Previous large observational cohort studies showed higher blood pressure (BP) positively associated with cancer. We used Mendelian randomization (MR) to obtain less confounded estimates of BP on total and sitespecific cancers. | Chan et al. BMC Cancer 2021 21 1338 https s12885-021-09067-x RESEARCH Open Access Blood pressure and risk of cancer a Mendelian randomization study Io Ieong Chan1 Man Ki Kwok1 and C. Mary Schooling1 2 Abstract Background Previous large observational cohort studies showed higher blood pressure BP positively associated with cancer. We used Mendelian randomization MR to obtain less confounded estimates of BP on total and site- specific cancers. Methods We applied replicated genetic instruments for systolic and diastolic BP to summary genetic associations with total cancer 37387 cases 367856 non-cases from the UK Biobank and 17 site-specific cancers 663 17881 cases from a meta-analysis of the UK Biobank and the Kaiser Permanente Genetic Epidemiology Research on Adult Health and Aging. We used inverse-variance weighting with multiplicative random effects as the main analysis and sensitivity analyses including the weighted median MR-Egger and multivariable MR adjusted for body mass index and for smoking. For validation we included breast Breast Cancer Association Consortium 133384 cases 113789 non-cases prostate Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome Consortium 79194 cases 61112 non-cases and lung International Lung and Cancer Consortium 10246 cases 38295 non-cases cancer from large consortia. We used asthma as a negative control outcome. Results Systolic and diastolic BP were unrelated to total cancer OR per standard deviation higher 95 confi- dence interval CI and OR 95 CI and to site-specific cancers after accounting for multiple testing with consistent findings from consortia. BP was nominally associated with melanoma and possibly kidney cancer and as expected not associated with asthma. Sensitivity analyses using other MR methods gave similar results. Conclusions In contrast to previous observational evidence BP does not appear to be a risk factor for cancer although
