Effect of Age on Interdependence and Hierarchy of Cardiovascular Risk Factors in Hypertensive Patients

Study Questions:

Is there an age-related interdependence between blood pressure (BP), other metabolic syndrome components, and high-sensitivity C-reactive protein (hs-CRP) in hypertensive subjects?

Methods:

A total of 5,712 nondiabetic patients evaluated in outpatient hypertension clinics were included and divided into five age groups (ages 40-49, 50-59, 60-69, 70-79, and >80 years). BP, evaluated by both office and 24-hour ambulatory BP monitoring, and the metabolic and inflammation parameters were determined after a >2-week drug washout period. Insulin resistance was assessed with the Homeostasis Model of Assessment–Insulin Resistance index (HOMA-IR).

Results:

A total of 50.1% were men; age range 40-95 years. The prevalence of the metabolic syndrome remained stable across the age groups. There was a stable or increased association between waist circumference and HOMA-IR and fasting plasma glucose. However, the association between waist circumference and ambulatory BP monitoring systolic BP (r2 decreased from 9.9% to 1.0%, p < 0.001), high-density lipoprotein cholesterol (HDL-C; r2 decreased from 21% to 4.9%, p = 0.002), and triglyceride levels (r2 decreased from 17.5% to 1.9%, p < 0.001) decreased with age. Hs-CRP correlated with all metabolic syndrome components in all age groups (p < 0.001 for all). It became the strongest determinant of ambulatory BP monitoring systolic BP (p < 0.001) and HDL-C (p < 0.05) in patients >80 years old. In contrast, its association with waist circumference markedly decreased.

Conclusions:

In conclusion, hypertension and dyslipidemia, but not fasting plasma glucose, dissociate from central obesity with advancing age. They are increasingly determined by low-grade inflammation, independently of central obesity. These changing associations might underlie the weakening of obesity as a cardiovascular risk factor in older persons.

Perspective:

The authors infer that hs-CRP is a determinate of systolic BP and low HDL-C. There is no evidence that it is more than an epiphenomenon. The long-term cardiovascular event rates in this cohort will provide interesting information.

Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins, Hypertension

Keywords: Metabolic Syndrome X, Obesity, Abdominal, Cholesterol, Waist Circumference, Dyslipidemias, Risk Factors, Blood Pressure, Homeostasis, Insulin Resistance, Hypertension, Glucose


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