Background: Epidemiologic data suggest an association between obesity and depression, however findings vary considerably across different studies. Both depression and obesity are disabling disorders associated with loss over appetite control, influenced by genetic and environmental factors and are risk factors for diseases like hypertension, cardiovascular disorders, etc. This study attempts to establish a link between the symptoms of depression, metabolic disorders, and obesity, to unravel the underlying association/s.
Methods: This exploratory case-control study comprises 133 clinically diagnosed depressed individuals and 136 age matched controls. DNA from all 269 subjects was genotyped for D7S1875 repeat polymorphism in the promoter region of Leptin (LEP) gene using polymerase chain reaction.
Results: Frequency of the shorter allele of D7S1875 (<208 bp) was 0.73 in the depressive group versus 0.67 in the control group (P=.01). Cases homozygous for D7S1875> or =208 bp alleles had significantly higher value of systolic (130 versus 122; P<.009) and diastolic (85.4 versus 81; P=.01) blood pressure (SBP and DBP) than the individuals homozygous for<208 bp allele. A similar trend was observed for SBP (127.8 versus 123.6; P=.03) among controls homozygous for the longer or the shorter allele. Thus, the LEP gene appears to be an important genetic determinant for susceptibility to depression in the Indian population (OR=1.4913, 95% CI=1.0334-2.1522; P=.04).
Conclusions: Our findings suggest that LEP gene variants could be related to depression and associated co-morbidities such as hypertension.