December 21, 2011

expert reaction to cohort study of brain tumour risk as published in Journal of Hypertension

New research looked at the association between blood pressure and other metabolic factors, and the risk of developing brain tumours.

Professor Peter Johnson, Cancer Research UK’s chief clinician, said:

“It’s right for the authors to be cautious about these results. While interesting, this research shows that some people in this study who developed a brain tumour also had high blood pressure. This does not show that high blood pressure causes brain tumours. More research is needed before any association between blood pressure and brain tumours might be confirmed as a cause.”

Kevin McConway, Professor of Applied Statistics at the Open University, said:

“It’s important to realise that this study doesn’t tell us anything about whether reducing your blood pressure, if it’s high, would reduce your chances of a brain tumour anyway. It’s possible something going on in one’s body might separately cause high blood pressure and, later, a brain tumour. Changing your blood pressure might or might not change your chances of a tumour, and this study couldn’t tell you which. Not enough is known yet about the causes of high blood pressure, let alone brain tumours. In any case, the absolute risk of a brain tumour is low.”

Professor David Spiegelhalter, Winton Professor of the Public Understanding of Risk at the University of Cambridge, said:

“This study was set up to examine all cancers and many risk factors – it is very difficult to interpret these findings in isolation without knowing if brain cancer and blood pressure has been selected for publication because it produced the most notable association.

“It is important that the absolute risks are low: roughly 2 in 1000 over 10 years for people with very low blood pressure compared with 3 in 1000 for those with high blood pressure. And people with high blood pressure are different in other ways: for example they are taking medication, and seeing doctors more which may bring forward diagnosis of cancers.”

‘Blood pressure and other metabolic syndrome factors and risk of brain tumor in the large population-based Me-Can cohort study’ by Michael Edlinger et al., published in Journal of Hypertension on Wednesday 21st December 2011.