Noncommunicable Diseases: An overview of Africa’s new silent killers Introduction H eart disease, stroke, cancer, diabetes and other chronic diseases are often thought to be public health problems of significance only in high-income countries. In reality, only 20% of chronic disease deaths occur in high-income countries, while 80% occur in low- and middle-income countries where most of the world’s populations live.1 Moreover, as described in detail in the WHO publication “Preventing chronic diseases: a vital investment,” the impact of chronic diseases in many low- and middle-income countries is steadily growing. In these countries, around 28 million people died in 2005 from a chronic disease, and cardiovascular disease alone killed five times as many people as HIV/AIDS. In these settings, middle-aged adults are especially vulnerable to chronic disease. Thus, people tend to develop disease at younger ages, suffer longer and die sooner than those in high-income countries. This undermines countries’ economic development as many of those affected are at the peak of their productive and economic activity. African Health Monitor January-June 2008 * Dr Matshidiso Moeti Noncommunicable diseases are the major cause of death and disability worldwide. The WHO African Region has not been spared this global epidemic. Noncommunicable diseases are debilitating and often present fatal complications such as blindness, renal failure and gangrene leading to lower limb amputations and hemiplegic conditions. In the Region, chronic diseases are projected to account for more than a quarter of all deaths by 2015.2 Chronic disease mortality Noncommunicable diseases, the silent killers, have insidious onset, provide debilitating complications and result in painful deaths. The estimated number of chronic disease-related deaths in the WHO African Region in 2005 was 2 446 0001, 2 (see Figure 1 for other estimates). WHO projects that 28 million people in the Region will die from a chronic disease over the next 10 years. The rate of increase of deaths from chronic diseases will outstrip that from infectious diseases, maternal and perinatal conditions, and nutritional deficiencies more than four-fold in the next 10 years. Most significantly, deaths from diabetes will increase by 42%.1 Figure 1: Projected deaths by cause, all ages, WHO African Region, 2005 Morbidity related to chronic diseases The burden of illness from chronic diseases in the Region is already significant and is set to increase considerably in the next decades, adding to the overwhelming and unmet demand for health services due to communicable diseases. The health care burden will be of a different scale, given the chronic course and the need for longterm and often life-long treatment. Figure 2: New cases of cancer annually Cancer Cancer is an emerging and increasingly serious public health problem in the WHO African Region. Existing data (Globocan 2002) suggest that there were 582 000 new cancer cases in The sub-Saharan Africa in 2002.3 most common cancers recorded were cervical cancer (12%), breast cancer (10%), liver cabcer (8%), Karposi’s sarcoma (5%), non-Hodgkin’s lymphoma (5%) and prostate cancer (5%). In 2007, overall, the most frequently observed cancers were Kaposi’s sarcoma and liver cancer. The commonest cancers in males were Kaposi’s sarcoma and cancers of the liver and prostate; in females, Kaposi’s sarcoma and cancers of the cervix and breast were observed most frequently. Globally, with appropriate interventions and services, one third of cancers can be prevented, one third are curable while the remaining one third are incurable. The situation in Africa is quite different: by the time of diagnosis, 80% to 90% of patients have incurable cancers, with only 10% to 15% being curable when given appropriate treatment.3 This clearly shows that populations in the Region are not benefiting from primary prevention and cure. In 2002, cancer deaths were estimated at 412 100 in sub-Saharan Africa. If interventions to intensify and scale up prevention and treatment are not put in place, it is projected that in the year 2020 there will be 804 000 new cancer cases and 626 400 cancer-related deaths (see Figure 2). African Health Monitor January-June 2008 The main risk factors for cancer are infections such as HIV/AIDS, human papillomavirus, hepatitis, or schistosomiasis; tobacco use; environmental pollution; unhealthy diet; excessive alcohol intake; old age; and lack of physical exercise. Prevention offers the most cost-effective longterm strategy for cancer control. Preventive measures are doubly beneficial as they can also contribute to preventing noncommunicable diseases that share the same risk factors, such as cardiovascular diseases and diabetes. Diabetes Diabetes mellitus is no longer rare in Africa (Figure 3). Meta-analytic estimates and recent investigations based on the WHO STEPwise approach to monitoring risk factors for noncommunicable diseases indicate a mean estimated prevalence of 2.8% in 2000, ranging from 1% in some countries such as Ethiopia, Madagascar, Mali and Niger among others, to as high as 20% in Mauritius and Seychelles. The overall regional prevalence is projected to reach 4.8% in 2030.3 The total number of persons affected globally is projected to rise from 171 million in 2000 to 366 million in 2030 if prevention measures are not scaled up. In Africa, the number of people with diabetes in 2006 was 10.4 million, expected to increase to 18.7 million in 2025. The majority of cases of diabetes in Africa go undetected; the undiagnosed cases are estimated to be as high as 60% to 80% in Cameroon, Ghana and African Health Monitor January-June 2008 Tanzania.5 Undiagnosed diabetes evolves silently into complications such as renal failure, retinopathies, foot disease and disease of the heart. Between 1.4% and 6.7% of diabetic foot cases result in amputation. Annual mortality linked to diabetes worldwide is estimated at more than one million. In some countries in Africa, the mortality rate is very high, more than 40 per 10 000 inhabitants. Figure 3: Diabetes prevalence rate in the WHO African Region Cardiovascular diseases Hypertension is a main physiological risk factor for other cardiovascular diseases (CVDs). It is estimated that more than 20 million people are affected in the African Region, mainly in urban areas. Prevalence ranges from 25% to 35% in adults aged 25 to 64 years.5 Some studies reveal a clear relationship between level of blood pressure, salt and fat consumption, and body weight. Studies in Ghana, Mauritius, South Africa and Zimbabwe show an increase in stroke mortality that could be related to increasing levels of hypertension, obesity, tobacco use and diabetes. Prevention and control of hypertension could avoid at least 250 000 deaths per year.6 Stroke is a major cause of death and the biggest single cause of disability worldwide. Annually, 15 million people suffer a stroke. Of these, 5 million die and another 5 million are left permanently disabled, placing a heavy burden on individuals, families and communities. The African Region has not been spared. Rheumatic heart disease is the most important form of acquired CVD in children and adolescents in sub-Saharan Africa. Several studies show a prevalence of rheumatic heart disease of 15–20 per 1000 population.6 Of the 18 million people currently affected by rheumatic fever or rheumatic heart disease, two thirds are children between 5 and 15 years of age.6 There are around 300 000 deaths each year, with 2 million people requiring repeated hospitalization and 1 million likely to require surgery in the next 5 to 20 years.5 The impact of this disease on patients, families, health systems and society is severe. The increasing burden of CVDs and other chronic diseases in Africa has not been accompanied by corresponding adjustments in health service structures, human resources and service delivery modes. Current health care systems were developed to provide acute, episodic care. They are inadequately designed and resourced to care for people with chronic conditions such as CVD, who require repeated visits, information and counselling on lifestyle changes to minimize complications and support with adherence to treatment and self-care. Conclusion The WHO African Region now faces a double burden of disease. While combating communicable diseases, countries are now confronted with noncommunicable diseases (NCDs) which are projected to increase significantly. They are related to risk factors linked mainly to lifestyles which must be dealt with simultaneously. The NCD burden is likely to be even more untenable in the future if interventions are not immediately intensified and scaled up in countries. Investment in this effort now will yield considerable benefits if the projected morbidity and mortality due to chronic noncommunicable diseases are averted. The WHO Regional Office for Africa strongly advocates for and will support Member States to scale up actions, particularly primary prevention interventions and other cost-effective interventions, in NCD management. These actions need to start immediately. References 1 WHO, Preventing Chronic Diseases: a vital investment, Geneva, World Health Organization, 2005. 2 WHO, Noncommunicable diseases: a strategy for the African Region (AFR/RC50/10), Brazzaville, World Health Organization, Regional Office for Africa, 1990. 3 WHO, Cancer prevention and control in the WHO African Region (AFR/RC57/RT/1), Brazzaville, World Health Organization, Regional Office for Africa, 2007. 4 WHO, Diabetes prevention and control: A strategy for the WHO African Region (AFR/RC57/7), Brazzaville, World Health Organization, Regional Office for Africa, 2007. 5 WHO, Cardiovascular diseases in the African Region: current situation and perspectives (AFR/ RC55/12), Brazzaville, World Health Organization, Regional Office for Africa, 2005. 6 WHO, Cardiovascular diseases in the African Region: current situation and perspectives (AFR/ RC55/12), Brazzaville, World Health Organization, Regional Office for Africa, 2005. * Dr Moeti is the Director, Division of Prevention and Control of Noncommunicable Diseases at the WHO Regional Office for Africa. African Health Monitor January-June 2008