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 DOI: 10.1177/0883073811435326

2012 27: 545J Child NeurolBody Mass Index of Children With Attention-Deficit/Hyperactivity Disorder

  

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Correspondence

Body Mass Index of Children WithAttention-Deficit/HyperactivityDisorder

DOI: 10.1177/0883073811435326

We read with great interest the article by Dubnov-Raz et al1 pub-

lished in this journal. The authors use a cross-sectional method

to demonstrate the prevalence of overweight and obesity in chil-

dren with attention deficit hyperactivity disorder (ADHD) and

to examine changes in height and body mass index z scores of

children in the ADHD group compared with the controls after

a relatively long-term follow-up (17 months). The authors con-

clude that children with ADHD have lower rates of overweight

and obesity compared with controls. In addition, methylpheni-

date treatment does not significantly affect overweight status.

These results are inconsistent with most of previous studies

regarding the same issue.2-6 This conflicting result is partly

explained in the article. However, there are 3 issues not specif-

ically addressed by the authors that should be taken into consid-

eration and clarified when the conclusions are interpreted.

The first issue is that the clinical characteristics between the

control and ADHD groups are different in some items, which

may foster many chances for the introduction of bias. The two

groups may not be well-matched on some baseline characteris-

tics, such as age (10.4 vs 8.8, P < .01) and sample size (275 vs

51). Therefore, we are concerned how well matched the ADHD

and control groups are on other key characteristics that may

confound the results. The children in different age groups have

different preferred foods and physical activity levels that would

influence the balance of calorie input and consumption.7,8

Furthermore, absence of demographic data and markers of

socioeconomic status of the participants prevents an analysis

of possible mediating factors. Children of different socioeco-

nomic status have different lifestyles and diets, which will

greatly affect the prevalence of obesity in these popula-

tions.9–11 Therefore, lack of demographic information and

unmatched clinical characteristics can mislead the conclusion.

The second issue, as stated by the authors, is that the present

study is not conducted in children who were diagnosed with

ADHD for the first time and were medication-naive, which does

not minimize the potential influence of drugs on the growth sta-

tus.12,13 The body of literature shows that medications for

ADHD would lead to weight reduction.14,15 So, if the recruited

children with ADHD have been prescribed psychostimulants for

a long time, the indexes of weight and body mass index will be

changed and not reflect the real growth status of the ADHD

group. This selection bias would confound the results of preva-

lence of obesity in ADHD group.

The third issue is the relatively small sample size of children

(n ¼ 28) with a follow-up of 1 year. Although there is no sta-

tistically significant change in mean body mass index z scores

between baseline and after methylphenidate treatment (P ¼.53), the mean body mass index z scores are greatly lower post

treatment (1.73 vs 1.47). According to the Centers for Disease

Control and Prevention growth charts,16 a subject with a mean

body mass index z score of 1.73 at baseline is considered

‘‘obese,’’ whereas a subject with a score of 1.47 post methyl-

phenidate treatment is considered ‘‘overweight.’’17 From this

point, the mean body mass index z scores are changed greatly

after medication for 1 year. However, the differences have no

statistical significance, probably due to the small sample size,

which lessens the power of the test.

These 3 issues should be taken into consideration when the

results are interpreted.

Rongwang Yang, MD

The Children’s Hospital

Zhejiang University School of Medicine,

Hangzhou, Zhejiang Province, China

Shujiong Mao, MD

The First People’s Hospital of Hangzhou

Hangzhou, Zhejiang Province, China

Suhan Zhang, MD

The Children’s Hospital

Zhejiang University School of Medicine,

Hangzhou, Zhejiang Province, China

Rong Li, MD

The Children’s Hospital

Zhejiang University School of Medicine,

Hangzhou, Zhejiang Province, China

Zhengyan Zhao, MD

The Children’s Hospital

Zhejiang University School of Medicine,

Hangzhou, Zhejiang Province, China

Journal of Child Neurology27(4) 545-546ª The Author(s) 2012Reprints and permission:sagepub.com/journalsPermissions.navDOI: 10.1177/0883073811435326http://jcn.sagepub.com

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Acknowledgments

The authors thank Ms Lili Yang (assistant editor of World Journal of

Pediatrics) and Dr Edward Chen (Department of Pediatrics, Loma

Linda University Children’s Hospital) for their excellent proofreading

of the manuscript.

References

1. Dubnov-Raz G, Perry A, Berger I. Body mass index of children

with attention-deficit/hyperactivity disorder. J Child Neurol.

2011;26:302-308.

2. Agranat-Meged AN, Deitcher C, Goldzweig G, Leibenson L,

Stein M, Galili-Weisstub E. Childhood obesity and attention def-

icit/hyperactivity disorder: a newly described comorbidity in

obese hospitalized children. Int J Eat Disord. 2005;37:357-359.

3. Altfas JR. Prevalence of attention deficit/hyperactivity disorder

among adults in obesity treatment. BMC Psychiatry. 2002;2:9.

4. Cortese S, Angriman M, Maffeis C, et al. Attention-deficit/hyper-

activity disorder (ADHD) and obesity: a systematic review of the

literature. Crit Rev Food Sci Nutr. 2008;48:524-537.

5. Davis C, Levitan RD, Smith M, Tweed S, Curtis C. Associations

among overeating, overweight, and attention deficit/hyperactivity

disorder: a structural equation modelling approach. Eat Behav.

2006;7:266-274.

6. Cortese S, Morcillo Penalver C. Comorbidity between ADHD and

obesity: exploring shared mechanisms and clinical implications.

Postgrad Med. 2010;122:88-96.

7. Elbel B, Gyamfi J, Kersh R. Child and adolescent fast-food choice

and the influence of calorie labeling: a natural experiment. Int J

Obes (Lond). 2011;35:493-500.

8. Reedy J, Krebs-Smith SM. Dietary sources of energy, solid fats,

and added sugars among children and adolescents in the United

States. J Am Diet Assoc. 2010;110:1477-1484.

9. Wang Y, Jahns L, Tussing-Humphreys L, et al. Dietary intake pat-

terns of low-income urban african-american adolescents. J Am

Diet Assoc. 2010;110:1340-1345.

10. Kestens Y, Daniel M. Social inequalities in food exposure around

schools in an urban area. Am J Prev Med. 2010;39:33-40.

11. McDermott AJ, Stephens MB. Cost of eating: whole foods versus

convenience foods in a low-income model. Family Med. 2010;42:

280-284.

12. Safer D, Allen R, Barr E. Depression of growth in hyperactive

children on stimulant drugs. N Engl J Med. 1972;287:217-220.

13. Mattes JA, Gittelman R. Growth of hyperactive children on main-

tenance regimen of methylphenidate. Arch Gen Psychiatry. 1983;

40:317-321.

14. Levy LD, Fleming JP, Klar D. Treatment of refractory obesity in

severely obese adults following management of newly diagnosed

attention deficit hyperactivity disorder. Int J Obes (Lond). 2009;

33:326-334.

15. Waring ME, Lapane KL. Overweight in children and adolescents

in relation to attention-deficit/hyperactivity disorder: results from

a national sample. Pediatrics. 2008;122: e1-e6.

16. Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC Growth

Charts for the United States: methods and development: data from

the National Health Survey. Vital Health Stat 11. 2002:1-190.

17. Krebs NF, Himes JH, Jacobson D, Nicklas TA, Guilday P, Styne

D. Assessment of child and adolescent overweight and obesity.

Pediatrics. 2007;120(suppl 4): S193-228.

546 Journal of Child Neurology 27(4)

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