Ozone depletion will bring big rise in number of cataracts
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《英国医生杂志》
Ozone depletion may result in up to 830 000 additional cases of cataract by 2050 in the United States, new research shows.
The excess cost of such a rise in the number of cases would be $2.8bn (?.6bn; �2.4bn), say the authors of the report in the American Journal of Epidemiology (2005;162:1080-8).
"We believe that our estimates represent the most reasonable model to date of an ocular health effect and the consequences of ozone depletion. This model demonstrates the magnitude of the increase in cortical opacity that might result and the importance of vigilance in adopting sun avoidance behaviours," wrote the authors, who are from the Wilmer Eye Institute at the Johns Hopkins School of Medicine, Baltimore, the Institute for Global Risk Research, Fairfax, Virginia, and the Joint Global Change Research Institute, College Park, Maryland.
Although progress is being made in reducing the degree of stratospheric ozone depletion, say the authors, the effects on health of ozone depletion in terms of greater exposure to ultraviolet B radiation are likely to be seen for a century or more.
They say that cataract is one health effect of particular concern. A number of epidemiological studies show that exposure to ultraviolet radiation is an important risk factor for cortical cataract but not for nuclear or posterior subcapsular cataract.
The researchers used data on cataracts from a study of 2520 residents of Salisbury, Maryland. Information available included job history, amount of time spent outdoors, and the use of glasses, sunglasses, and hats. The data provide specific average annual and cumulative exposures for each person in the study, as well as information on cataracts.
They calculated exposure estimates for the US population as a whole, drawing on other data such as satellite ozone measurements, and used US Census Bureau population estimates to work out the numbers of cases of cataract under different scenarios of ozone depletion.
Their results show that by 2050 the prevalence of cortical cataract will increase above expected levels by between 1.3% and 6.9% if ozone is depleted by between 5% and 20%. This will result in between 167 000 and 830 000 additional cases of cortical cataract, costing an extra $563m to $2.8bn. A 10% depletion in ozone would result in an extra 358 500 cases.
The results also show differences for white and black Americans. The estimated absolute increase in the probability of cortical cataract among white people was between 0.5% and 1% with an increase in ozone depletion from zero to 20%. There was greater variability in the black population: from 0.5% to 4%.(Abergavenny Roger Dobson)
The excess cost of such a rise in the number of cases would be $2.8bn (?.6bn; �2.4bn), say the authors of the report in the American Journal of Epidemiology (2005;162:1080-8).
"We believe that our estimates represent the most reasonable model to date of an ocular health effect and the consequences of ozone depletion. This model demonstrates the magnitude of the increase in cortical opacity that might result and the importance of vigilance in adopting sun avoidance behaviours," wrote the authors, who are from the Wilmer Eye Institute at the Johns Hopkins School of Medicine, Baltimore, the Institute for Global Risk Research, Fairfax, Virginia, and the Joint Global Change Research Institute, College Park, Maryland.
Although progress is being made in reducing the degree of stratospheric ozone depletion, say the authors, the effects on health of ozone depletion in terms of greater exposure to ultraviolet B radiation are likely to be seen for a century or more.
They say that cataract is one health effect of particular concern. A number of epidemiological studies show that exposure to ultraviolet radiation is an important risk factor for cortical cataract but not for nuclear or posterior subcapsular cataract.
The researchers used data on cataracts from a study of 2520 residents of Salisbury, Maryland. Information available included job history, amount of time spent outdoors, and the use of glasses, sunglasses, and hats. The data provide specific average annual and cumulative exposures for each person in the study, as well as information on cataracts.
They calculated exposure estimates for the US population as a whole, drawing on other data such as satellite ozone measurements, and used US Census Bureau population estimates to work out the numbers of cases of cataract under different scenarios of ozone depletion.
Their results show that by 2050 the prevalence of cortical cataract will increase above expected levels by between 1.3% and 6.9% if ozone is depleted by between 5% and 20%. This will result in between 167 000 and 830 000 additional cases of cortical cataract, costing an extra $563m to $2.8bn. A 10% depletion in ozone would result in an extra 358 500 cases.
The results also show differences for white and black Americans. The estimated absolute increase in the probability of cortical cataract among white people was between 0.5% and 1% with an increase in ozone depletion from zero to 20%. There was greater variability in the black population: from 0.5% to 4%.(Abergavenny Roger Dobson)