Background: Although family history is a major predictor of hypertension, other risk factors have been linked to elevated blood pressure (BP). This study explored the relationship of norepinephrine (NE), insulin resistance and lipids to family history of hypertension, and attempted to determine the combined effects of family history and these factors on BP.
Methods: A total of 220 healthy men and women, aged 22-50 years, completed two 24 h ambulatory BP sessions. Based on family history information obtained from parents, three groups were formed: subjects with two hypertensive parents, one hypertensive parent or normotensive parents. Plasma samples were obtained to derive fasting catecholamine levels, insulin, glucose and lipids.
Results: Individuals with two hypertensive parents had high insulin, insulin resistance and low-density lipoprotein cholesterol. Although NE was not directly linked to family history, high NE levels were associated with increased BP, after controlling for family history and body mass index. Women with two hypertensive parents and elevated NE levels had higher systolic BP and diastolic BP during waking and sleep periods. In men the combination of two hypertensive parents and high NE was related only to diastolic BP during waking.
Conclusions: NE results provide evidence of sympathetic activation in the identification of individuals at risk for hypertension. Studying family history of hypertension and other risk factors in healthy individuals provides a unique opportunity to explore factors leading to elevated BP long before a diagnosis of hypertension is made.