Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island.
BACKGROUND
Mt. Oyama in Miyakejima Island erupted in June, 2000. All Miyake villagers were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, Miyake villagers returned to the island despite volcanic gas still being emitted.


OBJECTIVE
This study examines the 2-yr changes in Miyake residents' respiratory systems from autumn 2004 to November 2006.


METHODS
The study population was 823 Miyake adult residents who participated in the health check-up in 2006. Respiratory effects were evaluated by a questionnaire for respiratory symptoms and spirometry. SO2 has been continuously monitored at 7 sampling points of the inhabited area. The mean SO2 concentration from February 2005 to November 2006 was 0.031 ppm. The area was categorized into 4 areas by SO2 concentration, namely, areas L, H-1, H-2 and H-3, where average SO2 concentrations were 0.019, 0.026, 0.032, and 0.045 ppm, respectively.


RESULTS
The study subjects showed no deterioration in lung function. Prevalence of cough and phlegm among all participants were significantly higher in 2006 than in 2004, and age-, sex- and smoking-adjusted odds ratios of cough and phlegm were 1.75 (95%CI 1.33-2.30) and 1.44 (1.12-1.87). Prevalence of chronic bronchitis-like symptoms among normosusceptive subjects in 2006 was 4.1% which was significantly higher than that of 2.1% in 2004 (p=0.035). Compared to area L, the frequencies of phlegm and irritation of the nose were significantly increased in areas H-2 and H-3.


CONCLUSIONS
SO2 exposure-related respiratory symptoms were observed in adult Miyakejima residents after returning to the island.
Iwasawa
Satoko
S
Department of Preventive Medicine and Public Health, School of Medicine, Keio University, Shinjuku, Tokyo, Japan. di055005@sc.itc.keio.ac.jp
Kikuchi
Yuriko
Y
Nishiwaki
Yuji
Y
Nakano
Makiko
M
Michikawa
Takehiro
T
Tsuboi
Tazuru
T
Tanaka
Shigeru
S
Uemura
Takamoto
T
Ishigami
Ai
A
Nakashima
Hiroshi
H
Takebayashi
Toru
T
Adachi
Mitsuru
M
Morikawa
Akihiro
A
Maruyama
Kouichi
K
Kudo
Shoji
S
Uchiyama
Iwao
I
Omae
Kazuyuki
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D029481:Bronchitis, Chronic / Q000139:chemically induced / Q000453:epidemiology; D003371:Cough / Q000139:chemically induced; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D005260:Female; D005843:Geography; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009093:Mucus; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D012140:Respiratory Tract Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D013147:Spirometry; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity*; D011795:Surveys and Questionnaires; D013997:Time Factors; D018707:Volcanic Eruptions / Q000009:adverse effects* / Q000032:analysis
D052638:Particulate Matter; D013458:Sulfur Dioxide