Tea and coffee drinking and ovarian cancer risk: results from the Netherlands Cohort Study and a meta-analysis

Abstract

In a cohort study, ovarian cancer (280 cases) showed no significant association with tea or coffee, the multivariable rate ratios being 0.94 (95% confidence interval (CI): 0.89, 1.00) and 1.04 (95% CI: 0.97, 1.12) per cup per day, respectively. A meta-analysis also produced no significant findings overall, though the cohort studies showed a significant inverse association for tea. British Journal of Cancer (2007) Tea and coffee are widely consumed around the world and may affect human health. Several case-control and cohort studies have analysed the relationship with ovarian cancer risk, yielding inconclusive results. We analysed the association between tea, coffee and ovarian cancer in a prospective cohort study and summarised results of previous studies in a meta-analysis.

Tea consumption and risk of ovarian cancer

“…Previous meta-analyses reported borderline inverse associations for all tea combined (OR 0.84 [9]; OR 0.85 [8]), similar to our finding of an inverse association (albeit not statistically significant), between green tea consumption and ovarian cancer. Our case-control results for all types of tea combined are consistent with two recent meta-analyses.…”

“…The systematic review was restricted to green tea as two recent meta-analyses have previously considered the association between consumption of all types of tea combined (in practice this was predominantly black tea) and ovarian cancer [8,9] and furthermore it is the specific polyphenols in green tea that are widely thought to possess cancer inhibitory properties [1]. Eligible studies published prior to March 2009 were identified by searching Medline 1950-(U.S. National Library of Medicine, Bethesda, MD), Embase 1966-(Elsevier Science, Amsterdam, Holland), Conference Papers Index 1982-(CSA, Bethesda, MD), ISI Science Citation Index and by hand-searching the reference lists of the retrieved articles.…”

“…Since the mid-1980s, the association between tea consumption and ovarian cancer has been investigated in at least 17 epidemiological studies, but a risk reduction has been reported in only five: three casecontrol [3][4][5] and two cohort studies [6,7]. Furthermore, two recently published meta-analyses reported non-significant inverse associations with tea consumption overall [8,9], although one, in analyses restricted to five cohort studies, identified a significant inverse association between drinking tea and ovarian cancer risk (RR 0.71, 95% CI 0.55-0.93) [8]. The few relevant studies [4,5,10] do, however, suggest a more consistent risk reduction with green tea intake than for black tea, possibly due to the greater abundance of bioavailable polyphenols in green tea and its higher antioxidant capacity [1,11].…”

Epidemiologic Evidence on Coffee and Cancer

“…None of these has shown significant associations between coffee consumption and ovarian cancer incidence (25,28,33,34). One of these is the previously mentioned Aichi Cancer Center study that reported no clear association between intake of coffee and risk among Japanese women among the 166 ovarian cancer cases as compared with 12,425 women free of cancer (28).…”

“…A cohort study conducted (34) in the Netherlands also observed no significant association with coffee and ovarian cancer, the multivariable rate ratios being 1.04 (95% CI = 0.97-1.12) per cup per day among the 280 ovarian cancer cases and cohort comparisons. These authors also conducted a meta-analysis and found no significant associations between ovarian cancer occurrence and coffee consumption (34) across the various studies from various populations and differing consumption patterns.…”