Introducing new data on gestation-specific infant mortality among babies born in 2005 in England and Wales

Gestational age is highly correlated with birth outcomes including birthweight and infant mortality. Since gestational age is not recorded at the registration of live births in England and Wales, it has not been possible to produce routine statistics on gestation-specific infant mortality rates. A new system, introduced in 2002, for allocating NHS numbers at birth (NN4B) provided the opportunity to obtain gestational age information. NN4B records have been linked with birth registration data for all births occurring in 2005, and further linked with registration records for deaths in the first year of life. Thus, for the first time, we produce gestation-specific infant mortality rates for England and Wales as a whole, including in relation to birthweight, multiplicity, age of mother, marital status/registration type, and the National Statistics Socio-Economic Classification.     

Trends in suicide by marital status in England and Wales, 1982-2005

This article examines trends in suicide by marital status in England and Wales over the period 1982 to 2005. A protective effect of marriage has been observed in a number of previous studies and this article updates figures up to 2005. The article shows that despite changes in marriage patterns over the last 25 years, those who are married still have the lowest risk of suicide, and there has generally been no obvious decline in the difference in suicide rates between those who are married and those who are not.     

Classification of births by birth weight and gestational age: an application of multivariate mixture models

BACKGROUND: Classifications such as low birth weight, premature, and small for gestational age. i.e. compromised births, have been criticized because they depend upon arbitrary standards that may not be appropriate for all populations. AIM: This study applies multivariate Gaussian mixture models with covariates to characterize birth weight by gestational age distributions. SUBJECTS AND METHODS: The data consist of Asian, African, Hispanic and European American births in New York State in 1988. The analysis employs maximum likelihood methods. RESULTS: Birth cohorts appear heterogeneous and composed of at least two sub-populations. One sub-population accounts for the majority of births, has a higher mean birth weight and gestational age but small variances. The other sub-population has a lower mean birthweight and gestational age but very large variances. As a result of the large variances this sub-population accounts for compromised births. The model also suggests that a number of compromised births occur within the normal birth weight and gestational age range.Among normal births, birth weight increases and gestational age declines with maternal age. The effects on compromised births vary among populations. CONCLUSIONS: Multivariate Gaussian mixture models provide a method of identifying compromised births that is not dependent upon arbitrary standards.     

Tends in avoidable mortality in England and Wales, 1993-2005

Avoidable mortality is a major public health concern but there has been little consensus among researchers on how it should be defined and reported. In this article two definitions of avoidable mortality are considered. These are used to present trends in avoidable deaths in England and Wales from 1993 to 2005, using two statistical indicators of mortality. Analysis of both definitions shows a substantial decline in causes of mortality that are considered amenable to medical intervention over this period. This article discusses which mortality indicator is most appropriate for measuring avoidable deaths, and highlights key issues in developing a National Statistics definition of avoidable mortality.     

The impact of introducing ICD-10 on analysis of respiratory mortality trends in England and Wales

This article examines the impact of the introduction of ICD-10 on respiratory disease mortality statistics in England and Wales, specifically focussing on pneumonia, chronic lower respiratory diseases, and influenza. The main changes are highlighted and the article explains how figures can be adjusted to take account of these changes so that trends over time can be analysed. The number of deaths assigned to the respiratory disease chapter of the ICD as a whole decreased by 22 per cent as a result of the introduction of ICD-10. Although it is not usually recommended that comparability ratios from the CD-10 bridge-coding study are used to adjust rates prior to 1993, our analysis shows that unadjusted data for 1984 to 1992 can be used to examine longer time trends for respiratory diseases as a whole.     

Anencephalus: variation with maternal age, parity, social class and region in England, Scotland and Wales

The analysis of 491 singleton anencephalic births compared with 16,994 control births has revealed several independent trends within the United Kingdom: (i) There is a strong regional distribution. (ii) There is a rise in incidence with falling social class. (iii) There is a maternal age/parity distribution, whereby the older the primipara the lower is the incidence, but the older the multipara, the higher the incidence.     

The impact of introducing ICD-10 on trends in mortality from circulatory diseases in England and Wales

This article examines the impact of the introduction of ICD-10 on mortality from circulatory diseases in England and Wales. The article examines changes to specific types of circulatory disease, focussing on ischaemic heart disease (IHD) and cerebrovascular disease (stroke). The main changes are highlighted and the article explains how data can be adjusted to take account of these changes so that trends over time can be analysed. The article then looks at the impact of the changes on baselines for Government targets to reduce mortality from circulatory diseases. The number of deaths assigned to circulatory diseases increases by 3-4 per cent as a result of the introduction of ICD-10, replacing ICD-9. For cerebrovascular diseases specifically, the increase is 9 per cent for females and 13 per cent for males. Trends in mortality from IHD are unaffected by the introduction of ICD-10. However, the number of deaths assigned to acute myocardial infarction, which forms part of IHD, decreases by around 10 per cent when ICD-10 is used instead of ICD-9.     

Trends in live births by mother's country of birth and other factors affecting low birthweight in England and Wales, 1983-2001

This article investigates trends in low birthweight singleton live births by mother's country of birth. 11.4 million birth records from registration data in England and Wales from 1983 to 2001 were used. The analysis focuses on births to mothers born in the UK and countries that contribute to the main ethnic minority groups in England and Wales. The results show that the prevalence of low birthweight babies varies by mother's country of birth. Important differentials also exist by mother's age at birth, multiplicity and registration status.