Kramer Michael S, Barros Fernando C, Demissie Kitaw, Liu Shiliang, Kiely John, Joseph K S
Departments of Pediatrics and of Epidemiology and Biostatistics, McGill University Faculty of Medicine, Montreal, Quebec, Canada.
Paediatr Perinat Epidemiol. 2005 Nov;19(6):445-51. doi: 10.1111/j.1365-3016.2005.00681.x.
Low birthweight (LBW) is highly associated with death during infancy, and countries with the highest LBW rates also have the highest infant mortality rates. We compared temporal trends in LBW with both overall and birthweight-specific infant mortality in United States, Canada, Argentina, Chile, and Uruguay over two time periods, using cohort and cross-sectional analysis of national population-based vital statistics for 1985-89 and 1995-98. Infant mortality diminished substantially (RR = 0.60-0.80 for the later vs. earlier periods) and to a similar degree in all birthweight categories in all five study countries, despite an increase in LBW in the US and Uruguay, minimal changes in Canada and Argentina, and a decrease in Chile. The strength of the (positive) association between LBW and overall infant mortality diminished over the two time periods (from r(s) = +0.80 to +0.25 and RR per SD increase in LBW rate from 2.13 [2.09, 2.17] to 1.76 [1.74, 1.79]). The proportion of infant deaths occurring among LBW infants was negatively correlated with overall infant mortality in both time periods (r(s) = -0.30 and -0.60, RR = 0.68 [0.67, 0.68] and 0.47 [0.46, 0.47]). Developed and less developed countries in the Americas have succeeded in reducing infant mortality in all birthweight groups despite inconsistent changes in LBW rates, and none has achieved this success primarily by reducing LBW. Although our results are not necessarily generalisable to the least developed countries in South Asia and sub-Saharan Africa, it is likely that all countries can substantially reduce their infant mortality rates by improving the care of infants at normal and low birthweights.
低出生体重（LBW）与婴儿期死亡高度相关，低出生体重率最高的国家婴儿死亡率也最高。我们使用1985 - 1989年和1995 - 1998年基于全国人口的生命统计数据进行队列研究和横断面分析，比较了美国、加拿大、阿根廷、智利和乌拉圭两个时间段内低出生体重的时间趋势与总体及按出生体重分类的婴儿死亡率。尽管美国和乌拉圭的低出生体重有所增加，加拿大和阿根廷变化极小，智利则有所下降，但所有五个研究国家中所有出生体重类别的婴儿死亡率均大幅下降（后期与早期相比RR = 0.60 - 0.80），且下降程度相似。在这两个时间段内，低出生体重与总体婴儿死亡率之间（正向）关联的强度减弱（从r(s)= +0.80降至 +0.25，低出生体重率每标准差增加的RR从2.13[2.09, 2.17]降至1.76[1.74, 1.79]）。两个时间段内低出生体重婴儿中发生的婴儿死亡比例与总体婴儿死亡率均呈负相关（r(s)= -0.30和 -0.60，RR = 0.68[0.67, 0.68]和0.47[0.46, 0.47]）。尽管低出生体重率变化不一致，但美洲的发达国家和欠发达国家都成功降低了所有出生体重组的婴儿死亡率，且没有一个国家主要通过降低低出生体重来实现这一成功。虽然我们的结果不一定能推广到南亚和撒哈拉以南非洲的最不发达国家，但所有国家都有可能通过改善正常和低出生体重婴儿的护理大幅降低其婴儿死亡率。
