Seasonal variation of growth in body weight of Japanese children and its relationship to physique.

The present study examined the pattern and amplitude of seasonality of growth in body weight of Japanese children living in Tokyo, and analyzed the relationship between physique and seasonal variation. The body weights of 125 school children were measured monthly for 6 years (excluding August). The data were analyzed by time-series analysis. Significant seasonal variations were observed in about 80% of the children. Although individual seasonal patterns and amplitudes varied among children, minimum seasonal factors generally appeared in the Summer. Seasonal variations of group means of body weight were significant in both sexes. The seasonal pattern in boys was low in the Summer and high in the Fall and Winter. Deceleration of weight growth in the Summer was observed in both sexes, even though there were no major stresses in the Summer. The amplitudes of seasonal variation were 1.2% for body weight in boys and 0.7% in girls. In addition, children who were high on the BMI or Rohrer's index had larger amplitudes of seasonal variation, even when body weight of each child was taken into consideration. © 1994 Wiley-Liss, Inc.