Reproductive and sex hormonal factors and oesophageal and gastric junction adenocarcinoma: A pooled analysis

Abstract

Background The rapidly rising incidence and the striking male predominance are as yet unexplained features of oesophageal and gastric junction adenocarcinoma. Few and underpowered studies have examined the impact of female reproductive factors on risk of these adenocarcinomas in women. We therefore pooled data on women from four population-based case-control studies to examine the association of female reproductive and sex hormonal factors with oesophageal and gastric junction adenocarcinoma. Methods Data on women from case-control studies conducted in Ireland, the United Kingdom (UK), Australia and United States of America (USA) were pooled. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for a range of reproductive factors, adjusted for age, study and major risk factors for oesophageal and gastric junction adenocarcinoma. Results We included 218 cases and 862 controls. Among parous women, a reduced risk of oesophageal and gastric junction adenocarcinoma was found after breastfeeding (OR = 0.58, 95% CI = 0.37–0.92) and the risk decreased with increased duration of breastfeeding (>12 months OR = 0.42, 95% CI = 0.23–0.77). The endogenous reproductive factors such as parity, menstruation, history of pregnancy and the exogenous factors such as use of oral contraceptives and of hormone replacement therapy were not statistically significantly associated with oesophageal and gastric junction adenocarcinoma. Conclusion Our findings suggest that breastfeeding is associated with a decreased risk of oesophageal and gastric junction adenocarcinoma. The potential mechanism of this association warrants further investigation.

Hormone Replacement Therapy and Oral Contraceptives and Risk of Oesophageal Adenocarcinoma: A Systematic Review and Meta-analysis.

“…[11][12][13] These five studies were published in English during the period 2006 and 2011. Two studies were cohort studies 11,13,14 and three were case-control studies 12,14,15 (Table 1 11 The WHI included both a randomised controlled trial and an observational cohort study, both examining effects of HRT and OC, where data were analysed combined. The study adjusted the results for confounding by age, study type, ethnicity, BMI, reflux and hysterectomy.…”

“…These studies together identified 451 women with OAC and 367,033 female controls. [11][12][13][14][15] All selected studies addressed HRT exposure, [11][12][13][14][15] while three of these also had data on OC exposure. [11][12][13] These five studies were published in English during the period 2006 and 2011.…”

“…[11][12][13][14][15] All selected studies addressed HRT exposure, [11][12][13][14][15] while three of these also had data on OC exposure. [11][12][13] These five studies were published in English during the period 2006 and 2011. Two studies were cohort studies 11,13,14 and three were case-control studies 12,14,15 (Table 1 11 The WHI included both a randomised controlled trial and an observational cohort study, both examining effects of HRT and OC, where data were analysed combined.…”

“…[11][12][13][14][15] Study-specific point ORs of ever HRT use versus never HRT use ranged from 0.62 to 0.96 but each of the 95% CIs included OR 5 1. The pooled OR showed a statistically significant 25% decreased risk of OAC among ever users of HRT compared to never users (OR 0.75, 95% CI: 0.58-0.98).…”

“…10 Individual investigations of the potential role of exogenous hormonal therapy in women, including hormone replacement therapy (HRT) and oral contraceptives (OC), in the aetiology of OAC have failed to provide conclusive results. [11][12][13][14][15] The low incidence of OAC in women has hampered the statistical precision in the available studies. HRT is used to mitigate discomfort caused by decreased levels of circulating oestrogen and progesterone after menopause.…”