Overweight, obesity up CV risk regardless of metabolic markers in long-term study
The Mongolian Death Worm
term study
JANUARY 5, 2010 | Michael O'Riordan
Uppsala, Sweden - Middle-aged men with the metabolic syndrome are at
an increased risk of cardiovascular disease and death regardless of
their body-mass index (BMI), new research shows [1]. On the flip side
of that combination, investigators also showed that overweight and
obese individuals without the metabolic syndrome are at an increased
risk of cardiovascular events and death.
Publishing their results online December 28, 2009 and in the January
19, 2010 issue of Circulation, Dr Johan Ärnlöv (Uppsala University,
Stockholm, Sweden) and colleagues say the "data refute the notion that
overweight and obesity without the metabolic syndrome are benign
conditions."
As the researchers note in their paper, previous studies have shown
that obese individuals without the metabolic syndrome—sometimes
referred to metabolically healthy obese, or even healthy fat—were not
at an increased risk of cardiovascular disease events. Follow-up in
these studies was around 13 years, leaving some question as to the
long-term impact of different BMI/metabolic-syndrome combinations.
In this new Swedish examination, cardiovascular risk factors were
assessed in 1758 middle-aged individuals without diabetes in the
Uppsala Longitudinal Study of Adult Men (ULSAM). During a median
follow-up of 30 years, 788 participants died and 681 developed
cardiovascular disease. In hazard models that adjusted for age,
smoking, and LDL cholesterol, metabolic syndrome was associated with
an increased risk in normal, overweight, and obese individuals. As
noted, even obese and overweight individuals without metabolic
syndrome were at an increased risk for death and cardiovascular
events.
ULSAM: Death and major cardiovascular events (HR, 95% CI) in the
different groups
End point
Normal weight without metabolic syndrome
Normal weight with metabolic syndrome
Overweight without metabolic syndrome
Overweight with metabolic syndrome
Obese without metabolic syndrome
Obese with metabolic syndrome
Total death
Referent
1.28 (0.90-1.82)
1.21 (1.03-1.40)
1.53 (1.19-1.96)
1.65 (1.03-2.66)
2.43 (1.81-3.27)
CV death
Referent
1.77 (1.11-2.83)
1.44 (1.14-1.83)
2.19 (1.57-3.06)
1.20 (0.49-2.93)
3.20 (2.12-4.82)
Major CV events
Referent
1.63 (1.11-2.37)
1.52 (1.28-1.80)
1.74 (1.32-2.30)
1.95 (1.14-3.34)
2.55 (1.82-3.58)
The researchers note that there appeared to be a lag time of
approximately 10 years before the Kaplan-Meier curves for overweight
and obese individuals without the metabolic syndrome diverged from the
curve of normal-weight participants without the syndrome.
"This could be important, because it is possible that the transition
from overweight/obesity without metabolic derangements to overt
cardiovascular disease is a pathological process that spans several
decades," write Ärnlöv and colleagues.
They note that based on previous studies, weight loss in these so-
called metabolically healthy obese and overweight individuals had been
questioned, with some researchers even suggesting it might be harmful
for them to lose weight. Based on their results, however, the
"potential benefits of diagnosing metabolically healthy obese in
clinical practice appears limited," and the data do not support the
existence of a healthy obese phenotype based on the absence of
metabolic syndrome or insulin resistance.
Ärnlöv J, Ingelsson E, Sundström J, Lind L. Impact of body mass index
and the metabolic syndrome on the risk of cardiovascular disease and
death in middle-aged men. Circulation 2010; 121:230-236.