Table 2

Adjusted logistic regression models for periodontitis and vitamin D exposures associated with HOMA-IR, pre-diabetes, and type 2 diabetes among adults over 30 years of age from the 2009–2010 NHANES

OutcomesExposuresPoint estimate (95% CI)
Unadjusted modelsMinimally adjusted models*Fully adjusted models†
HOMA-IR Periodontitis§1.31 (0.85 to 1.50)1.00 (0.67 to 1.49)1.09 (0.70 to 1.71)
Vitamin D3 insufficiency¶ 2.03 (1.62 to 2.53) 1.86 (1.44 to 2.39)** 1.40 (1.06 to 1.84)**
Vitamin D insufficiency 2.02 (1.51 to 2.69) 1.80 (1.29 to 2.51)** 1.34 (0.95 to 1.89)
Pre-diabetes†† Periodontitis§ 1.98 (1.5 to 2.62) 1.18 (0.85 to 1.63)1.13 (0.80 to 1.61)
Vitamin D3 insufficiency¶1.17 (0.88 to 1.54)1.04 (0.74 to 1.47)0.89 (0.64 to 1.23)
Vitamin D insufficiency 1.42 (1.08 to 1.86) 1.24 (0.84 to 1.83)1.06 (0.72 to 1.55)
Type 2 diabetes‡‡ Periodontitis§ 2.74 (1.65 to 4.54)** 1.51 (0.89 to 2.55) 1.65 (1.02 to 2.70)**
Vitamin D3 insufficiency¶ 1.82 (1.09 to 3.05)** 1.84 (1.07 to 3.15)** 1.60 (0.97 to 2.63)
Vitamin D insufficiency1.33 (0.85 to 2.09)1.24 (0.74 to 2.07)1.12 (0.70 to 1.80)
  • *Minimally adjusted model, age, sex, race/ethnicity, poverty income ratio, season, smoking, and physical activity.

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

  • ‡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.

  • §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.

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

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

  • ††Pre-diabetes based on the level of hemoglobin A1c 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 hemoglobin A1c of 6.5% or greater and fasting plasma glucose level of 126 mg/dL or greater.

  • 25(OH)D, 25-hydroxyvitamin D; 25(OH)D3, 25-hydroxyvitamin D3; HOMA-IR, homeostatic model assessment for insulin resistance; NHANES, National Health and Nutrition Examination Survey.