Patterns and variations in the relationship between infant mortality and socioeconomic status

Abstract

This study utilizes an ecological approach based on census tracts of residence to examine the relationship between infant mortality and socioeconomic status in metropolitan Ohio at two points in time (1959–61 and 1969–71). The data presented clearly indicate that the infant mortality rate continues to exhibit a pronounced inverse association with a wide variety of socio‐economic variables. Although there were some notable exceptions and/or variations from the general patterns, a basic inverse relationship was generally found to be characteristic of both neonatal and postnatal components of infant mortality, for both males and females, and for both major exogenous and endogenous causes of death. Of all the variables examined, the one factor that emerged as the strongest and most consistent determinant of census tract variations in infant mortality was the proportion of low income families. Thus, the overriding conclusion suggested by this study is that in spite of such things as continued advances in medicine and public health, the expansion of a variety of social programs during the 1960's, and the recent resumption of a downward trend in the overall infant mortality rate, there has been little if any progress in achieving more equitable life chances for the economically deprived segments of our population.     

The relationship between socioeconomic status and infant mortality in metropolitan Ohio, 1999-2001

Empirical evidence has consistently documented the direct relationship between infant mortality and socioeconomic inequality in the United States and numerous other countries. While the majority of these studies reveal an inverse relationship between socioeconomic level and infant mortality, not even this finding is free from disagreement. Furthermore, the specific nature and magnitude of this relationship has varied over time. This study will examine the relationship between socioeconomic status and infant mortality in metropolitan Ohio by using birth and infant death data centered on the 2000 Census. The analyses presented herein will describe and analyze the relationship between infant mortality and socioeconomic status in metropolitan Ohio in the year 2000. The key finding is that in spite of remarkable declines in infant mortality during the past several decades, most notably in neonatal mortality, there continues to be a pronounced inverse association between the infant death rate and the economic status of a population.     

Teenage fertility, socioeconomic status and infant mortality

This paper examines the relationship between infant mortality and a complex measure of socioeconomic status for evidence of diminution. In data on counties in the US with a minimum of 20 infant deaths over the 5-year period 1971-75, no evidence of a declining relationship between socioeconomic status and infant mortality was found. Both level of community affluence and racial composition of the population exerted direct effects on levels of infant deaths. In addition, both socioeconomic status and racial composition exhibited indirect effects which operated through teenage childbearing. When total infant mortality was subdivided, teenage fertility serves as a mediating variable in the link between socioeconomic status and neonatal mortality, but not for the postneonatal components. Given the nearly equivalent total effect of socioeconomic status on infant mortality, it is concluded that the classic division into neonatal (supposedly a function of biological and genetic agents) and postneonatal (traditionally attributed to social and environmental agents), may be too crude to allow the contemporary effects of the socioenvironmental milieu to be evaluated effectively.     

A methodological note on the relationship between infant mortality and socioeconomic status with evidence from San Antonio, Texas.

A number of previous studies have concluded from social area analyses of medium-size cities that there is no longer a significant correlation between socioeconomic status (SES) and infant mortality in the U.S. To determine if these findings were an artifact of too small samples, the total, neonatal, and postneonatal infant mortality rates were analyzed for 115 census tracts of San Antonio, Texas. The SES of each tract was measured by a score reflecting equally the variables of income, education, and occupation, and allowed assignment of the tracts to 1 of 4 socioeconomic rankings. All 3 infant mortality rates rose as SES decreased, with the most marked relationship being between SES and postneonatal rates. It was also found that of the 3 variables used to measure SES, income bore the strongest relationship to infant mortality. In general it should be noted that social area analysis of infant mortality is limited by the extreme reductions of sample size when additional variables are induced.     

Demographic and socioeconomic factors affecting infant mortality in Egypt

This paper analyses the relative importance of demographic and socioeconomic factors with respect to their role in reducing infant mortality in Egypt. Logit analyses of data from a nationally representative sample of Egyptian households, and for urban and rural households separately, indicate that demographic factors have more effect on infant mortality than socioeconomic factors. The results also show the need to improve housing in urban areas and sewerage systems in rural areas in order to reduce infant mortality. One of the most important policy conclusions, however, concerns the importance of providing a vigorous educational campaign to enlighten mothers and prospective mothers in both rural and urban areas on the positive effects of breast-feeding, longer birth intervals, and fewer children on the survival of infants.     

Racial differences in infant mortality attributable to birth defects in the United States, 1989-2002

BACKGROUND: The objective is to study racial differences in infant mortality attributable to birth defects (IMBD) in the United States. METHODS: We analyzed 1989-1991 and 1995-2002 linked birth/death files for trends and racial differences in IMBD by selected categories of birth defects for infants of non-Hispanic white, non-Hispanic black, and Hispanic mothers. RESULTS: In 1989-2002, the IMBD rates declined. However, the decline in postneonatal mortality attributable to birth defects (PMBD) rate was significantly slower than that of overall postneonatal mortality. The adjusted rate ratio for non-Hispanic black and Hispanic versus non-Hispanic white for neonatal mortality attributable to birth defects (NMBD) remained unchanged from 1989-1991 through 2000-2002. For PMBD, it increased from 0.97 (95% confidence interval [CI], 0.90-1.13) in 1989-1991 to 1.12 (95% CI, 1.04-1.21) in 2001-2002 and from 1.08 (95% CI, 1.00-1.16) to 1.18 (95% CI, 1.10-1.27) for non-Hispanic black and Hispanic, respectively. Infant mortality due to cardiovascular and central nervous system defects were the main contributors to the increased racial disparities in PMBD rates. CONCLUSIONS: The disparity in PMBD between infants of non-Hispanic black and Hispanic mothers and infants of non-Hispanic white mothers increased significantly from 1989-1991 to 2000-2002. Further studies are needed to assess the extent to which delays in care or lack of access to care for infants with birth defects might be contributing to the disparity in IMBD.     

Variation in the relationship between BMI and survival by socioeconomic status in Great Britain

We investigate the relationship between obesity and survival, and the extent to which this relationship varies by socioeconomic status (SES). The underlying model is based on the “Pathways to health” framework in which SES affects health by modifying the relationship between lifestyles and health. We use data from the British Health and Lifestyle Survey (1984–1985) and the longitudinal follow-up in June 2009, and run parametric Gompertz survival models to investigate the association between obesity and survival, also accounting for interactions between obesity and both age and SES. Generally we find that obesity is negatively associated with survival, and that SES is positively associated with survival, in both men and women. The interactions between obesity and SES predict survival among women but not among men. Obesity compared with normal weight is associated with a reduction in survival of 3.3, 3.2 and 2.8 years in men aged 40, 50 and 60 years, respectively. Corresponding numbers among women in the lowest SES group are 13.1, 9.7 and 6.1 years, respectively; in the highest SES group they are 6.2, 3.1 and 0.1 years, respectively, a difference of approximately 6 years between the highest and lowest SES groups.     

The relationship between socioeconomic status and health in two Papua New Guinean populations

Introduction of a cash economy in Melanesia has initiated a broadening range of individual acculturation and affluence. In the course of medical surveys in two Melanesian communities, socioeconomic status was assessed for 1,982 adults and correlated with a variety of biological and medical parameters. In one population that had had only brief exposure to modern technology, we were unable to identity status-dependent medical conditions, but in the other, more economically differentiated group, weight, respiratory disease, anemia, subnutrition, and skin disease demonstrated the biological advantage of the most affluent class. In general, striking differences in health between socioeconomic groups were not revealed in this study and either our investigation of effects of sociocultural change was premature or biological change was too subtle for detection.     

Women's status and infant mortality in rural Colombia

Abstract

This paper investigates the effects of maternal demographic characteristics and social and economic statuses on infant mortality in rural Colombia. Demographic characteristics include the age of the mother, parity and length of preceding interbirth interval, and sex of infant. Measures of women's status at the time of birth include education, wage labor and occupation, economic stratum, place of residence, and whether the mother is living with a husband. The life history data for the study (involving 4,928 births) were collected in 1986 from a representative sample of two cohorts of women resident in rural central Colombia. Overall diflFerentials in infant mortality by measures of women's status are small and are in good part associated with the differing reproductive behaviors of the women and variations in breastfeeding practices. The sharp declines in infant mortality recorded in rural Colombia in recent years appear less related to improved status of women than to reductions in fertility that enhance infant survivorship and to public health interventions shared by all segments of the population.     

Women's status and infant mortality in rural Colombia

This paper investigates the effects of maternal demographic characteristics and social and economic statuses on infant mortality in rural Colombia. Demographic characteristics include the age of the mother, parity and length of preceding interbirth interval, and sex of infant. Measures of women's status at the time of birth include education, wage labor and occupation, economic stratum, place of residence, and whether the mother is living with a husband. The life history data for the study (involving 4,928 births) were collected in 1986 from a representative sample of two cohorts of women resident in rural central Colombia. Overall differentials in infant mortality by measures of women's status are small and are in good part associated with the differing reproductive behaviors of the women and variations in breastfeeding practices. The sharp declines in infant mortality recorded in rural Colombia in recent years appear less related to improved status of women than to reductions in fertility that enhance infant survivorship and to public health interventions shared by all segments of the population.     

The age-cause proxy relationship in infant mortality

Data presented in this brief note show that one of the consequences of recent gains in the control of neonatal mortality has been an increase in the frequency of endogenous causes of death in the postneonatal period. Several conclusions are readily apparent from the data presented here. 1st, with respect to total infant mortality, the vast majority of the deaths under 1 year of age today are caused by the endogenous conditions that are most closely associated with the physiological processes of gestation and births. 2nd, both the exogenous and endogenous cause-specific death rates are inversely associated with family income status. The strength of the relationship, as measured by the difference between the death rates of the highest and lowest income areas, is much greater for the environmentally related exogenous causes. Further, there is an obvious tendency for the exogenous causes to account for an increasing proportion of total deaths as income status decreases. While these data support research findings that challenge the validity of the traditional age/cause of death proxy relationship in infancy, they suggest that recommendations for enhancing the neonatal/endogenous relationship by shortening the neonatal period may be premature.     

Racial/ethnic disparities in infant mortality: the role of behavioral factors

Using the National Maternal and Infant Health Survey 1988 (NMIHS), a nationally representative sample of mothers, we investigate the role of behavioral factors in explaining racial/ethnic disparities in infant mortality. In particular, we focus on the following variables: weight gain during pregnancy, prenatal care utilization, exercise, vitamin use, and substance use during pregnancy. These analyses are conducted by modeling both time of death (neonatal vs. postneonatal) and cause of death (infections, perinatal complications, delivery complications, congenital malformations, SIDS, other causes) outcomes. Our results suggest that behavioral factors are partially responsible for observed race/ethnic differentials in infant mortality, but are not as important as sociostructural determinants such as SES.     

Determinants of infant and early childhood mortality in Cameroon: The role of socioeconomic factors,housing characteristics,and immunization status

Abstract

This study examines factors impinging on the survival of children in Cameroon using longitudinal data collected by the United Nations Demographic Training and Research Institute of Yaounde, Cameroon. It deals especially with the role of socioeconomic factors (mother's education, employment, marital status, ethnicity, and household income), housing characteristics (construction materials, power source, source of water supply, extent of crowding), and immunization status on infant and child mortality. Two‐state parametric and nonparametric hazards models for the risk of death at any time within the course of the study are used, with and without accounting for unmeasured heterogeneity. Overall, overcrowding has robust deleterious effects on infant and child survival. As regards the effects of socioeconomic variables, the robustness of the effects of household income and ethnic differentials are unchanged, even after controlling for unmeasured heterogeneity; the deleterious effects of marital status are also apparent, but these effects are largely explained by unmeasured covariates. The data also suggest that the protective effects of full immunization status are robust and not contaminated by confounding factors, at least in the first 16 months of life. These findings provide solid ground to support immunization programs and efforts as a means to reduce significantly infant and child mortality.     

Sex/gender and socioeconomic differences in the predictive ability of self-rated health for mortality

Background

Studies have reported that the predictive ability of self-rated health (SRH) for mortality varies by sex/gender and socioeconomic group. The purpose of this study is to evaluate this relationship in Japan and explore the potential reasons for differences between the groups.

Methodology/Principal Findings

The analyses in the study were based on the Aichi Gerontological Evaluation Study''s (AGES) 2003 Cohort Study in Chita Peninsula, Japan, which followed the four-year survival status of 14,668 community-dwelling people who were at least 65 years old at the start of the study. We first examined sex/gender and education-level differences in association with fair/poor SRH. We then estimated the sex/gender- and education-specific hazard ratios (HRs) of mortality associated with lower SRH using Cox models. Control variables, including health behaviors (smoking and drinking), symptoms of depression, and chronic co-morbid conditions, were added to sequential regression models. The results showed men and women reported a similar prevalence of lower SRH. However, lower SRH was a stronger predictor of mortality in men (HR = 2.44 [95% confidence interval (CI): 2.14–2.80]) than in women (HR = 1.88 [95% CI: 1.44–2.47]; p for sex/gender interaction = 0.018). The sex/gender difference in the predictive ability of SRH was progressively attenuated with the additional introduction of other co-morbid conditions. The predictive ability among individuals with high school education (HR = 2.39 [95% CI: 1.74–3.30]) was similar to that among individuals with less than a high school education (HR = 2.14 [95% CI: 1.83–2.50]; p for education interaction = 0.549).

Conclusions

The sex/gender difference in the predictive ability of SRH for mortality among this elderly Japanese population may be explained by male/female differences in what goes into an individual''s assessment of their SRH, with males apparently weighting depressive symptoms more than females.