Abstract 14265: The Cerebrovascular Risk of High 24-Hour Blood Pressure is Greater in Lean Rather Than Obese Subjects Among Japanese Older Hypertensive Patients
Introduction: Although obesity is associated with hypertension, the role of obesity as an effect modifier in the association between high BP and cardiovascular disease is debatable. Especially, whether or not the impact of high BP on cerebrovascular abnormalities in older persons is augmented in lean or obese patients has never been examined.
Methods: We conducted 24-hour BP monitoring and brain MRI in 514 Japanese hypertensives aged 50 years (mean 72 years; 37% men) who had no history of stroke or cancer. The patients were classified into three groups by their BMI: lean was defined as the lowest quartile of BMI (mean 19.8 kg/m2,n=129); normal-weight: (mean 23.5 kg/m2,n=193); and obese was defined as BMI≥25 kg/m2 (mean 27.7 kg/m2, n=192).
Results: Compared with normal-weight or obese patients, lean patients had significantly higher levels of serum noradrenalin (NA) (405 vs. 336 vs. 329 pg/ml, P<0.01). The lean patients with high 24-hour BP levels (≥130/80 mmHg, n=80) had the greatest number of silent cerebral infarctions (SCIs) (upper figure), and showed the highest odds ratio of multiple (≥3) SCIs compared with normal-weight patients with normal 24-hour BP (lower figure). Such greater risk of high BP was partly explained by serum NA level. A logistic regression analysis showed both serum NA and 24-hour systolic BP, but not leanness itself, were independent determinants of multiple SCIs (both P<0.001). Moreover, there were significant interactions between serum NA levels and 24-hour SBP levels in determining the multiple SCIs (P=0.033).
Conclusions: The risk of high 24-hour BP on SCIs, in particular multiple SCIs, in older persons is much stronger in lean rather than obese hypertensives, in whom a high sympathetic nerve activation could provide a partial explanation for such risks in lean patients. Because SCIs can contribute to frailty in older persons, our data have important clinical implications for identifying older hypertensives most likely to develop frailty.
- © 2010 by American Heart Association, Inc.