Coffee consumption and cancers at other sitesPrint this page
Coffee and skin cancer
There is no evidence that coffee consumption is linked to skin cancer. Caffeine, however, may protect skin cells against the harmful effects of UVB radiation.
- In 2008, a study in mice reported that caffeine added to drinking water, or placed directly onto the skin, induced the death of cells damaged by UVB irradiation. In 2009, the same work performed on human skin cell cultures showed that caffeine doubled the mortality of the cells damaged by UVBs, hence decreasing the risk of cancer96.
- The underlying molecular mechanism is similar in both species, which led the authors to hypothesize that caffeine, or a substance with a similar mode of action, could protect human skin from the deleterious action of UVBs when applied topically97.
The WCRF 2007 Second Expert Report lists coffee under ‘Limited Evidence – No Conclusion’ for skin cancer18. However, a 2015 systematic review and meta-analysis concluded that there is some evidence for an association between regular coffee consumption and a reduced risk of melanoma, although the authors suggest further research is required98.
Two further studies have investigated a dose response effect. A 2015 publication suggested that cutaneous melanoma risk decreased by 3% and 4% for a 1 cup increment of total coffee and caffeinated coffee, respectively99. A subsequent 2016 paper concluded that a linear dose response effect was observed between a reduced risk of malignant melanoma and caffeinated coffee consumption, but not decaffeinated coffee100.
Coffee and lung cancer
Although a high consumption of coffee (more than 5 cups per day) has been associated with an increased risk of lung cancer, residual confounding effects of smoking or other factors may still exist, so results should be interpreted with caution.
- A 2010 meta-analysis, including 5 prospective and 8 case-control studies involving 5,347 lung cancer cases and 104,911 non-cases, reported a positive association between the highest coffee intake (at least 5-7 cups a day) and lung cancer, i.e. those who consumed the most coffee had a 27% higher risk of developing lung cancer (relative risk 1.27). The increase in coffee consumption of 2 cups per day led to a 14% increased risk for lung cancer (relative risk 1.14)101.
- The highest coffee consumption was significantly associated with increased risk of lung cancer in prospective studies, and studies conducted in America and Japan, but borderline significantly associated with decreased risk of lung cancer in non-smokers101.
- A 2015 meta-analysis of 12,276 cases of lung cancer and 102,516 controls suggested a significant association between intake of 3 or more cups of coffee per day and increased risk of lung cancer in men but not in women, in American and Asian populations but not in European populations, and in smokers but not non-smokers102.
- The WCRF 2007 Second Expert Report lists coffee under ‘Limited Evidence – No Conclusion’ for lung cancer19.
- IARC’s 2016 review stated that although a positive association is observed in some studies, this is most likely to be explained by confounding factors such as smoking. The report concluded that there was inadequate evidence to suggest any association between lung cancer and coffee consumption5.
Coffee and brain tumours
Coffee consumption may be linked to a reduced risk of brain tumours, in men in particular, but given that the number of studies is limited, more research is required to confirm this inverse association.
- The data from a synthesis of 3 cohort studies conducted in the USA, including 335 cases, showed that the consumption of at least 5 cups of coffee and tea daily, compared with no tea or coffee, was associated with a 40% lower risk of glioma (relative risk 0.60)103. No association was observed between decaffeinated coffee and glioma risk. Among women, the significant inverse association observed was weaker than among men.
- A European study of 343 cases of newly diagnosed glioma in nine countries showed the same results, i.e. a significant 34% lower risk of glioma among subjects consuming over 100 ml (1 cup) coffee and tea per day compared with those consuming less than 100 ml/day (relative risk 0.66)104. In this study, the association was also slightly stronger in men than in women.
- The WCRF 2007 Second Expert Report does not mention coffee in relation to cancers of the nervous system (including brain tumours)19. Similarly, IARC has not reviewed coffee consumption in relation to brain tumors5.
Maternal coffee consumption and childhood leukemia
There are limited studies in this area with some variable results, but IARC concluded that evidence was inadequate to suggest any associations. Pregnant and breastfeeding women are advised by EFSA to drink no more than 200mg of caffeine per day from all sources, which is equivalent to 2-3 cups of coffee15.
- Authors of a 2015 meta-analysis comprising a total of 3,649 cases and 5,705 controls conclude that their findings “confirm the detrimental association between maternal coffee consumption and childhood leukemia risk, and provide indications for a similar role for maternal cola consumption” 105.
- A further study published in 2015 examining parental smoking, maternal alcohol, coffee and tea consumption during pregnancy, and childhood acute leukemia concluded that childhood acute leukemia was not associated with coffee consumption during pregnancy, but an association was seen between coffee consumption and acute lymphoblastic leukemia106.
- IARC’s 2016 review concluded that a lack of consistency amongst studies led to inconclusive and inadequate evidence of any association between coffee consumption and childhood leukaemia5.
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