Department of Family and Preventive Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0631, USA.
Am J Prev Med. 2010 Mar;38(3):296-302. doi: 10.1016/j.amepre.2009.10.044.
Although nearly half of bladder cancer cases are due to smoking, the cause of nearly half is unexplained.
This study aims to determine whether an inverse association exists between ultraviolet B (UVB) irradiance and incidence rates of bladder cancer worldwide.
This study used an ecologic approach. Age-adjusted incidence rates of bladder cancer from 2002 were obtained for all 174 countries in GLOBOCAN, a database of the International Agency for Research on Cancer. The relationship of latitude and estimated serum 25-hydroxyvitamin D [25(OH)D] with incidence rates was determined. The independent contributions to incidence rates of bladder cancer of UVB, per capita cigarette consumption in 1980, and per capita health expenditure for 2001 were assessed using multiple regression. The analyses were performed in July 2008.
Bladder cancer incidence rates were higher in countries at higher latitudes than those nearer to the equator (r=-0.66, 95% CI=-0.74, -0.57, p<0.01). Ultraviolet B irradiance was independently inversely associated with incidence rates of bladder cancer after controlling for per capita cigarette consumption (beta=-0.28, 95% CI=-0.51, -0.05; R(2) for model=0.38, p<0.0001). Further, UVB irradiance was also inversely associated with incidence rates after controlling for per capita health expenditure (beta=-0.23, 95% CI=-0.36, -0.01; R(2) for model=0.49, p<0.0001) in a separate regression model.
Further investigation is needed to confirm the associations identified in this study using observational studies of individuals. The focus of this research should include the association of serum 25(OH)D levels with risk of bladder cancer.
尽管近一半的膀胱癌病例归因于吸烟，但近一半的病因仍未得到解释。
本研究旨在确定紫外线 B（UVB）辐射与全球膀胱癌发病率之间是否存在反比关系。
本研究采用生态研究方法。从国际癌症研究机构的 GLOBOCAN 数据库中获取了 2002 年所有 174 个国家的膀胱癌年龄调整发病率。确定了纬度和估计血清 25-羟维生素 D [25(OH)D]与发病率之间的关系。使用多元回归评估了 UVB、1980 年人均香烟消费量和 2001 年人均卫生支出对膀胱癌发病率的独立贡献。分析于 2008 年 7 月进行。
与靠近赤道的国家相比，纬度较高的国家膀胱癌发病率更高（r=-0.66，95%CI=-0.74，-0.57，p<0.01）。在控制人均香烟消费量后，UVB 辐射与膀胱癌发病率呈独立负相关（β=-0.28，95%CI=-0.51，-0.05；模型 R(2)=0.38，p<0.0001）。进一步，在单独的回归模型中，在控制人均卫生支出后，UVB 辐射与发病率也呈负相关（β=-0.23，95%CI=-0.36，-0.01；模型 R(2)=0.49，p<0.0001）。
需要进一步的研究来确认本研究中使用个体观察研究确定的关联。这项研究的重点应该包括血清 25(OH)D 水平与膀胱癌风险之间的关联。
