Bronchial Responsiveness in Children Exposed to Atmospheric Pollution in Hong Kong: Results
The mean (minimum and maximum) levels of SO2, NO2, RSP, and TSP (/лg/m) in ambient air in the two districts for the year 1989 to 1990 (September to June) as measured from fixed air monitoring stations situated in the two districts were as follows:
Kwai Tsing Southern
S02 117(72,177) 9( 4,16)
N02 40(31, 49) 21(15,26)
RSP 54(44, 68) 30(30,44)
TSP 94 (73, 133) 54 (43,70)
(Environmental Protection Department, Hong Kong Government). anti allergy
There were 423 (79.2 percent) eligible children who received a histamine challenge test, 222 from SDT and 201 from KDT. Ten children were excluded because of acute upper respiratory infection, one because of acute asthmatic symptoms. None of the subjects had an FEVi of <70 percent predicted. There were proportionately more asthmatics in the nonparticipants (10.1 percent) than participants (4.3 percent) but no other differences in terms of age, gender, socioeconomic status, skin allergy, or parental smoking. Table 1 shows the age distribution of children by district. There were 222 boys (116 from SDT, 106 from KDT) and 201 girls (106 from SDT and 95 from KDT). No significant differences were found between the two districts in gender (x2=0.010, df=l,p=0.921)orin age,(x2==4.775,df=:3,p=0.189). For the children’s responses to 13 questions on their respiratory health, there were no significant differences (p>0.155) in the crude prevalence ratios between districts except for wheezing which was higher in the KDT sample (x2=4.139, df = 1, p=0.042) (Table 2). Five out of 18 (27.8 percent) children with a doctor’s diagnosis of asthma did not declare a history of wheezing. Fifteen (3.7 percent) children with no history of asthma admitted to wheezing. The Student’s t tests on the BR slope, baseline FEVi, FVC, weight, and height indicated that there were no significant differences between districts except for BR slope for the nonwheezing and nonasthmatic children (Table 3).
Table 1—Age Distribution of the Sample by District
Age, yr | SDT, n(%) | KDT, n(%) | Total, n(%) |
<10 | 46 (21) | 36 (18) | 82 (20) |
10.0-10.4 | 35 (16) | 48 (24) | 83 (20) |
10.5-10.9 | 53 (24) | 40 (20) | 93 (22) |
>11 | 88 (40) | 77 (38) | 165 (39) |
Total | 222 (100) | 201(100) | 423 (100) |
Table 2—Respiratory Symptoms by District
Symptom | SDT, n(%) | KDT, n (%) | Sample Size | p-Value |
Cough in the morning | 20 (9) | 10(5) | 423 | 0.154 |
Cough in the evening | 13 (6) | 12(6) | 423 | 1.000 |
Cough for 3 months | 5(2) | 3(2) | 423 | 0.829 |
Phlegm in the morning | 17(8) | 21(10) | 423 | 0.405 |
Phlegm day/night | 21(10) | 17(9) | 423 | 0.850 |
Phlegm for 3 months | 10 (5) | 13 (7) | 423 | 0.500 |
Sore throat | 17(8) | 17(9) | 423 | 0.902 |
Nasal symptoms | 52 (23) | 53 (26) | 423 | 0.557 |
Cold in the last 10 days | 39 (18) | 30(15) | 422 | 0.533 |
Wheezing | 9(4) | 19(10) | 423 | 0.042 |
Doctor-diagnosed asthma | 6 (3) | 12(6) | 423 | 0.155 |
Doctor-diagnosed allergic rhinitis | 24 (11) | 25 (12) | 423 | 0.711 |
Doctor-diagnosed sinusitis | 3(1) | KD | 423 | 0.687 |
Table 3—Bronchial Reactivity Slope, Baseline FEVi, FVC, Weight, and Height of Nonwheezing, Nonasthmatic Children by District
Variable | SDT, (n=209), Mean (SD) | KDT, (n=175), Mean (SD) | Student’s t Value | p-Value |
BR slope | 0.42 (0.30) | 0.48 (0.33) | -1.85 | 0.07 |
FEVb L | 1.83 (0.36) | 1.80 (0.35) | 0.67 | 0.51 |
FVC, L | 1.99 (0.39) | 1.96 (0.40) | 0.70 | 0.48 |
Weight, kg | 33.61 (9.01) | 32.95 (8.07) | 0.76 | 0.45 |
Height, cm | 140.13 (7.58) | 139.73 (7.92) | 0.52 | 0.61 |