LEP and obesity due to melanocortin 4 receptor deficiency: Moreover, in the case of leptin levels a significant interaction between dementia status and abdominal obesity was shown (p = 0.018) indicating the opposite direction in differences of leptin levels in all-cause dementia, dependent on abdominal obesity presence i.e. tendency to higher leptin levels in demented patients with obesity and significantly decreased level in demented patients without abdominal obesity (as compared to appropriate control groups with and without abdominal obesity).