Hypertension and glomerular function decline: the chicken or the egg?

Eriksen et al. report a lack of association between baseline blood pressure and subsequent decline of iohexol measured glomerular filtration rate in a representative sample of over 1500 people from the general population in Norway. This is an innovative contribution to the ongoing debate on whether mild to moderate hypertension causes chronic kidney disease. While waiting for final clarification of the interconnection, one must keep in mind that absence of evidence is not evidence of absence.