Inflammation precedes sodium retention in raised blood pressure in young adults

Introduction: The pathogenesis of essential hypertension remains elusive. It is argued that that it could be a systemic, low-grade inflammatory disease, or renal angiotensin aldosterone system dysregulation leading to sodium retention. Most studies were conducted among the general population but data among young adults are lacking. This study aims to compare the inflammatory parameters and sodium in young adults with different blood pressure statuses. Methods and materials: We conducted analyses in healthy 240 individuals aged 18-45 years that had been included in young adults with essential hypertension study in Pahang between April to December 2017. We categorized them into normotension (<120/80 mmHg), prehypertension (120-139/80-89 mmHg) or hypertension (≥140/90 mmHg). We assessed the fasting blood for hematological, biochemistry, and high-sensitivity C-reactive protein (hsCRP). We excluded those with hsCRP more than 10 mg/L, suggestive of recent inflammation. We determined the best hsCRP cut-off for prehypertension or hypertension using the receiver-operating characteristic (ROC) curve. Results: Mean age was 32.5 (6.9) years, 35.4% was female. Mean white cell counts was 7.02 (1.68) mmol/L, sodium 140.0 (2.1) mmol/L and hsCRP was 1.9 (2.4) mg/L. After exclusion (n=34), we found that those with newly diagnosed hypertension had significantly higher white cell counts (p=0.043) and plasma sodium than normotensive subjects (p=0.024). HsCRP was also higher in prehypertension and hypertension compared to normotension (p =0.006 and p =0.003 respectively). The area under the ROC curve for hsCRP in predicting prehypertension or hypertension was 0.674 (0.598-0.751); the best hsCRP cut-off was 1.05 mg/L with 70.7% sensitivity, 56.0% specificity, 70.2% positive and 56.0% negative predictive value. Conclusion: Young adults with essential hypertension had significantly higher inflammatory markers and sodium compared to normotensive, whereas prehypertensive had higher hsCRP. We suggest that low-grade inflammation could precede sodium retention in the development of essential hypertension in young adults.