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Assessment of Child Anthropometry in a Large Epidemiologic Study
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Number of siblings, birth order, and childhood overweight: a population-based cross-sectional study in Japan

Hirotaka Ochiai1, Takako Shirasawa, Tadahiro Ohtsu

  • 1Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, 142-8555, Tokyo, Japan. h-ochiai@med.showa-u.ac.jp

BMC Public Health
|September 13, 2012
PubMed

Insights

Being an only child or the youngest increases childhood overweight risk. However, having more younger siblings is linked to a lower risk of childhood overweight, suggesting targeted interventions.

Area of Science:

  • Pediatric Health
  • Obesity Research
  • Family Studies

Background:

  • Inconsistent findings exist regarding sibling number/birth order and childhood overweight.
  • Limited understanding of how older vs. younger siblings impact childhood overweight.
  • This study addresses these gaps in Japanese elementary schoolchildren.

Purpose of the Study:

  • Investigate the relationship between sibling number and birth order with childhood overweight.
  • Evaluate the specific impact of having older or younger siblings on childhood overweight.
  • Identify at-risk family structures for childhood overweight prevention.

Main Methods:

  • Population-based study of 4026 fourth-grade schoolchildren (age 9-10) in Japan (1999-2009).
  • Data collected via questionnaire (siblings, birth order, lifestyle) and school measurements (height, weight).
  • Childhood overweight defined by International Obesity Task Force criteria; logistic regression used for analysis.

Main Results:

  • Only children (OR: 2.13) and youngest children (OR: 1.56) had significantly higher odds of overweight compared to middle children.
  • A greater number of siblings correlated with decreased odds of overweight (P < 0.001).
  • More younger siblings significantly lowered the odds of overweight (P < 0.001), while older siblings showed no significant association.

Conclusions:

  • Being an only or youngest child is associated with increased risk of childhood overweight.
  • A larger number of younger siblings is negatively associated with childhood overweight.
  • Public health strategies should target children from specific family structures (only/youngest child, fewer younger siblings) for overweight prevention.
Abstract

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