Supplemental analyses of recent trends in infant mortality.

U.S. preliminary data for 2002 show a significant increase in the infant mortality rate to 7.0 infant deaths per 1,000 live births, the first rise in the infant mortality rate since 1958. The increase in infant mortality was concentrated in the neonatal period, particularly in deaths occurring within seven days of birth. Partially edited fetal death data suggest that the increase in neonatal mortality was accompanied by a decline in the late fetal mortality rate, and thus it appears that the 2002 perinatal mortality rate will remain level. Potential explanatory factors for the changes in the infant mortality rate are examined, including causes of infant death, percentage of births that are preterm, and low birthweight. Data from the 2002 linked birth and infant death file will allow an assessment of the contribution of maternal and infant factors such as multiple births and management of labor and delivery.     

Preventing the sudden infant death syndrome

Current efforts in the US to prevent the sudden infant death syndrome (SIDS) are largely based on pneumocardiogram screening and home apnoea monitoring. This technology does not prevent most SIDS deaths because the screening procedures lack the sensitivity and specificity needed to identify most high risk infants. In the UK the largest efforts to prevent SIDS have been based on infant health surveillance. These efforts appear to have been ineffective and along with the US failures highlight the need for new strategies to prevent SIDS. One strategy might be to develop methods to avoid known risk factors for SIDS. Prominent among these risk factors are cigarette smoking and the use of psychotropic drugs during pregnancy, overheating and infections in infants. Possible approaches to avoid these and other risks are described in the present paper.     

State trends in infant mortality, 1968-83.

This paper presents an analysis of state trends in infant mortality rates (IMRs) for 1968-83. In order to take into account the large random error component associated with state IMRs, weighted least squares estimates are used to fit log-linear models to these trends. Using simulated data, these estimates are shown to be nearly unbiased and to provide valid significance tests. However, the power to detect changes in trend is rather limited, especially in small states. Using these methods, separate analyses of White IMRs in 49 states and non-White IMRs in 30 states were completed. Nine states are identified which had infant mortality trends less favorable than the national experience and 1981-83 rates more than 5 per cent above the national average.     

婴儿死亡率与新生儿死亡比的关系

目的:探讨婴儿死亡率与新生儿死亡比的关系及成因。方法:从WHO死亡数据库、人口数据库中收集婴儿死亡数、新生儿死亡数和活产数等数据,利用各国的婴儿死亡率-新生儿死亡比散点图分析、归纳两指标的关系,并通过对美国数据的分析探讨成因。结果:入选国家的婴儿死亡率与新生儿死亡比之间是一种曲线关系,随婴儿死亡率的下降,新生儿死亡比先上升至峰值(大致位置:婴儿死亡率为11.42‰、新生儿死亡比为70.32%),后下降至谷值(大致位置:婴儿死亡率为4.86‰、新生儿死亡比为61.22%),再上升。由于各国记录中婴儿死亡率范围的限制,各国散点图都只是完整曲线的一部分。美国新生儿期、新生儿后期主要死因别死亡率的变化导致新生儿期、新生儿后期死亡率大小关系发生变化,进而导致婴儿死亡率与新生儿死亡比呈现曲线关系。结论:婴儿死亡率与新生儿死亡比之间是一种曲线关系,出现原因可能为新生儿期、新生儿后期主要死因别死亡率的变化。婴儿死亡率较低(<11.42‰)的国家和地区需谨慎使用"婴儿死亡率与新生儿死亡比成负相关"的观点。     

Regional disparities in infant mortality in Canada: a reversal of egalitarian trends

Background  

Although national health insurance plans and social programs introduced in the 1960s led to reductions in regional disparities in infant mortality in Canada, it is unclear if such patterns prevailed in the 1990s when the health care and related systems were under fiscal duress. This study examined regional patterns of change in infant mortality in Canada in recent decades.     

Socioeconomic correlates and trends of infant mortality rate in Goa and Kerala

Infant mortality trends are projected for Goa and Kerala states in India for the year 2000. The impact of the net domestic product, the population per doctor, and literacy on infant mortality are assessed. Data are obtained from the Indian Yearbooks for 1990-91. The Gompertz curve was used to project the infant mortality rate per 1000 live births to the year 2000. Infant mortality in the year 2000 was estimated to be 17.02 in Goa and 20.22 in Kerala. A highly significant correlation was found between the infant mortality rate and literacy and the net domestic product in Goa. In Kerala only literacy was statistically significantly related to infant mortality. The population per doctor was found to be significantly positively related to the infant mortality rate in both Goa and Kerala. 82.96% of infant mortality in Goa was explained by the three factors. 79.33% of infant mortality in Kerala was explained by these same factors. The view is taken that program effort should be directed to improving literacy, economic conditions, and medical doctor coverage as a means of reducing infant mortality.     

婴儿期的死亡率特征和死因特征与健康保护

对婴儿生命统计资料进行观察,可以得出结论：传染病、呼吸系病和感染性疾病引起的婴儿死亡已大幅度递减,但生存环境等社会性因素对婴儿生命与健康的损害仍然居高不下,并越来越占主导地位。这个结论表明,随着经济和卫生事业的发展,社会性因素和先天性因素（最终也可追溯到社会性因素）已经成为损害婴儿生命与健康的主要因素。因此,对婴儿实施有效全面的健康保护,不但要继续巩固预防保健成果,而且要对婴儿实行社会化保护,即以生物－心理－社会医学模式的思路规划婴儿健康保护工作。爱婴行动正是对婴儿实施社会化保护的内容之一,它突破了单纯从医学角度实施婴儿健康保护的界限,是以社会为舞台进行婴儿健康保护的伟大实践     

The lowest birth-weight infants and the US infant mortality rate: NCHS 1983 linked birth/infant death data.

The National Center for Health Statistics Linked Birth and Infant Death Data Set, 1983 birth cohort, shows that infants weighing less than 750 g, comprising only 0.3% of all births, account for 25% of deaths in the first year of life and for 41% of deaths in the first week. If interventions had prevented the death of these very small babies, the infant mortality rate would have been 8.3 per 1000 live births instead of 10.9, and the Black/White mortality differential would have been reduced by 25%.     

Patterns of infant mortality and cancer death in Alabama, USA

Aim  To use recent information of infant and cancer mortality in Alabama counties of the USA to test their relationships with social, economic, and environmental conditions at a large scale to identify potential public health issues. Subjects and methods  The data of infant mortality rates and cancer deaths in the recent years, biodiversity, including species number of plants, fishes, reptiles, and amphibians, roadless areas, metropolitan areas, river basins, African-American and minority populations, and per person income for all 67 Alabama counties were obtained and organized by geographic information system. The relationships between infant mortality rates and cancer deaths and social, economic, and environmental conditions at a large scale were analyzed. Results  Infant mortality was significantly higher in African-American and other minority populations than in white populations, but cancer mortality was higher in white populations than in African-American and minority populations. There was no significant difference in infant mortality rate between populations in the urban areas and the rural areas, but the mortality rate of cancers was significantly higher in the rural population than in the urban population. Mortality rates for cancers in wealthy counties were lower than in poorer counties. The incidences of infant and cancer mortality were lower in counties with higher biodiversity. The emergent spatial pattern suggests that the incidences of infant and cancer mortality were higher in the Sipsey/Warrior River Basin, Coosa/Tallapoosa River Basin, and Conecuh River Basins. Conclusion  This study indicates that ethnic disparities in infant and cancer mortality still exist in Alabama. This study also suggests that pattern analyses at larger scales can provide new insight for understanding public health.     

Postneonatal mortality, sudden infant death syndrome: factors preventing the decline of infant mortality in France from 1979 to 1985

The sudden infant death syndrome (SIDS) is known to be associated with a peak in mortality rates at 3 months of age, and a seasonal peak in winter. The aim of this study was to analyse the relationship between the month of death, month of birth and age at death for cohorts of monthly births in France between 1979 and 1985. Statistics concerning the causes of death were collected and used to calculate life-tables firstly from SIDS and secondly from all other causes. They show that the specific age distribution at death was not the same for babies born in late summer or autumn as for other newborns. Total infant death rates were higher for cohorts born in the autumn, because of the peak in deaths from SIDS at about three months of age.     

A comparison of recent trends in infant mortality among twins and singletons

Overall infant mortality rates have steadily declined in recent years. The goal of this study was to examine whether recent declines in infant mortality were similar for twins and singletons, and to assess the impact of differing birthweight distributions on these relationships. Linked birth and infant death records for 1985-86 and 1995-96 were used to calculate infant mortality rates for twins and singletons for the two time periods. Bootstrap simulations were used to estimate rates of decrease between the two time periods and to determine whether these rates differed between twins and singletons. Between 1985-86 and 1995-96, infant mortality among twins declined significantly faster than among singletons (36% vs. 29%, P < 0.05). This difference was true for both black and white infants (black: 28% for twins vs. 22% for singletons; white: 38% for twins vs. 31% for singletons). Within birthweight categories, infant mortality declined more rapidly among twins than among singletons, although differences were not always significant. Factors and circumstances that contributed to the infant mortality decline in the United States have benefited twins to a greater extent than singletons.     

Importance of the first day death rate in infant mortality

The conventional partition of infant mortality into neonatal and postneonatal deaths, with the 28th day postpartum as the dividing line, has lost much of its epidemiological rationale in countries with low infant death rates. Infant deaths are concentrated increasingly at the start of the neonatal period: one out of three infant deaths in the United States occurs during the first 24 hours. Circumstances of early neonatal deaths differ considerably from those of later neonatal deaths. Failure to monitor separately early and late neonatal mortality can compromise the recognition of distinct epidemiological patterns. Racial disparities in the US tend to be larger for first day deaths than for any other infant deaths. Total US infant mortality declined rapidly in the 1950s and 1960s but first day deaths rose at a steady pace. Surveillance of infant mortality, whether on the national or the community level, should encompass first day, first month and first year death rates.     

Economic status differences in infant mortality by cause of death

Infant mortality differentials in a metropolitan aggregate of eight Ohio cities were examined for the years 1979-81. The primary analytical unit was the census tract of mother's usual residence. The independent variable was defined as the percentage of low-income families in each tract at the 1980 census. Results of the analysis revealed that in spite of some very substantial declines in the overall level of infant mortality in recent decades, there continues to be a pronounced inverse association between the aggregate economic status of an area and the probability that a newborn infant will not survive the first year of life. This inverse association characterizes both males and females, whites as well as nonwhites, and it is observed during both the neonatal and postneonatal age intervals. Moreover, it is apparent that the adverse influence of a low economic status is reflected in the incidence of mortality from all major exogenous and endogenous causes. Since these two cause groups have such different underlying determinants, this finding has important implications for the development and implementation of specific maternal and child health care policies and programs.     

Cohort-specific trends in stroke mortality in seven European countries were related to infant mortality rates

OBJECTIVES: To assess, in a population-based study, whether secular trends in cardiovascular disease mortality in seven European countries were correlated with past trends in infant mortality rate (IMR) in these countries. STUDY DESIGN AND SETTING: Data on ischemic heart disease (IHD) and stroke mortality in 1950-1999 in the Netherlands, England & Wales, France, and four Nordic countries were analyzed. We used Poisson regression to describe trends in mortality according to birth cohort, for the cohorts born between 1860 and 1939. Pearson correlation coefficients were calculated to determine associations between IMR and IHD, or stroke mortality. RESULTS: IHD mortality increased for successive cohorts up to 1900, and then started to decline. Stroke mortality levels were virtually stable among birth cohorts up to 1880, but declined rapidly among later cohorts. A strong positive association was found between cohort-specific IMR levels and stroke mortality rates. There were no strong cohort-wise associations between IMR and IHD mortality. CONCLUSION: These results support other studies in suggesting that living conditions in early childhood may influence population levels of stroke mortality. Future studies should determine the contribution of specific early life factors to the mortality decline in IHD and especially stroke.     

Fertility and infant mortality trends in Nicaragua 1964-1993. The role of women''s education

OBJECTIVES: To assess trends in fertility and infant mortality rates (IMR) in León, Nicaragua, and to examine the effect of women's education on these trends during 1964-1993, a period of rapid social change. DESIGN: Cross sectional survey, based on random cluster sampling. A retrospective questionnaire on reproductive events was used. SETTING: The municipality of León, which is the second largest city in Nicaragua, with a total population of 195,000 inhabitants. SUBJECTS: 10,867 women aged 15-49 years, corresponding to 176,281 person years of reproductive life. Their children contributed 22,899 person years under 12 months of age to the IMR analysis. MAIN OUTCOME MEASURES: Fertility rate (number of pregnancies per 1000 person years) for specific age groups and calendar periods, total fertility rate, and IMR. RESULTS: Fertility rates and IMR declined in parallel, especially during the 1980s. However, education specific fertility rates did not decline, but the proportion of educated young women increased from 20% to 46%. This had also an impact on the overall IMR decline, although IMR reduction mainly took place among infants of women without formal education, decreasing from 118 to 69 per 1000 during the observation period. CONCLUSIONS: In this demographic transition over three decades, fertility and IMR declined simultaneously. The decreasing trend in fertility was mainly explained by an increase in women's education, while the IMR decline seemed to be the result of health interventions, specially targeted to poorer groups of women and their infants. Thus, social differences in fertility rates remained unchanged, while equity in chances of child survival increased.     

Explaining the 2001-02 infant mortality increase: data from the linked birth/infant death data set.

The U.S. infant mortality rate increased from 6.8 infant deaths per 1,000 live births in 2001 to 7.0 in 2002, the first increase in more than 40 years. From 2001 to 2002 infant mortality rates increased for very low birthweight infants as well as for preterm and very preterm infants. Although infant mortality rates for very low birthweight infants increased, most of the increase in the infant mortality rate from 2001 to 2002 was due to a change in the distribution of births by birthweight and, more specifically, to an increase in infants born weighing less than 750 grams (1 lb 10 1/2 oz). The majority of infants born weighing less than 750 grams die within the first year of life; thus, these births contribute disproportionately to the overall infant mortality rate. Increases in births at less than 750 grams occurred for non-Hispanic white, non-Hispanic black, and Hispanic women. Most of the increase occurred among mothers 20-34 years of age. Although multiple births contributed disproportionately, most of the increase in births at less than 750 grams occurred among singletons. Three hypotheses were evaluated to assess their possible impact on the increase in less than 750-gram births: first, possible changes in the reporting of births or fetal deaths; second, possible changes in the risk profile of births; and third, possible changes in medical management of pregnancy. Although each of these factors may have contributed to the increase, the relative effects of these and other factors remain unclear. More-detailed studies are needed to further explain the 2001-02 infant mortality increase.