Perspective: Food Environment Research Priorities for Africa-Lessons from the Africa Food Environment Research Network

Over the last 2 decades, many African countries have undergone dietary and nutrition transitions fueled by globalization, rapid urbanization, and development. These changes have altered African food environments and, subsequently, dietary behaviors, including food acquisition and consumption. Dietary patterns associated with the nutrition transition have contributed to Africa's complex burden of malnutrition-obesity and other diet-related noncommunicable diseases (DR-NCDs)-along with persistent food insecurity and undernutrition. Available evidence links unhealthy or obesogenic food environments (including those that market and offer energy-dense, nutrient-poor foods and beverages) with suboptimal diets and associated adverse health outcomes. Elsewhere, governments have responded with policies to improve food environments. However, in Africa, the necessary research and policy action have received insufficient attention. Contextual evidence to motivate, enable, and create supportive food environments in Africa for better population health is urgently needed. In November 2020, the Measurement, Evaluation, Accountability, and Leadership Support for Noncommunicable Diseases Prevention Project (MEALS4NCDs) convened the first Africa Food Environment Research Network Meeting (FERN2020). This 3-d virtual meeting brought researchers from around the world to deliberate on future directions and research priorities related to improving food environments and nutrition across the African continent. The stakeholders shared experiences, best practices, challenges, and opportunities for improving the healthfulness of food environments and related policies in low- and middle-income countries. In this article, we summarize the proceedings and research priorities identified in the meeting to advance the food environment research agenda in Africa, and thus contribute to the promotion of healthier food environments to prevent DR-NCDs, and other forms of malnutrition.

Results of a hypertension and diabetes treatment program in the slums of Nairobi: a retrospective cohort study

Background

Cardiovascular diseases (CVD) are the world’s leading cause of death and their prevalence is rising. Diabetes and hypertension, major risk factors for CVD, are highly prevalent among the urban poor in Africa, but treatment options are often limited in such settings. This study reports on the results of an intervention for the treatment of diabetes and hypertension for adult residents of two slums in Nairobi, Kenya.

Methods

After setting up two clinics in two slums in Nairobi, hypertension and/or diabetes patients were seen by a clinician monthly. Socio-demographic characteristics and clinical data were collected over a 34-month period. Records were analyzed for 726 patients who visited the clinics at least once to determine clinic attendance and compliance patterns using survival analysis. We also examined changes in systolic blood pressure (SBP), diastolic blood pressure (DBP) and random blood glucose (RBG) during the course of the program.

Results

There was poor compliance with clinic attendance as only 3.4 % of patients attended the clinics on a regular (monthly) basis throughout the 34-month period. 75 % of hypertension patients were not compliant after four visits and 27 % of patients had only one clinic visit. Significant reduction of mean SBP and DBP (150.4 mmHg to 141.5 mmHg, P = .003, and 89.3 mmHg to 83.2 mmHg, P < .001) was seen for all patients that stayed in care for at least one year.

Conclusions

Establishing a preventative care and treatment system in low resource settings for CVD is challenging due to high dropout rates and non-compliance. Innovative strategies are needed to ensure that benefits of treatment programs are sustained for long-term CVD risk reduction in poor urban populations.

Profile of people with hypertension in Nairobi's slums: a descriptive study

BACKGROUND

Cardiovascular disease (CVD) is a rising health burden among the world's poor with hypertension as the main risk factor. In sub-Saharan Africa, hypertension is increasingly affecting the urban population of which a substantial part lives in slums. This study aims to give insight into the profile of patients with hypertension living in slums of Nairobi, Kenya.

METHODS

Sociodemographic and anthropometric data as well as clinical measurements including BP from 440 adults with hypertension aged 35 years and above living in Korogocho, a slum on the eastern side of Nairobi, Kenya, will be collected at baseline and at the first clinic visit.

CONCLUSION

The study population showed high prevalence of overweight and abdominal obesity as well as behavioral risk factors such as smoking, alcohol and a low vegetable and fruit intake. Furthermore, the majority of hypertensive patients do not take anti-hypertensive medication and the ones who do show little adherence.

TRIAL REGISTRATION

Current controlled trials ISRCTN84424579 .

Evidence of a Double Burden of Malnutrition in Urban Poor Settings in Nairobi, Kenya

Background

Many low- and middle-income countries are undergoing a nutrition transition associated with rapid social and economic transitions. We explore the coexistence of over and under- nutrition at the neighborhood and household level, in an urban poor setting in Nairobi, Kenya.

Methods

Data were collected in 2010 on a cohort of children aged under five years born between 2006 and 2010. Anthropometric measurements of the children and their mothers were taken. Additionally, dietary intake, physical activity, and anthropometric measurements were collected from a stratified random sample of adults aged 18 years and older through a separate cross-sectional study conducted between 2008 and 2009 in the same setting. Proportions of stunting, underweight, wasting and overweight/obesity were dettermined in children, while proportions of underweight and overweight/obesity were determined in adults.

Results

Of the 3335 children included in the analyses with a total of 6750 visits, 46% (51% boys, 40% girls) were stunted, 11% (13% boys, 9% girls) were underweight, 2.5% (3% boys, 2% girls) were wasted, while 9% of boys and girls were overweight/obese respectively. Among their mothers, 7.5% were underweight while 32% were overweight/obese. A large proportion (43% and 37%%) of overweight and obese mothers respectively had stunted children. Among the 5190 adults included in the analyses, 9% (6% female, 11% male) were underweight, and 22% (35% female, 13% male) were overweight/obese.

Conclusion

The findings confirm an existing double burden of malnutrition in this setting, characterized by a high prevalence of undernutrition particularly stunting early in life, with high levels of overweight/obesity in adulthood, particularly among women. In the context of a rapid increase in urban population, particularly in urban poor settings, this calls for urgent action. Multisectoral action may work best given the complex nature of prevailing circumstances in urban poor settings. Further research is needed to understand the pathways to this coexistence, and to test feasibility and effectiveness of context-specific interventions to curb associated health risks.

Trends in non-communicable disease mortality among adult residents in Nairobi's slums, 2003-2011: applying InterVA-4 to verbal autopsy data

BACKGROUND

About 80% of deaths from non-communicable diseases (NCDs) occur in developing countries such as Kenya. However, not much is known about the burden of NCDs in slums, which account for about 60% of the residences of the urban population in Kenya. This study examines trends in NCD mortality from two slum settings in Nairobi.

DESIGN

We use verbal autopsy data on 1954 deaths among adults aged 35 years and older who were registered in the Nairobi Urban Health and Demographic Surveillance System between 2003 and 2011. InterVA-4, a computer-based program, was used to assign causes of death for each case. RESULTS are presented as annualized cause-specific mortality rates (CSMRs) and cause-specific mortality fractions (CSMFs) by sex.

RESULTS

The CSMRs for NCDs did not appear to change significantly over time for both males and females. Among males, cardiovascular diseases (CVDs) and neoplasms were the leading NCDs--contributing CSMFs of 8 and 5%, respectively, on average over time. Among females, CVDs contributed a CSMF of 14% on average over time, while neoplasms contributed 8%. Communicable diseases and related conditions remained the leading causes of death, contributing a CSMF of over 50% on average in males and females over time.

CONCLUSIONS

Our findings are consistent with the Global Burden of Disease 2010 study which shows that communicable diseases remain the dominant cause of death in Africa, although NCDs were still significant contributors to mortality. We recommend an integrated approach towards disease prevention that focuses on health systems strengthening in resource-limited settings such as slums.

Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013

BACKGROUND

In 2010, overweight and obesity were estimated to cause 3·4 million deaths, 3·9% of years of life lost, and 3·8% of disability-adjusted life-years (DALYs) worldwide. The rise in obesity has led to widespread calls for regular monitoring of changes in overweight and obesity prevalence in all populations. Comparable, up-to-date information about levels and trends is essential to quantify population health effects and to prompt decision makers to prioritise action. We estimate the global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013.

METHODS

We systematically identified surveys, reports, and published studies (n=1769) that included data for height and weight, both through physical measurements and self-reports. We used mixed effects linear regression to correct for bias in self-reports. We obtained data for prevalence of obesity and overweight by age, sex, country, and year (n=19,244) with a spatiotemporal Gaussian process regression model to estimate prevalence with 95% uncertainty intervals (UIs).

FINDINGS

Worldwide, the proportion of adults with a body-mass index (BMI) of 25 kg/m(2) or greater increased between 1980 and 2013 from 28·8% (95% UI 28·4-29·3) to 36·9% (36·3-37·4) in men, and from 29·8% (29·3-30·2) to 38·0% (37·5-38·5) in women. Prevalence has increased substantially in children and adolescents in developed countries; 23·8% (22·9-24·7) of boys and 22·6% (21·7-23·6) of girls were overweight or obese in 2013. The prevalence of overweight and obesity has also increased in children and adolescents in developing countries, from 8·1% (7·7-8·6) to 12·9% (12·3-13·5) in 2013 for boys and from 8·4% (8·1-8·8) to 13·4% (13·0-13·9) in girls. In adults, estimated prevalence of obesity exceeded 50% in men in Tonga and in women in Kuwait, Kiribati, Federated States of Micronesia, Libya, Qatar, Tonga, and Samoa. Since 2006, the increase in adult obesity in developed countries has slowed down.

INTERPRETATION

Because of the established health risks and substantial increases in prevalence, obesity has become a major global health challenge. Not only is obesity increasing, but no national success stories have been reported in the past 33 years. Urgent global action and leadership is needed to help countries to more effectively intervene.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013

BACKGROUND

In 2010, overweight and obesity were estimated to cause 3·4 million deaths, 3·9% of years of life lost, and 3·8% of disability-adjusted life-years (DALYs) worldwide. The rise in obesity has led to widespread calls for regular monitoring of changes in overweight and obesity prevalence in all populations. Comparable, up-to-date information about levels and trends is essential to quantify population health effects and to prompt decision makers to prioritise action. We estimate the global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013.

METHODS

We systematically identified surveys, reports, and published studies (n=1769) that included data for height and weight, both through physical measurements and self-reports. We used mixed effects linear regression to correct for bias in self-reports. We obtained data for prevalence of obesity and overweight by age, sex, country, and year (n=19,244) with a spatiotemporal Gaussian process regression model to estimate prevalence with 95% uncertainty intervals (UIs).

FINDINGS

Worldwide, the proportion of adults with a body-mass index (BMI) of 25 kg/m(2) or greater increased between 1980 and 2013 from 28·8% (95% UI 28·4-29·3) to 36·9% (36·3-37·4) in men, and from 29·8% (29·3-30·2) to 38·0% (37·5-38·5) in women. Prevalence has increased substantially in children and adolescents in developed countries; 23·8% (22·9-24·7) of boys and 22·6% (21·7-23·6) of girls were overweight or obese in 2013. The prevalence of overweight and obesity has also increased in children and adolescents in developing countries, from 8·1% (7·7-8·6) to 12·9% (12·3-13·5) in 2013 for boys and from 8·4% (8·1-8·8) to 13·4% (13·0-13·9) in girls. In adults, estimated prevalence of obesity exceeded 50% in men in Tonga and in women in Kuwait, Kiribati, Federated States of Micronesia, Libya, Qatar, Tonga, and Samoa. Since 2006, the increase in adult obesity in developed countries has slowed down.

INTERPRETATION

Because of the established health risks and substantial increases in prevalence, obesity has become a major global health challenge. Not only is obesity increasing, but no national success stories have been reported in the past 33 years. Urgent global action and leadership is needed to help countries to more effectively intervene.

FUNDING

Bill & Melinda Gates Foundation.

A community-based intervention for primary prevention of cardiovascular diseases in the slums of Nairobi: the SCALE UP study protocol for a prospective quasi-experimental community-based trial

BACKGROUND

The burden of cardiovascular disease is rising in sub-Saharan Africa with hypertension being the main risk factor. However, context-specific evidence on effective interventions for primary prevention of cardiovascular diseases in resource-poor settings is limited. This study aims to evaluate the feasibility and cost-effectiveness of one such intervention--the "Sustainable model for cardiovascular health by adjusting lifestyle and treatment with economic perspective in settings of urban poverty".

METHODS/DESIGN

DESIGN

A prospective quasi-experimental community-based intervention study.

SETTING

Two slum settlements (Korogocho and Viwandani) in Nairobi, Kenya.

STUDY POPULATION

Adults aged 35 years and above in the two communities.

INTERVENTION

The intervention community (Korogocho) will be exposed to an intervention package for primary prevention of cardiovascular disease that comprises awareness campaigns, household screening for cardiovascular diseases risk factors, and referral and treatment of people with high cardiovascular diseases risk at a primary health clinic. The control community (Viwandani) will continue accessing the usual standard of care for primary prevention of cardiovascular diseases in Kenya.

DATA

Demographic and socioeconomic data; anthropometric and clinical measurements including blood pressure. Population-based data will be collected at the baseline and endline--12 months after implementing the intervention. These data will be collected from a random sample of 1,610 adults aged 35 years and above in the intervention and control sites at both baseline and endline. Additionally, operational (including cost) and clinic-based data will be collected on an ongoing basis.

MAIN OUTCOMES

(1) A positive difference in the change in the proportion of the intervention versus control study populations that are at moderate or high risk of cardiovascular disease; (2) a difference in the change in mean systolic blood pressure in the intervention versus control study populations; (3) the net cost of the complete intervention package per disability-adjusted life year gained.

ANALYSIS

Primary outcomes comparing pre- and post-, and operational data will be analyzed descriptively and "impact" of the intervention will be calculated using double-difference methods. We will also conduct a cost-effectiveness analysis of the intervention using World Health Organization guidelines.

DISCUSSION

The outcomes of the study will be disseminated to local policy makers and health planners.

TRIAL REGISTRATION

Current controlled trials ISRCTN84424579.

The magnitude of diabetes and its association with obesity in the slums of Nairobi, Kenya: results from a cross-sectional survey

OBJECTIVES

To assess the prevalence, awareness, treatment and control of diabetes and to examine the relationship of obesity with raised blood glucose in the slums of Nairobi, Kenya.

METHODS

We used data from a cross-sectional population-based survey, conducted in 2008-2009, involving a random sample of 5190 (2794 men and 2396 women) adults aged ≥18 years living in two slums - Korogocho and Viwandani - in Nairobi.

RESULTS

The prevalence (weighted by sampling and response rates) of diabetes was 4.8% (95%CI 4.0-5.7) in women and 4.0% (95%CI 3.3-4.7) in men. Less than a quarter of those found to have diabetes were aware of their condition among which just over half of men and three-quarters of women reported being on any treatment in the 12 months preceding the survey. Overall, fewer than 5% of all people with diabetes had their blood sugar under control. Obesity and overweight were significantly associated with increased odds (1.7, 95%CI 1.1-2.6) of raised blood glucose only among women while adjusting for important covariates.

CONCLUSION

The prevalence of diabetes in this impoverished population is moderately high, while the levels of awareness, treatment and control are quite low. In this population, obesity is an important risk factor for raised blood glucose particularly among women. Prevention and control strategies that target modifiable risk factors for diabetes and increase access to treatment and control in such disadvantaged settings are urgently needed.

Verbal autopsy interpretation: a comparative analysis of the InterVA model versus physician review in determining causes of death in the Nairobi DSS

Background

Developing countries generally lack complete vital registration systems that can produce cause of death information for health planning in their populations. As an alternative, verbal autopsy (VA) - the process of interviewing family members or caregivers on the circumstances leading to death - is often used by Demographic Surveillance Systems to generate cause of death data. Physician review (PR) is the most common method of interpreting VA, but this method is a time- and resource-intensive process and is liable to produce inconsistent results. The aim of this paper is to explore how a computer-based probabilistic model, InterVA, performs in comparison with PR in interpreting VA data in the Nairobi Urban Health and Demographic Surveillance System (NUHDSS).

Methods

Between August 2002 and December 2008, a total of 1,823 VA interviews were reviewed by physicians in the NUHDSS. Data on these interviews were entered into the InterVA model for interpretation. Cause-specific mortality fractions were then derived from the cause of death data generated by the physicians and by the model. We then estimated the level of agreement between both methods using Kappa statistics.

Results

The level of agreement between individual causes of death assigned by both methods was only 35% (κ = 0.27, 95% CI: 0.25 - 0.30). However, the patterns of mortality as determined by both methods showed a high burden of infectious diseases, including HIV/AIDS, tuberculosis, and pneumonia, in the study population. These mortality patterns are consistent with existing knowledge on the burden of disease in underdeveloped communities in Africa.

Conclusions

The InterVA model showed promising results as a community-level tool for generating cause of death data from VAs. We recommend further refinement to the model, its adaptation to suit local contexts, and its continued validation with more extensive data from different settings.