|ISSN No. 1606-7754 Vol.16 No.3 December 2008|
Prevalence and risk factors of diabetes mellitus in Kinshasa Hinterland
JB Kasiam Lasi On’Kin1 B Longo-Mbenza1, Nge Okwe2, Kabangu NK2, Mpandamadi SD1, Wemankoy O3, J He4
Department of Internal Medicine, University of Kinshasa, DRC1, the Biostatistics Unit, Lomo Medical Center and Heart of Africa Center of Cardiology2, School of Public Health, University of Kinshasa3, Department of Public Health Medical School of Tulane University, USA4
Objective: To estimate the prevalence of diabetes mellitus (DM), impaired fasting glucose (IFG), and impaired glucose tolerance (IGT), and to determine the risk factors of DM among urban and rural areas of Kinshasa Hinterland. Research, Design and Methods: Data were collected from a multistage random sample cross-sectional surveys of adult black Africans from Kinshasa region DR Congo with the help of a structured questionnaire, physical examinations and blood samples, using the WHO stepwise approach and the new criteria of WHO to define glucose intolerance. Prevalence rates were adjusted using the standard world population of Waterhouse and the standard population of Kinshasa region. Results: A total of 9770 subjects age ≥ 12 years participated (response rate of 90.3%) in this study. Age-adjusted rates to world population of IFG, IGT, DM by fasting plasma only, DM by 2h-load test only, and all cases of DM were 9.3%, 9.6%, 16.1%, 8.4% and 25.3%, respectively. Male sex, rural residence, total obesity, abdominal obesity, viral infection, milk intake, and kwashiorkor were the univariate risk factors of all cases of DM. Adjusted for confounders, advancing age, rural-urban migration, physical inactivity, smoking, abstinence of alcohol, low intake of fruits-vegetables, family history of DM, refined sugar intake, high social class, high intake of animal fat and protein, and stress, were the independents determinants of all cases of DM. Conclusions: This study observed epidemic rates of glucose intolerance. Primary prevention through lifestyle changes is needed to control DM among Africans under demographic and nutrition transition.
Key words: Diabetes mellitus, obesity, urbanization, lifestyle, Socioeconomic status, sub-Saharan Africa, Congo.
Diabetes mellitus (DM), characterized by chronic hyperglycemia is a major global health problem emerging in developing countries. According to the World Health Organization (WHO) Regional Office for Africa, non communicable diseases including DM, will increase so rapidly in Sub-Saharan Africa (SSA) as an epidemic by year 2020.1 The current prevalence of adjusted DM is estimated to be 14.2% in a small random adult sample (n=250) of Kinshasa Metropolitan area2 and conflicting with low prevalence rate of 0-9.3% reported earlier in SSA.3 None of the earlier population-based studies of DM among black Africans confirmed its prevalence with a 75g oral glucose tolerance test according to WHO criteria.4 Studies reported earlier had limitations such as differing study populations and clinical tests, methodologies and criteria for the diagnosis of DM. The lack of efficient diagnosis performance in small sizes of populations and information on the relation between sex, age, poverty, environment, lifestyle changes, obesity and DM, hampers the development and implementation of specific prevention programs.
Indeed, in the Democratic Republic of Congo (DRC), populations are going through demographic change such as aging, better health care and nutrition, sedentary lifestyle and energy rich diet5,6 after migration from a rural setting to urban regions of Kinshasa, the capital of DRC. In the early stages of the transition, the economically active, urban and richer Africans have carried the highest risk of cardiovascular risk factors (including arterial hypertension and DM).2 However, as reported by data from Mexico,7 Brazil,8 and Chile,9 there are indications from Kinshasa2 that the under privileged rural populations will carry the same risks of developing arterial hypertension, a risk factor of DM if they adopt the “bad habits” prevalent in urban areas.
Because DM was determined by fasting capillary blood test, medical history or presence of glycosuria, it is likely that the condition was under diagnosed, in the absence of glucose tolerance test, in SSA and therefore not comparable with global data. What is also highlighted is the relative paucity of information on age-adjusted prevalence rates of DM in both upper-urban, urban and rural settings of SSA.2,10 The objective of this study was to estimate prevalence rates of DM, impaired fasting glycemia (IFG), and impaired glucose tolerance (IGT) among large upper-urban, urban and rural populations of Kinshasa Hinterland. We also examined the association between DM and the consequences of the epidemiologic and nutrition transition. Based on recent information on arterial hypertension (a risk factors of DM) in metropolitan area of Kinshasa,2 we first hypothesized that in Kinshasa Hinterland (Former Leopoldville Province) including 3 administrative regions of DRC (Kinshasa Metropolitan area, Bas-congo Region and Bandundu Region), a change to a sedentary lifestyle and the recent ethnic and military conflicts with the collapse of economy, might have had a significant effect on the epidemic of DM. We also hypothesized that aging, rural residence, low socioeconomic status, high socioeconomic status, and obesity (total obesity more limited than abdominal obesity) are the risk factors of DM in these communities with different stages of epidemiologic and nutrition transitions.2,5-9