Deceleration in the age pattern of mortality at olderages

The rate of mortality increase with age tends to slow down at very old ages. One explanation proposed for this deceleration is the selective survival of healthier individuals to older ages. Data on mortality in Sweden and Japan are generally compatible with three predictions of this hypothesis: (1) decelerations for most major causes of death; (2) decelerations starting at younger ages for more “selective” causes; and (3) a shift of the deceleration to older ages with declining levels of mortality. A parametric model employed to illustrate the third prediction relies on the distinction between senescent and background mortality. This dichotomy, though simplistic, helps to explain the observed timing of the deceleration.     

Age patterns of mortality for older women: an analysis using the age-specific rate of mortality change with age

"In this paper we propose a mortality measure that seems useful in analyzing age patterns of death rates. The measure, which will be denoted by k(x), indicates the proportional increase or decrease with age in the risk of death at a given age x, and is called the age-specific rate of mortality change with age." Estimations are presented for women in 10 countries. "Eight of the selected sets of data are for developed nations in the 1960s and 1970s, and the other two sets of data, for Taiwan, 1931-35, and for Germany, 1910-11, represent relatively high mortality. For France and West Germany, three different periods are included for an investigation of cohort effects on the observed age patterns." Other mathematical models of age-specific mortality rates are discussed and compared. (SUMMARY IN FRE)     

A simple equation for estimating the expectation of life at old ages

Abstract There is much direct and indirect evidence that in a number of populations the ages of older persons tend to be exaggerated, both when reported in censuses and in records of deaths. This results in overestimated expectations of life at old ages. The bias may be corrected by estimating the expectation of life at age a, e(a), from the mortality rate and growth rate at age a and above, M(a+) and r(a+), using the equation developed in this paper: 1/ê(a) = M(a+) exp (β . r(a+). M(a+)(-α)). For a ?, 65, α = 1.4 and β = 0.0951 have been chosen. The value of the equation rests on the following: since ages of older persons tend to be exaggerated, there may be an age a such that most age transfer occurs above that age, and age transfer across the age is small or cancels, so that reasonably accurate values of M(a+) and r(a +) can be obtained, even though ages are badly reported above a. The analysis of artificial data on Gompertzian stable popultions aged over 50 and actual statistics for some selected populations has suggested that the equation provides quite accurate estimates of e(a). The equation also seems useful in closing life tables, since it provides a value of e(a) for the highest age group.     

The narrowing sex differential in life expectancy in high-income populations: Effects of differences in the age pattern of mortality

Using data from the Human Mortality Database for 29 high-income national populations (1751–2004), we review trends in the sex differential in e(0). The widening of this gap during most of the 1900s was due largely to a slower mortality decline for males than females, which previous studies attributed to behavioural factors (e.g., smoking). More recently, the gap began to narrow in most countries, and researchers tried to explain this reversal with the same factors. However, our decomposition analysis reveals that, for the majority of countries, the recent narrowing is due primarily to sex differences in the age pattern of mortality rather than declining sex ratios in mortality: the same rate of mortality decline produces smaller gains in e(0) for women than for men because women's deaths are less dispersed across age (i.e., survivorship is more rectangular).     

A comparison of midwife-led care versus obstetrician-led care for low-risk women in Japan

BackgroundContinuity of midwife-led care is recommended in maternity care because of its various positive outcomes. In Japan, midwife-led care is receiving broad attention as well. In order to popularise midwifery care within the entire system of perinatal care in Japan, there is a need to show evidence that continuity of midwife care for women will bring about positive outcomes.AimThe objectives of this study were to compare the health outcomes of women and infants who received midwife-led care with obstetrician-led care in Japan.MethodsThis was an observational study using non-random purposive sampling with a survey questionnaire. Settings where midwife-led care and obstetrician-led care were chosen by purposive samples. Participants were low-risk women who received antenatal care and delivered a term-singleton-infant at the participating settings during the research period. Measurements were: Women-centred care pregnancy questionnaire, Stein's maternity blues questionnaire, and Edinburgh Postnatal Depression Scale.FindingsMidwife-led care was perceived by women to be beneficial and had no adverse outcomes compared to obstetrician-led care. Main findings are: (1) Perception of Women-centred care was higher; (2) Less premature rupture of membranes, and the Apgar scores of the infants were similar; (3) Exclusively breast-feeding during hospitalisation and at one-month postpartum; (4) Stein's maternity blues scale scores was lower in women who received midwife-led care than those who received obstetrician-led care.ConclusionsContinuity of midwife-led care was perceived by women to be beneficial and had no adverse outcomes. Therefore, midwife-led care in low-risk pregnancy could be applicable and recommended.     

Mortality estimation from registered deaths in less developed countries

Age-specific population growth rates were introduced to demographic analysis in earlier work by Bennett and Horiuchi (1981) and Preston and Coale (1982). In this paper, we derive a method which uses these growth rates to transform what may be a set of incompletely recorded deaths by age into a life table that accurately reflects the true mortality experience of the population under study. The method does not rely on the assumption of stability and, for example, in contrast to intercensal cohort survival techniques, is simple to implement when presented with nontraditional intercensal interval lengths. Thus we can obtain mortality estimates for less developed countries with defective data, despite departures from stability. Further, we assess the sensitivity of the method to violations in various assumptions underlying the procedure: error in estimated growth rates, existence of non-zero net intercensal migration, age dependence in the completeness of death registration, and misreporting of age at death and age in the population. We demonstrate the use of the method in an application to data referring to Argentine females during the period 1960 to 1970.