Evaluation of breast cancer risk associated with tea consumption by menopausal and estrogen receptor status among Chinese women in Hong Kong

Abstract

Tea or green tea drinking was not associated with overall breast cancer risk, which may be masked by the differential effect in pre- and post-menopausal women.

Suppressive Effects of Tea Catechins on Breast Cancer

“…The association between tea consumption and decreased risk of breast cancer was also confirmed by population-based case-control studies carried out in China [10,12,17], the USA [18,19,20], and Singapore [21,22]. There were studies showing that green tea consumption significantly reduced the risk of breast cancer [18] and the women who drank three or more cups of tea per day had a 37% reduced breast cancer risk than their counterparts that did not drink tea [20].…”

The association between green tea consumption and breast cancer risk: A systematic review and meta‐analysis

“…The quality of 10 case‐control studies was assessed, and it was observed that all of these studies had a NOS score ≥ 7 (Inoue et al, ; Iwasaki et al, ; Iwasaki, Inoue, Sasazuki, Miura, et al, ; Lee et al, ; Li et al, ; Mizoo et al, ; Shrubsole et al, ; Wang et al, ; Wu, Tseng, Van Den Berg, & Mimi, ; Zhang et al, ); however, one of the studies had not performed adequate adjustments for confounding variables and was not included in the meta‐analysis (Lee et al, ). Moreover, the quality of four cohort studies was assessed; all these studies had a NOS score ≥ 7 and were included in the meta‐analysis (Dai et al, ; Iwasaki, Inoue, Sasazuki, Miura, et al, ; Key et al, ; Suzuki et al, ).…”

“…It has been reported that GT drinking is associated with a reduced risk of breast cancer among premenopausal women but it is surprisingly associated with an increased risk among postmenopausal women. It has been suggested that GT effects might be modified by estrogen receptors (Li et al, ).…”

“…It has been reported that GT drinking is associated with a reduced risk of breast cancer among premenopausal women but it is surprisingly associated with an increased risk among postmenopausal women. It has been suggested that GT effects might be modified by estrogen receptors (Li et al, 2016). With regard to the above-mentioned gene-nutrient theory, the level of expression of genes associated with breast cancer is different in premenopausal and postmenopausal women (Mizoo et al, 2013).…”

“…Although the relationship between lifestyle‐related parameters and breast cancer risk has been studied and some of them like breastfeeding, body fat, and adult attained height reached a “convincing” level but evidence indicating a relationship between some foods and breast cancer risk remains insufficient (Li et al, ). The lower rates of breast cancer in the Asian population who consume high levels of green tea (GT), has made the scientists to suggest a protective effect for GT against breast cancer (Schulze, Melzer, Smith, & Teschke, ), but the results of published epidemiological studies, which have evaluated the possible chemopreventive effects of GT in humans, are inconsistent (Inoue et al, ; Nagano, Kono, Preston, & Mabuchi, ; Shrubsole et al, ; Suzuki et al, ; Zhang, Holman, Huang, & Xie, ).…”