Table 1

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

OverallAge group (years)Self-reported history of diabetes
18–3435–74≥75YesNo
n9,7733,5255,1381,1108998,874
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-Hispanic0.2169 (<0.0001)0.1440 (<0.0001)0.2825 (<0.0001)0.0782 (0.28)0.7571 (<0.0001)0.1607 (<0.0001)
    Mexican-American0.2331 (<0.0001)0.1416 (0.0002)0.3245 (<0.0001)0.1817 (0.0074)0.7937 (<0.0001)0.1802 (<0.0001)
    Other Hispanic0.2687 (0.0009)0.0570 (0.34)0.3817 (0.0003)0.6067 (0.16)0.9423 (0.15)0.1431 (0.0029)
    Other race0.1101 (0.0009)0.1461 (0.0008)0.0719 (0.08)0.3299 (0.0102)−0.1996 (0.31)0.1334 (<0.0001)
    Non-Hispanic CaucasianRef.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/AN/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.