Environmental and lifestyle risk factors of breast cancer in Malta-a retrospective case-control study.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Department of Physiology and Biochemistry, University of Malta, Room 111, Msida, MSD 2080 Malta.
John Paul
0000-0001-8983-8499
JP
Cauchi
Statistics and Operations Research, Faculty of Science, University of Malta, Room 509, Maths and Physics Building, Msida, Malta.
Liberato
L
Camilleri
Physiology and Biochemistry, Faculty of Medicine and Surgery, Biomedical Sciences Building, University of Malta, Msida, Malta.
Christian
C
Scerri
Breast cancer; Environment; Environmental health; Lifestyle; Predictive medicine; Targeted prevention
Am Soc Clin Oncol Educ Book. 2013;:52-9
23714455
Environ Health Perspect. 2014 Feb;122(2):165-71
24252436
Adv Exp Med Biol. 2011;720:91-104
21901621
JAMA. 2001 Nov 7;286(17):2143-51
11694156
World J Clin Oncol. 2016 Feb 10;7(1):54-86
26862491
EPMA J. 2013 Feb 19;4(1):6
23418957
J Natl Cancer Inst. 1990 Apr 4;82(7):561-9
2156081
Cancer Res. 2014 Jun 1;74(11):3076-83
24879566
Gynecol Oncol. 2016 Apr;141(1):10-6
27016223
Eur J Cancer. 1994;30A(7):969-73
7946593
Anticancer Res. 2014 Mar;34(3):1071-7
24596345
Int J Cancer. 2005 Jan 10;113(2):302-6
15386413
EPMA J. 2013 Sep 16;4(1):22
24228816
Exp Biol Med (Maywood). 2002 Nov;227(10):852-9
12424325
Toxicol Lett. 2016 Mar 30;246:42-8
26853153
Epigenetics. 2011 Jul;6(7):804-19
21758002
Cancer. 2016 Jun 15;122(12):1913-20
26992017
Ann Oncol. 2004 Oct;15(10):1460-5
15367404
Biomark Med. 2009 Aug;3(4):397-410
20477485
Biomed Rep. 2016 Mar;4(3):282-292
26998264
Eur J Cancer. 2016 Jan;52:138-54
26687833
Br J Cancer. 2015 Jun 30;113(1):159-65
26035701
Salud Publica Mex. 2011 Sep-Oct;53(5):440-7
22218798
Medicine (Baltimore). 1998 May;77(3):208-26
9653432
Br J Cancer. 2002 Nov 18;87(11):1234-45
12439712
Ann Oncol. 2012 Jun;23(6):1394-402
22234738
Br J Cancer. 2004 Jan 12;90(1):122-7
14710218
Breast Cancer Res Treat. 2011 Aug;129(1):135-47
21373874
Oncol Res. 2014;22(3):129-37
26168131
Obes Rev. 2003 Aug;4(3):157-73
12916817
Evid Rep Technol Assess (Full Rep). 2010 Nov;(197):1-151
23126574
CA Cancer J Clin. 2007 Sep-Oct;57(5):260-77
17855484
Am J Clin Nutr. 2016 Feb;103(2):454-64
26791185
Am J Hum Biol. 2012 Mar-Apr;24(2):158-64
22287066
Stat Med. 2004 Apr 15;23(7):1111-30
15057881
Oncology (Williston Park). 2011 Oct;25(11):994-1000
22106549
J Appl Toxicol. 2003 Sep-Oct;23(5):285-8
12975767
Am J Clin Nutr. 2008 Nov;88(5):1304-12
18996867
Crit Rev Food Sci Nutr. 2015 Feb 18;:0
25692500
BMC Cancer. 2011 Mar 15;11:96
21406107
Environ Health Perspect. 2008 Apr;116(4):426-33
18414622
Am J Clin Nutr. 2008 May;87(5):1384-91
18469262
Lancet. 1996 Jun 22;347(9017):1713-27
8656904
Mol Oncol. 2010 Jun;4(3):242-54
20627830
Cell. 2012 Jul 6;150(1):12-27
22770212
J Breast Cancer. 2013 Jun;16(2):171-7
23843849
Nutr Cancer. 2003;45(1):1-16
12791499