Objective: i) To evaluate plasma levels of IL6, adiponectin and resistin in subjects with diabetic foot in comparison with subjects without foot complications. ii) To assess the impact of vitamin D status on the levels of above inflammatory markers.
Methods: A total 100 diabetic foot cases and 100 diabetic controls were recruited in the study. Serum level of 25OH vitamin D was estimated from the cases & controls by RIA. Serum IL6, adiponectin and resistin were assayed by ELISA. Data were analyzed using online graphpad quickcalc software and P<0.05 was considered statistically significant.
Results: Mean age of the study population was 54.3±12.4 years (male:female=68:32). Mean age of the controls was 52.5±13.6 (male:female=60:40). HbA1c was comparable (10.3 vs 10.9%). Diabetic foot cases were having lower vitamin D status (16.1±16.0 ng/ml) than the diabetic controls (19.8±14.1 ng/ml). Prevalance of vitamin D deficiency was higher in cases than controls (62 vs 57%). Females outnumbered males in terms of prevalence of vitamin D deficiency (22/32 females (68%) vs 40/68 (58%) males in cases and 25/ 40 females (62%) vs 32/60 (53%) males in control group). Severity of vitamin D deficiency (<10 ng/ml) was higher in cases (48.2%) than controls (26.2%).
IL6 level was higher in cases (128.3 pg/ml) than the controls (63.8 pg/ml) (P-0.01). Similarly lower median plasma levels of adiponectin (7.7 vs 8.4 μg/ml) and higher median plasma levels of resistin (3.8 vs 3.6 ng/ml) were observed in cases (P<0.05). No significant difference was observed in the levels of these markers between male and female study participants in both the groups. Patients under vitamin D deficient group (<30 ng/ml) demonstrated higher IL6 (130.8 vs 100.0 pg/ml), higher resistin (3.9 vs 3.6 ng/ml) and lower adiponectin (7.6 vs 8.3 μg/ml) levels compared to vitamin D sufficient (≥ 30 ng/ml) group in diabetic foot (P<0.05).
Discussion: Immuno-regulatory role of vitamin D is well established. Diabetic foot infections reflect the immune-compromised state of the patients and therefore it is speculative that vitamin D deficiency is more common and severe in diabetic foot. Our study demonstrated that diabetic subjects with diabetic foot showed in comparison with diabetics without diabetic foot higher IL6 and resistin plasma levels and lower adiponectin plasma levels. Hypovitaminosis D is more prevalent in patients with diabetic foot and Vitamin D deficiency is more severe in patients with diabetic foot infections. The levels of the above markers are more in diabetic foot patients with vitamin D deficiency.
Conclusion: Assumption is made that Vitamin D deficiency enhances inflammatory response in addition to hyperglycemia, in diabetic foot.