Cauchi John Paul, Camilleri Liberato, Scerri Christian
Department of Physiology and Biochemistry, University of Malta, Room 111, Msida, MSD 2080 Malta.
Statistics and Operations Research, Faculty of Science, University of Malta, Room 509, Maths and Physics Building, Msida, Malta.
EPMA J. 2016 Sep 20;7(1):20. doi: 10.1186/s13167-016-0069-z. eCollection 2016.
Environmental exposures are known to play a role in the development of cancer, including breast cancer. There are known associations of breast cancer with environmental factors such as sunlight exposure, diet and exercise and alcohol consumption as well as physiological factors. This study examines the prevalence of risk factors for breast cancer related to dietary intake, environment and lifestyle in the female population of Malta. Malta has had little research in this area, and therefore an exploratory study was carried out.
A retrospective case-control design was applied. Two hundred cases and 403 controls were included. Both cases and controls were subjects without a known family history for breast cancer. Controls were age-matched to cases in an age-decade category roughly at a 2:1 ratio. Interviews were carried out face-to-face using a questionnaire designed by Maltese and Sicilian researchers, encompassing various factors including diet, lifestyle, physiological factors and medical history. Breast cancer risk was then analysed using both univariate and multivariate analyses. For factors having a metric scale, the Mann-Whitney test was used to compare mean scores, while for categorical factors, the chi-square test was used to compare percentages between the case and control groups. Statistical modelling was carried out using binary logistic regression to relate the likelihood of breast cancer to over 50 risk/protective factors analysed collectively.
Univariate analysis showed around 20 parameters of interest, 14 of which were statistically significant at a 0.05 level of significance. Logistic regression analysis identified 11 predictors of interest that were statistically significant. Tomato, coffee and canned meat consumption were associated with lower likelihood of breast cancer (OR = 0.988, 0.901, 0.892, respectively), whereas beans and cabbage consumption and low sodium salt were positively associated with breast cancer (OR = 1.045, 1.834, 1.028, respectively). Premenopausal status was associated with a lower risk of breast cancer compared to postmenopausal status (OR = 0.067). Not having experienced myocardial infarction was associated with lower odds of breast cancer (OR = 0.331). Increased height was also found to have a strong association with risk of breast cancer, with the odds of having breast cancer increasing for every centimetre increase in height (OR = 1.048). In terms of quantity, odds of having breast cancer were lower in those exposed to sunlight (OR = 0.891). The odds of having breast cancer were also lower in those not using the oral contraceptive pill (OR = 0.454).
Various factors in this exploratory study were found to be associated with development of breast cancer. While causal conclusions cannot be made, tomato consumption is of particular interest, as these results corroborate findings found in other studies. A negative association of breast cancer with sunlight exposure and oral contraceptive pill use corroborates findings in other studies. Other associations with dietary intake can be explained by dietary changes. More robust studies in this area, including possible longitudinal studies, are warranted.
已知环境暴露在癌症（包括乳腺癌）的发生发展中起作用。乳腺癌与阳光照射、饮食、运动、饮酒等环境因素以及生理因素之间存在已知关联。本研究调查了马耳他女性人群中与饮食摄入、环境和生活方式相关的乳腺癌危险因素的流行情况。马耳他在这一领域的研究较少，因此开展了一项探索性研究。
采用回顾性病例对照设计。纳入200例病例和403例对照。病例和对照均为无乳腺癌家族史的受试者。对照在年龄十年组中与病例年龄匹配，比例约为2:1。使用由马耳他和西西里岛研究人员设计的问卷进行面对面访谈，问卷涵盖饮食、生活方式、生理因素和病史等各种因素。然后使用单变量和多变量分析来分析乳腺癌风险。对于具有度量尺度的因素，使用曼-惠特尼检验比较平均得分，而对于分类因素，使用卡方检验比较病例组和对照组之间的百分比。使用二元逻辑回归进行统计建模，以将乳腺癌的可能性与共同分析的50多个风险/保护因素相关联。
单变量分析显示约20个感兴趣的参数，其中14个在0.05的显著性水平上具有统计学意义。逻辑回归分析确定了11个具有统计学意义的感兴趣的预测因素。食用番茄、咖啡和罐装肉与患乳腺癌的可能性较低相关（OR分别为0.988、0.901、0.892），而食用豆类和卷心菜以及低钠盐与乳腺癌呈正相关（OR分别为1.045、1.834、1.028）。与绝经后状态相比，绝经前状态与较低的乳腺癌风险相关（OR = 0.067）。未经历过心肌梗死与较低的乳腺癌几率相关（OR = 0.331）。还发现身高增加与乳腺癌风险密切相关，身高每增加一厘米，患乳腺癌的几率就会增加（OR = 1.048）。在暴露量方面，暴露于阳光下的人患乳腺癌的几率较低（OR = 0.891）。未使用口服避孕药的人患乳腺癌的几率也较低（OR = 0.454）。
在这项探索性研究中发现多种因素与乳腺癌的发生有关。虽然不能得出因果结论，但番茄消费特别值得关注，因为这些结果证实了其他研究中的发现。乳腺癌与阳光照射和口服避孕药使用之间的负相关证实了其他研究中的发现。与饮食摄入的其他关联可以通过饮食变化来解释。在这一领域需要进行更有力的研究，包括可能的纵向研究。
