TNF and obesity due to melanocortin 4 receptor deficiency: Obesity, a risk factor for dementia, increases the risks of various diseases by causing adipocyte hypertrophy, which increases the production of inflammatory adipokines (i.e. adipocyte-derived bioactive substances) including interleukin (IL)-6, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein-1, and leptin; this process leads to mild chronic inflammation throughout the body [13].