Biomarkers · Inflammation

Fibrinogen

Lower values go with lower risk of death. Not measured in our NHANES panel. The curve is drawn from the published study (source below).

Fibrinogen and risk of death

Published curve higher than the NHANES fitNHANES fit higher

Risk of death relative to the curve's reference value, drawn from the published study (source below).

Published risk of death1.51×Q4 vs Q1 of plasma fibrinogen (95% CI 1.23–1.87) · Long-term cohort of 5,690 adults (abstract does not name the population; median fibrinogen 370 mg/dL)

Fibrinogen 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

Each row is one sex and age band: the values below which 5%, 25%, 50%, 75% and 95% of people fall (mg/dL), from the survey named in the row. Not a reference range or a target.
Sex	Age	5th	25th	Median	75th	95th	n	Cycle / source
All	40-59	248	304	346	396	486	2,663	NHANES 1999-2002
All	60+	278	337	381	437	543	3,020	NHANES 1999-2002
All	all	254	314	358	412	510	5,683	NHANES 1999-2002
Men	40-59	244	296	337	384	471	1,333	NHANES 1999-2002
Men	60+	272	331	376	424	548	1,495	NHANES 1999-2002
Men	all	248	306	350	400	500	2,828	NHANES 1999-2002
Women	40-59	252	312	354	408	498	1,330	NHANES 1999-2002
Women	60+	282	342	385	446	538	1,525	NHANES 1999-2002
Women	all	258	321	367	422	517	2,855	NHANES 1999-2002

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 Fibrinogen, study by study

3 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. Green points move the marker the way lower risk of death lies; amber the other way. Study results in the groups studied, not predictions for a person.

Each row is one study: what was changed, the effect it reported on this marker, and the source.
Type	Intervention	Reported effect	Evidence	Source
behavioral	Smoking cessation	Smoking cessation inversely related to 13-year fibrinogen change; quitters' fibrinogen rise comparable to never-smokers (effect size not reported)	prospective cohort	Okwuosa TM, et al. 13-year long-term associations between changes in…
behavioral	Cessation of cigarette smoking	Fibrinogen fell by 11.8% after 12 months of smoking abstinence	prospective cohort	Mandraffino G, et al. Biglycan expression, earlier vascular damage and…
exercise	Regular moderate aerobic endurance exercise	Exercise lowered fibrinogen vs control in CAD patients (SMD: -0.52, 95% CI: -0.74, -0.29)	meta-analysis	Thompson G, et al. Exercise and inflammation in coronary artery disease: A…
pharmacologic	Fibrate therapy (Fenofibrate 145-200 mg/day)	Fenofibrate lowered fibrinogen more than statins (WMD: -43.7 mg/dL, 95% CI: -61.3, -26.2) in head-to-head RCTs	meta-analysis	Sahebkar A, et al. Head-to-head comparison of statins versus fibrates in…

Things that worsen it

Each row is one study: what was changed, the effect it reported on this marker, and the source.
Type	Condition or exposure	Reported effect	Evidence	Source
behavioral	Cigarette smoking and chronic tobacco inhalation	Fibrinogen higher in current smokers (men 3.13 vs 2.80 g/l; women 3.03 vs 2.95 g/l), dose-response with pack-years	cross-sectional	Sinha S, et al. Fibrinogen and cigarette smoking in men and women in the…
environmental	High particulate air pollution exposure (PM2.5)	+1.76% circulating fibrinogen per 10 μg/m3 increase in PM2.5	meta-analysis	Zhu H, et al. Effect of PM2.5 exposure on circulating fibrinogen and IL-6…

What else moves this marker

They describe those study groups, not an individual, and an association is not a cause.

Genetic predisposition

Each row is one study: what it compared and the change it reported in this marker.
What	Effect on the marker	Comparison · population	Source
↑ FGB -148C>T promoter variant (beta-fibrinogen) · per copy of the T allele	+14 mg/dL per T allele per allele	C/C vs C/T vs T/T genotype, additive trend · Controls without coronary disease, ISIS case-control study	mendelian randomization · PMID 16870675
↓ IL6R rs7529229 (tags p.Asp358Ala) · per copy of the IL6R variant allele (functional IL-6 receptor blockade proxy)	-0.85 % change in circulating fibrinogen per allele per allele (95% CI -1.1 to -0.6)	per additional IL6R rs7529229 allele · Adults from 40 studies, mostly European ancestry	mendelian randomization · PMID 22421340

Sources

Risk curve: Hu 2025 (PMID 40266502): all-cause HR 1.51 (1.23-1.87) Q4 vs Q1 of plasma fibrinogen. Scaled to US values (NHANES).
Hu et al. Associations between fibrinogen levels and the risk of all-cause mortality: a long-term cohort study. Journal of thrombosis and thrombolysis. 2025;58:514-525.

Map Fibrinogen against another biomarker.

Map Fibrinogen against another marker