Health Analysis Division, Statistics Canada, Ottawa, Ontario.
Environment and Climate Change Canada, Toronto, Ontario.
Health Rep. 2017 May 17;28(5):3-11.
Depletion of the ozone layer has meant that ambient ultraviolet radiation (UVR) has increased in recent decades. At the same time, the incidence of skin cancers, including melanoma, has risen. The relatively few large-scale studies that linked ambient UVR to melanoma found a trend toward rising incidence closer to the equator, where UVR estimates are highest. Similar research has not been conducted in Canada, where ambient UVR is generally lower than in countries further south.
Modelled UVR data for the months of June through August during the 1980-to-1990 period were spatially linked in Geographic Information Systems to 2.4 million white members of the 1991 Canadian Census Health and Environment Cohort and tracked for melanoma diagnosis over an 18-year period (1992 to 2009). Standard Cox proportional hazards models were used to estimate melanoma risk associated with increases of ambient summer UVR, assigned by residence at baseline. Models were adjusted for age, sex and socioeconomic (SES) characteristics. Separate analyses by body site of melanoma were conducted. Effect modification of the association between ambient UVR and melanoma by sex, age, outdoor occupation and selected SES characteristics was evaluated.
Differences of one standard deviation (446 J/m², or 7% of the mean) in average ambient summer UVR were associated with an increased hazard ratio (HR) for melanoma of 1.22 (95% CI: 1.19 to 1.25) when adjusting for sex, age and SES characteristics. The HR for melanoma in relative UVR (per 1 standard deviation) was larger for men (HR = 1.26; 95% CI: 1.21 to 1.30) than for women (HR = 1.17; 95% CI: 1.13 to 1.22).
Ambient summer UVR is associated with a greater risk of melanoma among the white population, even in a country where most people live within a narrow latitudinal belt. A stronger association between melanoma and ambient UVR was evident among men and among people of lower SES.
臭氧层的消耗意味着近年来环境中的紫外线辐射（UVR）增加了。与此同时，皮肤癌（包括黑色素瘤）的发病率也有所上升。为数不多的将环境 UVR 与黑色素瘤联系起来的大型研究发现，在接近赤道的地方，紫外线辐射估计值最高，发病率呈上升趋势。在加拿大，还没有进行类似的研究，那里的环境 UVR 通常低于更靠南的国家。
在地理信息系统中将 1980 年至 1990 年期间 6 月至 8 月的 UVR 模型数据与 1991 年加拿大人口普查健康与环境队列中的 240 万白人成员进行空间链接，并在 18 年期间（1992 年至 2009 年）追踪黑色素瘤的诊断情况。使用标准的 Cox 比例风险模型来估计与夏季环境 UVR 增加相关的黑色素瘤风险，该风险按基线时的居住地分配。模型调整了年龄、性别和社会经济地位（SES）特征。对黑色素瘤的不同身体部位进行了单独的分析。评估了性别、年龄、户外职业和选定的 SES 特征对环境 UVR 与黑色素瘤之间关联的修饰作用。
在调整了性别、年龄和 SES 特征后，环境夏季 UVR 平均差异一个标准差（446 J/m²，或平均值的 7%）与黑色素瘤的危险比（HR）增加 1.22（95%CI：1.19 至 1.25）。在相对 UVR（每标准差）中，男性（HR=1.26；95%CI：1.21 至 1.30）的黑色素瘤 HR 大于女性（HR=1.17；95%CI：1.13 至 1.22）。
即使在大多数人生活在狭窄纬度带的国家，环境夏季 UVR 与白人人口的黑色素瘤风险增加有关。在男性和 SES 较低的人群中，黑色素瘤与环境 UVR 之间的关联更强。
