Relationship between white blood cell count and incident hypertension

BACKGROUND: Elevated white blood cell (WBC) count is considered to be prospectively associated with cardiovascular disease. However, its relationship to hypertension, independent of smoking and other established cardiovascular risk factors, is not clear, especially among women. METHODS: We used data from a large population-based study in Wisconsin (Beaver Dam Eye study) to examine the prospective association between elevated WBC count and incident hypertension among 2459 hypertension-free women (48.6%) and men (51.4%) after adjusting for, and stratifying by smoking and several other potential confounding factors. RESULTS: In multivariable proportional hazards models, increasing tertiles of WBC count was associated with increased risk ratios (RR) of hypertension in the whole cohort (WBC count tertiles 1-3; RR 1, 1.2, 1.7; P <.01), and separately among women (WBC count tertiles 1-3; RR 1, 1.1, 1.4; P <.05) and men (WBC count tertiles 1-3; RR 1, 1.3, 1.9; P <.01). Results from subsequent analyses stratified by smoking and several other related factors were consistent with this finding. CONCLUSIONS: Elevated WBC count is associated with incident hypertension among women and men independent of smoking and most traditional cardiovascular risk factors in this predominantly white cohort. Further research is required to determine whether this association is true among racial minorities (eg, African Americans), and independent of C-reactive protein, a more specific marker of inflammation.