[Development of anterior fontanelle in Chinese children in 2015].

Objective: To observe the development of the anterior fontanel (AF) in healthy Chinese children from 1 to 36 months, and to assess the relationship between the closure of the AF and physical development in Chinese children. Method: This was a cross-sectional evaluation of the AF in a series of 104 147 healthy children between June 2015 and October 2015 from nine cities in China. The size and closure of AF of the children were measured and recorded, and the age for the closure of AF was calculated using probit analysis. The data in 2015 were compared with the data from the same surveys in 1985, 1995 and 2005 respectively. Result: (1) Totally, 104 147 healthy children (52 216 boys and 51 931 girls; range 1 month to 36 months) from nine cities enrolled in this cross-sectional study. (2)The size of AF gradually decreased with age, and the mean size of AF was 2.0(95% confidence interval ( CI )2.0-2.1) cm at the age of 1 month, 0.6(95% CI 0.5-0.6) cm at the ages of 12-14 months, and 0.0(95% CI 0.0-0.0) cm at the ages of 21-23 months, respectively. (3) The percentage for the closure of AF was 0.1% at the age of 3 months, 67.5% at the ages of 15-17 months. The oldestt age for closure was 35 months. The mean age for the closure of AF was 14.5 months (95% CI 14.4-14.6), and the 3rd and 97th centiles of the age for the closure of AF were 6.6 and 22.4 months. (4) Over the past 30 years from 1985 to 2015, no significant change was found regarding the mean age for the closure of AF in children from urban area, contrarily, the mean age was 1.1 months earlier in suburban area. (5) The height and weight of children in the closed AF group were significantly higher than those of children in unclosed AF group(all P <0.01), but no significant difference was found regarding the head circumference between the two groups. Conclusion: The size of AF at 1 month was maximum, then decreases gradually with age, and the mean age for the closure of AF was 14.5 (95% CI 14.4-14.6) months. No significant correlation was found between the development of AF and the head circumference, but there was a positive correlation between the development of AF and the height and weight. There was no significant change regarding the secular trend of the age for the closure of AF.