Biomarkers · Hematology
Hemoglobin Concentration
Both low and high values go with higher risk of death. In NHANES 1999–2018 with linked mortality to 2019, each standard deviation above average goes with 20% lower risk of death. Risk rises at both ends: not comparable
Hemoglobin Concentration and risk of death
NHANES, our fit with 95% CIPublished curve
Published curve higher than the NHANES fitNHANES fit higher
Risk of death 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.
Risk of death per SD (NHANES)0.80×95% CI 0.78–0.83 · 49,105 adults, 7,188 deaths
Published risk of death1.33×lowest hemoglobin quintile (<13.7 g/dL men; <12.6 g/dL women) vs fourth quintile… (95% CI 1.15–1.54) · Cardiovascular Health Study: community-dwelling men and women aged 65+ in 4 US communities, enrolled 1989-1990 or 1992-1993
Hemoglobin Concentration across cohorts
0.750.80.91HR per SD (95% CI)
NHANES · United States, 20–8449,105 people · 7,188 deaths0.80 0.78–0.82
CHARLS · China, 50+7,692 people · 1,189 deaths0.87 0.81–0.95
Hemoglobin Concentration by age and sex
Each bar runs from the 5th to the 95th percentile, the darker part from the 25th to the 75th, and the tick is the median. Not a reference range or a target.
The percentiles as a table
| Sex | Age | 5th | 25th | Median | 75th | 95th | n | Cycle / source |
|---|---|---|---|---|---|---|---|---|
| All | 20-39 | 12.0 | 13.4 | 14.4 | 15.3 | 16.5 | 1,457 | NHANES 2017-2018 |
| All | 40-59 | 11.9 | 13.4 | 14.4 | 15.2 | 16.4 | 1,584 | NHANES 2017-2018 |
| All | 60+ | 11.7 | 13.2 | 14.0 | 15.0 | 16.3 | 1,940 | NHANES 2017-2018 |
| All | all | 11.9 | 13.3 | 14.2 | 15.2 | 16.4 | 4,981 | NHANES 2017-2018 |
| Men | 20-39 | 13.8 | 14.6 | 15.2 | 15.8 | 17.0 | 698 | NHANES 2017-2018 |
| Men | 40-59 | 13.4 | 14.5 | 15.1 | 15.9 | 16.8 | 740 | NHANES 2017-2018 |
| Men | 60+ | 11.9 | 13.7 | 14.6 | 15.6 | 16.9 | 981 | NHANES 2017-2018 |
| Men | all | 13.1 | 14.4 | 15.1 | 15.8 | 16.8 | 2,419 | NHANES 2017-2018 |
| Women | 20-39 | 11.2 | 12.7 | 13.4 | 14.0 | 14.9 | 759 | NHANES 2017-2018 |
| Women | 40-59 | 11.4 | 12.9 | 13.5 | 14.2 | 15.2 | 844 | NHANES 2017-2018 |
| Women | 60+ | 11.6 | 12.9 | 13.6 | 14.3 | 15.4 | 959 | NHANES 2017-2018 |
| Women | all | 11.4 | 12.8 | 13.5 | 14.2 | 15.2 | 2,562 | NHANES 2017-2018 |
What studies found when this marker was changed
They describe what happened in those study groups, not a recommendation. See all catalogued interventions.
Measured changes in Hemoglobin Concentration, study by study
6 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Study results in the groups studied, not predictions for a person.
| Type | Intervention | Reported effect | Evidence | Source |
|---|---|---|---|---|
| diet | Supervised isocaloric servings (~1300 kJ) of a polyphenol-, omega-3- and micronutrient-rich, high-protein food supplement 5 mornings per week for 23 weeks in children at risk of undernutrition | Haemoglobin increased by 0.65 g/dL (95% CI 0.23-1.07) vs control meal among anaemic children under 4 years | RCT | Roberts SB, Franceschini MA, Silver RE, et al. Effects of food supplementation… |
| exercise | Altitude conditioning (live high-train low) | Live high-train low raised haemoglobin concentration/mass by 0.82% (limits 0.62% to 1.03%) in cyclists | meta-analysis | Torres-Pérez J, et al. Hematological and performance enhancements using live… |
| nutraceutical | Daily oral iron supplementation in menstruating women | Daily oral iron raised haemoglobin vs control (MD 5.30, 95% CI 4.14 to 6.45; 51 studies, 6861 women) and cut anaemia risk (RR 0.39) | meta-analysis | Low MS, et al. Daily iron supplementation for improving anaemia, iron status… |
| pharmacologic | Roxadustat (oral HIF-PH inhibitor) in CKD anemia not on dialysis | Hemoglobin +1.9 g/dL with roxadustat vs -0.4 g/dL with placebo (mean change, weeks 7 through 9) | RCT | Chen N, et al. N Engl J Med. 2019;381:1001-1010. |
| pharmacologic | Oral vadadustat titrated to target haemoglobin instead of darbepoetin alfa in patients with anaemia and prevalent dialysis-dependent CKD | Haemoglobin change 0.17 g/dL lower than darbepoetin (95% CI -0.23 to -0.10) at weeks 24-36 in prevalent dialysis patients; non-inferior | RCT | Eckardt KU, Agarwal R, Aswad A, et al. Safety and Efficacy of Vadadustat for… |
| supplement | Ferrous sulfate drops 3 mg/kg elemental iron once daily for 12 weeks in infants and children aged 9-48 months with nutritional iron-deficiency anaemia | Mean haemoglobin rose from 7.9 to 11.9 g/dL over 12 weeks, 1.0 g/dL (95% CI 0.4 to 1.6) more than with iron polysaccharide complex | RCT | Powers JM, Buchanan GR, Adix L, et al. Effect of Low-Dose Ferrous Sulfate vs… |
Things that worsen it
| Type | Condition or exposure | Reported effect | Evidence | Source |
|---|---|---|---|---|
| clinical | Chronic occult gastrointestinal blood loss (Colorectal lesion / PUD) | GI blood loss (colonic/gastric cancer) is a leading cause of iron deficiency anaemia; lower Hb signals more serious pathology (effect size not reported) | clinical guideline | Goddard AF, et al. Gut. 2011;60:1309-1316. |
| clinical | Polycythemia vera (JAK2 mutation) | PV (JAK2-defined) causes erythrocytosis; phlebotomy to keep hematocrit below 45% (Hb magnitude not reported) | review | Tefferi A, et al. Polycythemia vera and essential thrombocythemia: 2017 update… |
What else moves this marker
They describe those study groups, not an individual, and an association is not a cause.
Genetic predisposition
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↓ ACO1 p.Cys506Ser (rare missense) · carriers vs non-carriers of the Cys506Ser mutation | SMD -1.61 (95% CI -1.98 to -1.35) | Cys506Ser carriers vs non-carriers · Adults from Iceland and the UK Biobank | gwas · PMID 32327693 |
| ↑ ACO1 p.Lys334Ter (stop-gained) · carriers vs non-carriers of the Lys334Ter mutation | SMD +0.63 (95% CI 0.36 to 0.91) | Lys334Ter carriers vs non-carriers · Adults from Iceland and the UK Biobank | gwas · PMID 32327693 |
Environmental and occupational exposures
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↓ Alcoholic drinks per week (genetically proxied) · instrument for an increased number of alcoholic drinks consumed per week | SMD -0.22 (95% CI -0.42 to -0.02) | higher vs lower genetically predicted weekly alcohol intake · Adults of mostly European ancestry (GWAS summary statistics) | mendelian randomization · PMID 39236005 |
| ↓ Smoking initiation (genetically proxied) · 113-SNP instrument for ever initiating smoking | SMD -0.07 (95% CI -0.1 to -0.03) | genetic liability to smoking initiation vs none · Adults of mostly European ancestry (GWAS summary statistics) | mendelian randomization · PMID 39236005 |
| ↑ Tobacco consumption via CHRNA3 rs1051730 (current smokers) · per copy of the T allele, which increases tobacco consumption, among current smokers | +0.26 % higher hemoglobin per T allele per allele (95% CI 0.09 to 0.43) | per additional CHRNA3 rs1051730 T allele in current smokers · White Danish adults aged 20-100, Copenhagen General Population Study (17,852 current smokers) | mendelian randomization · PMID 30866659 |
Sources
- Risk curve: Zakai NA 2005 (PMID 16246985): all-cause HR 1.33 (1.15-1.54) lowest hemoglobin quintile (<13.7 g/dL men; <12.6 g/dL women) vs fourth quintile (reference); fifth vs fourth quintile 1.17 (1.01-1.36). Scaled to US values (NHANES).
- Zakai NA, et al. A prospective study of anemia and all-cause mortality in community-dwelling older adults: the Cardiovascular Health Study. Arch Intern Med. 2005;165(19):2214-2220.
- NHANES curve: our Cox model adjusted for age and sex, NHANES 1999–2018 with linked mortality to 2019.
Map Hemoglobin Concentration against another biomarker.
Related markers: Absolute Lymphocyte Count · Absolute Neutrophil Count · Basophil Count · Eosinophil Count · Hematocrit · Immature Reticulocyte Fraction · Lymphocyte Percentage · Mean Corpuscular Volume (MCV)