Vioque J, Ferrer P J, Bolúmar F
Departamento de Salud Pública, Universidad de Alicante.
Med Clin (Barc). 1997 Jan 18;108(2):41-4.
The aim of the present study was to analyze breast cancer mortality by provinces in Spain during the period 1975-91, and to assess the relationship with the geographical distribution of income level, percent of women living in rural areas and average parity of women in each province.
Data were obtained from national statistical sources. Standardized mortality ratios (SMR) for breast cancer were estimated by provinces for the periods 1975-1980, 1981-1986 and 1987-1991, and for the whole period 1975-1991. Poisson regression analysis was used to explore the association between breast cancer mortality and the above mentioned variables. Provinces were categorized according to the quintile distribution of independent variables, and ecological relative risks were estimated for each category.
Higher SMR were observed in island provinces (Canary and Balearic island), Catalonia, Basque Country, Navarre and the provinces of Saragosa, Seville and Valencia. Lowest SMR were observed in the inner provinces of Spain and the east part of Andalusian region. This pattern has remained very similar along the study period: income level showed a positive association with mortality from breast cancer. On the contrary, percent of women living in rural areas and parity were negatively associated to breast cancer mortality. The relative risk estimated for each child of parity adjusted by the other factors was 0.92 (95% confidence interval: 0.89-0.94).
The highest mortality from breast cancer in Spain has been observed in those provinces with the highest income level, the lowest percent of women living in rural areas and the lowest parity. These findings at the ecological (provinces) level are in concordance with results from other studies at the individual level, and further supports the hypothesis that for the etiology of breast cancer, environmental factors could play a dominant role.
本研究旨在分析1975 - 1991年期间西班牙各省的乳腺癌死亡率，并评估其与各省收入水平的地理分布、农村地区女性比例以及女性平均生育胎次之间的关系。
数据来自国家统计来源。按省份估算了1975 - 1980年、1981 - 1986年、1987 - 1991年以及1975 - 1991年整个期间乳腺癌的标准化死亡率（SMR）。采用泊松回归分析来探讨乳腺癌死亡率与上述变量之间的关联。根据自变量的五分位数分布对各省进行分类，并估算每类的生态相对风险。
在岛屿省份（加那利群岛和巴利阿里群岛）、加泰罗尼亚、巴斯克地区、纳瓦拉以及萨拉戈萨、塞维利亚和瓦伦西亚等省份观察到较高的SMR。在西班牙内陆省份和安达卢西亚地区东部观察到最低的SMR。在整个研究期间，这种模式一直非常相似：收入水平与乳腺癌死亡率呈正相关。相反，农村地区女性比例和生育胎次与乳腺癌死亡率呈负相关。经其他因素调整后，每生育一个孩子的相对风险估计为0.92（95%置信区间：0.89 - 0.94）。
在西班牙，乳腺癌死亡率最高的省份是那些收入水平最高、农村地区女性比例最低且生育胎次最低的省份。这些在生态（省份）层面的发现与其他在个体层面的研究结果一致，并进一步支持了以下假设：对于乳腺癌的病因，环境因素可能起主导作用。
