Relationship between insulin resistance and plasma vitamin D in adults

Figures & data

Table 1 Characteristics of the study population

Variable	Mean ± SE (or %) n=1,925
Age	43.5±0.20
Sexa (%)
Men	48 (927)
Women	52 (1,001)
Racea (%)
Caucasian	84.8 (1,636)
Asian	8.0 (155)
Other	4.6 (89)
Unknown	2.6 (48)
Obesity
Energy expenditure (kcal/kg/d)	1.8±0.11
BMI (kg/m^2)	26.8±0.31
Waist circumference (cm)	90.2±0.87
Cardiometabolic factors
Systolic blood pressure (mmHg)	111.2±0.79
Diastolic blood pressure (mmHg)	70.7±0.56
Triglycerides (mmol/L)	1.3±0.03
HbA1c (%)	5.6±0.05
Total cholesterol (mmol/L)	4.9±0.08
HDL-C (mmol/L)	1.3±0.03
LDL-C (mmol/L)	3.0±0.05
Total: HDL-C	3.9±0.05
ApoA1 (g/L)	1.4±0.03
ApoB (g/L)	0.91±0.01
CRP (mg/L)	2.3±0.13
Insulin resistance
Glucose (mmol/L)	5.1±0.03
Insulin (pmol/L)	70.9±2.81
HOMA-IR	2.4±0.11
Vitamin D
25(OH)D (nmol/L)	67.5±1.58

Note:

a Number in parentheses represents the number of subjects.

Abbreviations: SE, standard error; BMI, body mass index; HbA_1c, hemoglobin A_1c; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; ApoA1, apolipoprotein A1; ApoB, apolipoprotein B; CRP, C-reactive protein; HOMA-IR, homeostatic model assessment–insulin resistance; 25(OH)D, serum 25-hydroxyvitamin D.

Table 2 Linear regression examining insulin resistance and vitamin D in males and females

Variablea	Men			Women			P d
	Mean ± SE	β ± SEb	P c	Mean ± SE	β ± SEb	P c
Glucose (mmol/L)	5.2±0.05	−0.03±0.02	0.32	5.0±0.03	−0.02±0.02	0.35	<0.001
Insulin (pmol/L)	72.4±3.16	−0.21±0.05	0.002	69.5±3.95	−0.13±0.06	0.05	0.18
HOMA-IR	2.5±0.11	−0.24±0.06	0.002	2.3±0.15	−0.14±0.06	0.03	0.05

Notes:

a Variables were natural log-transformed for analysis

b values for linear relationship between 25(OH)D and factors related to insulin resistance for men and women

c P-values for linear regression adjusted for waist circumference, physical activity, season, and hormone drug use

d P-values are for test for differences between sexes (t-test).

Abbreviations: SE, standard error; HOMA-IR, homeostatic model assessment–insulin resistance.

Figure 1 Insulin resistance and related markers by quartile of vitamin D.

Notes: Values are crude means ± SE for each 25(OH)D (weighted). Quartiles of 25(OH)D (Q1–Q4) are depicted in panel (A), together with the range and the number of subjects in each quartile. Regression coefficient (β), SE, and P-values for the linear relationship between 25(OH)D and glucose (B), insulin (C), and HOMA-IR (D) are adjusted for sex, waist circumference, physical activity, season, and hormone drug use (in women). Insulin resistance factors were natural log-transformed for analysis.
Abbreviations: SE, standard error; Q, quartile; HOMA-IR, homeostatic model assessment–insulin resistance; 25(OH)D, plasma 25-hydroxyvitamin D.