Non-communicable disease mortality trends in South Africa reveals different stages of epidemiological transition B Nojilana MPH, Pillay-van Wyk PhD, J D Joubert PhD, RA Roomaney MPH, D Bradshaw DPhil Introduction Accounting for relatively low proportions of the total deaths in low income countries, a high proportion of the global non-communicable disease (NCD) burden, none-the-less, occurs in these settings, making the prevention of these conditions an important consideration for improving global health (Beaglehole et al, 2011, WHO, 2013). Mortality estimates from the 2 nd South African National Burden of Disease (SA NBD) Study highlights rapid changing mortality trends in the past 16 years, largely due to the impact of the HIV/AIDS pandemic (Pillay van Wyk et al, 2016). However, they reveal a considerable burden of non-communicable diseases which accounted for 43.4% of all deaths in 2012, higher than the 33.6% of deaths from HIV/AIDS and TB combined. South Africa is an upper middle-income country with a variety of living conditions spanning wealthy and middle-income suburbs, deprived peri-urban areas, rural farms and under-developed rural areas. It has a diverse population, currently totalling approximately 56 million people. Historically, people of Khoi, San, Bantu, European and Indian descent pioneered the country and have been joined by immigrants from most continents (Steyn et al, 2005). According to the 2011 Census, 79% were black African, 9% were coloured, 3% were Indian /Asian and 9% were white 1 (Stats SA, 2017). Males constituted 49% of the population (Ibid). The introduction of a non-racial democracy has marked the start of overcoming the complex systems of neo-colonial and Apartheid repression and oppression that had been endured by the South African population. However, racial classification remains an important influence on the life course in South Africa with population group wealth inequalities remaining. Poverty and inequalities are dominant socio-economic features in South African society: a detailed analysis of poverty in the country highlights the decline in poverty from 66.6% in 2006 to 53.2% in 2011. A reversal has been observed with the poverty headcount increasing to 55.5% in 2015. According to the Stats SA report on poverty between 2006 and 2015 (Stasts SA 2017), black Africans experienced higher proportions of people living below the poverty line (47%) compared to 23% coloured, 1% of Indians and less than 0.5% of white South Africans. The Gini coefficient has declined from 0.72 in 2006 to 0.68 in 2015. From the same report, the estimated percentage of persons vulnerable to hunger has declined from almost 30% in 2002 to 13% in 2016. Urbanisation and migration are also strong demographic features of the South African population, particularly in the post-Apartheid era and following the abolishment of “influx control” legislation that prevented black African population from settling in urban areas. Currently, 62% of the population live in urban areas. Based on indicators such as the Human Development Index, the African continent stands out as being somewhat lower than the global average in terms of health, education and living standards (Adogu et al, 2015). None-the-less, African countries are undergoing varying degrees of human development, and this is accompanied by demographic and epidemiological transition (Omran AR 1971, Mensah &, Mayosi 2011). This transition from infectious diseases to NCDs is posing a major challenge to the health of those affected, but also places an enormous burden on the already stretched and under- resourced health systems (Levitt et al, 2011, Boutayeb A, 2006). 1 The population group classification is based on self-reporting according to the groups defined by the Population Registration Act of 1950, i.e. black African, coloureds (persons of mixed descent), Indian/Asian (persons of Indian descents), white (persons of European descent). This classification is being used to highlight issues that reflect effects of historical disparities, and the authors do not subscribe to this classification for another purpose.
This study aims to explore the differences in population group mortality trends for specific causes and disease categories of NCDs for South Africa for the period 2000 - 2012 from the 2 nd SA NBD Study with a view to informing interventions to reduce the burden and identify trends that might be experienced in other countries in the region as they undergo health transitions. Method The 2nd SA NBD Study used vital registration cause-of-death data from Statistics SA for the period 1997-2012. Detailed analysis of population group was done from 2000 onwards due to the large proportion labelled unknown from 1997-1999. Data integrity was assessed using data cleaning processes and validity checks. Causes of death with multiple underlying causes, were recoded to address identified inconsistencies based on epidemiological and clinical expertise within the team. Adjustments for under-registration of deaths were made using demographic methods. The number of cause-specific non-natural deaths were derived using data from a national survey of mortuaries and a national injury mortality surveillance system. Misclassified HIV/AIDS deaths were identified using a regression approach and these deaths were reallocated to HIV/AIDS. Causes that were not regarded as valid underlying causes of death were redistributed by age, sex and population group. More detail about the cleaning and recoding of the data can be found in the technical report on the cleaning and validation of the data (Pillay van-Wyk, 2014). Causes of death were grouped according to the SA NBD List. This list comprises of 140 single causes of death, 24 disease categories and four broad cause groups. Age-standardised death rates (ASDRs) were calculated using mid-year population estimates (Dorrington, 2013) and the WHO world standard (Ahmed et al, 2001). Population group information was available from 2000 onwards, categorised according to apartheid defined (racial) population groups (see footnote) Results While 43% of all deaths in South Africa in 2012 were due to NCDs, Figure 1 shows a large difference in the proportions of deaths due to NCDs by population group. The proportion for whites and Asians was close to 80% over the whole period, the proportion of deaths among coloureds that were due to NCDs was about 60% and the proportion among Africans was below 40%. This proportion decreased from 1997 to 2005 and then increased, largely reflecting the substantial impact of the HIV/AIDS pandemic and the effect of treatment roll-out. 100 90 80 Percentage deaths (%) 70 60 50 40 30 20 10 0 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Years Africans Whites Asians Coloureds Figure 1: Trends in NCD deaths as a proportion of total deaths by population group, SA NBD 2012
Cardiovascular disease was the major cause of death from NCDs and accounted for 43% of deaths in 2012. The proportion of death by disease category varied by population groups (Fig 1). Cardiovascular disease ranged from 49% for Asians to 38% for coloureds. Mortality from cancer accounted for higher proportions in whites (29%) and coloureds (27%) while it accounted for 19% in Asians and 16% in black Africans. Black Africans had higher mortality from diabetes (10%) while respiratory disease deaths were higher among coloureds (12%) compared to the remaining population groups. Figure 2: Non-communicable disease mortality by disease categories per population group, SA NBD 2012 Figure 3 shows the trends in specific causes of NCDs by population group. Asians have a uniquely high level of ischaemic heart disease (IHD) mortality, which, although declining since 2006, remains high with a rate that is nearly twice as high as that of whites and coloureds. IHD was lowest in black Africans. The mortality rate from cancers was highest in coloureds, followed by whites, and then Asians, with black Africans reporting the lowest rates. Black Africans had the highest mortality rates for cerebrovascular disease (stroke) since 2003 compared to the other population groups. There has, however, been a decline in mortality from stroke in all population.
Figure 3: Trends in selected non-communicable disease age-standardised death rates by population group, SA NBD 2000 - 2012
Recommend
More recommend
