Abstract
BackgroundSex hormones play a role in gastric cancer and colorectal cancer etiology, however, epidemiological evidence is inconsistent. This study examines the influence of menstrual and reproductive factors over the risk of both tumors.MethodsIn this case-control study 128 women with gastric cancer and 1293 controls, as well as 562 female and colorectal cancer cases and 1605 controls were recruited in 9 and 11 Spanish provinces, respectively. Population controls were frequency matched to cases by age and province. Demographic and reproductive data were directly surveyed by trained staff. The association with gastric, colon and rectal cancer was assessed using logistic and multinomial mixed regression models.ResultsOur results show an inverse association of age at first birth with gastric cancer risk (five-year trend: OR = 0.69; p-value = 0.006). Ever users of hormonal contraception presented a decreased risk of gastric (OR = 0.42; 95%CI = 0.26–0.69), colon (OR = 0.64; 95%CI = 0.48–0.86) and rectal cancer (OR = 0.61; 95%CI = 0.43–0.88). Postmenopausal women who used hormone replacement therapy showed a decreased risk of colon and rectal tumors. A significant interaction of educational level with parity and months of first child lactation was also observed.ConclusionThese findings suggest a protective role of exogenous hormones in gastric and colorectal cancer risk. The role of endogenous hormones remains unclear.
Highlights
Colorectal cancer (CRC) in Spain, with an estimated 16071 new cases in 2014 [1], represents the second most common tumor in women and the second leading cause of death, accounting for 15.3% of all female cancer-related deaths in 2013 [2]
Our results show an inverse association of age at first birth with gastric cancer risk
A significant interaction of educational level with parity and months of first child lactation was observed. These findings suggest a protective role of exogenous hormones in gastric and colorectal cancer risk
Summary
Colorectal cancer (CRC) in Spain, with an estimated 16071 new cases in 2014 [1], represents the second most common tumor in women and the second leading cause of death, accounting for 15.3% of all female cancer-related deaths in 2013 [2]. Gastric cancer (GC) in Spanish women occupies the tenth position in incidence, with an adjusted rate of 7.5 cases per 100,000 estimated for 2012 [6]. The rate estimated for this same year was 4.8 per 100,000, accounting for 5.3% of all female cancer-related deaths in 2013 [2]. The small difference between the incidence and mortality rates is due to the low survival recorded for this tumor, which is estimated in Spain to be 26.0% at 5 years [1]. This study examines the influence of menstrual and reproductive factors over the risk of both tumors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
