Cardiorespiratory and all-cause mortality after restrictions on sulphur content of fuel in Hong Kong: an intervention study.
BACKGROUND
In July, 1990, a restriction was introduced over one weekend that required all power plants and road vehicles in Hong Kong to use fuel oil with a sulphur content of not more than 0.5% by weight. This intervention led to an immediate fall in ambient sulphur dioxide (SO2). We assessed the effect of this intervention on mortality over the next 5 years.


METHODS
Changes in trends in deaths were estimated by a Poisson regression model of deaths each month between 1985 and 1995. Changes in seasonal deaths immediately after the intervention were measured by the increase in deaths from warm to cool season. We also estimated the annual proportional change in number of deaths before and after the intervention. We used age-specific death rates to estimate person-years of life gained.


RESULTS
In the first 12 months after introduction of the restriction, a substantial reduction in seasonal deaths was noted, followed by a peak in the cool-season death rate between 13 and 24 months, returning to the expected pattern during years 3-5. Compared with predictions, the intervention led to a significant decline in the average annual trend in deaths from all causes (2.1%; p=0.001), respiratory (3.9%; p=0.0014) and cardiovascular (2.0%; p=0.0214) diseases, but not from other causes. The average gain in life expectancy per year of exposure to the lower pollutant concentration was 20 days (females) to 41 days (males).


CONCLUSIONS
Pollution resulting from sulphur-rich fuels has an effect on death rates, especially respiratory and cardiovascular deaths. The outcome of the Hong Kong intervention provides direct evidence that control of this pollution has immediate and long-term health benefits.
Hedley
Anthony Johnson
AJ
Department of Community Medicine, University of Hong Kong, Pokfulam, Hong Kong. commed@hkucc.hku.hk
Wong
Chit-Ming
CM
Thach
Thuan Quoc
TQ
Ma
Stefan
S
Lam
Tai-Hing
TH
Anderson
Hugh Ross
HR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D002318:Cardiovascular Diseases / Q000139:chemically induced* / Q000453:epidemiology / Q000401:mortality; D004781:Environmental Exposure; D005260:Female; D005648:Fuel Oils; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality; D012140:Respiratory Tract Diseases / Q000139:chemically induced* / Q000453:epidemiology / Q000401:mortality; D012621:Seasons; D013458:Sulfur Dioxide / Q000009:adverse effects* / Q000032:analysis; D015996:Survival Rate
D000393:Air Pollutants; D005648:Fuel Oils; D013458:Sulfur Dioxide