Biomarkers · Urine Biomarkers
Urine Specific Gravity
U-shaped: both low and high values carry risk. Not measured in our NHANES panel; the curve is synthesised from the published association.
Hazard ratio relative to the curve's reference value, as synthesised from the published association.
Published hazard ratio1.29top vs bottom quarter (95% CI 1.11–1.50) · NHANES III Prospective Mortality Linkage (1988-2011)
Where people sit
Population percentiles (ratio) 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 | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 2,560 | 2017-2018 |
| All | 40-59 | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 2,540 | 2017-2018 |
| All | 60+ | 1.00 | 1.01 | 1.02 | 1.02 | 1.03 | 2,650 | 2017-2018 |
| All | all | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 7,750 | 2017-2018 |
| Men | all | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 3,760 | 2017-2018 |
| Women | all | 1.00 | 1.01 | 1.02 | 1.02 | 1.03 | 3,990 | 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 | End-stage renal medullary destruction / isosthenuria | Fixed specific gravity at 1.010 unable to concentrate or dilute | clinical guideline | Rose BD, Post TW. Clinical physiology of acid-base and electrolyte disorders. 5t… |
| diet | Consistent daily fluid hydration (2.5-3.5 L/day water intake) | Maintains urine specific gravity in optimal euvolemic range (1.010-1.020) | cohort | National Center for Health Statistics. National Health and Nutrition Examination… |
| environmental | Severe hypertonic dehydration and heat exhaustion | +0.015 to +0.025 elevation (USG > 1.030) | prospective cohort | Casa DJ, et al. J Athl Train. 2000;35:212-224. |
| exercise | Electrolyte and fluid replacement during heavy endurance exercise | Prevents hypersthenuric dehydration (USG > 1.030) | rct | Sawka MN, et al. Med Sci Sports Exerc. 2007;39:377-390. |
| lifestyle | Structured consistent hydration (2.5-3.5 L/day water intake) | Maintains optimal euhydrated USG (1.012-1.018) | rct | Armstrong LE, et al. Int J Sport Nutr Exerc Metab. 2010;20:471-479. |
| pharmacologic | Desmopressin (dDAVP) therapy in central diabetes insipidus | Increases hyposthenuric USG from <1.005 to >1.015 | clinical guideline | Fenske W, et al. N Engl J Med. 2018;379:428-439. |
Sources
- Hazard curve: Recalculated from mortality_association (HR=1.29 quartile_extreme); per-SD log(HR)=0.1987.
- Perrier ET, et al. Relation of spot urine specific gravity and hydration status to all-cause mortality in US adults: NHANES analysis. Eur J Clin Nutr. 2017;71(12):1428-1433.