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Sex differences in essential hypertension
1Department of Internal Medicine, Ullevål Hospital, University of Oslo, Norway.
Insights
Hypertensive men exhibit greater athero-thrombogenic risk factors than women. Obese hypertensive women show decreased sympathetic activity, suggesting distinct hypertension mechanisms and potential weight gain risks.
Area of Science:
- Cardiology
- Endocrinology
- Metabolic Syndrome
Background:
- Hypertension affects men and women differently, with varying risk factors.
- Understanding sex-based differences in hypertension pathophysiology is crucial for targeted treatment.
- Lipid profiles and sympathetic nervous system activity are key indicators of cardiovascular risk.
Purpose of the Study:
- To compare athero-thrombogenic risk factors in untreated hypertensive men and women of similar age and body mass index.
- To investigate the relationship between body mass index, plasma catecholamines, and metabolic factors in hypertensive individuals.
- To explore potential differences in the pathophysiological mechanisms of hypertension between lean and obese hypertensive women.
Main Methods:
- Comparative analysis of blood pressure, lipid profiles, hemoglobin, hematocrit, and plasma catecholamines in hypertensive men and women.
- Statistical correlation analysis to determine relationships between body mass index, plasma catecholamines (noradrenaline, adrenaline), and insulin.
- Stratification of women by body mass index (above vs. below 25 kg m-2) to assess sympathetic activity differences.
Main Results:
- Hypertensive men displayed a more atherogenic lipid profile (lower HDL, higher total cholesterol and triglycerides) and higher hemoglobin/hematocrit compared to women.
- Plasma catecholamines were inversely related to body mass index in women only.
- Obese hypertensive women (BMI > 25 kg m-2) had significantly lower plasma adrenaline and noradrenaline levels than leaner hypertensive women.
- A negative curvilinear relationship was observed between arterial adrenaline and insulin levels.
Conclusions:
- Hypertensive men have a greater propensity for athero-thrombogenic risk factors compared to similarly aged and hypertensive women.
- Metabolic risk factors appear closely interrelated even within the normal range in hypertensive women.
- Decreased sympathetic activity in obese hypertensive women suggests different pathophysiological mechanisms, potentially linked to reduced energy expenditure and weight gain, and may explain the inverse insulin-adrenaline relationship.
Abstract:
A group of 41-year-old hypertensive men (n = 35, blood pressure (BP) 149.9 +/- 2.1/98.9 +/- 1.1 mmHg, mean +/- SEM) who had never received treatment for their condition were compared with hypertensive women of the same age (n = 18, BP 155.9 +/- 4.3/98.1 +/- 1.6 mmHg) with comparable body mass index (BMI, 25.9 +/- 0.5 vs. 24.9 +/- 4.5 kg m-2) who, also, had never received treatment. The lipid profile was more atherogenic in the men, with lower HDL cholesterol (1.21 +/- 0.04 vs. 1.38 +/- 0.06 mmol l-1, P = 0.04), higher total cholesterol (6.04 +/- 0.14 vs. 5.54 +/- 0.18 mmol l-1, P = 0.04) and triglycerides (1.80 +/- 0.16 vs. 0.96 +/- 0.10 mmol l-1, P < 0.001). The hypertensive men had higher haemoglobin (P < 0.001) and haematocrit. Plasma catecholamines were inversely related to BMI in the women only (r = -0.52, P < 0.05 for both noradrenaline and adrenaline). Women with BMI above 25 kg m-2 had significantly lower arterial plasma adrenaline and noradrenaline than those with BMI below 25 kg m-2 (28 +/- 5 vs. 78 +/- 16 pg ml-1, P < 0.01 and 101 +/- 17 vs. 206 +/- 33 pg ml-1, P < 0.01 respectively). A negative curvilinear relationship appeared between arterial adrenaline and insulin (r = 0.49, P = 0.05). These results suggest a male propensity for athero-thrombogenic risk factors in otherwise comparable hypertensive subjects. A close relationship between metabolic risk factors within the normal range seems to exist even in hypertensive women. The decreased sympathetic activity at rest in the obese hypertensive women indicates different pathophysiological mechanism for hypertension in lean and obese. Decreased sympathetic activity and thus reduced energy expenditure, promotes a risk for weight gain, and could explain the inverse relationship between insulin and adrenaline.