Association may not be causalBMJ 1996; 312 doi: https://doi.org/10.1136/bmj.312.7025.251a (Published 27 January 1996) Cite this as: BMJ 1996;312:251
- Quentin D Sandifer,
- Su Vuilo,
- Gareth Crompton
- Senior registrar in public health medicine Consultant in public health medicine Department of Public Health Medicine and Strategic Planning, South Glamorgan Health Authority, Cardiff CF1 3NW
- Professor of public health medicine University of Wales College of Medicine, Centre for Applied Public Health Medicine, Cardiff CF1 3NW
EDITOR,—P Patel and colleagues report a causal relation between infection with Helicobacter pylori and the presence of ischaemic heart disease.1 We do not believe that this assertion is supported by the evidence.
Firstly, their findings were based on a cross sectional survey, and it is difficult to separate cause and effect from such surveys. This means …