Higher coffee intake is linked to a lower risk of endometrial cancer, according to a meta-analysis published in The Journal of Obstetrics and Gynaecology Research.
Researchers found that coffee may provide a protective effect against endometrial cancer, but the amount of coffee consumed, caffeine intake, body mass index (BMI), smoking history, geographic region, and use of hormone replacement therapy (HRT) may impact that protection.
The meta-analysis included data from 24 studies — 12 case-control studies and 12 cohort studies. Of the 699,234 individuals evaluated, 9833 had endometrial cancer.
The data showed that higher coffee intake was associated with a lower risk of endometrial cancer. The pooled relative risk (RR) of endometrial cancer across studies was 0.71 when comparing the highest and lowest categories of coffee intake (95% CI, 0.65-0.77).
Findings were similar for the case-control studies (RR, 0.68; 95% CI, 0.56-0.83) and the cohort studies (RR, 0.70; 95% CI, 0.63-0.77).
However, the results varied by geographic region. The pooled RR was 0.74 for Europe (95% CI, 0.62-0.88), 0.71 for the United States and Canada (95% CI, 0.64-0.79), and 0.40 for Japan (95% CI, 0.28-0.57).
According to data from 6 studies, there was a significant association with caffeinated coffee (RR, 0.66; 95% CI, 0.52-0.83) but not decaffeinated coffee (RR, 0.86; 95% CI, 0.71-1.04).
Data from 8 studies suggested that patients with a higher BMI had a high risk of endometrial cancer and might derive more benefit from increased coffee drinking, according to the researchers. The pooled RR was 0.65 for a higher BMI (95% CI, 0.54-0.79) and 0.88 for a lower BMI (95% CI, 0.75-1.03).
According to data from 6 studies, there was a greater risk reduction with coffee drinkers who had a history of smoking. The pooled RR was 0.68 for those who never smoked (95% CI, 0.56-0.84) and 0.56 for those who ever smoked (95% CI, 0.45-0.70).
Data from 3 studies showed a significantly greater inverse association with coffee among HRT nonusers than HRT users. The pooled RR was 0.88 for coffee drinkers who never used HRT (95% CI, 0.79-0.98) and 0.97 for those who ever used HRT (95% CI, 0.92-1.02).
“In conclusion, the results of this meta-analysis demonstrate that high coffee consumption might lower the risk of endometrial cancer,” the researchers wrote. “The results may suggest an actual protective link between coffee consumption and anti-endometrial cancer effects.”
Gao Y, Zhai P, Jiang F, Zhou F, Wang X. Association between coffee drinking and endometrial cancer risk: A meta-analysis. J Obstet Gynaecol Res. Published online January 19, 2022. doi:10.1111/jog.15139