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This slide summarises the relationships between intra-abdominal adiposity (IAA) and increased cardiometabolic risk. Intra-abdominal adiposity drives the progression of multiple risk factors directly, through the secretion of excess free fatty acids and inflammatory adipokines, and decreased secretion of adiponectin. The important contributions of IAA to dyslipidaemia and insulin resistance provide an indirect, though clinically important, link to the genesis and progression of atherosclerosis and cardiovascular disease.
The location of excess IAA is an important determinant of cardiometabolic risk. IAA is associated with insulin resistance, hyperglycaemia, dyslipidaemia, hypertension, and prothrombotic/proinflammatory states. Excess IAA typically is accompanied by elevated levels of C-reactive protein (CRP) and free fatty acids (FFAs), as well as decreased levels of adiponectin. Elevated CRP is an indicator of inflammation. Abdominal obesity has been shown to be associated with the inflammation cascade, with adipose tissue expressing a number of inflammatory cytokines. Inflammation is now believed to play a role in the development of atherosclerosis and type 2 diabetes. Elevated levels of CRP are considered to be predictive of cardiovascular disease and insulin resistance.
Elevated FFA levels appear to play a significant role in the cause of insulin resistance. It has been suggested that elevated FFAs and intracellular lipids inhibit the insulin signaling mechanism, leading to decreased glucose transport to muscle. FFAs also play a mediating role between insulin resistance and β-cell dysfunction, indicating that a reduction in FFA level could be a desirable therapeutic target.
Adiponectin is an adipose tissue-specific circulating protein which is involved in the regulation of lipid and glucose metabolism. Adiponectin has been shown to be reduced in adults with obesity and type 2 diabetes. In non-diabetics, hypertriglyceridaemia and low HDL-cholesterol have been shown to be associated with low plasma adiponectin concentrations.
All of these components help to explain why excess abdominal adiposity is considered to be a great threat to cardiovascular and metabolic health.