A new study has reported an association between high intake of coffee and lower risk of prostate cancer, especially aggressive prostate cancers.

The researchers from Harvard School of Public Health have been surveying around 48,000 health professionals every four years for over 20 years to find out how much coffee they drink.  Their results show a lower risk of getting aggressive prostate cancer amongst the men who said they drank more coffee.

Updated, 3.10pm, 18th May:

The researchers found that men who reported drinking more than six cups of coffee per day had a lower risk of getting prostate cancer than men who did not drink coffee.

We note that:

• this finding was only marginally statistically significant.
• although the researchers adjusted their findings to account for some variables, the abstract does not mention known risk factors for prostate cancer, such as ethnicity.
• this type of study cannot rule out the possibility of unknown factors causing the observed association.
  

The BBC report of the research also points out that these findings contradict other studies. Unfortunately, it seems that the consensus is "more research needed", yet again.  Observational studies cannot establish cause, and therefore we need to see the results replicated consistently in order to establish a causal link.

Find out more

• Abstract of the original research
• Prostate cancer risk factors, causes and prevention.
  
• Analysis by the BBC, press release from Harvard School of Public Health.
• Detailed analysis by NHS Choices, the American Cancer Society blog and Health News Review