Association of A1C Levels With Vitamin D Status in U.S. Adults: Data from the National Health and Nutrition Examination Survey

Jatupol Kositsawat; Vincent L. Freeman; Ben S. Gerber; Stephen Geraci

doi:10.2337/dc09-2150

Original Research

Association of A1C Levels With Vitamin D Status in U.S. Adults

Data from the National Health and Nutrition Examination Survey

Jatupol Kositsawat, MD, DMSC, MPH¹,² ⇓,
Vincent L. Freeman, MD, MPH³,
Ben S. Gerber, MD, MPH⁴,⁵ and
Stephen Geraci, MD⁶

¹Medical Service, GV (Sonny) Montgomery VA Medical Center, Jackson, Mississippi;
²Division of Geriatrics, Department of Medicine, University of Mississippi, Jackson, Mississippi;
³Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois;
⁴Section of Health Promotion Research, University of Illinois at Chicago, Chicago, Illinois;
⁵Center for Management of Complex Chronic Care, Jesse Brown VA Medical Center, Chicago, Illinois;
⁶Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Mississippi, Jackson, Mississippi.

Corresponding author: Jatupol Kositsawat, Jatupol.Kositsawat{at}va.gov.

Diabetes Care 2010 Jun; 33(6): 1236-1238. https://doi.org/10.2337/dc09-2150

Article Figures & Tables

Tables

Table 1

Association of A1C levels with 25(OH)D status and other variables^*

	Overall	Age group (years)			Self-reported history of diabetes
	Overall	18–34	35–74	≥75	Yes	No
n	9,773	3,525	5,138	1,110	899	8,874
Vitamin D (ng/ml)	−0.0016 (0.08)	0.0008 (0.40)	−0.0035 (0.0045)	0.0012 (0.63)	0.0013 (0.90)	−0.0014 (0.0282)
Race/ethnicity
Black, non-Hispanic	0.2169 (<0.0001)	0.1440 (<0.0001)	0.2825 (<0.0001)	0.0782 (0.28)	0.7571 (<0.0001)	0.1607 (<0.0001)
Mexican-American	0.2331 (<0.0001)	0.1416 (0.0002)	0.3245 (<0.0001)	0.1817 (0.0074)	0.7937 (<0.0001)	0.1802 (<0.0001)
Other Hispanic	0.2687 (0.0009)	0.0570 (0.34)	0.3817 (0.0003)	0.6067 (0.16)	0.9423 (0.15)	0.1431 (0.0029)
Other race^†	0.1101 (0.0009)	0.1461 (0.0008)	0.0719 (0.08)	0.3299 (0.0102)	−0.1996 (0.31)	0.1334 (<0.0001)
Non-Hispanic Caucasian	Ref.	Ref.	Ref.	Ref.	Ref.	Ref.
Female^‡	−0.0634 (0.0001)	−0.0896 (0.0002)	−0.0569 (0.0086)	−0.0062 (0.83)	−0.0999 (0.51)	−0.0597 (<0.0001)
BMI (kg/m²)	0.0146 (<0.0001)	0.0100 (<0.0001)	0.0150 (<0.0001)	0.0145 (0.0067)	−0.0095 (0.36)	0.0159 (<0.0001)
Self-reported history of diabetes^§	1.6237 (<0.0001)	2.3946 (<0.0001)	1.6397 (<0.0001)	1.0802 (<0.0001)	N/A	N/A
PTH (ng/ml)	−0.0019 (0.0002)	−0.0004 (0.45)	−0.0028 (0.0002)	<−0.0001 (0.95)	−0.0085 (<0.0001)	−0.0007 (0.0176)
Age (years)	0.0101 (<0.0001)	0.0096 (<0.0001)	0.0105 (<0.0001)	0.0044 (0.46)	−0.0164 (0.0037)	0.0110 (<0.0001)
Vigorous physical activity in last 30 days^‖	−0.0272 (0.06)	−0.0057 (0.75)	−0.0387 (0.07)	−0.1427 (0.0137)	−0.1091 (0.71)	−0.0242 (0.0366)
Dietary supplement^¶	−0.0850 (<0.0001)	−0.0461 (0.05)	−0.1121 (<0.0001)	−0.0569 (0.18)	−0.4260 (0.0073)	−0.0591 (0.0006)

Data are parameter estimates (P values). Note: Self-reported history of diabetes means that the participant answered “yes” to the question, “Have you ever been told by a doctor that you have diabetes or sugar diabetes?” or reported current use of insulin or an oral antihyperglycemic medication.
↵*Model: A1C = β1 25(OH)D + β2 race + β3 sex + β4 BMI + β5 diabetes + β6 PTH + β7 age + β8 physical activity + β9 dietary supplement use.
↵†Including “multi-racial”.
↵‡Versus male;
↵§versus no history;
↵‖yes versus no;
↵¶versus no dietary supplement use. N/A, not applicable.