Pollán Marina, Ramis Rebeca, Aragonés Nuria, Pérez-Gómez Beatriz, Gómez Diana, Lope Virginia, García-Pérez Javier, Carrasco Jose Miguel, García-Mendizábal Maria José, López-Abente Gonzalo
Environmental and Cancer Epidemiology Unit, National Centre for Epidemiology, Carlos III Institute of Public Health, Madrid, Spain.
BMC Cancer. 2007 May 8;7:78. doi: 10.1186/1471-2407-7-78.
Spain has one of the lowest rates of breast cancer in Europe, though estimated incidence has risen substantially in recent decades. Some years ago, the Spanish Cancer Mortality Atlas showed Spain as having a heterogeneous distribution of breast cancer mortality at a provincial level. This paper describes the municipal distribution of breast cancer mortality in Spain and its relationship with socio-economic indicators.
Breast cancer mortality was modelled using the Besag-York-Molliè autoregressive spatial model, including socio-economic level, rurality and percentage of population over 64 years of age as surrogates of reproductive and lifestyle risk factors. Municipal relative risks (RRs) were independently estimated for women aged under 50 years and for those aged 50 years and over. Maps were plotted depicting smoothed RR estimates and the distribution of the posterior probability of RR>1.
In women aged 50 years and over, mortality increased with socio-economic level, and was lower in rural areas and municipalities with higher proportion of old persons. Among women aged under 50 years, rurality was the only statistically significant explanatory variable. For women older than 49 years, the highest relative risks were mainly registered for municipalities located in the Canary Islands, Balearic Islands, the Mediterranean coast of Catalonia and Valencia, plus others around the Ebro River. In premenopausal women, the pattern was similar but tended to be more homogeneous. In mainland Spain, a group of municipalities with high RRs were located in Andalusia, near the left bank of the Guadalquivir River.
As previously observed in other contexts, mortality rates are positively related with socio-economic status and negatively associated with rurality and the presence of a higher proportion of people over age 64 years. Taken together, these variables represent the influence of lifestyle factors which have determined the increase in breast cancer frequency over recent decades. The results for the younger group of women suggest an attenuation of the socio-economic gradient in breast cancer mortality in Spain. The geographical variation essentially suggests the influence of other environmental variables, yet the descriptive nature of this study does not allow for the main determinants to be established.
西班牙是欧洲乳腺癌发病率最低的国家之一，不过近几十年来估计发病率大幅上升。几年前，《西班牙癌症死亡率地图集》显示西班牙省级层面的乳腺癌死亡率分布不均。本文描述了西班牙乳腺癌死亡率的市级分布及其与社会经济指标的关系。
使用贝萨格-约克-莫利埃自回归空间模型对乳腺癌死亡率进行建模，将社会经济水平、农村地区以及64岁以上人口百分比作为生殖和生活方式风险因素的替代指标。分别对50岁以下女性和50岁及以上女性的市级相对风险（RR）进行独立估计。绘制地图展示平滑后的RR估计值以及RR>1的后验概率分布。
在50岁及以上女性中，死亡率随社会经济水平升高而增加，在农村地区以及老年人比例较高的城市较低。在50岁以下女性中，农村地区是唯一具有统计学意义的解释变量。对于49岁以上女性，相对风险最高的主要是位于加那利群岛、巴利阿里群岛、加泰罗尼亚和瓦伦西亚地中海沿岸的城市，以及埃布罗河周边的其他城市。在绝经前女性中，模式相似但趋于更均匀。在西班牙大陆，一组RR较高的城市位于安达卢西亚，靠近瓜达尔基维尔河左岸。
正如之前在其他情况下所观察到的，死亡率与社会经济地位呈正相关，与农村地区以及64岁以上人口比例较高呈负相关。综合来看，这些变量代表了生活方式因素的影响，这些因素决定了近几十年来乳腺癌发病率的上升。年轻女性群体的结果表明西班牙乳腺癌死亡率的社会经济梯度有所减弱。地理差异本质上表明了其他环境变量的影响，但本研究的描述性质不允许确定主要决定因素。
