Table 4

Logistic regression models assessing the joint effects of serum vitamin D (25(OH)D) levels and periodontitis with HOMA-IR, pre-diabetes, and type 2 diabetes among adults over 30 years of age from the 2009–2010 NHANES

OutcomesHOMA-IR*Pre-diabetes†Type 2 diabetes‡
ExposuresWith/without outcome§ (n)OR (95% CI)With/without outcome§ (n)OR (95% CI) With/without outcome§ (n)OR (95% CI)
G=0 (periodontitis none or mild)E=0 25(OH)D sufficiency124/434Reference (1.00)281/277Reference (1.00)56/558Reference (1.00)
E=1 25(OH)D insufficiency¶68/156 1.74 (1.18 to 2.57)** 126/981.26 (0.77 to 2.06)34/2241.02 (0.42 to 2.48)
G=1 (periodontitis moderate or severe)††E=025(OH)D sufficiency94/3080.98 (0.66 to 1.45)279/1231.19 (0.80 to 1.77)109/4021.38 (0.76 to 2.51)
E=125(OH)D insufficiency¶57/128 1.86 (1.10 to 3.17)** 131/541.46 (0.80 to 2.64)63/185 2.02 (0.98 to 4.16)**
P values‡‡0.690.920.50
With/without outcome§§ (n) With/without outcome§§ (n) With/without outcome§§ (n)
G=0 (periodontitis none or mild)E=025(OH)D sufficiency124/434Reference (1.00)281/277Reference (1.00)56/558Reference (1.00)
E=125(OH)D insufficiency¶68/1561.23 (0.79 to 1.91)126/981.07 (0.64 to 1.77)34/2240.85 (0.36 to 2.01)
G=1 (periodontitis moderate or severe)††E=025(OH)D sufficiency94/3081.02 (0.61 to 1.70)279/1231.14 (0.74 to 1.75)109/4021.45 (0.83 to 2.53)
E=125(OH)D insufficiency ¶57/1281.56 (0.88 to 2.77)131/541.19 (0.68 to 2.09)63/185 1.98 (1.04 to 3.76)**
P values‡‡0.440.960.37
  • *HOMA-IR ≥4.17 (population-specific 75th percentile) established using fasting glucose and insulin levels by the following formula: HOMA-IR=[glucose (mmol/L)×insulin (μU/mL) / 22.5]. HOMA-IR excluded those with diagnosed and undiagnosed type 2 diabetes.

  • †Pre-diabetes based on the level of HbA1c of 5.7%–6.4% (39–47 mmol/mol), fasting plasma glucose level of 100–125 mg/dL, or adults who reported having been told by a health professional that they have any of the following: pre-diabetes, impaired fasting glucose, impaired glucose tolerance, or borderline diabetes. Pre-diabetes excluded those with diagnosed and undiagnosed type 2 diabetes.

  • ‡Type 2 diabetes based on self-report of a previous diagnosis by a physician or other health professionals, or based on the level of HbA1c of 6.5% (48 mmol/mol) or greater and fasting plasma glucose level of 126 mg/dL or greater.

  • §Minimally adjusted model for age, sex, race/ethnicity, PIR, season, smoking, and physical activity.

  • ¶Serum vitamin D3 (25(OH)D) insufficiency defined as levels <50 nmol/L or <20 ng/mL.

  • **Significance at p<0.05. Statistically significant values are shown in bold.

  • ††Case definitions for periodontitis based on the definition from the Division of Oral Health at the Centers for Disease Control and Prevention, in collaboration with the American Academy of Periodontology.

  • ‡‡Represents multiplicative interaction p value results from adjusted survey logistic models.

  • §§Fully adjusted model for age, sex, race/ethnicity, education, insurance, season, smoking, physical activity, and body mass index.

  • 25(OH)D, 25-hydroxyvitamin D; HbA1c, hemoglobin A1c; HOMA-IR, homeostatic model assessment for insulin resistance; NHANES, National Health and Nutrition Examination Survey.