Biomarkers · Nutritional

Serum Cotinine

Lower values go with lower risk of death. In NHANES 1999–2018 with linked mortality to 2019, each standard deviation above average goes with 41% higher risk of death. We found the same pattern in NHANES

Serum Cotinine 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)1.41×95% CI 1.37–1.46 · 27,994 adults, 3,712 deaths

Published risk of death1.46×per 10 ng/mL increase in salivary cotinine (non-smokers) (95% CI 1.16–1.83) · Pooled 12 English/Scottish cohorts (1998-2008), self-reported non-smokers aged 16-85 with salivary cotinine

Value of the measurement+0.043gain in concordance within age bands; rank 3 of 56 · all tests

Serum Cotinine 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 (ng/mL), 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	20-39	0.01	0.01	0.05	31.4	340	1,440	NHANES 2017-2018
All	40-59	0.01	0.01	0.02	3.41	392	1,561	NHANES 2017-2018
All	60+	0.01	0.01	0.01	0.08	294	1,910	NHANES 2017-2018
All	all	0.01	0.01	0.03	2.23	342	4,911	NHANES 2017-2018
Men	20-39	0.01	0.02	0.11	108	381	689	NHANES 2017-2018
Men	40-59	0.01	0.01	0.03	28.0	438	731	NHANES 2017-2018
Men	60+	0.01	0.01	0.02	0.31	328	967	NHANES 2017-2018
Men	all	0.01	0.01	0.03	33.3	389	2,387	NHANES 2017-2018
Women	20-39	0.01	0.01	0.03	1.87	273	751	NHANES 2017-2018
Women	40-59	0.01	0.01	0.02	0.37	323	830	NHANES 2017-2018
Women	60+	0.01	0.01	0.01	0.04	264	943	NHANES 2017-2018
Women	all	0.01	0.01	0.02	0.22	290	2,524	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 Serum Cotinine, study by study

2 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
lifestyle	Switching to gradually reduced nicotine cigarettes (11.6 mg down to 0.2 mg) vs usual nicotine content cigarettes over 18 weeks in smokers with low SES or mental health conditions	Plasma cotinine fell 190 ng/mL vs usual nicotine cigarettes in White smokers (ITT, 18 weeks); 118 ng/mL in Black smokers	RCT	Lin W, et al. J Racial Ethn Health Disparities. 2025;12(5):3537-3542.
pharmacologic	Reduced Nicotine Content Cigarettes vs usual nicotine content cigarettes for 3 weeks: Reduced Nicotine Cigarettes in Smokers With Mood and Anxiety Disorders	Plasma Cotinine Concentration: -175.7 ng/mL (95% CI -218.3 to -133.1) vs usual nicotine content cigarettes at 3 weeks (posted between-group difference, n=245)	RCT	Milton S. Hershey Medical Center. Reduced Nicotine Cigarettes in Smokers With…

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
↑ CHRNA3/CHRNA5 rs1051730-rs16969968 · per risk allele, current smokers	+138.72 nmol/L per allele (95% CI 97.91 to 179.53)	per copy of the rs1051730/rs16969968 risk allele · 2932 current cigarette smokers from six studies (12,364 subjects screened)	meta analysis · PMID 22534784

Sources

Risk curve: Kvaavik 2021 (PMID 33542031): all-cause HR 1.46 (1.16-1.83) per 10 ng/mL increase in salivary cotinine (non-smokers). Scaled to US values (NHANES).
Kvaavik et al. Biomarker-assessed passive smoking in relation to cause-specific mortality: pooled data from 12 prospective cohort studies comprising 36 584 individuals. Journal of epidemiology and community health. 2021;75:794-799.
NHANES curve: our Cox model adjusted for age and sex, NHANES 1999–2018 with linked mortality to 2019.

Map Serum Cotinine against another biomarker.

Map Serum Cotinine against another marker