Common variants in serum/glucocorticoid regulated kinase 1 (SGK1) and blood pressure responses to dietary sodium or potassium interventions: A family-based association study

Background/Aims: Serum/Glucocorticoid Regulated Kinase 1 (SGK1) plays a significant role in regulating renal Na+ reabsorption, K+ secretion, and blood pressure (BP). This study aimed to assess the association of common genetic variants in the SGK1 gene with BP responses to controlled dietary sodium or potassium interventions. Methods: A total of 334 subjects from 124 families were recruited from the rural areas of northern China. After a three-day baseline observation, they were sequentially maintained a seven-day low-sodium diet (3g/day of NaCl or 51.3mmol/day of sodium), a seven-day high-sodium diet (18g/day of NaCl or 307.8 mmol/ day of sodium) and a seven-day high-sodium plus potassium supplementation intervention (4.5g/day of KCl or 60mmol/day of potassium). Six single-nucleotide polymorphisms (SNPs) in the SGK1 gene were selected. Results: After adjustment for multiple testing, SNP rs9376026 was significantly associated with diastolic BP (DBP) and mean arterial pressure (MAP) responses to low-sodium intervention (P = 0.018 and 0.022, respectively). However, the associations between selected SNPs in the SGK1 gene and BP responses to high-sodium or high-sodium plus potassium-supplementation intervention did not reach statistical significance. In addition, SNP rs9389154 and two other SNPs (rs1763509 and rs9376026) were associated respectively with systolic BP (SBP) and DBP at baseline (P = 0.040, 0.032, and 0.031, respectively). SNP rs3813344 was significantly associated with SBP, DBP, and MAP (P = 0.049, 0.015 and 0.018, respectively). Conclusion: Our study indicates that the genetic polymorphism in the SGK1 gene is significantly associated with BP responses to dietary sodium intervention.