我国初生儿体格发育水平30年变化

Changes in body size of newborns at birth from 1975 to 2005 in China

目的分析1975年至2005年我国初生儿体格发育水平的变化情况。方法资料来源于1975、1985、1995和2005年4次“中国9个城市城郊7岁以下儿童体格发育调查研究”的初生组（0～3d）新生儿体格指标测量数据。调查点为哈尔滨、北京、西安、上海、南京、武汉、广州、福州、昆明9个城市的城区和郊区，采用分层随机整群抽样方法调查出生72h之内的足月健康新生儿。4次调查样本量分别为：1975年7325例，1985年6660例，1995年7109例，2005年6144例。采用“检验、方差分析及χ2检验比较体格指标的30年变化及城郊、地区差异。结果（1）1975年至2005年城、郊、男、女初生儿体重平均水平有不同程度增长，增幅为40～100g；体重各百分位均有增加，分布明显右移；巨大儿的比例从1985年的3．2％（212／6660）增至2005年的4．3％（265／6144）。（2）30年间城、郊、男、女初生儿身长未见明显的变化；头围变化甚微，平均值增长0．1NO．3cm。（3）城、郊、男、女初生儿重量指数（ponderal index，PI）在1975年至2005年间呈逐渐增高趋势，平均值从1975年的25．4kg／m^3增长至2005年的26．0kg／m^3。（4）城区初生儿体格发育水平始终略高于郊区农村，但体重、身长城郊差异有缩小趋势，PI城郊差异在2005年时略有增大。（5）初生儿体重、身长、头围呈现为北、中部地区高于南部地区，且地区差异在30年间变化不明显。PI在1975年表现为北、中部高于南部，而2005年南部反超北中部，南部30年增幅最大。结论1975年至2005年30年问我国初生儿体格发育水平略有提高，巨大儿比例逐渐增加；城乡差异逐渐缩小，但依然存在。

Objective To analyze the changes in body size of Chinese newborns in nine cities during 1975-2005. Methods The data of weight, height and head circumference of newborns within 3 days after birth from four national physical growth surveys named ＂a national survey on growth of children under seven years of age in nine cities of China＂ in 1975, 1985, 1995 and 2005 were used. The investigation areas were urban and suburban areas of Beijing, Harbin and Xi＇an in the northern part; Shanghai, Nanjing and Wuhan in the central part; Guangzhou, Fuzhou and Kunming in the southern part of China. Random cluster sampling method was used, 7325, 6660, 7109 and 6144 healthy newborns were examined in 1975, 1985, 1995 and 2005, respectively. The changes of body size between 1975 and 2005, urban-suburban difference and regional difference were compared with u test, ANOVA or χ2 test. Results （1） The average weight had increased during the past 30 years no matter boys and girls, from urban and suburban areas. The increments was 40- 100 g. The percentiles of weight had also increased and the distribution had shifted noticeably towards heavier weights. The proportion of macrosomia had increased from 3.2% （212/6660） in 1985 to 4.3% （265/6144） in 2005. （2） The length of newborns remained unchanged over the 30-year period no matter boys and girls, from urban and suburban areas. Head circumference of newborns showed only a minor increase （0.1--0.3 cm）. （3） Ponderal index （PI） had increased gradually from 1975 to 2005. The means of PI had increased from 25.4 kg/m3 in 1975 to 26.0 kg/m3 in 2005. （4） Body size of urban newborns was slightly bigger than that of suburban newborns. The urban-suburban difference of weight and height became smaller and smaller in the 30 years, while the urban-suburban difference in PI became slightly bigger in 2005. （5） Weight, height and head circumference of newborns in northern and central areas were higher than those of southern newborns and the regional difference had not significant changes in the 30 years. The PI of newborns in northern and central areas was higher than that of southern part in 1975, while the PI of southern part became the highest in 2005. Conclusions The body size of newborns became slightly bigger and the proportion of macrosomia increased between 1975 and 2005. The urban-suburban difference became smaller and the regional difference remained in the 30 years.