To the Editor.
—The suggestion by Dr Hu and colleagues1 that long-term lead accumulation, as reflected by the tibia bone lead level, may be an independent risk factor for developing hypertension in men should be cautiously interpreted.Of the subjects classified as hypertensive, 44% had a blood pressure higher than 160 mm Hg systolic, 95 mm Hg diastolic, or both.1 These thresholds are 1 mm Hg more than the published World Health Organization (WHO)/International Society of Hypertension (ISH) limits, which Dr Kim and colleagues applied in a second article in the same issue of THE JOURNAL.2 Reclassifying individuals may impact on the association size and its significance. The analyses treating blood pressure as a continuous variable and avoiding the problem of having to define arbitrary cutoff points will be reported elsewhere, but a reference was not provided.According to WHO/ISH guidelines, the diagnosis of hypertension requires that pressure is measured
Staessen JA, Roels H, Fagard R. Hypertension and Lead Exposure. JAMA. 1996;276(13):1037–1038. doi:10.1001/jama.1996.03540130035024