The prevalence of obesity has increased worldwide and is a source of concern since
the negative consequences of obesity start as early as in childhood. The most commonly
used anthropometric tool to assess relative weight and classify obesity is the body
mass index (BMI); BMI alone shows a U- or a J-shaped association with clinical outcomes
and mortality. Such an inverse relationship fuels a controversy in the literature,
named the 'obesity paradox', which associates better survival and fewer cardiovascular
(CV) events in patients with elevated BMI afflicted with chronic diseases compared
to non-obese patients. However, BMI cannot make the distinction between an elevated
body weight due to high levels of lean vs. fat body mass. Generally, an excess of
body fat (BF) is more frequently associated with metabolic abnormalities than a high
level of lean body mass. Another explanation for the paradox is the absence of control
for major individual differences in regional BF distribution. Adipose tissue is now
considered as a key organ regarding the fate of excess dietary lipids, which may determine
whether or not body homeostasis will be maintained (metabolically healthy obesity)
or a state of inflammation/insulin resistance will be produced, with deleterious CV
consequences. Obesity, particularly visceral obesity, also induces a variety of structural
adaptations/alterations in CV structure/function. Adipose tissue can now be considered
as an endocrine organ orchestrating crucial interactions with vital organs and tissues
such as the brain, the liver, the skeletal muscle, the heart and blood vessels themselves.
Thus, the evidence reviewed in this paper suggests that adipose tissue quality/function
is as important, if not more so, than its amount in determining the overall health
and CV risks of overweight/obesity.
© 2013.