Study Duration and Validity

Letter to the Editor: At the NHLBI workshop on sodium and blood pressure held on January 28–29, 1999, to re-examine the US recommendation on sodium intake for healthy people, two meta-analyses addressing this issue were harshly criticized for including randomized clinical trials of less than 2 weeks duration. It was argued that their inclusion invalidated estimates of the blood pressure lowering potential of a sodium-restricted diet. This viewpoint has been expressed before in letters to the editor1 and in editorials.2 3 Yet, Hypertension continues to publish short-term intervention studies such as that by He et al, which compared the effects of a 5-day low sodium diet (10 mmol/d) on …