Table II.
Determination of study variable associations according to vitamin D status.
| 25-hydroxyvitamin D status | ||||
|---|---|---|---|---|
| Variable | Sufficient, >30 ng/ml (n=16) | Insufficient, 20–30 ng/ml (n=34) | Deficient, <20 ng/ml (n=74) | P-value |
| Age, years | 58.0±10.2 | 58.6±8.6 | 59.3±9.5 | 0.76 |
| Sex | 0.20 | |||
| Male | 3 (18.8) | 15 (44.1) | 29 (39.2) | |
| Female | 13 (81.2) | 19 (55.9) | 45 (60.8) | |
| BMI (kg/m2) | 0.66 | |||
| Normal (18.6–24.9) | 1 (6.2) | 0 (0.0) | 4 (5.4) | |
| Overweight (25–29.9) | 7 (43.8) | 15 (44.1) | 28 (37.8) | |
| Obese (>30) | 8 (50.0) | 19 (55.9) | 42 (56.8) | |
| Duration of diabetes mellitus, years | 4.9±4.1 | 4.7±2.6 | 5.2±3.5 | 0.80 |
| HbA1c | 0.69 | |||
| <7% (controlled) | 7 (43.8) | 14 (41.2) | 25 (33.8) | |
| ≥7% (uncontrolled) | 9 (56.2) | 20 (58.8) | 49 (66.2) | |
| Log[fasting blood sugar (mmol/l)] | 0.9±0.1 | 0.9±0.2 | 0.9±0.2 | 0.35 |
| Smoking status | 0.92 | |||
| Current smoker | 2 (12.5) | 6 (17.6) | 13 (17.6) | |
| Former smoker | 2 (12.5) | 7 (20.6) | 11 (14.9) | |
| None smoker | 12 (75.0) | 21 (61.8) | 50 (67.7) | |
| Number of painful sites | 4.69±3.0 | 6.7±3.8 | 5.8±2.6 | 0.09 |
| Pain intensity over the last month (0–10 scale) | 3.8±2.7 | 4.2±2.6 | 3.4±2.2 | 0.24 |
| Anxiety score | 0.18 | |||
| Normal (0–7) | 5 (31.2) | 21 (61.8) | 45 (60.8) | |
| Borderline (8–10) | 5 (31.2) | 6 (17.6) | 17 (23.0) | |
| Abnormal (11–21) | 6 (37.5) | 7 (20.6) | 12 (16.2) | |
| Depression score | 0.40 | |||
| Normal (0–7) | 6 (37.5) | 11 (32.4) | 29 (39.2) | |
| Borderline (8–10) | 2 (12.5) | 11 (32.4) | 24 (32.4) | |
| Abnormal (11–21) | 8 (50.0) | 12 (35.3) | 21 (28.4) | |
| Neuropathy score | 0.68 | |||
| Nociceptive (0–12) | 6 (37.5) | 18 (38.2) | 31 (41.9) | |
| Unclear (13–18) | 4 (25.0) | 18 (38.2) | 19 (25.7) | |
| Neuropathic (19–38) | 6 (37.5) | 8 (23.5) | 24 (32.4) | |
| Statin therapy | 0.15 | |||
| Yes | 7 (43.8) | 16 (47.1) | 47 (63.5) | |
| No | 9 (56.2) | 18 (52.9) | 27 (36.5) | |
P-values were determined by χ2 or Fisher's exact tests for categorical variables and one-way analysis of variance test for continuous variables. Data are presented as frequency (%) or mean ± standard deviation. Vitamin D reference ranges were as defined by Sadat-Ali et al (26) in their study based on the same method of vitamin D determination. Anxiety, depression and neuropathy score reference ranges were defined as in the PainDETECT and Hospital Anxiety and Depression Scale scoring systems (22,23). Reference ranges for BMI were as defined by Nuttall (33). HbA1c reference levels were as defined by Esposito et al (34). BMI, body mass index; HbA1c, glycated hemoglobin.