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Dive into the research topics where Felix K. Assah is active.

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Featured researches published by Felix K. Assah.


The Lancet | 2010

Diabetes in sub-Saharan Africa

Jean Claude Mbanya; Ayesha A. Motala; Eugene Sobngwi; Felix K. Assah; Sostanie T Enoru

In Sub-Saharan Africa, prevalence and burden of type 2 diabetes are rising quickly. Rapid uncontrolled urbanisation and major changes in lifestyle could be driving this epidemic. The increase presents a substantial public health and socioeconomic burden in the face of scarce resources. Some types of diabetes arise at younger ages in African than in European populations. Ketosis-prone atypical diabetes is mostly recorded in people of African origin, but its epidemiology is not understood fully because data for pathogenesis and subtypes of diabetes in sub-Saharan African communities are scarce. The rate of undiagnosed diabetes is high in most countries of sub-Saharan Africa, and individuals who are unaware they have the disorder are at very high risk of chronic complications. Therefore, the rate of diabetes-related morbidity and mortality in this region could grow substantially. A multisectoral approach to diabetes control and care is vital for expansion of socioculturally appropriate diabetes programmes in sub-Saharan African countries.


eLife | 2016

A century of trends in adult human height

James Bentham; M Di Cesare; Gretchen A Stevens; Bin Zhou; Honor Bixby; Melanie J. Cowan; Lea Fortunato; James Bennett; Goodarz Danaei; Kaveh Hajifathalian; Yuan Lu; Leanne Riley; Avula Laxmaiah; Vasilis Kontis; Christopher J. Paciorek; Majid Ezzati; Ziad Abdeen; Zargar Abdul Hamid; Niveen M E Abu-Rmeileh; Benjamin Acosta-Cazares; Robert Adams; Wichai Aekplakorn; Carlos A. Aguilar-Salinas; Charles Agyemang; Alireza Ahmadvand; Wolfgang Ahrens; H M Al-Hazzaa; Amani Al-Othman; Rajaa Al Raddadi; Mohamed M. Ali

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. DOI: http://dx.doi.org/10.7554/eLife.13410.001


International Journal of Epidemiology | 2011

Accuracy and validity of a combined heart rate and motion sensor for the measurement of free-living physical activity energy expenditure in adults in Cameroon

Felix K. Assah; Ulf Ekelund; Soren Brage; Antony Wright; Jean Claude Mbanya; Nicholas J. Wareham

BACKGROUND The increasing burden of non-communicable diseases in sub-Saharan Africa (SSA) warrants rigorous studies of contributing lifestyle factors. Combined heart rate (HR) and movement monitoring make it possible to objectively measure physical activity in free-living individuals. We examined the validity of a combined HR and motion sensor in estimating physical activity energy expenditure (PAEE) in free-living adults in rural and urban Cameroon compared with doubly-labelled water (DLW) as criterion. METHODS PAEE was measured in 33 free-living rural and urban dwellers by DLW over 7 consecutive days. Simultaneously, the combined sensor recorded HR and uni-axial acceleration. Individual HR vs PAEE calibration was done by a step test. Branched equation modelling was used to estimate PAEE from HR and acceleration. Validity and accuracy of prediction were expressed as mean bias and root mean square error (RMSE). Agreement was analysed using Bland and Altman limits of agreement (LOA). RESULTS There was no significant mean bias between PAEE estimated from the combined sensor or measured by DLW [mean bias (standard error): -5.4 (5.1) kJ/kg/day; P = 0.3; RMSE = 29.3 kJ/kg/day]. The bias doubled for group compared with individual calibration of HR [-9.1 (5.0) kJ/kg/day, P = 0.08]. PAEE prediction was more accurate in urban compared with rural volunteers. The 95% LOAs between predicted and measured PAEE were ∼50-60 kJ/kg/day above or below perfect agreement. CONCLUSIONS Combined HR and movement sensing is a valid method for estimating free-living PAEE on group level in adults in SSA.


Diabetes Care | 2011

Urbanization, Physical Activity, and Metabolic Health in Sub-Saharan Africa

Felix K. Assah; Ulf Ekelund; Soren Brage; Jean Claude Mbanya; Nicholas J. Wareham

OBJECTIVE We examined the independent associations between objectively measured free-living physical activity energy expenditure (PAEE) and the metabolic syndrome in adults in rural and urban Cameroon. RESEARCH DESIGN AND METHODS PAEE was measured in 552 rural and urban dwellers using combined heart rate and movement sensing over 7 continuous days. The metabolic syndrome was defined using the National Cholesterol Education Program-Adult Treatment Panel III criteria. RESULTS Urban dwellers had a significantly lower PAEE than rural dwellers (44.2 ± 21.0 vs. 59.6 ± 23.7 kJ/kg/day, P < 0.001) and a higher prevalence of the metabolic syndrome (17.7 vs. 3.5%, P < 0.001). In multivariate regression models adjusted for possible confounders, each kJ/kg/day of PAEE was associated with a 2.1% lower risk of prevalent metabolic syndrome (odds ratio 0.98, P = 0.03). This implies a 6.5 kJ/kg/day difference in PAEE, equivalent to 30 min/day of brisk walking, corresponds to a 13.7% lower risk of prevalent metabolic syndrome. The population attributable fraction of prevalent metabolic syndrome due to being in the lowest quartile of PAEE was 26.3% (25.3% in women and 35.7% in men). CONCLUSIONS Urban compared with rural residence is associated with lower PAEE and higher prevalence of metabolic syndrome. PAEE is strongly independently associated with prevalent metabolic syndrome in adult Cameroonians. Modest population-wide changes in PAEE may have significant benefits in terms of reducing the emerging burden of metabolic diseases in sub-Saharan Africa.


Journal of Applied Physiology | 2014

Autocalibration of accelerometer data for free-living physical activity assessment using local gravity and temperature: an evaluation on four continents

Vincent T. van Hees; Zhou Fang; Joss Langford; Felix K. Assah; Anwar Mohammad; Inacio Cm da Silva; Michael I. Trenell; Tom White; Nicholas J. Wareham; Soren Brage

Wearable acceleration sensors are increasingly used for the assessment of free-living physical activity. Acceleration sensor calibration is a potential source of error. This study aims to describe and evaluate an autocalibration method to minimize calibration error using segments within the free-living records (no extra experiments needed). The autocalibration method entailed the extraction of nonmovement periods in the data, for which the measured vector magnitude should ideally be the gravitational acceleration (1 g); this property was used to derive calibration correction factors using an iterative closest-point fitting process. The reduction in calibration error was evaluated in data from four cohorts: UK (n = 921), Kuwait (n = 120), Cameroon (n = 311), and Brazil (n = 200). Our method significantly reduced calibration error in all cohorts (P < 0.01), ranging from 16.6 to 3.0 mg in the Kuwaiti cohort to 76.7 to 8.0 mg error in the Brazil cohort. Utilizing temperature sensor data resulted in a small nonsignificant additional improvement (P > 0.05). Temperature correction coefficients were highest for the z-axis, e.g., 19.6-mg offset per 5°C. Further, application of the autocalibration method had a significant impact on typical metrics used for describing human physical activity, e.g., in Brazil average wrist acceleration was 0.2 to 51% lower than uncalibrated values depending on metric selection (P < 0.01). The autocalibration method as presented helps reduce the calibration error in wearable acceleration sensor data and improves comparability of physical activity measures across study locations. Temperature ultization seems essential when temperature deviates substantially from the average temperature in the record but not for multiday summary measures.


The Lancet | 2006

Diabetes care in Africa

Jean Claude Mbanya; Andre Pascal Kengne; Felix K. Assah

1628 www.thelancet.com Vol 368 November 11, 2006 No-one should have to die of untreated diabetes. Although this disease is only one among a host of health problems that afflict the poorest countries, it is one for which effective and potentially inexpensive remedies are available. Sustainable, locally-appropriate, and cost-effective strategies are what we need, and affordable insulin is a necessary part of any solution. Philanthropic initiatives, such as that of Novo Nordisk, are immensely welcome, but equity pricing needs to extend to the private pharmacies where most patients still have to buy their insulin. On a wider perspective, the marketing policy of the pharmaceutical industry has escalated the costs of diabetes for diminishing benefit, thereby exacerbating existing inequalities. Africa’s problem is indeed our problem too. Edwin A M Gale Diabetes and Metabolism, Department of Clinical Science, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK [email protected]


Obesity | 2008

Ten-year Changes in Central Obesity and BMI in Rural and Urban Cameroon

Leopold K. Fezeu; Felix K. Assah; Beverley Balkau; Dora S. Mbanya; Andre-Pascal Kengne; Jean-Claude Mbanya

Objective: To compare the 10‐year changes in the distribution of adiposity in rural and urban Cameroonian populations.


Obesity | 2009

Predicting Physical Activity Energy Expenditure Using Accelerometry in Adults From Sub-Sahara Africa

Felix K. Assah; Ulf Ekelund; Soren Brage; Kirsten Corder; Antony Wright; Jean Claude Mbanya; Nicholas J. Wareham

Lack of physical activity may be an important etiological factor in the current epidemiological transition characterized by increasing prevalence of obesity and chronic diseases in sub‐Sahara Africa. However, there is a dearth of data on objectively measured physical activity energy expenditure (PAEE) in this region. We sought to develop regression equations using body composition and accelerometer counts to predict PAEE. We conducted a cross‐sectional study of 33 adult volunteers from an urban (n = 16) and a rural (n = 17) residential site in Cameroon. Energy expenditure was measured by doubly labeled water (DLW) over a period of seven consecutive days. Simultaneously, a hip‐mounted Actigraph accelerometer recorded body movement. PAEE prediction equations were derived using accelerometer counts, age, sex, and body composition variables, and cross‐validated by the jack‐knife method. The Bland and Altman limits of agreement (LOAs) approach was used to assess agreement. Our results show that PAEE (kJ/kg/day) was significantly and positively correlated with activity counts from the accelerometer (r = 0.37, P = 0.03). The derived equations explained 14–40% of the variance in PAEE. Age, sex, and accelerometer counts together explained 34% of the variance in PAEE, with accelerometer counts alone explaining 14%. The LOAs between DLW and the derived equations were wide, with predicted PAEE being up to 60 kJ/kg/day below or above the measured value. In summary, the derived equations performed better than existing published equations in predicting PAEE from accelerometer counts in this population. Accelerometry could be used to predict PAEE in this population and, therefore, has important applications for monitoring population levels of total physical activity patterns.


Global Health Promotion | 2010

Traditional healers and diabetes: results from a pilot project to train traditional healers to provide health education and appropriate health care practices for diabetes patients in Cameroon

George Mbeh; Richard Edwards; George Ngufor; Felix K. Assah; Leopold Fezeu; Jean-Claude Mbanya

In resource-limited countries where the challenge of diabetes management is especially severe, there has been a recent call for the inclusion of traditional healers in the fight against diabetes. In response, some researchers have highlighted the dangers of incorporating traditional healers while others, have presented them as a potential asset to the health care system if well trained and guided. We report here on a pilot intervention to include traditional healers in the health promotion and prevention efforts for diabetes in Cameroon, as part of the Cameroon Burden of Diabetes (CAMBoD) project. We trained 106 healers in a range of topics and practices relating to diabetes prevention and care. Eight months later we carried out a field evaluation of 36 of them using in-depth semi-structured interviews and direct observation methods to find out if they remembered and applied the learning from the training. Most healers recalled and were applying some of the lessons learnt, including referral of patients for blood glucose tests at biomedical health facilities, desisting from scarifying patients with diabetes, and educating their patients, peers and other people in their communities about diabetes. Healers were enthusiastic about collaboration with the diabetes control program, though some wanted additional responsibilities. We conclude that healers could learn prevention strategies of diabetes relatively rapidly and collaborate in health promotion.


Diabetes Care | 2009

Free-living physical activity energy expenditure is strongly related to glucose intolerance in Cameroonian adults independently of obesity.

Felix K. Assah; Ulf Ekelund; Soren Brage; Jean Claude Mbanya; Nicholas J. Wareham

OBJECTIVE—We examined the cross-sectional association between objectively measured free-living physical activity energy expenditure (PAEE) and glucose tolerance in adult Cameroonians without known diabetes. RESEARCH DESIGN AND METHODS—PAEE was measured in 34 volunteers using the doubly labeled water method and indirect calorimetry (resting). Fasting blood glucose and 2-h postload blood glucose were measured during a standard 75-g oral glucose tolerance test. RESULTS—There was a significant negative correlation between PAEE and 2-h glucose (r = −0.43; P = 0.01) but not fasting glucose (r = 0.1; P = 0.57). The inverse association between PAEE and 2-h glucose remained after adjustment for age, sex, smoking, alcohol consumption, and BMI (β = −0.017 [95% CI −0.033 to −0.002]) and was unchanged after further adjustment for waist circumference, body fat percentage, or aerobic fitness. CONCLUSIONS—PAEE is inversely associated with 2-h glucose independently of adiposity or fitness. Interventions aimed at increasing PAEE could play an important role in diabetes prevention in developing countries.

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Soren Brage

University of Cambridge

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Andre Pascal Kengne

South African Medical Research Council

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