**2. Increasing urbanization and health consequences in Africa**

While the African continent remains largely rural, it is one of the fastest urbanizing regions in the world [1]. Africa's transition into the 'urban age' is seen in the prolific growth of megacities as well as smaller towns [10]. The urban population increased from 14 to 32% between 1950 and 1990 and is projected to rise to 54.1% by the year 2025 [11]. In absolute terms, the urban population will rise from 395 million in 2010 to 1.339 billion in 2050 [12]. Currently, the continent has seven megacities (cities with populations over 10 million): Cairo, Kinshasa, Lagos, Accra, Johannesburg, –Pretoria and Khartoum with cities such as Lagos having an average annual growth rate of 5.8% (**Table 1**).

Other big cities expected to join the megacity list include Nairobi, Luanda, Dar es Salaam and Addis Ababa [13]. Urbanization trends in most of African


**33**

**Figure 1.**

*Korogocho slums in Nairobi. Credit: APHRC.*

*Non-Communicable Diseases and Urbanization in African Cities: A Narrative Review*

countries are mainly demographically driven without commensurate socioeconomic development [14]. With no massive social, economic and infrastructural transformations in place, growing cities and towns in Africa experience high rates of poverty, unemployment, low wages and inequality [15, 16]. Urbanization in African is rather chaotic and is dogged with complex urban health crises arising from inadequate safe water supply, squalor and shanty settlements (**Figure 1**), poor sanitation, poor solid waste and toxins disposal that contaminates food and water [3]. These living conditions drive a high incidence of

Injuries are also common because of inefficient, congested, and risky transport system [18]. It is estimated that up to 62 percent of SSA's urban population live in informal settlements characterized by pervasive poverty and overcrowding [19]. While the poor in the cities continue to suffer marginalization and experience excess social and economic vulnerability from unstable employment, external shocks such as natural disasters, the affluent section of cities are much more planned and with significant policy attention, and development that ensures healthy living such as presence of walk ways, parks and playing fields (**Figure 2**) [20, 21]. Therefore, the divide between the rich and poor urban dwellers remains wide in African cities, and the extent of inequality reduces access to healthy living as well as essential and quality health services particularly for the poor. Young people face several challenges when transitioning to adulthood

There is substantial evidence from studies conducted in Nairobi slums, indicating an increase of smoking along decreasing social economic status (SES) gradient, and within overcrowded settings, thereby elevating the risks of second hand smoking [22]. While urban poverty remains a critical trigger of NCD risks, the existing obesogenic environments and weak health systems in most of urban Africa portend a bleak future for NCD prevention and control. Studies in Kenya, Ghana and South Africa have also shown that living in a city is associated with higher odds of obesity and cardio-metabolic risk factors [23–25]. Similarly, Peer et al., (2013) [26], in South Africa found that urban environments are associated with an increase in prevalence of the traditional risk factors for NCDs including smoking, harmful alcohol consumption, inadequate physical activity, and inadequate fruit/ vegetable consumption. In addition, early life exposure to urban environment has been linked to an increased risk of obesity and impaired fasting glucose in later

*DOI: http://dx.doi.org/10.5772/intechopen.89507*

infectious diseases [17].

within such settings.

adulthood [27].

#### **Table 1.**

*Urbanization of low-income countries in sub-Saharan Africa.*

#### *Non-Communicable Diseases and Urbanization in African Cities: A Narrative Review DOI: http://dx.doi.org/10.5772/intechopen.89507*

countries are mainly demographically driven without commensurate socioeconomic development [14]. With no massive social, economic and infrastructural transformations in place, growing cities and towns in Africa experience high rates of poverty, unemployment, low wages and inequality [15, 16]. Urbanization in African is rather chaotic and is dogged with complex urban health crises arising from inadequate safe water supply, squalor and shanty settlements (**Figure 1**), poor sanitation, poor solid waste and toxins disposal that contaminates food and water [3]. These living conditions drive a high incidence of infectious diseases [17].

Injuries are also common because of inefficient, congested, and risky transport system [18]. It is estimated that up to 62 percent of SSA's urban population live in informal settlements characterized by pervasive poverty and overcrowding [19]. While the poor in the cities continue to suffer marginalization and experience excess social and economic vulnerability from unstable employment, external shocks such as natural disasters, the affluent section of cities are much more planned and with significant policy attention, and development that ensures healthy living such as presence of walk ways, parks and playing fields (**Figure 2**) [20, 21]. Therefore, the divide between the rich and poor urban dwellers remains wide in African cities, and the extent of inequality reduces access to healthy living as well as essential and quality health services particularly for the poor. Young people face several challenges when transitioning to adulthood within such settings.

There is substantial evidence from studies conducted in Nairobi slums, indicating an increase of smoking along decreasing social economic status (SES) gradient, and within overcrowded settings, thereby elevating the risks of second hand smoking [22]. While urban poverty remains a critical trigger of NCD risks, the existing obesogenic environments and weak health systems in most of urban Africa portend a bleak future for NCD prevention and control. Studies in Kenya, Ghana and South Africa have also shown that living in a city is associated with higher odds of obesity and cardio-metabolic risk factors [23–25]. Similarly, Peer et al., (2013) [26], in South Africa found that urban environments are associated with an increase in prevalence of the traditional risk factors for NCDs including smoking, harmful alcohol consumption, inadequate physical activity, and inadequate fruit/ vegetable consumption. In addition, early life exposure to urban environment has been linked to an increased risk of obesity and impaired fasting glucose in later adulthood [27].

**Figure 1.** *Korogocho slums in Nairobi. Credit: APHRC.*

*Public Health in Developing Countries - Challenges and Opportunities*

authors' own experiences on the subject in Africa.

annual growth rate of 5.8% (**Table 1**).

*Figures in parenthesis are estimates of total population in millions.*

*Urbanization of low-income countries in sub-Saharan Africa.*

NCDs represent a leading threat to human health and development [6]. In 2015 alone, four major NCDs-cardiovascular diseases (CVDs), cancers, diabetes, and chronic respiratory diseases accounted for 72% of all deaths globally; 85% of these were from low and middle income countries (LMICs) [7]. In urban areas of SSA, NCDs are rising faster than anywhere else in the world [8]. The economic consequences of NCDs are enormous across the globe, and are felt at the individual, household, community and health systems levels. Bloom et al. (2011) [9], estimated that economic losses due to NCDs could amount to approximately 75% of the global GDP. While there is wider recognition of the increasing burden of NCDs across Africa [5], scanty literature exists on the link between urban environments and NCD risks in Africa, as well as the associated health and social consequences, and access to health services. Considering that future population growth will take place predominantly in African cities, there is need for a deeper understanding of urban health and the context of NCDs in African cities to identify tailored interventions to curb the epidemic. Urbanization in sub-Saharan Africa provides a unique opportunity to explore the mechanisms by which urban environment influences NCD

This chapter describes both the health determinants and outcomes in African cities with special attention to low-income urban areas. It further highlights the burden, impact and possible interventions for NCDs in African cities. The chapter draws on insights from relevant peer-reviewed and gray literature on NCDs, and the

While the African continent remains largely rural, it is one of the fastest urbanizing regions in the world [1]. Africa's transition into the 'urban age' is seen in the prolific growth of megacities as well as smaller towns [10]. The urban population increased from 14 to 32% between 1950 and 1990 and is projected to rise to 54.1% by the year 2025 [11]. In absolute terms, the urban population will rise from 395 million in 2010 to 1.339 billion in 2050 [12]. Currently, the continent has seven megacities (cities with populations over 10 million): Cairo, Kinshasa, Lagos, Accra, Johannesburg, –Pretoria and Khartoum with cities such as Lagos having an average

Other big cities expected to join the megacity list include Nairobi, Luanda, Dar es Salaam and Addis Ababa [13]. Urbanization trends in most of African

**1970 1991 2000 1970–**

Kenya 10 24 (25) 32 (34) 8.5 7.8 7 Zimbabwe 17 28 (10) 35 (12) 5.6 5.8 5.4 Nigeria 20 36 (99) 43 (128) 6.1 5.8 5.4

**Urban population average annual growth rate**

> **1980– 1990**

**1991– 2000**

**1980**

28 39 (3127) −3686 3.7 5 2.4

**Urban population as a percentage of total population\***

**2. Increasing urbanization and health consequences in Africa**

**32**

*\**

**Table 1.**

Low-income countries

epidemiology.

**Figure 2.** *A section of the Nairobi Central Business District (CBD).*
