What is the most common cause of hypertension?

Most Common Cause of Hypertension

Primary (essential) hypertension is the most common cause of hypertension, accounting for approximately 90-95% of all cases, while secondary hypertension represents only 5-10% of cases in the general population. 1, 2

Primary Hypertension: The Dominant Etiology

Primary hypertension results from complex interactions between genetic predisposition, environmental factors, and multiple organ system dysregulation, with no single identifiable cause. 1 This polygenic disorder involves:

• Genetic susceptibility combined with environmental triggers, though no single genetic variant has emerged as consistently causative across all populations 3
• Dysregulation of the renin-angiotensin-aldosterone system (RAAS), hormonal networks, and immune mechanisms leading to persistently elevated arterial blood pressure 1
• Endothelial dysfunction, increased peripheral vascular resistance, vascular remodeling, and fibrosis with inflammation 1
• Abnormal renal sodium handling and disrupted pressure natriuresis mechanisms 1

Major Modifiable Risk Factors for Primary Hypertension

The following lifestyle and environmental factors drive the development of primary hypertension:

• Obesity is responsible for 40% of hypertension cases overall and up to 78% in men and 65% in women, with a continuous, almost linear relationship between body mass index and blood pressure 1
• Excess dietary sodium intake far exceeds the physiologic requirement of less than 10 mmol per day, with sodium positively associated with blood pressure and accounting for much of the age-related increase 1. Average dietary salt ingestion in resistant hypertension patients exceeds 10 g per day 4
• Physical inactivity and prolonged sedentary lifestyles combined with caloric intake exceeding energy expenditure lead to steep rises in blood pressure, particularly systolic, with advancing age 1
• Excessive alcohol consumption (≥3 standard drinks per day) shows a strong, direct relationship with blood pressure elevation 1. Heavy alcohol intake (≥30 drinks per week) increases the risk of treatment-resistant hypertension 4, 2

Secondary Hypertension: The Minority

Secondary hypertension accounts for only 5-10% of cases in the general population, though this increases to 10-35% among patients with resistant hypertension. 1, 2 The most common secondary causes include:

• Renal parenchymal disease (prevalence 1-2%) 2
• Renovascular disease (prevalence 5-34% in resistant hypertension) 2
• Primary aldosteronism (prevalence 8-20% in resistant hypertension) 2
• Obstructive sleep apnea (prevalence 25-50% in resistant hypertension, with 83% of consecutive resistant hypertension patients having unsuspected sleep apnea) 4, 2

Clinical Implications

Screen for secondary causes only when specific red flags are present, including: 2

• Resistant hypertension (uncontrolled on ≥3 antihypertensive agents including a diuretic)
• Hypertension onset before age 30 years (especially pre-pubertal) or after age 50 years
• Abrupt onset or sudden worsening of previously controlled blood pressure
• Severe hypertension (SBP >180 mmHg or DBP >110 mmHg)
• Disproportionate target-organ damage relative to blood pressure duration/severity
• Unprovoked hypokalemia

In the absence of these red flags, primary hypertension is the diagnosis by default and should be managed with lifestyle modifications and pharmacological therapy targeting the modifiable risk factors outlined above. 4, 1