NCHS Data Brief ■ No. 59 ■ March 2011

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Vitamin D Status: United States, 2001–2006

Anne C. Looker, Ph.D.; Clifford L. Johnson, M.P.H.; David A. Lacher, M.D.; Christine M. Pfeiffer, Ph.D.; 

Rosemary L. Schleicher, Ph.D.; and Christopher T. Sempos, Ph.D.

The	Institute	of	Medicine	(IOM)	recently	released	new	dietary	reference	

intakes	for	calcium	and	vitamin	D	(1).	The	IOM	defined	four	categories	of	

vitamin	D	status	based	on	serum	25-hydroxyvitamin	D	(25OHD):	(i)	risk	

of	deficiency,	(ii)	risk	of	inadequacy,	(iii)	sufficiency,	and	(iv)	above	which	

there	may	be	reason	for	concern	(1).	This	brief	presents	the	most	recent	

national	data	on	vitamin	D	status	in	the	U.S.	population	based	on	these	IOM	

categories.	Results	are	presented	by	age,	sex,	race	and	ethnicity,	and,	for	

women,	by	pregnancy	and	lactation	status.

Keywords: serum 25-hydroxyvitamin D • prevalence • deficiency • inadequacy

In 2001–2006, what was the vitamin D status of the U.S. 

population based on the IOM thresholds for serum 25OHD?

In	2001–2006,	two-thirds	(67%)	of	persons	aged	1	year	and	over	had	serum	

25OHD	values	considered	sufficient	(Figure	1).	Roughly	one	quarter	of	the	

population	had	serum	25OHD	values	that	put	them	at	risk	of	inadequacy.	

Eight	percent	were	at	risk	of	deficiency,	and	1%	had	a	high	serum	25OHD	

value	that	may	possibly	be	harmful.	Serum	25OHD	percentile	values,	which	

provide	a	more	detailed	description	of	the	serum	25OHD	distribution	in	the	

U.S.	population,	are	shown	in	the	Table.

Key findings

Data from the National 

Health and Nutrition 

Examination Surveys 

(NHANES)

•	 In	2001–2006,	two-thirds	of	

the	population	had	sufficient	

vitamin	D,	defined	by	the	

Institute	of	Medicine	as	a	

serum	25-hydroxyvitamin	D	

(25OHD)	value	of	50–125	

nmol/L.	About	one-quarter	

were	at	risk	of	vitamin	D	

inadequacy	(serum	25OHD	

30–49	nmol/L),	and	8%	were	

at	risk	of	vitamin	D	deficiency	

(serum	25OHD	less	than	30	

nmol/L).

•	 The	risk	of	vitamin	D	

deficiency	differed	by	age,	

sex,	and	race	and	ethnicity.	

The	prevalence	was	lower	in	

persons	who	were	younger,	

male,	or	non-Hispanic	

white.	Among	women,	the	

prevalence	at	risk	was	also	

lower	in	pregnant	or	lactating	

women.

•	 The	risk	of	vitamin	D	

deficiency	increased	between	

1988–1994	and	2001–2002	in	

both	sexes	but	did	not	change	

between	2001–2002	and	

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NCHS Data Brief ■ No. 59 ■ March 2011

■  2  ■

Table. Selected percentile values for serum 25-hydroxyvitamin D (25OHD), by sex and age, and by pregnancy 

and lactation status in females: United States, 2001–2006

Serum 25OHD (nmol/L) percentile

Characteristic n 5th 10th 25th 50th 75th 90th 95th

Male

Age (years)

1–3 581 40.7 48.3 58.2 69.5 84.4 94.7 101.0

4–8 970 42.6 47.8 58.0 67.3 78.8 92.0 99.9

9–13 1,473 32.5 40.4 49.9 62.1 74.5 87.4 98.5

14–18 1,978 25.3 33.0 45.7 58.5 71.2 84.9 95.7

19–30 1,611 23.0 29.4 41.9 55.3 68.7 83.6 94.3

31–50 2,244 25.1 31.3 44.2 57.4 71.5 84.5 94.3

51–70 1,853 25.6 32.7 44.1 58.1 71.3 83.7 91.8

Over 70 1,217 25.4 31.7 44.6 57.2 69.7 82.7 90.1

Female

Age (years)

1–3 584 43.3 49.8 58.5 68.3 79.4 89.2 94.9

4–8 989 38.4 44.2 54.5 67.2 80.0 93.4 101.0

9–13 1,515 27.7 34.6 46.3 57.6 68.4 80.9 87.5

14–18 1,823 20.8 27.2 41.1 57.2 71.6 87.1 104.0

19–30 1,346 18.5 25.4 40.0 55.9 76.2 95.6 111.0

31–50 2,097 19.2 25.3 38.9 55.3 71.0 87.6 101.0

51–70 1,866 21.2 27.0 39.7 54.7 69.7 85.4 93.4

Over 70 1,197 22.6 27.1 40.5 55.5 69.6 84.1 93.6

Pregnant or 

lactating 1,067 24.5 31.4 44.5 62.4 78.2 94.7 109.0

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey (NHANES), 2001–2006; data for ages 1–5 years from NHANES 2003–2006.

What is the prevalence of serum 25OHD values indicating risk of deficiency, 

by age and sex?

The season-adjusted prevalence at risk of deficiency by age ranged from 1% to 8% in males and

1% to 12% in females (Figure 2). In both sexes, the prevalence was lowest in children aged 1–8

years. Risk of deficiency increased significantly with age until age 30 in males and age 18 in

females, after which it did not change significantly with age.
NCHS Data Brief ■ No. 59 ■ March 2011

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What is the prevalence of serum 25OHD values indicating risk of 

inadequacy, by age and sex?

The	season-adjusted	prevalence	at	risk	of	inadequacy	by	age	ranged	from	9%	to	28%	in	males	

and	11%	to	28%	in	females	(Figure	3).	In	both	sexes,	the	prevalence	was	lowest	in	children	aged	

1–8	years.	Risk	of	inadequacy	increased	significantly	with	age	until	age	30	in	males,	after	which	

it	did	not	change	further	with	age.	Risk	of	inadequacy	increased	significantly	with	age	until	age	

14	years	in	females.	After	age	14,	risk	of	inadequacy	among	females	remained	constant	until	

age	51,	when	it	increased	significantly.	After	the	increase	at	age	51,	risk	of	inadequacy	remained	

stable	in	females.


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NCHS Data Brief ■ No. 59 ■ March 2011

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Does the prevalence of serum 25OHD values indicating risk of deficiency 

and inadequacy differ by sex or race and ethnicity? Among women of 

childbearing age, does this prevalence differ by pregnancy and lactation 

status?

Males were less likely to be at risk of deficiency than females, after adjusting for age and 

season (Figure 4). The age- and season-adjusted prevalence at risk of inadequacy did not differ 

by sex. Non-Hispanic white persons were less likely to be at risk of deficiency or at risk of 

inadequacy than non-Hispanic black or Mexican American persons, after adjusting for age and 

season. According to IOM (1), interpretation of serum 25OHD thresholds for risk of deficiency 

or inadequacy in nonwhite persons is uncertain because many nonwhite groups have better 

skeletal status than white persons despite having lower serum 25OHD values. Among women of 

childbearing age, those who were pregnant or lactating were less likely to be at risk of deficiency 

than women who were not pregnant or lactating, after adjusting for age and season. The age- and 

season-adjusted prevalence at risk of inadequacy did not differ by pregnancy and lactation status 

in women of childbearing age.

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NCHS Data Brief ■ No. 59 ■ March 2011

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Has the prevalence at risk of deficiency and inadequacy changed since

the 1990s?

In 1988–1994, 3% of males aged 12 years and over had serum 25OHD values that put them at 

risk of deficiency, after adjusting for age and season; in comparison, the age- and season-adjusted 

prevalence at risk of deficiency in 2001–2002 increased to 7% (Figure 5). The corresponding 

figures for those at risk of inadequacy were 20% and 24%, respectively. The age- and seasonadjusted prevalence at risk of deficiency or inadequacy did not change between 2001–2002 and 

2005–2006 in adolescent and adult men.

The age- and season-adjusted prevalence at risk of deficiency also increased between 1988–1994 

and 2001–2002 among females aged 12 years and over (Figure 5). In 1988–1994, 7% of females 

aged 12 and over were at risk of deficiency, after adjusting for age and season, compared with 

11% in 2001–2002. However, the age- and season-adjusted prevalence of adolescent and adult 

women at risk of inadequacy decreased from 29% in 1988–1994 to 26% in 2001–2002. The 

age- and season-adjusted prevalence at risk of deficiency or inadequacy did not change between 

2001–2002 and 2005–2006 in adolescent and adult women.

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NCHS Data Brief ■ No. 59 ■ March 2011

■  6  ■

Summary

Most persons in the United States are sufficient in vitamin D, based on serum 25OHD thresholds

proposed by IOM. Roughly one-quarter were at risk of inadequacy and 8% were at risk of

deficiency. The prevalence at risk of deficiency or inadequacy differed by age, sex, and race

and ethnicity. Groups at lower risk included children, males, non-Hispanic white persons,

and pregnant or lactating women. Between 1988–1994 and 2001–2002, the prevalence at risk

of deficiency increased in adolescents and adults of both sexes, but the prevalence at risk of

deficiency or inadequacy did not change between 2001–2002 and 2005–2006.

Definitions

At risk of vitamin D deficiency: Serum 25OHD less than 30 nmol/L (12 ng/mL) (1).

At risk of vitamin D inadequacy: Serum 25OHD 30–49 nmol/L (12–19 ng/mL) (1).

Sufficient in vitamin D: Serum 25OHD 50–125 nmol/L (20–50 ng/mL) (1).

Possibly harmful vitamin D: Serum 25OHD greater than 125 nmol/L (50 ng/mL) (1).

Season: Two categories, based on month of blood draw: November–March and April–October.

Season is important to consider for two reasons: (i) vitamin D is produced in the skin by sunlight

exposure, so it varies by season; and (ii) for practical reasons, data are collected in NHANES in

the South during the winter and North during the summer.

NHANES III (1988–1994) serum 25OHD adjustment: The assay method used to measure serum

25OHD in NHANES III differed from the method used in NHANES 2001–2006. A statistical

adjustment was applied to the NHANES III serum 25OHD so that the data could be validly

compared with serum 25OHD from NHANES 2001–2006. Details about the adjustment have

been published elsewhere (2).

Data source and methods

NHANES data were used for these analyses. NHANES is a cross-sectional survey designed to

monitor the health and nutritional status of the civilian noninstitutionalized U.S. population (3).

The survey consists of interviews conducted in participants’ homes and standardized physical

examinations that include laboratory tests utilizing blood and urine specimens provided by

participants during the examination.

The NHANES sample is selected through a complex, multistage design that includes selection of

primary sampling units (counties), household segments within the counties, and finally sample

persons from selected households. The sample design includes oversampling to obtain reliable

estimates of health and nutritional measures for population subgroups. In 1988–1994 and 2001–

2006, non-Hispanic black and Mexican-American persons were oversampled. In 1999, NHANES

became a continuous survey, fielded on an ongoing basis. Each year of data collection is based on

a representative sample covering all ages of the civilian noninstitutionalized population. Publicuse data files are released in 2-year cycles.
NCHS Data Brief ■ No. 59 ■ March 2011

■  7  ■

Sample weights, which account for the differential probabilities of selection, nonresponse,

and noncoverage, were incorporated into the estimation process. The standard errors of the

percentages were estimated using Taylor series linearization, a method that incorporates the

sample weights and sample design. Prevalence estimates were statistically adjusted for age

when making comparisons by sex, race and ethnicity, and pregnancy or lactation status. Serum

25OHD data were statistically adjusted for season when making comparisons by age, sex,

race and ethnicity, and pregnancy or lactation status, to control for differences in the time of

year when blood was drawn in different groups. Differences between groups were evaluated

using a t statistic at the p < 0.05 significance level. Tests of trends were done using the p <

0.05 significance level. All results presented have a relative standard error less than 30%. All

differences reported are statistically significant unless otherwise indicated. Statistical analyses

were conducted using the SAS System for Windows (release 9.2; SAS Institute, Cary, NC) and

SUDAAN (release 10.0; Research Triangle Institute, Research Triangle Park, NC).

About the authors

Anne C. Looker, Clifford L. Johnson, and David A. Lacher are with the Centers for Disease

Control and Prevention’s (CDC) National Center for Health Statistics, Division of Health and

Nutrition Examination Surveys. Christine M. Pfeiffer and Rosemary L. Schleicher are with

CDC’s National Center for Environmental Health, Division of Laboratory Sciences. Christopher

T. Sempos is with the National Institutes of Health, Office of Dietary Supplements.

References

1.	 Institute of Medicine. Dietary reference intakes for calcium and vitamin D. Washington, DC:

National Academies Press. 2010.

2.	 Looker AC, Pfeiffer CM, Lacher DA, Schleicher RL, Picciano MF, Yetley EA. Serum 25-

hydroxyvitamin D status of the U.S. population: 1988–1994 compared with 2000–2004. Am J

Clin Nutr 88(6):1519–27. 2008.

3.	 National Center for Health Statistics. National Health and Nutrition Examination Survey,

2001–2006. Available from: http://www.cdc.gov/nchs/nhanes/nhanes_questionnaires.htm.

Accessed February 25, 2011.
NCHS Data Brief ■ No. 59 ■ March 2011

Suggested citation

Looker	AC,	Johnson	CL,	Lacher	DA,	et	al.	

Vitamin	D	status:	United	States,	2001–2006.	

NCHS	data	brief,	no	59.	Hyattsville,	MD:	

National	Center	for	Health	Statistics.	2011.

Copyright information

All	material	appearing	in	this	report	is	in	

the	public	domain	and	may	be	reproduced	

or	copied	without	permission;	citation	as	to	

source,	however,	is	appreciated.

National Center for Health 

Statistics

Edward	J.	Sondik,	Ph.D.,	Director

Jennifer	H.	Madans,	Ph.D.,	Associate 

Director for Science

Division of Health and Nutrition 

Examination Surveys 

Clifford	L.	Johnson,	M.S.P.H.,	Director

U.S.	DEPARTMENT	OF	

HEALTH	&	HUMAN	SERVICES

Centers	for	Disease	Control	and	Prevention	

National	Center	for	Health	Statistics	

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