Levels of mortality of the South African aged population using the method of extinct generations

Abstract This paper investigates the reasons for the levelling off of the mortality estimates at the oldest age groups and the possibility of estimating the level of the mortality rates at these ages.The research applies the method of extinct generations to estimate indirectly the population numbers at the oldest-old age groups (75 to 100+) using data on reported deaths alone, and hence, the mortality rates. After observing that the estimated mortality rates are levelling off with age at the advanced ages (age 90 to 100+) due to age exaggeration in both the deaths and the population, the Gompertz curve was fitted to the estimated mortality rates at age groups 75, 80 and 85. Our estimates are generally lower but close to the estimates derived by Dorrington et al., (2004) and the estimates from the United Nations Population Division (UNPD) and the US Census Bureau (USCB) population projections.Keywords: Old age mortality; extinct generations; age exaggeration; completeness; South AfricaRésumé Cet article examine les raisons de la stabilisation des estimations de la mortalité des groupes d’âgede plus vieux et la possibilité d’estimer le niveau de taux de mortalité à ces âges. La recherche applique la méthode des générations éteintespour estimer indirectement les nombres de la population des groupes d’age de plus vieux (75 à 100+) en utilisant seuls les données sur lesdécèsrapportés et donc le taux de mortalité. Après avoir abservé que le taux de mortalité estimés sont nivellés avec l'âge à des âges avancés (âge 90 à 100+) dû à l’exaggeration dans les décès ainsi que dans la poplation, la courbe de Gompertz était ajusté au taux de mortalité estimé aux groupes d’age 75, 80, 85. Nos estimations sont généralement plus faibles mais à proximités des estimations dérivées par Dorrington et al., (2004) et les estimations de la Division de la Population des Nations Unies (UNPD: United Nations Population Division) et le projection de populations du Bureau du recensement des États-Unis (USCB: US Census Bureau)

Old age mortality in South Africa

Includes bibliographical references (leaves 71-74).This study estimates the mortality of the South African oldest old age population (in five year age groups from age 75 up to the open age interval 100 and above) and in the process re-estimates the numbers of people in the population at these ages at the time of the 1996 and 2001 censuses, and the 2007 Community Survey. In countries where the data on the old age population have been verified, it has been observed that the data are marred by errors in the form of age exaggeration, age digit preference, relative under/over count of the population and under-registration of deaths. These errors have been observed to have the net effect of underestimating mortality of the oldest old age groups. The current research applies the method of extinct generations to estimate indirectly the population numbers at the oldest old age groups (75 up to 100 and above) using data on reported deaths alone. Age heaping and year of birth preference in the reported deaths are assessed using ratios of the probability of death estimated from the data. Age exaggeration in the data on reported deaths is assessed using ratios of deaths compared with same ratios from a standard population. Age heaping and year of birth preference in the census/survey population is assessed using the modified Whipple's Index of age accuracy. The Generalized Growth Balance (GGB) and Synthetic Extinct Generations (SEG+delta) methods are applied to adjust for under reporting of deaths and to assess patterns of age exaggeration in the census/survey population. The difference between the estimates of the completeness of reporting of deaths from the two methods is small (less than 1 per cent) and has been observed to have little impact on the mortality estimates. Final estimates of the completeness of reporting of deaths used are those derived using the SEG+delta method. After re-estimating the population numbers and adjusting for completeness of reporting of deaths, mortality rates were then estimated. Results obtained from the method of extinct generations suggest that there is no systematic difference between the census/ survey population and the population numbers estimated from deaths except at ages 95 and above. Measures of age accuracy show that there are patterns of preferring 1910, 1914, 1918, 1920 and 1930 as the years of birth in the census/survey population and these patterns are also found in the registered deaths. The impact of these errors was investigated and the results show that preference of certain years of birth cause fluctuations in the mortality rates. Patterns observed after applying the SEG+delta method suggest that the completeness of reporting of deaths falls with age at the advanced ages (from age 90 and above) and as a result, the estimated mortality rates above this age are lower than those estimated from the United Nations Population Division (UNPD) and US Census Bureau (USCB) population projections, and Dorrington, Moultrie and Timaeus (2004). Conclusions reached are that the mortality rates for the age groups 75 to 89 derived after re-estimating the population numbers and after allowing for the fall in the completeness of reporting of deaths are lower but not significantly different from those inferred from the UNPD and USCB population projections, and estimates derived by Dorrington, Moultrie and Timaeus (2004). The research recommends mortality estimates from the UNPD since they are the closest to the estimates derived using the published census population numbers for the whole period between the nights of 9-10 October 1996 and 9-10 October 2001. However, the research produced better estimates of the oldest old age population numbers relative to the census/survey numbers

Exploring possible influences of HIV/AIDS-related stigma on risky sexual behaviour and childbearing decisions: Cape Town 2002-2009

This dissertation uses survey data to explore HIV/AIDS-related stigma as it is manifested in the general population of young adults in Cape Town and amongst people living with HIV/AIDS (PLWHA) on highly active antiretroviral treatment (HAART) in Khayelitsha (an African township in Cape Town). For the general population, we assessed how 'symbolic stigma' (negative attitudes and moral assessments of PLWHA) was related to risky sexual behaviour and whether this was mediated by perceived risk of HIV infection. For PLWHA, we assessed whether 'internalized stigma' and perceptions of stigmatizing attitudes in the broader population (mediated through disclosure of HIV sero-status to sexual partners and experiences of depression and anxiety symptoms) were associated with condom use. We also assessed the relationship between experiences of stigma, internalization of stigma, perceptions of stigma and childbearing desires of PLWHA The study found out that young Black and Coloured women who held symbolic HIV/AIDS-related stigma attitudes were more likely to perceive themselves at a reduced risk of infection with HIV and continue to engage in risky sexual behaviours. There were indications of possible race-gender differences in perceived risk of HIV infection and the practice of risky sexual behaviours. For PLWHA, there was evidence to suggest that both internalized and perceived stigma deterred women's disclosure of their HIV status to sexual partners. However, disclosure of sero-status to sexual partners did not necessarily translate into initiation of safer sex practices. Results suggest that women in this community were disadvantaged when it came to condom use negotiation. Both internalized stigma and disclosure of HIV status to a sexual partner were associated with higher levels of depression and anxiety symptoms which in turn was associated with inconsistent or no condom use. Results also suggest that there may be pathways connecting internalized stigma and condom use other than experiences of depression/anxiety and disclosure of one's HIV status to a sexual partner. We found various experiences of stigma among people living with HIV/AIDS in Khayelitsha to be associated with both increased and decreased odds of intending to have children (or more children). Experienced stigma was significantly associated with childbearing intentions. However, women's decisions to bear children appeared to be more influenced by whether they had a live-in sexual partner than experiences of stigma. We could not establish statistically significant relationships between perceived stigma and childbearing intentions both independently and after controlling for other variables. Internalized stigma was independently associated with reduced childbearing intentions but not after controlling for other relevant variables. Reported childbearing intentions among this sample of PLWHA were associated with the occurrence of at least one pregnancy after two years but are not statistically significantly related to condom use practices

Levels of mortality of the South African aged population using the method of extinct generations

This paper investigates the reasons for the levelling off of the mortality estimates at the oldest age groups and the possibility of estimating the level of the mortality rates at these ages.The research applies the method of extinct generations to estimate indirectly the population numbers at the oldest-old age groups (75 to 100+) using data on reported deaths alone, and hence, the mortality rates. After observing that the estimated mortality rates are levelling off with age at the advanced ages (age 90 to 100+) due to age exaggeration in both the deaths and the population, the Gompertz curve was fitted to the estimated mortality rates at age groups 75, 80 and 85. Our estimates are generally lower but close to the estimates derived by Dorrington et al., (2004) and the estimates from the United Nations Population Division (UNPD) and the US Census Bureau (USCB) population projections.Cet article examine les raisons de la stabilisation des estimations de la mortalité des groupes d’âgede plus vieux et la possibilité d’estimer le niveau de taux de mortalité à ces âges. La recherche applique la méthode des générations éteintespour estimer indirectement les nombres de la population des groupes d’age de plus vieux (75 à 100+) en utilisant seuls les données sur lesdécèsrapportés et donc le taux de mortalité. Après avoir abservé que le taux de mortalité estimés sont nivellés avec l'âge à des âges avancés (âge 90 à 100+) dû à l’exaggeration dans les décès ainsi que dans la poplation, la courbe de Gompertz était ajusté au taux de mortalité estimé aux groupes d’age 75, 80, 85. Nos estimations sont généralement plus faibles mais à proximités des estimations dérivées par Dorrington et al., (2004) et les estimations de la Division de la Population des Nations Unies (UNPD: United Nations Population Division) et le projection de populations du Bureau du recensement des États-Unis (USCB: US Census Bureau)