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Age-dependent changes in infant head shape: a smartphone app-based study in Japan.
Satoshi Narumi1, Yui Honda2, Yoriko Kotoku2
1Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
Summary
This study establishes reference curves for infant head shape in Japan. Cranial vault asymmetry peaks at 3-4 months, while head proportionality increases until 6 months, with sex-based differences noted.
Area of Science:
- Pediatrics
- Anthropology
- Biometrics
Background:
- Infant head shape changes rapidly, but age-dependent cranial asymmetry is not well understood.
- Characterizing normal head shape development is crucial for identifying potential health issues.
Purpose of the Study:
- To analyze factors influencing head shape parameters in Japanese infants.
- To establish normative reference curves for cranial vault asymmetry index (CVAI) and cranial index (CI) in Japanese infants.
Main Methods:
- Collected head shape data (CVAI and CI) from 127,605 Japanese infants using a smartphone app.
- Performed univariate and multivariate analyses to identify associated factors.
- Constructed reference curves using data from 72,726 infants born via spontaneous vaginal delivery with normal birth weight.
Main Results:
- CVAI peaked at 3-4 months and then declined; CI increased until approximately 6 months.
- Boys exhibited significantly higher CVAI than girls.
- Low birth weight was associated with lower CI.
Conclusions:
- This study provides the first reference curves for CVAI and CI specific to Japanese infants.
- The findings illustrate the natural progression of cranial asymmetry and proportionality during infancy.
- Age-specific assessment is vital for interpreting head shape parameters.
