98.8 ± 15
91.1 ± 26.2
<0.001
FEV1/FVC predicted
91.8 ± 14.2
93.8 ± 11.7
87 ± 18.1
<0.001
Lung function
Restriction, yes
26 (5.1)
11 (3)
15 (10.2)
0.001
COPD, yes
92 (18.2)
43 (11.9)
49 (33.6)
<0.001
CO2 flux, g/m2/de
15.36
508
<0.001
aP value comparing reference and study groups, by Mann-Whitney for continuous variables and by for categorical variables. bCut-off defined according to the mean value (i.e., 41.3 years) of the observed age distribution in the whole population. cCut-off defined according to the mean value (i.e., 26.1 BMI) of the observed BMI distribution in the whole population. dPredicted values from the National Health and Nutrition Examination Survey Cohort. eCO2 flux is expressed in mean.
