Variations in early gross motor milestones and in the age of walking in Japanese children

Background: Gross motor development is usually assessed in terms of age of achievement of motor milestones. Although we generally have an impression that one developed faster, if one achieved younger milestone faster than usual; there are no longitudinal study about these association among each milestones especially in Japan. As a part of Japan Children's Study, we researched whether the achievement of gross motor milestones in infancy were related with the age of walking. Methods: This is a prospective cohort study of 290 healthy and term infants born in a district of Osaka City, Japan. Three milestones; rolling over, sitting and crawling were observed in laboratory at the age of 4 and 9 months by a pediatrician and a developmental psychologist, and the age of walking was confirmed in questionnaires filled in by the parents at the age of 18 and 27 months. Results: Whether or not roll over at 4 months, and sit and crawl at 9 months were related to the age of walking. About crawling and sitting, the age of walking varies not only able or unable but the variation of its form at the 9 month observation point. Multiple regression analysis revealed these three milestones were positively associated with walking; rolling over (β= 0.567), sitting (β= 1.973) and crawling (β= 1.473). Conclusion: The age and the patterns of sitting, crawling and rolling over were all related to the age of independent walking among Japanese infants. Consideration of milestone' definition and variations proves to be essential in medical check-up. Language: en