Estimating the burden of selected non-communicable diseases in Africa: a systematic review of the evidence

Background The burden of non-communicable diseases (NCDs) is rapidly increasing globally, and particularly in Africa, where the health focus, until recently, has been on infectious diseases. The response to this growing burden of NCDs in Africa has been affected owing to a poor understanding of the burden of NCDs, and the relative lack of data and low level of research on NCDs in the continent. Recent estimates on the burden of NCDs in Africa have been mostly derived from modelling based on data from other countries imputed into African countries, and not usually based on data originating from Africa itself. In instances where few data were available, estimates have been characterized by extrapolation and over-modelling of the scarce data. It is therefore believed that underestimation of NCDs burden in many parts of Africa cannot be unexpected. With a gradual increase in average life expectancy across Africa, the region now experiencing the fastest rate of urbanization globally, and an increase adoption of unhealthy lifestyles, the burden of NCDs is expected to rise. This thesis will, therefore, be focussing on understanding the prevalence, and/or where there are available data, the incidence, of four major NCDs in Africa, which have contributed highly to the burden of NCDs, not only in Africa, but also globally. Methods I conducted a systematic search of the literature on three main databases (Medline, EMBASE and Global Health) for epidemiological studies on NCDs conducted in Africa. I retained and extracted data from original population-based (cohort or cross sectional), and/or health service records (hospital or registry-based studies) on prevalence and/or incidence rates of four major NCDs in Africa. These include: cardiovascular diseases (hypertension and stroke), diabetes, major cancer types (cervical, breast, prostate, ovary, oesophagus, bladder, Kaposi, liver, stomach, colorectal, lung and non-Hodgkin lymphoma), and chronic respiratory diseases (chronic obstructive pulmonary disease (COPD) and asthma). From extracted crude prevalence and incidence rates, a random effect meta-analysis was conducted and reported for each NCD. An epidemiological model was applied on all extracted data points. The fitted curve explaining the largest proportion of variance (best fit) from the model was further applied. The equation generated from the fitted curve was used to determine the prevalence and cases of the specific NCD in Africa at midpoints of the United Nations (UN) population 5-year age-group population estimates for Africa. Results From the literature search, studies on hypertension had the highest publication output at 7680, 92 of which were selected, spreading across 31 African countries. Cancer had 9762 publications and 39 were selected across 20 countries; diabetes had 3701 publications and 48 were selected across 28 countries; stroke had 1227 publications and 19 were selected across 10 countries; asthma had 790 publications and 45 were selected across 24 countries; and COPD had the lowest output with 243 publications and 13 were selected across 8 countries. From studies reporting prevalence rates, hypertension, with a total sample size of 197734, accounted for 130.2 million cases and a prevalence of 25.9% (23.5, 34.0) in Africa in 2010. This is followed by asthma, with a sample size of 187904, accounting for 58.2 million cases and a prevalence of 6.6% (2.4, 7.9); COPD, with a sample size of 24747, accounting for 26.3 million cases and a prevalence of 13.4% (9.4, 22.1); diabetes, with a sample size of 102517, accounting for 24.5 million cases and a prevalence of 4.0% (2.7, 6.4); and stroke, with a sample size of about 6.3 million, accounting for 1.94 million cases and a prevalence of 317.3 per 100000 population (314.0, 748.2). From studies reporting incidence rates, stroke accounted for 496 thousand new cases in Africa in 2010, with a prevalence of 81.3 per 100000 person years (13.2, 94.9). For the 12 cancer types reviewed, a total of 775 thousand new cases were estimated in Africa in 2010 from registry-based data covering a total population of about 33 million. Among women, cervical cancer and breast cancer had 129 thousand and 81 thousand new cases, with incidence rates of 28.2 (22.1, 34.3) and 17.7 (13.0, 22.4) per 100000 person years, respectively. Among men, prostate cancer and Kaposi sarcoma closely follows with 75 thousand and 74 thousand new cases, with incidence rates of 14.5 (10.9, 18.0) and 14.3 (11.9, 16.7) per 100000 person years, respectively. Conclusion This study suggests the prevalence rates of the four major NCDs reviewed (cardiovascular diseases (hypertension and stroke), diabetes, major cancer types, and chronic respiratory diseases (COPD and asthma) in Africa are high relative to global estimates. Due to the lack of data on many NCDs across the continent, there are still doubts on the true prevalence of these diseases relative to the current African population. There is need for improvement in health information system and overall data management, especially at country level in Africa. Governments of African nations, international organizations, experts and other stakeholders need to invest more on NCDs research, particularly mortality, risk factors, and health determinants to have evidenced-based facts on the drivers of this epidemic in the continent, and prompt better, effective and overall public health response to NCDs in Africa

Tobacco consumption and nicotine dependence in Bengo Province, Angola: A community-based survey.

There is concern about the potentially increasing use of tobacco in Angola. However, information on the frequency and determinants of this use is not systematised. This study aimed to estimate the prevalence of tobacco consumption and nicotine dependence among smokers in an Angolan population and considering individual socio-demographic and behavioural characteristics. A community-based survey with 2,472 respondents (age range: 15-64 years) was conducted in 2013-2014 in the country's Bengo Province. The collection methodology for assessing each type of tobacco consumption and its daily quantification followed the World Health Organization STEPwise approach to chronic disease risk factor surveillance. The Fagerström Test for Nicotine Dependence was also used to assess smokers. Mean values for prevalence of tobacco use and nicotine dependence were estimated by sex and by previously defined variables. Daily smoking (6.1%) was found to be higher for males (10.0%) them among females (2.6%), and the amount of ex-smokers (7.5%) was higher them smokers. Only 0.2% of those surveyed reported use of smokeless (chewing) tobacco. One-third of ever-smokers reported having started smoking daily before age 18. Nicotine dependence levels were classified as very low or low in 83.6% of the smokers. Daily smoking prevalence increased with age, and was higher in rural areas and among individuals with no formal education, lower incomes, and alcohol consumption. This population presented a low smoking prevalence, along with a low number of daily smoked cigarettes and low levels of nicotine dependency, despite the low prices of, and easy access to, manufactured cigarettes. These two factors conjugated with the current absence of an Angolan policy for tobacco control, enhance the susceptibility for rising overall tobacco use in the near future

Mortalidade por raça/cor: evidências de desigualdades sociais em Vitória (ES), Brasil Mortality by race/color: evidence of social inequalities in Vitória (ES), Brazil

OBJETIVO: Analisar a mortalidade por causa básica, sexo e raça/cor a partir do sistema de informações sobre mortalidade (SIM), em Vitória (ES), no período de 2003 a 2006. MÉTODOS: Foram calculados e analisados os coeficientes de mortalidade, segundo causa básica e sexo por raça/cor, bem como a idade média e mediana de óbito por causa básica, sexo e raça/cor. Foi calculado o risco relativo (RR) por sexo, idade e causa básica (p<0,05 e IC 95%). RESULTADOS: A completitude da variável raça/cor no SIM variou de 1% em 1996 para 81% em 2006. Foi observado maior RR de óbito entre negros para transtornos mentais e comportamentais (RR=9,29), causas mal definidas (RR=8,71) e causas externas (RR=5,71). Entre mulheres negras, as causas externas apresentaram maior RR (2,38). Foi encontrada uma variação de até 33 anos na idade mediana do óbito entre brancos e negros. Conclusão: Este estudo reitera a existência de desigualdades raciais/étnicas na mortalidade, destacando-se a mortalidade por transtornos mentais e causas externas, além da mortalidade precoce que ocorre na população negra.<br>OBJECTIVE: To analyze mortality by cause and sex among groups of race or color from the mortality information system (MIS) in Vitória (Brazil), in the period from 2003 to 2006. METHODS: We calculated and analyzed the mortality rates according to underlying cause, sex and race/color, and the mean and median age of death by underlying cause, sex and race. We calculated the relative risk (RR) for age, sex and underlying cause (p<0.05 and CI 95%). RESULTS: The completeness of race/color in SIM ranged from 1% in 1996 to 81% in 2006. There was a greater RR of death among blacks for mental and behavioral disorders (RR=9.29), Ill-defined causes (RR=8.71), and external causes (RR=5.71). For black women, we highlight the external causes (RR=2.38). We found a variation of up to 33 years (nervous system) between whites and blacks. CONCLUSION: This study confirms the existence of unequal racial/ethnic mortality, highlighting the mortality from mental disorders and external causes, in addition to early mortality that occurs in the black population