Letters

Birth weight and blood pressure No evidence for a U shaped relation

BMJ 1994; 308 doi: https://doi.org/10.1136/bmj.308.6927.532 (Published 19 February 1994) Cite this as: BMJ 1994;308:532
  1. P M Fayers,
  2. M De Swiet
  1. MRC Cancer Trials Office, Cambridge CB2 2BW
  2. Institute of Obstetrics and Gynaecology, Queen Charlotte's Hospital, London W6 0XG
  3. 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 …

    View Full Text

    Sign in

    Log in through your institution

    Free trial

    Register for a free trial to thebmj.com to receive unlimited access to all content on thebmj.com for 14 days.
    Sign up for a free trial

    Subscribe