International Journal of Noncommunicable Diseases

REVIEW ARTICLE
Year
: 2021  |  Volume : 6  |  Issue : 4  |  Page : 166--171

Epidemiological transition and the dual burden of communicable and noncommunicable diseases in Zimbabwe


Prosper Nyabani 
 Department of Community Medicine, College of Health Sciences, University of Zimbabwe; Department of Health Studies, College of Human Sciences, University of South Africa

Correspondence Address:
Prosper Nyabani
3369, 259 Close, Kuwadzana 3, P.O.BOX Dzivarasekwa, Harare

Abstract

Background: The epidemiological transition model, coined by Abdel Omran in 1971, building on the demographic transition theory developed by Frank Notestein in 1945, has been largely credited for describing epidemiological situations both globally and nationally in many parts of the world. However, owing to its origins in the United States of America (USA), scholars critique the model's applicability to various geographical, socioeconomic, and epidemiological contexts, which are diversely different from the USA and vary from region to region. It was imperative to test the applicability of this model in sub-Saharan Africa (SSA), particularly Zimbabwe to ascertain versatility in describing epidemiological transitions, predicting population health status and whether the assumption of a shift from communicable diseases (CDs) to noncommunicable diseases (NCDs) could be confirmed in a low-income developing nation focusing on Zimbabwe. Methods: The study was a retrospective document review case study, using the existing framework of the epidemiological transition model, as a guiding principle, applying the model to describe the demographic and epidemiological circumstances prevailing within Zimbabwe. The researcher reviewed, compared, analyzed, and described the existing literature on population dynamics and epidemiological profile of the country for the period 1990–2020. Results: The epidemiological transition model attempts to describe the changes in epidemiological circumstances both at national and global scales. The model presumes a shift in CDs to NCDs. However, many scholars question the applicability of the model to diverse contexts, particularly within the SSA context. The Zimbabwean case was considered in light to its rising population growth, dual burden characterized by a high burden of communicable and rising NCDs. Findings from this study indicate that NCDs are on the rise in Zimbabwe. However, owing to a high burden of CDs, a dual disease burden model is the best fit to explain the epidemiological transition currently obtaining within Zimbabwe. Conclusions: Consequentially, funding streams targeting CDs should take heed of the currently obtaining epidemiological situation in the country and respond by challenging funding to public health interventions with a view to address the rising NCDs. Further, public health authorities should craft Public health policies that create supporting environments conducive for the populace to fight NCDs. Informed by the Ottawa charter, reorientation of health services to ensure more health systems responsiveness in the face of emerging NCDs is imperative. In addition, developing interpersonal skills for individuals to be able to act against NCD's risk behaviors and factors is key; at the same time, strengthening community action by capacitating community health workers to address risk behaviors and factors associated with NCDs at community level is imperative. Finally, the inadequacy of the epidemiological transition model inadvertently challenges epidemiologists to step up efforts to review, refine, and extend the model to suit SSA countries like Zimbabwe and elsewhere countries in similar circumstances.



How to cite this article:
Nyabani P. Epidemiological transition and the dual burden of communicable and noncommunicable diseases in Zimbabwe.Int J Non-Commun Dis 2021;6:166-171


How to cite this URL:
Nyabani P. Epidemiological transition and the dual burden of communicable and noncommunicable diseases in Zimbabwe. Int J Non-Commun Dis [serial online] 2021 [cited 2022 Jan 22 ];6:166-171
Available from: https://www.ijncd.org/text.asp?2021/6/4/166/334619


Full Text



 Introduction and Background



Abdel Omran coined the epidemiological transition model in 1971, its purpose was to explain the significant major epidemiological changes in the world's populations.[1] Omran tracked epidemiological trends in four countries, namely the UK, Japan, Cylon, and Chile, over a period of more than 150 years. From the data he gathered, he postulated three transitional phases, namely, “Age of pestilence and femine,” “age of receding pandemics,” and “the age of degenerative and man made diseases.” Building on the back of the demographic transition theory coined by Frank Notestein in 1945 which explained how fertility and mortality rates impacted the age distribution and growth rate of populations. A change in pattern from one disease to another could offer a plausible explanation to these dynamics. The logical sequence was that population's health was shifting from a high burden of communicable diseases (CDs) to degenerative and noncommunicable diseases (NCDs) accompanied by mortality and fertility rate consequences.[1]

Omran iteratively improved the model several times; following the 1971 proposition.[2],[3] It was clear that the model was inadequate to explain epidemiological variations in diverse settings. Based on that understanding, Omran postulated multiple variants of the model, namely (i) classical or western model, focusing on the US and Western Europe, (ii) the accelerated classical model, suited for Eastern European countries, Japan, and Russia, (iii) the delayed model to explain the developing countries, and the (iv) the transitional variant of the delayed model for some countries with more accelerated transition as in the case of China, Taiwan, and Sri Lanka. Omran admitted that the change could be either faster or slower, but the direction of shift was clearly from CDs to NCDs regardless.[2]

Notwithstanding Omran's model's criticism by many scholars, his work has significantly influenced multiple fields and from its inception to date. Subsequently, the model has been applied to diverse contexts with varying results. Quite a plethora of submissions have been made; Armelagos and Harper (2005)[4] argued that the first transition should be characterized by a shift from agriculture to urbanization, coupled with a rise in CDs, with a second transition parallel and reflecting. Omran's second transition from CDs to NCDs, identified the last transition as characterised by NCDs only. In the present study, the researcher refers to Omran's theory and the three models he presented in 1983. The versatility of the model lies in its ability to adapt to different settings of the developed world, thus a major strength, The model's short fall is in failing to explain the epidemiological transitions in the majority of Sub-Saharan African (SSA) countries such as Zimbabwe, which are grappling with the duet of Communicable and non-communicable diseases.

 Zimbabwe's Epidemiological Landscape



The research study reviewed available data and analyzed it with a view to understand population dynamics and the respective epidemiological context. A sequel of Zimbabwe Health strategy documents and health financing policy documents and various census documents were the main sources of data, which are predominantly available online.[5],[6],[7]

As observed by Santosa, Wall, Fottrell, Högberg, and Byass (2014), human development index (HDI) is important in the population and economic growth of a society, thus consequentially affecting epidemiological status of a population.[8] Noteworthy, Zimbabwe's HDI value for 2019 is 0.571, up from 0.478 to 0.571, an increase of 19.5% between 1990 and 2019, hence placing the country in the medium human development category, thus positioning it at 150 out of 189 countries and territories. Similarly, Zimbabwe's life expectancy at birth increased by 3.4 years, mean years of schooling increased by 3.9 years and expected years of schooling increased by 1.2 years. In addition, gross national income per capita increased by about 42.8% between 1990 and 2019.

 Source: Adopted and Adapted from World Bank, (2020)



Crude death rate dropped from 14.4 to 7.70 per 1000 between 1960 and 2020 [Table 1], notwithstanding fluctuations in between.[9] This represents a 46.5% drop in crude death rate. Correspondingly, the birth rate also dropped from 48 to 29.6 in 1960 and 2020, respectively, although some intermediate fluctuations in between the periods under review [Figure 1]. This is consistent with the works of Bongaarts J and Casterline J (2008), who posits that developing nations, particularly in SSA, have higher population growth.[10] The difference between birth rate and death rate helps to explain the population growth, outside migration.{Table 1}{Figure 1}

 Adopted from World Bank 2018



Population growth of 11.06% from 3.77 to 14.83 in 1960 and 2020, respectively, is a huge rise in population growth, as indicated by UN (2019), Africa is poised for a huge population bulge.[11]

 Adopted and Adapted from Institute for Health Metrics and Evaluation (2016; 2018; 2020) and the Zimbabwe Health Strategy (2021–2025)[12],[13],[14]



CDs occupied the top 6 of the first 10 causes of death in Zimbabwe, both in 1990 and 2010; however, although CDs dropped in 2020, they still occupy the first three positions of top 5 causes of deaths, as shown in [Table 2]. However, only 1 NCD featured in the top ten (10) causes of deaths in Zimbabwe during 1990 and 2010. Anecdotally, five (5) NCDs feature in the top 10 causes of death in Zimbabwe, as depicted above. These findings resonate with the works of Kabatereine et al., (2010) who submits that many developing countries are still heavily burden by CDs.[15]{Table 2}

As expected and confirmed by Sanders et al. (2008),[16] SSA is still under the albatross of HIV/AIDS. HIV/AIDS, lower respiratory infections, and diarrheal diseases have maintained the top three positions across the three decades, thus continuing to burden the health system, as shown below. The combination of 5 CDs and 5 NCDs in Zimbabwe during 2020 indicates the dual burden Zimbabwe's health system has to grapple with regarding prevention, promotion, curative, and rehabilitative services. These findings resonate with this submission that SSA is grappling with a dual burden of CDs and NCDs, [Figure 1] was adopted from World Bank (2020).[17]

In Zimbabwe NCDs, CDs and injuries have a fair share in 2020 at 47.6%, 39.3%, and 13.1%, respectively. This is consistent with the works of Sanders, Fuhrer, Johnson, and Riddle (2008)[16], who observed that majority of developing countries are still grappling with CDs by comparison to developed countries. It is evident that death caused by CDs is still substantially high, leading the pack to nearly half at 47.6%. However, although NCDs are still trailing behind, their contribution nearly two-fifth, at 39.3%, is significantly high to warrant urgent public health attention. Marshall (2004) posits that developing nations continue to grapple with the duality of communicable and NCDs.[18]

Zimbabwe confirmed its first COVID-19 case on March 20, 2020, in Victoria falls.[19] Since then, there has been a high burden of morbidity and mortality associated with COVID-19, although of late, during the month of October 2021, cases seem to have subsided. This pandemic has further strained Zimbabwe's health system that was on the pathway to recovery. Gilbert (2020) recommends that developing countries need to strengthen their health systems to create resilient health systems in the face of the COVID-19 pandemic.[20]

In addition, the slower transition observed could be attributed to slower decline of the CDs, as opposed to a depressed increase in NCDs. Ciccacci, Orlando, Majid, and Marazzi (2020) works posited a similar proposition in their study conducted in Mozambique on a similar research subject.[17] This scenario is driving a dual disease burden in Zimbabwe, a more appropriate model to describe the epidemiological situation in Zimbabwe could be a dual disease burden epidemiological model. Just like some countries in SSA, Zimbabwe is experiencing a population growth, this puts the urban health system under a lot of pressure; Dye (2004) confirms this phenomenon that population growth is accompanied by urbanization, which is associated with a spiral in NCDs due to urban sedentary life.[21] Africa is characterized by population growth.[11] In search of better economic and educational opportunities, rural population migrates to urban areas, thus populations end up concentrated in cities; resultantly, urbanization is at play. Eckert and Kohler (2014) submit that developing countries suffer from the brunt of urbanization and rural to urban migration, thus fueling the emergence of NCDs.[22]

Literature points to a strong correlation between urbanization and behavioral and risk factors, such as alcoholism, smoking, and sedentary life, which are known NCD's risk behaviours contributing to overweight and obesity, strongly associated with mellitus diabetes, hypertension and cardiovascular.[23] This is exacerbated by economic hardship currently experienced in Zimbabwe, leading to drug abuse, strongly related to mental disorders, stress, anxiety, and depression. Based on this evidence, it is plausible that urbanization linked to population growth and the currently prevailing challenging economic conditions will continue to drive both the incidence and prevalence of NCDs within the Zimbabwean context.[4] It is a given that NCDs are on the rise; however, the existential dominance of CDs suggests that the epidemiological transition within the Zimbabwe's context is yet to be fully realized. Debate on the effectiveness of disease-specific funding is characterising the scholarly discourse, with divergent views on the topic. Either way, the dual disease burden model calls for disease-specific funding to pay urgent attention to NCDs, cognisant of the prevailing epidemiological context. Kabatereine Malecela, Lado, Zaramba, Amiel, and Kolaczinski (2010) observed the importance of integrating programs,[15] as opposed to running vertical and parallel programs. As such, integration of interventions that tackle CDs and NCDs is important.

Evidence shows that some interventions have already started to take this direction. Incidentally, it is imperative to reorient health-care services from CDs orientation to a health system that dually addresses both the traditional CDs and emerging NCDs, by creating supporting environments as recommended by the Ottawa Charter (1986), of making the healthier decision, the easier one.[18] This could be achieved through increasing access to fitness centers such as gyms and sporting facilities. In addition, this should be backed up by public health policy, which sets the tone and gives direction regarding ways of tackling NCDs and the underlying risk factors and associated behaviors. Health education (HE) is key in the fight against NCDs given their “silent” nature, HE provides information, thereby developing personal skills, necessary to take the needed action by individuals against NCDs.

Finally, community health workers, who were initially trained to fight CDs such as malaria, through the distribution of insecticides treated bed nets, provision of medication and testing services for malaria and HIV/AIDs, as community cadres embedded within the society, now need to be trained in NCDs prevention activities such as screening and physical activities, thereby strengthening community action.[18]

 Conclusions



Although the model broadly captured the key elements of demography and epidemiology, it had some shortcomings in comprehensively predicting the evolution of health status in Zimbabwe, regarding national response to CDs. Notwithstanding the slow demographic and economic growth, real social development and socio-economic improvement benefits are not equitably shared. It is critical to create the supporting environment as recommended by the Ottawa Charter (1986), the easier choice, in terms of physical activities, access to fitness facilities such as gyms and sporting facilities.[18] In some way, these factors may help explain the slower shift toward NCDs, than expected, Fausto Ciccacci et al. (2020) drew similar conclusions from the study conducted in Mozambique.

Based on these observations, a dual disease burden model could better explain the current prevailing epidemiological transition in Zimbabwe and elsewhere in similar situations. The key implications of this conclusion lie in the public health interventions, health-care policy, and planning.

Zimbabwe offers a graphical example of how global and local should be cognizant of multiple local variables and should always be guided by local demographic, socioeconomic, and epidemiological contexts, in order to craft appropriate health interventions aimed at improving population health.

Ethical approval statement

The study utilised secondary data, hence there was no need for ethical approval, given that the study did not deal directly with human subjects.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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