Carotid intima media thickness (CIMT) in adults in the AWI-Gen Nairobi site study: Profiles and predictors / Grosor de la íntima-media carotídea (GIMc) en adultos en el estudio del sitio de AWI-Gen en Nairobi: perfiles y factores predictivos

Background: Carotid intima media thickness (CIMT) is used as a marker of subclinical and asymptomatic atherosclerotic vascular disease. Increased CIMT is associated with future cerebrovascular and cardiovascular events. There is limited data on the profile and correlates of CIMT in Africa. The aim of this study was to describe the profile and correlates of CIMT in apparently normal younger-age adults in an urban setting in Kenya. Methods: This study used population-based data collected from 2003 adults between the ages of 40 and 60 years in two slums of Nairobi as part of a genetic study. CIMT was measured using LOGIQ e (GE Healthcare, CT, USA) ultrasound on both left and right carotid arteries, whereby maximum, mean, and minimum values were recorded. Age- and sex-specific CIMT measurements were calculated and their association with basic sociodemographic, behavioral and body composition indicators were investigated. Results: The median (IQR) CIMT were 0.58 (0.51, 0.66) and 0.59 (0.53, 0.66) in men and women, respectively. About 16% of the study population had CIMT greater than 0.7mm, the cut off for higher CIMT. Nearly 60% had CIMT values ≥75th percentile. Age, current use of alcohol, systolic blood pressure, subcutaneous fat thickness, pulse rate and pulse pressure were found to be the main predictors of CIMT in our study population. Conclusion: This study provided population-based reference values and predictors for CIMT for an adult population living in urban poor settings in Kenya. Future studies need to consider biochemical and genetic predictors of CIMT in this population. (AU)

Antecedentes: El grosor de la íntima-media carotídea (GIMc) se utiliza como marcador de la aterosclerosis subclínica y asintomática. El incremento del GIMc está asociado a episodios cerebrovasculares y cardiovasculares futuros. Existen datos limitados sobre el perfil y la correlación del GIMc en África. El objetivo de este estudio fue describir el perfil y la correlación del GIMc en adultos jóvenes aparentemente normales en un contexto urbano de Kenia. Métodos: Este estudio utilizó datos basados en población de 2.003 adultos con edades comprendidas entre 40 y 60 años en dos suburbios de Nairobi, como parte de un estudio genético. El GIMc se midió utilizando el ecógrafo LOGIQ E (GE Healthcare, CT, EE. UU.) en ambas carótidas, izquierda y derecha, donde se registraron los valores máximo, medio y mínimo. Se calcularon las medidas de GIMc específicas de la edad y el sexo, así como su asociación con los indicadores sociodemográficos, conductuales y corporales básicos. Resultados: Los valores medios (RIC) de GIMc fueron 0,58 (0,51, 0,66) y 0,59 (0,53, 0,66) en hombres y mujeres, respectivamente. Cerca del 16% de la población de estudio tuvo un GIMc superior a 0,7mm, siendo el punto de corte de GIMc elevado. Cerca del 60% reflejó valores de GIMc ≥percentil 75. La edad, el consumo actual de alcohol, la presión arterial sistólica, el grosor de la grasa subcutánea, la frecuencia cardiaca y la presión del pulso fueron los principales factores predictivos de GIMc en la población de nuestro estudio. Conclusión: Este estudio aportó valores de referencia basados en población y factores predictivos de GIMc para una población adulta en un entorno urbano de pocos recursos de Kenia. Los estudios futuros deberán considerar los factores predictivos bioquímicos y genéticos de GIMc en dicha población. (AU)

Carotid intima media thickness (CIMT) in adults in the AWI-Gen Nairobi site study: Profiles and predictors.

BACKGROUND: Carotid intima media thickness (CIMT) is used as a marker of subclinical and asymptomatic atherosclerotic vascular disease. Increased CIMT is associated with future cerebrovascular and cardiovascular events. There is limited data on the profile and correlates of CIMT in Africa. The aim of this study was to describe the profile and correlates of CIMT in apparently normal younger-age adults in an urban setting in Kenya. METHODS: This study used population-based data collected from 2003 adults between the ages of 40 and 60 years in two slums of Nairobi as part of a genetic study. CIMT was measured using LOGIQ e (GE Healthcare, CT, USA) ultrasound on both left and right carotid arteries, whereby maximum, mean, and minimum values were recorded. Age- and sex-specific CIMT measurements were calculated and their association with basic sociodemographic, behavioral and body composition indicators were investigated. RESULTS: The median (IQR) CIMT were 0.58 (0.51, 0.66) and 0.59 (0.53, 0.66) in men and women, respectively. About 16% of the study population had CIMT greater than 0.7mm, the cut off for higher CIMT. Nearly 60% had CIMT values ≥75th percentile. Age, current use of alcohol, systolic blood pressure, subcutaneous fat thickness, pulse rate and pulse pressure were found to be the main predictors of CIMT in our study population. CONCLUSION: This study provided population-based reference values and predictors for CIMT for an adult population living in urban poor settings in Kenya. Future studies need to consider biochemical and genetic predictors of CIMT in this population.

Household air pollution in Nairobi's slums: A long-term policy evaluation using participatory system dynamics.

58% of Nairobi's population live in informal settlements in extremely poor conditions. Household air pollution is one of the leading causes of premature death and disease in these settlements. Regulatory frameworks and government budgets for household air pollution do not exist and humanitarian organisations remain largely inattentive and inactive on this issue. The purpose of this paper is to evaluate the effectiveness of potential indoor-air related policies, as identified together with various stakeholders, in lowering household air pollution in Nairobi's slums. Applying a novel approach in this context, we used participatory system dynamics within a series of stakeholder workshops in Nairobi, to map and model the complex dynamics surrounding household air pollution and draw up possible policy options. Workshop participants included community members, local and national policy-makers, representatives from parastatals, NGOs and academics. Simulation modelling demonstrates that under business-as-usual, the current trend of slowly improving indoor air quality will soon come to a halt. If we aim to continue to substantially reduce household PM2.5 levels, a drastic acceleration in the uptake of clean stoves is needed. We identified the potentially high impact of redirecting investment towards household air quality monitoring and health impact assessment studies, therefore raising the public's and the government's awareness and concern about this issue and its health consequences. Such investments, due to their self-reinforcing nature, can entail high returns on investment, but are likely to give 'worse-before-better' results due to the time lags involved. We also discuss the usefulness of the participatory process within similar multi-stakeholder contexts. With important implications for such settings this work advances our understanding of the efficacy of high-level policy options for reducing household air pollution. It makes a case for the usefulness of participatory system dynamics for such complex, multi-stakeholder, environmental issues.

Body mass index and wealth index: positively correlated indicators of health and wealth inequalities in Nairobi slums.

INTRODUCTION: Wealth index is a known predictor of body mass index (BMI). Many studies have reported a positive association between BMI and socioeconomic status (SES). However, an in-depth investigation of the relationship between BMI and wealth index is lacking for urban slum settings. OBJECTIVE: To examine the association between BMI and wealth index in an urban slum setting in Nairobi, Kenya. METHODS: A total of 2003 adults between 40 and 60 years of age were included. BMI was derived from direct weight and height measurements. Wealth Index was computed using the standard principal component analysis of household amenities ownership. The relationship between BMI and wealth index was assessed using both linear and logistic regression models. RESULTS: We found that BMI linearly increased across the five quintiles of wealth index in both men and women, after adjusting for potential confounding factors. The prevalence of obesity increased from 10% in the first wealth quintile to 26.2% in the fifth wealth quintile. The average BMI for women entered the overweight category at the second quintile wealth status, or the third quintile for the total population. CONCLUSION: There exists a strong positive relationship between BMI and wealth index in slum settings. Health promotion interventions aimed at reducing obesity may consider using wealth index in priority setting.

Potential effectiveness of Community Health Strategy to promote exclusive breastfeeding in urban poor settings in Nairobi, Kenya: a quasi-experimental study.

Early nutrition is critical for later health and sustainable development. We determined potential effectiveness of the Kenyan Community Health Strategy in promoting exclusive breastfeeding (EBF) in urban poor settings in Nairobi, Kenya. We used a quasi-experimental study design, based on three studies [Pre-intervention (2007-2011; n=5824), Intervention (2012-2015; n=1110) and Comparison (2012-2014; n=487)], which followed mother-child pairs longitudinally to establish EBF rates from 0 to 6 months. The Maternal, Infant and Young Child Nutrition (MIYCN) study was a cluster randomized trial; the control arm (MIYCN-Control) received standard care involving community health workers (CHWs) visits for counselling on antenatal and postnatal care. The intervention arm (MIYCN-Intervention) received standard care and regular MIYCN counselling by trained CHWs. Both groups received MIYCN information materials. We tested differences in EBF rates from 0 to 6 months among four study groups (Pre-intervention, MIYCN-Intervention, MIYCN-Control and Comparison) using a χ(2) test and logistic regression. At 6 months, the prevalence of EBF was 2% in the Pre-intervention group compared with 55% in the MIYCN-Intervention group, 55% in the MIYCN-Control group and 3% in the Comparison group (P<0.05). After adjusting for baseline characteristics, the odds ratio for EBF from birth to 6 months was 66.9 (95% CI 45.4-96.4), 84.3 (95% CI 40.7-174.6) and 3.9 (95% CI 1.8-8.4) for the MIYCN-Intervention, MIYCN-Control and Comparison group, respectively, compared with the Pre-intervention group. There is potential effectiveness of the Kenya national Community Health Strategy in promoting EBF in urban poor settings where health care access is limited.

H3Africa AWI-Gen Collaborative Centre: a resource to study the interplay between genomic and environmental risk factors for cardiometabolic diseases in four sub-Saharan African countries.

Africa is experiencing a rapid increase in adult obesity and associated cardiometabolic diseases (CMDs). The H3Africa AWI-Gen Collaborative Centre was established to examine genomic and environmental factors that influence body composition, body fat distribution and CMD risk, with the aim to provide insights towards effective treatment and intervention strategies. It provides a research platform of over 10 500 participants, 40-60 years old, from Burkina Faso, Ghana, Kenya and South Africa. Following a process that involved community engagement, training of project staff and participant informed consent, participants were administered detailed questionnaires, anthropometric measurements were taken and biospecimens collected. This generated a wealth of demographic, health history, environmental, behavioural and biomarker data. The H3Africa SNP array will be used for genome-wide association studies. AWI-Gen is building capacity to perform large epidemiological, genomic and epigenomic studies across several African counties and strives to become a valuable resource for research collaborations in Africa.

Vulnerability to food insecurity in urban slums: experiences from Nairobi, Kenya.

Food and nutrition security is critical for economic development due to the role of nutrition in healthy growth and human capital development. Slum residents, already grossly affected by chronic poverty, are highly vulnerable to different forms of shocks, including those arising from political instability. This study describes the food security situation among slum residents in Nairobi, with specific focus on vulnerability associated with the 2007/2008 postelection crisis in Kenya. The study from which the data is drawn was nested within the Nairobi Urban Health and Demographic Surveillance System (NUHDSS), which follows about 70,000 individuals from close to 30,000 households in two slums in Nairobi, Kenya. The study triangulates data from qualitative and quantitative sources. It uses qualitative data from 10 focus group discussions with community members and 12 key-informant interviews with community opinion leaders conducted in November 2010, and quantitative data involving about 3,000 households randomly sampled from the NUHDSS database in three rounds of data collection between March 2011 and January 2012. Food security was defined using the Household Food Insecurity Access Scale (HFIAS) criteria. The study found high prevalence of food insecurity; 85% of the households were food insecure, with 50% being severely food insecure. Factors associated with food security include level of income, source of livelihood, household size, dependence ratio; illness, perceived insecurity and slum of residence. The qualitative narratives highlighted household vulnerability to food insecurity as commonplace but critical during times of crisis. Respondents indicated that residents in the slums generally eat for bare survival, with little concern for quality. The narratives described heightened vulnerability during the 2007/2008 postelection violence in Kenya in the perception of slum residents. Prices of staple foods like maize flour doubled and simultaneously household purchasing power was eroded due to worsened unemployment situation. The use of negative coping strategies to address food insecurity such as reducing the number of meals, reducing food variety and quality, scavenging, and eating street foods was prevalent. In conclusion, this study describes the deeply intertwined nature of chronic poverty and acute crisis, and the subsequent high levels of food insecurity in urban slum settings. Households are extremely vulnerable to food insecurity; the situation worsening during periods of crisis in the perception of slum residents, engendering frequent use of negative coping strategies. Effective response to addressing vulnerability to household food insecurity among the urban poor should focus on both the underlying vulnerabilities of households due to chronic poverty and added impacts of acute crises.

Absolute temperature, temperature changes and stroke risk: a case-crossover study.

Studies suggest that there is an association between weather patterns and ischemic stroke risk. Exposure to a sudden decrease in temperature may increase stroke risk through altering blood viscosity and/or by triggering infections. We investigated the association between ischemic stroke risk and change in temperature. We used a case-crossover study design with 303 consecutive patients admitted to Heidelberg University, Department of Neurology over a one and a half year period (Aug 1998-Jan 2000). We used one day before stroke as the hazard (case) period matched to two control periods 2-7 days before and after stroke onset and took both ambient maximum temperature and the 24-hour difference in maximum temperature as exposure. There was no risk associated with ambient maximum temperature at all lag times and in all subgroup analyses. For the 24-hour difference, large changes in temperature (>5 degrees C) were associated with an increased risk of acute ischemic stroke regardless of whether the change was negative or positive. The odds ratio for temperature increases >5 degrees C compared to no change in temperature was 2.0 (95% confidence interval (CI): 0.7-5.9) at a lag time of 3 days. We found no relevant relation between temperature and stroke risk. The results suggest that the risk of ischemic stroke may increase with large day-to-day variations upwards or downwards in temperature.