Birth weight and blood pressure No evidence for a U shaped relationBMJ 1994; 308 doi: https://doi.org/10.1136/bmj.308.6927.532 (Published 19 February 1994) Cite this as: BMJ 1994;308:532
- P M Fayers,
- M De Swiet
- MRC Cancer Trials Office, Cambridge CB2 2BW
- Institute of Obstetrics and Gynaecology, Queen Charlotte's Hospital, London W6 0XG
- Department of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, Netherlands.
EDITOR, - Lenore J Launer and colleagues claim “a distinct U shaped relation between birth weight and blood pressure.”1 We have re-examined data from the Brompton study of 2000 children followed up until the age of 10.2,3 We found no evidence for a U shaped relation; that birth weight seems to be weakly associated with blood pressure at age 4 years and later; and that the main influence of birth weight seems to be indirect.
We believe that the statistical analysis of Launer and colleagues are misleading. Firstly, they imply that a U shape has been established despite observing a P value of only 0.06. They declare in the methods section that P<0.05 will be interpreted as significant. Thus it is curious to assume proof of a U shape after obtaining P<0.06 at 4 years of age. Their claims for a U shaped …