What causes hypertension?

Causes of Hypertension

Hypertension develops from a complex interplay of genetic predisposition and environmental factors, with approximately 90% of cases being primary (essential) hypertension with no identifiable cause, while 10% have secondary hypertension with specific identifiable causes. 1

Primary (Essential) Hypertension

Primary hypertension results from the interaction of multiple factors:

Genetic Factors

• More than 25 rare mutations and 120 single-nucleotide polymorphisms have been identified in hypertension development 1
• Genetic predisposition creates susceptibility that requires environmental triggers for clinical expression

Modifiable Risk Factors

• Obesity: Central obesity (measured by waist-to-hip ratio) has a stronger relationship with blood pressure than BMI 1
• Dietary Factors:
  • Excessive sodium consumption directly linked to blood pressure increases 1
  • Salt sensitivity is more common in Black individuals, older adults, and those with comorbidities 1
  • Low potassium intake contributes to hypertension development 1
• Physical Inactivity: Sedentary lifestyle increases hypertension risk 1
• Alcohol Consumption: Excessive alcohol intake raises blood pressure 1, 2
• Stress: Chronic stress and job strain may contribute to hypertension, particularly in men 3

Secondary Hypertension (10% of cases)

Secondary hypertension has specific identifiable causes:

Sleep Disorders

• Obstructive sleep apnea (OSA) is a common cause of resistant hypertension 4, 1
• Moderate to severe OSA (AHI >15) requires CPAP treatment to improve BP control 4

Drug-Induced Hypertension

• Over-the-counter medications, prescribed drugs, and recreational substances can cause hypertension 4
• Anticancer drugs, particularly vascular endothelial growth factor inhibitors, can cause hypertension in 80-90% of treated patients 4
• Other culprits include tyrosine kinase inhibitors, proteasome inhibitors, corticosteroids, NSAIDs, and anti-androgen therapy 4

Endocrine Disorders

• Primary aldosteronism
• Pheochromocytoma (can cause sudden severe hypertension) 4
• Cushing's syndrome
• Hyperparathyroidism 1
• Thyroid disease 4

Renal Causes

• Renal parenchymal disease (chronic glomerulonephritis, polycystic kidney disease) 1
• Renovascular disease

Other Causes

• Coarctation of the aorta 4, 1
• Genetic syndromes (Liddle's syndrome, glucocorticoid-remediable aldosteronism) 4
• Excessive licorice consumption 4
• Acromegaly 4
• Gut microbiota alterations (emerging risk factor) 1

Pathophysiological Mechanisms

• Sympathetic nervous system overactivity plays a key role, particularly in early stages of hypertension 3
• Environmental and lifestyle factors often operate through sympathetic nervous system activation 3
• Multiple systems are affected, including vascular, renal, endocrine, and neural pathways 5

Clinical Implications

• Untreated hypertension leads to hypertension-mediated organ damage affecting the heart, brain, kidneys, and blood vessels 1
• Progression from asymptomatic to symptomatic organ damage can result in cardiovascular events like stroke, heart failure, and kidney disease 1
• Severe acute hypertension can lead to hypertensive emergencies with acute microvascular damage affecting multiple organs 4

Prevention Approach

• Weight reduction to normal BMI 1
• DASH diet rich in fruits, vegetables, whole grains, and low-fat dairy 1
• Sodium restriction (<2300 mg/day) 1
• Regular physical activity (150+ minutes/week) 1
• Limited alcohol consumption 1
• Stress management and adequate sleep 1

Understanding these multifactorial causes of hypertension is essential for effective prevention and management strategies that can reduce the global burden of cardiovascular disease.