What causes hypertension in young individuals?

Causes of Hypertension in Young Individuals

The primary causes of hypertension in young individuals include obesity, kidney disease, genetic factors, and secondary causes such as endocrine disorders, with obesity being the most significant modifiable risk factor.

Primary vs. Secondary Hypertension

Primary (Essential) Hypertension

Primary hypertension is now the most common form of hypertension in children and adolescents above age 6 years 1. Key risk factors include:

• Obesity: The strongest modifiable risk factor with a fourfold increase in hypertension risk among those with severe obesity (BMI >99th percentile) versus a twofold increase in those with obesity (BMI 95th-98th percentiles) 1
• Family history: Hypertension before age 55 occurs 3.8 times more often among persons with a strong positive family history 2
• Genetic factors: Heritability estimates range from 25% in pedigree studies to 65% in twin studies 2
• Lifestyle factors: Excessive sodium intake, physical inactivity, poor diet quality, and inadequate sleep

Secondary Hypertension

Secondary causes are more common in younger children, those with severe hypertension (above 99th percentile), and those with little family history 1. Important causes include:

1. Renal disease:

   • Renal parenchymal disease
   • Renovascular disease
   • Chronic kidney disease (CKD) - nearly 50% of children with CKD are hypertensive 1

2. Cardiovascular abnormalities:

   • Coarctation of the aorta

3. Endocrine disorders:

   • Primary aldosteronism
   • Cushing's syndrome
   • Pheochromocytoma
   • Thyroid disorders

4. Monogenic forms:

   • Single gene mutations affecting renal sodium handling or mineralocorticoid activity 3

5. Other factors:

   • Medications and substances (e.g., corticosteroids, NSAIDs, stimulants)
   • Sleep-disordered breathing/obstructive sleep apnea
   • Premature birth (associated with 4-mm Hg higher SBP and 3-mm Hg higher DBP in adulthood) 1

Age-Related Differences

Young Children (<6 years)

• Secondary causes more likely, especially renal disease and coarctation of the aorta 1
• Requires more thorough evaluation for underlying causes

School-Age Children and Adolescents (>6 years)

• Primary hypertension becomes predominant 1
• Obesity is a major contributing factor
• Often presents with mild to moderate BP elevation

Risk Assessment

Young individuals with hypertension should be evaluated for:

1. Target organ damage:

   • Left ventricular hypertrophy
   • Vascular changes (increased carotid intima-media thickness)
   • Brain volume and white matter changes 1

2. Comorbid conditions:

   • Dyslipidemia (particularly in "familial dyslipidemic hypertension") 2
   • Insulin resistance/glucose intolerance
   • Sleep disorders

Clinical Pearls and Pitfalls

• Don't dismiss elevated BP in young patients: Young patients have lower awareness, slower time to diagnosis, and poorer BP control than older patients 1

• Consider ambulatory blood pressure monitoring (ABPM): Particularly useful for high-risk patients (obesity, CKD, repaired aortic coarctation) to evaluate for masked hypertension 1

• Evaluate for secondary causes: Especially important in young children, those with severe hypertension, or those with minimal family history 1

• Watch for "familial dyslipidemic hypertension": About 12% of hypertensive patients have this condition, characterized by hypertension before age 55, lipid abnormalities, hyperinsulinemia, and central obesity, with high risk of early coronary heart disease 2

• Don't delay treatment in young adults: Elevated BP in young adults is associated with increased risk of cardiovascular disease, including coronary heart disease, heart failure, stroke, and peripheral arterial disease 1

By identifying and addressing hypertension early in young individuals, clinicians can potentially prevent or delay the development of cardiovascular complications later in life.