VDR Gene Polymorphisms and Weight Loss in Non-diabetic Overweight and Obese Subjects

The Influence of Vitamin D Receptor (VDR) Gene Polymorphisms (BsmI, TaqI, ApaI, FokI) on Weight Loss by Diet and Exercise Interventions in Non-diabetic Overweight and Obese Subjects

This is a six months intervention study in non-diabetic overweight and obese subjects. Subjects will be counseled for weight loss through diet and exercise. Diet and exercise will be recommended as per the regular norms for weight loss (weight loss ≥10% from baseline weight will be considered as a significant loss of weight) for overweight and obese subjects. A sample size of 90 subjects was calculated but assuming a drop out rate of 20%, 110 subjects will be enrolled. Enrolled subjects will be measured at every visit (monthly) for weight, body composition measures of abdominal obesity and skin folds. They would be assessed for compliance with diet and exercise. Detailed analysis of body composition including DXA, biochemical analysis will be performed at enrollment and after six months intervention. Statistical analysis will be performed to find association between measures of body composition for weight loss and genotypes of the VDR polymorphisms.

This is a six months intervention study in non-diabetic overweight and obese subjects. Subjects will be counseled for weight loss through diet and exercise. Diet and exercise will be recommended as per the regular norms for weight loss (weight loss ≥10% from baseline weight will be considered as a significant loss of weight) for overweight and obese subjects. A sample size of 90 subjects was calculated but assuming a drop out rate of 20%, 110 subjects will be enrolled. Enrolled subjects will be measured at every visit (monthly) for weight, body composition measures of abdominal obesity and skin folds. They would be assessed for compliance with diet and exercise. Detailed analysis of body composition including DXA, biochemical analysis will be performed at enrollment and after six months intervention. Statistical analysis will be performed to find association between measures of body composition for weight loss and genotypes of the VDR polymorphisms.

VDR Polymorphisms

Polymorphisms in the VDR gene have been identified through out the complete VDR gene region and associated with cancer and autoimmune diseases. The FokI polymorphism is present in the translation site and results in the VDR protein being shortened by three amino acids and is not linked with any other VDR polymorphisms. This polymorphism predisposes to bone-disease, risk of cancer, immune mediated diseases 147-149,150, 151.

The common VDR gene polymorphisms are BsmI, TaqI, ApaI and FokI. These polymorphisms have shown varying results with insulin sensitivity and secretion.

Inclusion Criteria:

• 20-60 yrs
• BMI ≥ 23 kg/m2

Exclusion Criteria:

• Type 1 or Type 2 Diabetes.
• On drugs or meal supplements for weight loss.
• On calcium and or vitamin D supplement currently or in the previous six months.
• Have past or current history or family history of renal stones.
• Have participated in any other investigational drug study in the previous three months.
• Have any systemic diseases (cardiac, hepatic, endocrine or renal) or taking any kind of treatment more than one month in the last six months.
• Diagnosed malabsorption (celiac disease, Cohn's, ulcerative colitis) or history suggestive of malabsorption.
• Have past history of bariatric surgery