Matsuda S, Sone T, Doi T, Kahyo H
Department of Human Ecology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Hum Biol. 1993 Jun;65(3):481-501.
Seasonal variations of mean birth weight from January 1974 to December 1983 and of mean gestational period from January 1979 to December 1983 in Japan are analyzed by time-series analysis. This analysis decomposes the variation in a series into trend, seasonal variation, other cyclic changes, and a remaining irregular fluctuation. The results of the present analysis support the existence of a seasonal rhythm of mean birth weight and mean gestational period in Japan with statistical significance (p < 0.001). Seasonal patterns of mean birth weight show two peaks in May and October-November and two troughs in June-September and December. Mean gestational periods shows two peaks in October and February-March and a deep trough in winter and a much smaller one in June-September. Two time series demonstrated a coincidence in monthly variations with statistical significance. These results indicate that a part of seasonality in birth weight could be explained by the seasonal variations in mean gestational period.
采用时间序列分析方法，分析了1974年1月至1983年12月日本平均出生体重的季节性变化以及1979年1月至1983年12月平均妊娠期的季节性变化。该分析将序列中的变化分解为趋势、季节性变化、其他周期性变化和剩余的不规则波动。本分析结果支持日本平均出生体重和平均妊娠期存在季节性节律，具有统计学意义（p < 0.001）。平均出生体重的季节性模式在5月和10月至11月出现两个峰值，在6月至9月和12月出现两个谷值。平均妊娠期在10月和2月至3月出现两个峰值，冬季出现一个深谷，6月至9月出现一个小得多的谷值。两个时间序列在月度变化上具有统计学意义的一致性。这些结果表明，出生体重季节性的一部分可以用平均妊娠期的季节性变化来解释。
