To the Editor:
The prevalence of childhood overweight and obesity is considerably
increased in most industrialized countries over the past twenty years and
the long term effects of childhood overweigh/obesity are numerous1. This
rapid increase has opened a large debate about the role of BMI as a risk
factor for co-morbidities and ensuing excess mortality in adulthood2,3.
However, BMI value in the overweight or obese class I group includes a
wide range of patients with different proportions of body fat for their
BMI and with very different degrees of abdominal obesity4. Therefore, BMI
cannot be used to reassure the moderately overweight about their risk of
complications, which seems more responsive to increases in body fat and
its abdominal distribution.
In the cross-sectional and longitudinal analyses, published in a recent
issue of this journal5, Freedman and CoAuthors demonstrated that the sum
of subscapular and triceps skinfold thicknesses are more strongly
associated with body fatness than BMI. However, in overweight children
skinfold sum weakly associated with obesity-related risk factors and adult
BMI. This results is fully in agreement with another recent work of
Freedman et al6 highlighting that skinfold thickness do not provide a more
accurate assessment of cardiovascular risk features than BMI.
The investigators also showed unquestionably that in overweight children
waist/height ratio is a better predictor of adverse health outcomes than
BMI. It is reasonable, also because, it has also been suggested that waist
circumference or waist-to-hip ratio (WHR) are stronger predictors of
adverse cardiovascular events than BMI7.
Despite the huge work these collaborative studies still have some
significant shortcomings, including the exclusion from the analysis of the
incidence of duration of the overweigh/obese status on adverse risk
factors. Time or duration of weight gain, in fact, may be an
underestimated confounder able to explain the incongruence in some data
regarding BMI and overweight/obesity associated co-morbidities.
REFERENCES
1. Lavoie PM, Pham C, Jang KL. Heritability of bronchopulmonary
dysplasia, defined according to the consensus statement of the
National Institutes of Health. Pediatrics. 2008;122(3):479485
1. Ebbeling CB, Pawlak DB, Ludwig DS. Childhood obesity: public-
health crisis, common sense cure. Lancet. 2002;360(9331):473482.
2. Guh DP, Zhang W, Bansback N, Amarsi Z, Birmingham CL, Anis AH. The
incidence of co-morbidities related to obesity and overweight: A
systematic review and metaanalysis.
BMC Public Health. 2009;9:88.
3. Flegal KM, Graubard BI. Estimates of excess deaths associated with
body mass
index and other anthropometric variables. Am J Clin Nutr.
2009;89(4):12131219.
4. Manco M, Bedogni G, Marcellini M, et al. Waist circumference
correlates with liver fibrosis in children with non-alcoholic
steatohepatitis. Gut. 2008;57(9):12831287.
5. Freedman DS, Dietz WH, Srinivasan SR, Berenson GS. Risk factors and
adult body mass index among overweight children: the Bogalusa Heart Study.
Pediatrics. 2009;123(3):750757.
6. Freedman DS, Katzmarzyk PT, Dietz WH, Srinivasan SR, Berenson GS.
Relation of body mass index and skinfold thicknesses to cardiovascular
disease risk factors in children: the Bogalusa Heart Study. Am J Clin
Nutr. 2009 May 6. [Epub ahead of print]
7. Yusuf S, Hawken S, Ounpuu S, et al. Obesity and the risk of myocardial
infarction in 27,000 participants from 52 countries: a case-control study.
Lancet. 2005;366(9497):16401649.
Conflict of Interest:
None declared
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