Biomarkers · Electrolytes & Minerals
Serum Sodium
U-shaped: both low and high values carry risk. In NHANES 1999–2018 with linked mortality to 2019, each standard deviation is associated with a hazard ratio of 0.91. U-shaped: slope not comparable
NHANES, our fit with 95% CIPublished curve
Hazard ratios relative to each curve's own reference value, so the two curves need not cross 1 at the same point. The dotted vertical line marks the NHANES median.
NHANES hazard per SD0.9195% CI 0.89–0.93 · 48,364 adults, 7,025 deaths
Published hazard ratio1.48top vs bottom quarter (95% CI 1.25–1.76) · NHANES III US Population Cohort
Where people sit
Population percentiles (mmol/L) by sex and age band. Cycle or source as recorded in the catalogue.
| Sex | Age | 5th | 25th | Median | 75th | 95th | n | Cycle / source |
|---|---|---|---|---|---|---|---|---|
| All | 20-39 | 136 | 138 | 140 | 141 | 143 | 2,700 | 2017-2018 |
| All | 40-59 | 135 | 138 | 139 | 141 | 143 | 2,650 | 2017-2018 |
| All | 60+ | 134 | 137 | 139 | 140 | 143 | 2,800 | 2017-2018 |
| All | all | 135 | 138 | 139 | 141 | 143 | 8,150 | 2017-2018 |
| Men | all | 135 | 138 | 139 | 141 | 143 | 3,950 | 2017-2018 |
| Women | all | 135 | 137 | 139 | 141 | 143 | 4,200 | 2017-2018 |
What studies found when this marker was changed
Effects on the biomarker reported in the cited studies. They describe what happened in those populations, not a recommendation for anyone. See all catalogued interventions.
| Type | Intervention | Reported effect | Evidence | Source |
|---|---|---|---|---|
| clinical | Fluid restriction (1.0-1.5 L/day) in syndrome of inappropriate ADH secretion (SIADH) | +3 to +6 mEq/L increase towards normal range | clinical guideline | Spasovski G, et al. Eur J Endocrinol. 2014;170:G1-G47. |
| clinical | Severe unreplaced water loss and hypertonic dehydration | +10 to +25 mEq/L dangerous hypernatremia (>150 mEq/L) | clinical guideline | Adrogue HJ, et al. N Engl J Med. 2000;342:1493-1499. |
| diet | Adequate fluid hydration and moderate dietary sodium intake (1500-2300 mg/day) | Stabilizes serum sodium in optimal 138-142 mmol/L range | cohort | National Center for Health Statistics. National Health and Nutrition Examination… |
| diet | Balanced dietary sodium (2.0-3.0 g/day) and hydration management | Maintains optimal eunatremic baseline (138-142 mEq/L) | meta-analysis | Mente A, et al. Lancet. 2018;392:496-506. |
| pharmacologic | Vasopressin V2 receptor antagonists (Tolvaptan) in hypervolemic / euvolemic hyponatremia | +4 to +8 mEq/L normalization | rct | Schrier RW, et al. N Engl J Med. 2006;355:2099-2112. |
| pharmacologic | Thiazide diuretic induced hyponatremia | -5 to -15 mEq/L drop (<130 mEq/L) | systematic review | Barber J, et al. J Clin Endocrinol Metab. 2014;99:3497-3504. |
Sources
- Hazard curve: Recalculated from mortality_association (HR=1.48 quartile_extreme); per-SD log(HR)=0.3059.
- Waikar SS, et al. Serum sodium and risk of death in the US population: NHANES III analysis. Am J Med. 2011;124(8):777-784.
- Empirical curve: our Cox model with age and sex, NHANES 1999–2018 with linked mortality to 2019.