HDL cholesterol is considered a component of insulin resistance syndrome or metabolic syndrome, but LDL cholesterol is not considered a component of metabolic syndrome (1,–3). We have reviewed the literature and have found that there may be no report regarding the association between LDL cholesterol and blood pressure.
We studied cross-sectional relationships between LDL cholesterol and other metabolic risk factors using medical checkup data from 2,449 Japanese men (age 51.9 ± 9.6 years) and 1,448 Japanese women (age 51.5 ± 9.8 years) who visited our Medical Checkup Center at Tachikawa Medical Center, Nagaoka, Japan, between April 2008 and March 2009 and gave signed informed consent, excluding subjects with blood levels of high-sensitivity C-reactive protein ≥10 mg/l and those without other relevant data. The prevalence of metabolic syndrome (as defined by revised National Cholesterol Education Program criteria [(2)] for Japanese: waist circumference ≥90 cm in men and ≥80 cm in women) was 14.5% in men and 9.0% in women. The mean serum levels of HDL and LDL cholesterol were 57.7 ± 14.5 and 121.0 ± 29.7 mg/dl, respectively, in men and 67.1 ± 14.7 and 120.8 ± 29.6 mg/dl, respectively, in women. The mean systolic blood pressure (sBP) and diastolic blood pressure (dBP) were 122.0 ± 17.4 and 77.4 ± 10.8 mmHg, respectively, in men and 112.6 ± 17.2 and 70.4 ± 10.4 mmHg, respectively, in women. The Pearson's correlation coefficients between HDL cholesterol and sBP, between HDL cholesterol and dBP, between LDL cholesterol and sBP, and between LDL cholesterol and dBP were −0.019 (P = 0.3), −0.009 (P = 0.7), 0.016 (P = 0.4), and 0.017 (P = 0.04), respectively, in men and −0.083 (P = 0.002), −0.060 (P = 0.02), 0.194 (P < 0.0001), and 0.190 (P < 0.0001), respectively, in women. Thus, LDL cholesterol was significantly associated with blood pressure in Japanese women.
The mechanisms of this association are unknown but may be related to selective leptin resistance. Serum levels of leptin are higher in women than in men. Morgan et al. (4) reported that selectively preserved renal sympathetic nerve activity response to intracerebroventricular leptin represents a potential mechanism for hypertension in obesity. In addition, Ozbey et al. (5) reported that a positive correlation was observed between leptin and total cholesterol concentrations in growth hormone–deficient hypopituitary patients (particularly women) on conventional replacement therapy.
Acknowledgments
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