Metabolic syndrome for sub-Saharan Africans diabetes with peripheral arterial disease: a case-control study

BACKGROUND

Currently, there is no value for the definition of abdominal obesity by measuring waist circumference in the Sub-Saharan Africa. Several definitions of metabolic syndrome (MS) have disparities concerning use of waist circumference, including International Diabetes Federation (IDF), American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) and National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) definitions. The aim of the study was to determine what value of waist circumference should be used and whether to use it as obligatory criterion in the metabolic syndrome in case of peripheral arterial disease (PAD).

METHODS

We conducted a case-control study in Cameroon. We included patients with diabetic foot and type 2 diabetes and excluded those with an Ankle Brachial Index (ABI) > 1.3. Cases were defined as patients with ABI ≤ 0.9 and controls with ABI > 0.9. The significant p value was < 0.05 and odds ratio (OR) with 95% confidence interval was used to measured risk for have PAD with MS.

RESULTS

We included 19 cases and 48 controls. The risk for having PAD with MS are for the IDF: OR = 4.7 (1.4-15.1), p = 0.008, for the AHA/NHLBI: OR = 5.8 (1.5-22.5), p = 0.007, for the NCEP-ATPIII: OR = 1.8 (0.6-5.6), p = 0.286.

CONCLUSION

Abdominal obesity should be defined according to the recommendations of the IDF and AHA/NHLBI and should not be an obligatory criterion in the definition of MS for research risk to have PAD on sub-Saharan Africa.

Influence of migration on characteristics of type 2 diabetes in sub-Saharan Africans

AIM

This study compared the clinical and biochemical characteristics and microvascular complications found in three groups of type 2 diabetes (T2D) patients: Africans living in Africa; African immigrants living in France; and Caucasians living in France.

METHODS

Diagnosed T2D Africans living in Cameroon (n=100) were compared with 98 African migrants diagnosed with T2D after having moved to France, and a group of 199 T2D Caucasian patients living in France. All underwent clinical and biochemical evaluations, and all were assessed for microvascular complications.

RESULTS

The median duration of stay of the migrants in France was 15years before being diagnosed with diabetes. Despite similar durations of diagnosis, they were 8.9years younger at the time of diagnosis than Africans living in Cameroon (P<0.001). Caucasians and African immigrants in France had lower HbA1c values than Africans in Cameroon (P<0.001); they were also more aggressively treated for hypertension and dyslipidaemia and, therefore, had significantly lower blood pressure levels and better lipid profiles. Diabetic nephropathy and retinopathy rates were higher in Cameroon than in the two other groups. After adjusting for age, diabetes duration, HbA1c, hypertension and other covariates, only the prevalence of diabetic nephropathy (OR: 5.61, 95% CI: 2.32-13.53; P<0.0001) was higher in Cameroon compared with those living in France.

CONCLUSION

Our results suggest that Africans who emigrate to France may develop diabetes earlier than those staying in their home country. However, the latter may be a reflection of late diagnosis of diabetes. Also, the less adequate diabetes and hypertension control in the latter would explain their higher rates of nephropathy. Large-scale cohorts are now warranted to substantiate these observations.

Validation of an enzyme-linked immunosorbent assay for C-peptide analysis in Cameroon

AIMS

To validate an ELISA method for C-peptide analysis in Cameroon.

METHODS

We evaluated the linearity, detection limit, functional sensitivity, precision and accuracy, and further investigated for cross-reactivity by proinsulin, and interferences by lipids, bilirubin and hemoglobin. This method was compared with the Roche electrochemiluminescence immunoassay. C-peptide stability was assessed following a series of freeze-thaw cycles, and after storage at room temperature. The C-peptide reference range was determined by analyzing fifty plasma samples of Cameroonians without diabetes.

RESULTS

The ELISA was linear at least up to 7.09 μg/L, and had a detection limit of 0.09 μg/L, and a functional sensitivity of 0.32 μg/L. The inter- and intraassay %CV were 2.9-9.9%, and 5.2-9.4%, respectively. Recoveries were 81-94% in serum, and 93-98% in buffer. Comparison with the ECLIA yielded a good correlation coefficient (R(2)=0.98). There was no cross-reactivity with proinsulin, and no interference with lipids, bilirubin and hemoglobin. C-peptide was stable at room temperature for 24 h and up to 7 freeze-thaw cycles for medium (1-6 μg/L) and high (>6 μg/L) levels (<-15°C and <-70°C). The reference range for C-peptide was 0.38-3.63 μg/L.

CONCLUSIONS

This method is suitable for C-peptide analysis in low-income countries like Cameroon.

Fasting blood glucose and insulin sensitivity are unaffected by HAART duration in Cameroonians receiving first-line antiretroviral treatment

AIMS

This study assessed the relationship between highly active antiretroviral therapy (HAART) duration and cardiometabolic disorders in HIV-infected Cameroonians.

METHODS

HIV-infected Cameroonians aged 21 years or above were cross-sectionally recruited at the Yaoundé Central Hospital, a certified HIV care centre, and their anthropometry, body composition (impedancemetry), fasting blood glucose (FBG) and lipid levels, and insulin sensitivity (IS; short insulin tolerance test) were measured.

RESULTS

A total of 143 participants with various durations of HAART [treatment-naïve (n=28), 1-13 months (n=44), 14-33 months (n=35) and 34-86 months (n=36)] were recruited. They were mostly women (72%), and had a mean age of 39.5 (SD: 9.8) years. Half (52%) were using a stavudine-containing regimen. There was a significant trend towards a positive change in body mass index and waist-to-hip ratio with increasing duration of HAART (all P=0.02). Systolic (P=0.04) and diastolic (P=0.03) blood pressure, total cholesterol (P=0.01), prevalence of hypertension (P=0.04) and hypercholesterolaemia (P=0.007) were also significantly increased with HAART duration, whereas triglycerides, FBG and IS were unaffected. Clustering of metabolic disorders increased (P=0.02 for ≥1 component of the metabolic syndrome and P=0.09 for ≥2 components) with HAART duration.

CONCLUSION

HAART duration is associated with obesity, fat distribution, blood pressure and cholesterol levels in HIV-infected Cameroonians, but does not appear to significantly affect glucose metabolism.

Would sickle cell trait influence the metabolic control in sub-Saharan individuals with type 2 diabetes?

AIMS

To determine the prevalence and effects of sickle cell trait on metabolic control in a Cameroonian diabetic population in a tertiary care setup.

METHODS

This was a cross-sectional study involving 73 consecutive outpatients with Type 2 diabetes recruited from the Yaounde National Diabetes and Obesity Centre. Sickle cell trait status was based on haemoglobin electrophoresis. Metabolic control was assessed by plasma glucose and HbA(1c), and comparisons made between participants with and without sickle cell trait, with adjustment for confounders through linear regressions models.

RESULTS

The prevalence of sickle cell trait was 19%, without sex difference, and comparable with figures in individuals without diabetes in this setting. Participants with diabetes and sickle cell trait were older than the non-trait participants (66 vs. 58 years, P = 0.02). Otherwise, clinical and biological profile including indicators of metabolic control were similarly distributed between trait and non-trait participants (all P >0.08). After adjustment for confounders, sickle cell trait was unrelated to fasting glucose (β = 0.02; 95% confidence interval -37.68-43.30) and HbA(1c) (β = -0.03, 95% confidence interval -1.18-0.93), and did not affect the relationship between the two markers of diabetes control (β = -0.03, 95% confidence interval -1.18-0.89).

CONCLUSIONS

Sickle cell trait was as frequent in this subgroup of patients with Type 2 diabetes as in the general population, suggesting no specific association with diabetes. It does not affect the metabolic control of diabetes. However, how this translates into long-term outcome needs to be fully elucidated in this setting, with an increasing population with both sickle cell trait and diabetes mellitus.

Rural and urban differences in metabolic profiles in a Cameroonian population

INTRODUCTION

The difference between modern lifestyle in urban areas and the traditional way of life in rural areas may affect the population's health in developing countries proportionally. In this study, we sought to describe and compare the metabolic (fasting blood sugar and lipid profile) profile in an urban and rural sample of a Cameroonian population, and study the association to anthropometric risk factors of obesity.

METHODS

332 urban and 120 rural men and women originating from the Sanaga Maritime Department and living in the Littoral Region in Cameroon voluntarily participated in this study. In all participants, measurement of height, weight, waist circumference, hip circumference, blood pressure systolic (SBP) and blood pressure diastolic (DBP), resting heart rate (RHR), blood glucose and lipids was carried out using standard methods. Total body fat (BF%) was measured using bio-impedancemetry. Body mass index (BMI) and waist to hip ratio (WHR) were calculated. Low Density Lipoprotein-cholesterol (LDL-c) concentrations were calculated using the Friedwald formula. World Health Organization criteria were used to define high and low levels of blood pressure, metabolic and anthropometric factors.

RESULTS

The highest blood pressure values were found in rural men. Concerning resting heart rate, only the youngest women's age group showed a significant difference between urban and rural areas (79 ± 14 bpm vs 88 ± 12 bpm, p = 0.04) respectively. As opposed to the general tendency in our population, blood glucose was higher in rural men and women compared to their urban counterparts in the older age group (6.00 ± 2.56 mmol/L vs 5.72 ± 2.72 mmol/L, p = 0.030; 5.77 ± 3.72 vs 5.08 ± 0.60, p = 0,887 respectively). Triglycerides (TG) were significantly higher in urban than rural men (1.23 ± 0.39 mmol/L vs 1.17 ± 0.64 mmol/L, p = 0.017). High Density Lipoprotein-cholesterol (HDL-c) levels were higher in rural compared to urban men (2.60 ± 0.10 35mmol/L vs 1.97 ± 1.14 mmol/L, p<0.001 respectively). However, total Cholesterol (TC) and LDL-c were significantly higher in urban than in rural men (p<0.001 and p = 0.005) and women (p<0.001 respectively. Diabetes' rate in this population was 6.6%. This rate was higher in the rural (8.3%) than in the urban area (6.0%). Age and RHR were significantly higher in diabetic women than in non-diabetics (p = 0.007; p = 0.032 respectively). In a multiple regression, age was an independent predictor of SBP, DBP and RHR in the entire population. Age predicted blood glucose in rural women only. BMI, WC and BF% were independent predictors of RHR in rural population, especially in men. WC and BF% predicted DBP in rural men only. Anthropometric parameters did not predict the lipid profile.

CONCLUSION

Lipid profile was less atherogenic in rural than in urban area. The rural population was older than the urban one. Blood pressure and blood glucose were positively associated to age in men and women respectively; this could explain the higher prevalence of diabetes in rural than in urban area. The association of these metabolic variables to obesity indices is more frequent and important in urban than in rural area.

Potential of Spirulina Platensis as a Nutritional Supplement in Malnourished HIV-Infected Adults in Sub-Saharan Africa: A Randomised, Single-Blind Study

BACKGROUND

Malnutrition is a major global public health issue and its impact on communities and individuals is more dramatic in Sub-Saharan Africa, where it is compounded by widespread poverty and generalized high prevalence of human immunodeficiency virus (HIV). Therefore, malnutrition should be addressed through a multisectorial approach, and malnourished individuals should have access to nutritional rehabilitation molecules that are affordable, accessible, rich in nutrient and efficient. We thus assessed the efficacy of two affordable and accessible nutritional supplements, spirulina platensis versus soya beans among malnourished HIV-infected adults.

METHODS

Undernourished patients, naïve of, but eligible to antiretroviral treatment (ART), aged 18 to 35 years were enrolled and randomly assigned to two groups. The first group received spirulina (Group A) as food supplement and the second received soya beans (Group B). Patients were initiated ART simultaneously with supplements. Food supplements were auto-administered daily, the quantity being calculated according to weight to provide 1.5 g/kg body weight of proteins with 25% from supplements (spirulina and soya beans). Patients were monitored at baseline and followed-up during twelve weeks for anthropometric parameters, body composition, haemoglobin and serum albumin, CD4 count and viral load.

RESULTS

Fifty-two patients were enrolled (Group A: 26 and Group B: 26). The mean age was 26.4 ± 4.9 years (Group A) and 28.7 ± 4.8 (Group B) with no significant difference between groups (P = 0.10). After 12 weeks, weight and BMI significantly improved in both groups (P < 0.001 within each group). The mean gain in weight and BMI in Group A and B were 4.8 vs. 6.5 kg, (P = 0.68) and 1.3 vs. 1.90 Kg/m(2), (P = 0.82) respectively. In terms of body composition, fat free mass (FFM) did not significantly increase within each group (40.5 vs. 42.2 Kg, P = 0.56 for Group A; 39.2 vs. 39.0 Kg, P = 0.22 for Group B). But when compared between the two groups at the end of the trial, FFM was significantly higher in the spirulina group (42.2 vs. 39.0 Kg, P = 0.01). The haemoglobin level rose significantly within groups (P < 0.001 for each group) with no difference between groups (P = 0.77). Serum albumin level did not increase significantly within groups (P < 0.90 vs. P < 0.82) with no difference between groups (P = 0.39). The increase in CD4 cell count within groups was significant (P < 0.01 in both groups), with a significantly higher CD4 count in the spirulina group compared to subjects on soya beans at the end of the study (P = 0.02). Within each group, HIV viral load significantly reduced at the end of the study (P < 0.001 and P = 0.04 for spirulina and soya beans groups respectively). Between the groups, the viral load was similar at baseline but significantly reduced in the spirulina group at the end of the study (P = 0.02).

CONCLUSION

We therefore conclude in this preliminary study, firstly, that both spirulina and soja improve on nutritional status of malnourished HIV-infected patients but in terms of quality of nutritional improvement, subjects on spirulina were better off than subjects on soya beans. Secondly, nutritional rehabilitation improves on immune status with a consequent drop in viral load but further investigations on the antiviral effects of this alga and its clinical implications are strongly needed.

Continuous interstitial glucose monitoring in non-diabetic subjects with end-stage renal disease undergoing maintenance haemodialysis

Haemodialysis improves uraemia-induced insulin sensitivity and is therefore likely to induce significant changes in circulating glucose concentrations in end-stage renal disease (ESRD). We aimed to assess clinically relevant circulating glucose changes in patients undergoing chronic maintenance haemodialysis using continuous interstitial monitoring. We investigated 14 non-diabetic ESRD subjects aged 40.6+/-2.4 years. Participants were examined 24-h day pre-dialysis, during the index dialysis session and 24-h post-dialysis with simultaneous measurement of capillary blood glucose and continuous interstitial glucose (CGMS). Participants performed five capillary blood glucose measurements the day before dialysis, and 10 during and after dialysis. Mean capillary blood glucose was 128+/-20mg/dl the day before, 93+/-8mg/dl during haemodialysis, and 105+/-13mg/dl after haemodialysis. There was a significant trend towards lower blood glucose during the session from 105+/-16mg/dl to a 3rd hour nadir of 83+/-15mg/dl (Anova F=2.89, p=0.029). No hypoglycaemia was recorded. Interstitial glucose profile was comparable to capillary glucose profile. Glucose concentrations varied significantly from 126+/-13mg/dl before to 112+/-12mg/dl after haemodialysis respectively (p=0.006). This study provides evidence for the use of CGMS in ESRD and haemodialysis, and demonstrates significant changes in glucose concentrations during and after haemodialysis that would guide treatment monitoring and adjustments.

Waist circumference and obesity-related abnormalities in French and Cameroonian adults: the role of urbanization and ethnicity

OBJECTIVES

To evaluate the effect of urbanization and ethnicity on correlations between waist circumference (WC) and obesity-related cardiovascular risk factors.

METHODS

1471 rural and urban Cameroonians, and 4185 French, from community-based studies, aged > or =25 years, not treated for hypertension, diabetes and dyslipidemia participated in this study. Slopes of obesity-related abnormalities with WC were compared using an interaction term between place of residence and WC.

RESULTS

Women in urban Cameroon and men in France had significantly higher WC and BMI relative to their gender counterparts. Urban Cameroonians had higher abdominal adiposity, but lower BP and better metabolic profile than the French. WC was positively associated to all the obesity-related abnormalities in the three sites except to FPG (both genders) and blood lipids (women) in rural Cameroon. A 5 cm larger WC was associated with a higher increment among urban than rural Cameroonians for diastolic blood pressure (DBP) (women, 1.95/0.63 mm Hg; men, 2.56/1.44 mm Hg), HOMA-IR (women, 0.11/0.05), fasting plasma glucose (FPG) (men, 0.09/-0.01 mmol/l) and triglycerides (women, 0.06/0.01 mmol/l; men, 0.09/0.03 mmol/l), all P<0.05. A 5 cm larger WC was associated with a higher increment among urban Cameroon than French people for DBP (women, 1.95/1.28 mm Hg, P<0.01; men, 2.56/1.49 mm Hg, P<0.01), but with a lower increment for HOMA-IR (women, 0.11/0.14, P<0.05), FPG (women, 0.05/0.09 mmol/l), total cholesterol (women, 0.07/0.11 mmol/l; men, 0.10/0.13 mmol/l) and triglycerides (women, 0.06/0.11 mmol/l; men, 0.09/0.13 mmol/l) all P<0.05.

CONCLUSION

Ethnicity and urbanization modify the association of WC with obesity-related metabolic abnormalities. WC cutoff points derived from Caucasians may not be appropriate for black Sub-Saharan Africans.

Ketosis-prone type 2 diabetes mellitus and human herpesvirus 8 infection in sub-saharan africans

CONTEXT

An atypical form of type 2 diabetes mellitus (DM-2) is revealed by ketosis (ketosis-prone type 2 diabetes mellitus), frequently occurring in individuals who are black and of African origin, and characterized by an acute onset requiring transient insulin therapy. Its sudden onset suggests precipitating factors.

OBJECTIVE

To investigate the putative role of human herpesvirus 8 (HHV-8) in the pathogenesis of ketosis-prone DM-2.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study in which antibodies were searched against latent and lytic HHV-8 antigens using immunofluorescence. The presence of HHV-8 in genomic DNA was investigated in 22 of the participants at clinical onset of diabetes. We also tested whether HHV-8 was able to infect human pancreatic beta cells in culture in vitro. The study was conducted at Saint-Louis University Hospital, Paris, France, from January 2004 to July 2005. All participants were black and of African origin: 187 were consecutive diabetic patients of whom 81 had ketosis-prone DM-2 and 106 had nonketotic DM-2, and 90 individuals were nondiabetic control participants who were matched for age and sex.

MAIN OUTCOME MEASURES

Seroprevalence of HHV-8 and percentage of patients with HHV-8 viremia at onset in ketosis-prone DM-2.

RESULTS

HHV-8 antibodies were found in 71 patients (87.7%) with ketosis-prone DM-2 vs 16 patients (15.1%) with nonketotic DM-2 (odds ratio, 39.9; 95% confidence interval, 17.1-93.4; P < .001) and 36 of the control participants (40.0%) (odds ratio, 10.7; 95% confidence interval, 4.9-23.4; P < .001). HHV-8 in genomic DNA was present in 6 of 13 patients with ketosis-prone DM-2 tested at acute onset and in 0 of 9 patients with nonketotic DM-2. HHV-8 proteins were present in human islet cells that were cultured for 4 days in the presence of HHV-8.

CONCLUSIONS

In this preliminary cross-sectional study, the presence of HHV-8 antibodies was associated with ketosis-prone DM-2 in patients of sub-Saharan African origin. Longitudinal studies are required to understand the clinical significance of these findings.

Waist circumference does not predict circulating adiponectin levels in sub-Saharan women

Background

Because of previously reported ethnic differences in determinants and markers of obesity and related metabolic disorders, we sought to investigate circulating levels of adiponectin and their correlates in a sub-Saharan African (sSA) population.

Subjects and Methods

We studied 70 non-diabetic volunteers (33M/37F) living in Yaoundé, Cameroon, aged 24–69 yr, with BMI 20–42 kg/m². In all participants we measured waist circumference and total body fat by bioimpedance, and obtained a fasting venous blood sample for measurement of plasma glucose, serum insulin and adiponectin concentrations. We performed a euglycaemic hyperinsulinaemic clamp in 1/4 subjects, and HOMA_IR was used as surrogate of fasting insulin sensitivity index since it best correlates to clamp measurements.

Results

Males had lower adiponectin levels than females (8.8 ± 4.3 vs. 11.8 ± 5.5 μg/L). There was no significant correlation between adiponectin and total body fat (r_s = -0.03; NS), whereas adiponectin was inversely correlated with waist circumference (r_s = -0.39; p = 0.001). Adiponectin correlated negatively with insulin resistance (r_s = -0.35; p = 0.01). In a regression analysis using fasting adiponectin concentration as the dependent variable, and age, HOMA_IR, waist circumference, and fat mass as predictors, waist circumference (β = -3.30; p = 0.002), fat mass (β = -2.68; p = 0.01), and insulin resistance (β = -2.38; p = 0.02) but not age (β = 1.11; p = 0.27) were independent predictors of adiponectin. When considering gender, these relations persisted with the exception of waist circumference in females.

Conclusion

Adiponectin correlates in this study population are comparable to those observed in Caucasians with the exception of waist circumference in women. The metabolic significance of waist circumference is therefore questioned in sSA women.

Metabolic syndrome in a sub-Saharan African setting: central obesity may be the key determinant

OBJECTIVES

To determine, in a rural and urban population in Cameroon, the prevalence of the metabolic syndrome (MS) using three definitions and to assess the association between components of the MS, central obesity and HOMA insulin resistance (HOMA-IR) index.

METHODS

A representative sample of 1573 adults (638 rural, 935 urban) were interviewed on their personal medical history. Blood pressure and anthropometric measures used standardised methods. After an overnight fast, blood samples were collected before and 2h after an OGTT and plasma glucose, plasma insulin and blood lipids determined. Modified WHO, NCEP-ATP III, and IDF definitions of the MS were used.

RESULTS

Central obesity was the most prevalent component of the syndrome, but prevalence varied widely according to the definition used. Hypertriglyceridemia was almost non-existent. The highest prevalence of the MS was with the WHO definition and the lowest with the NCEP-ATP III definition. Central obesity was more tightly associated with components of the MS than was HOMA-IR.

CONCLUSIONS

The prevalence of the MS varied greatly by rural/urban residence with the various definitions used. Central obesity appears to be the key determinant of the prevalence of the MS in sub Saharan Africa. Many MS definitions may not be appropriate for African populations.

Consequences of fetal exposure to maternal diabetes in offspring

CONTEXT

Type 2 diabetes is the result of both genetic and environmental factors. Fetal exposure to maternal diabetes is associated with a higher risk of abnormal glucose homeostasis in offspring beyond that attributable to genetic factors, and therefore, may participate in the excess of maternal transmission of type 2 diabetes.

EVIDENCE ACQUISITION

A MEDLINE search covered the period from 1960-2005.

EVIDENCE SYNTHESIS

Human studies performed in children and adolescents suggest that offspring who had been exposed to maternal diabetes during fetal life exhibit higher prevalence of impaired glucose tolerance and markers of insulin resistance. Recent studies that directly measured insulin sensitivity and insulin secretion have shown an insulin secretory defect even in the absence of impaired glucose tolerance in adult offspring. In animal models, exposure to a hyperglycemic intrauterine environment also led to the impairment of glucose tolerance in the adult offspring. These metabolic abnormalities were transmitted to the next generations, suggesting that in utero exposure to maternal diabetes has an epigenetic impact. At the cellular level, some findings suggest an impaired pancreatic beta-cell mass and function. Several mechanisms such as defects in pancreatic angiogenesis and innervation, or modification of parental imprinting, may be implicated, acting either independently or in combination.

CONCLUSION

Thus, fetal exposure to maternal diabetes may contribute to the worldwide diabetes epidemic. Public health interventions targeting high-risk populations should focus on long-term follow-up of subjects who have been exposed in utero to a diabetic environment and on a better glycemic control during pregnancy.

An unusual somatotropin and thyreotropin secreting pituitary adenoma efficiently controlled by Octreotide and Pegvisomant

We describe the first case of a 36 year-old male patient with a somatotropin and thyreotropin secreting pituitary adenoma, co-treated by a long-acting releasing somatostatin analog (Octreotide) and a GH receptor antagonist (Pegvisomant). The patient normalized his biological disease activity reflected by hormone levels but his tumor size remained unchanged as measured by MRI. The co-treatment was well tolerated and induced a synergic effect on IGF1 levels that allowed us to use low doses of both therapies.

Hyperglycaemia acutely decreases circulating dehydroepiandrosterone levels in healthy men

OBJECTIVE

This study was conducted in order to evaluate the effect of glucose-insulin homeostasis on adrenal steroids and was designed to separate the effects of hyperglycaemia from those of insulin.

DESIGN

Eight healthy men aged 22.6 +/- 3.4 (SD) underwent an 80 mU/m2/min hyperinsulinaemic euglycaemic 100-min clamp, a 200-min graded glucose infusion at 2-16 mg/kg/min and a measurement of fat mass.

MEASUREMENTS

Circulating glucose, insulin and adrenal steroid levels including dehydroepiandrosterone (DHEA) were determined before and during both infusion tests. Steroid variations in relation to insulinaemia and glycaemia were analysed using univariate, multivariate tests and nonlinear mixed models.

RESULTS

Hyperinsulinaemia induced no significant modification of adrenal steroid levels. By contrast, hyperglycaemia decreased all adrenal steroids except DHEA-sulphate by 47-66%. The drop occurred early, averaging 51% for 17OH pregnenolone and 57% for DHEA at the 80th minute of glucose infusion, whereas blood glucose was 7.1 +/- 1.2 mmol/1. This effect was independent of insulinaemia, fat mass and waist circumference. Thus, we estimated models that could best predict steroid variations according to blood glucose. At thresholds defining impaired fasting glycaemia and diabetes, the estimated decrease in DHEA was 40% and 45%, respectively, culminating at 60% at 9.3 mmol/1 glycaemia, with no detectable further decrease.

CONCLUSIONS

Our data suggest that hyperglycaemia dramatically decreases adrenal androgen levels in men, possibly by acting at early steps of synthesis, independently of insulinaemia and fat mass.

Is capillary ketone determination useful in clinical practice? In which circumstances?

A new method is now available to measure capillary levels of 3-hydroxybutyrate (3HB), one of the three ketone bodies. It is a quantitative and enzymatic test that uses the same equipment as for home capillary blood glucose determination but with specific strips. In comparison to urine ketone test, there is no false negative or false positive results, it is highly correlate to standard automate assays and patients find it more acceptable. Clinical implementations of this new test begin to be reported. Some studies showed an advantage of ketonemia versus ketonuria measurement to detect and to treat diabetic ketoacidosis in the emergency room. In diabetic patients treated with continuous subcutaneous insulin infusion, ketonemia seems to be more relevant to detect lack of insulin. In the current care of patient with type 1 diabetes and especially in children blood ketone test is more effective than urine ketone test to prevent hospitalisation during sick days. For other situations such as diabetic pregnancy or type 2 diabetes, more data are needed to determine if capillary measurement of 3HB is really useful. This new test is easier and less unpleasant than doing urinary test but it is still far more expensive. Further clinical studies are needed to define whether self 3HB monitoring should substitute urinary test in outpatient care.

Biological actions of the incretins GIP and GLP-1 and therapeutic perspectives in patients with type 2 diabetes

Incretin hormones are defined as intestinal hormones released in response to nutrient ingestion, which potentiate the glucose-induced insulin response. In humans, the incretin effect is mainly caused by two peptide hormones, glucose-dependent insulin releasing polypeptide GIP, and glucagon-like peptide-1 GLP-1. GIP is secreted by K cells from the upper small intestine while GLP-1 is mainly produced in the enteroendocrine L cells located in the distal intestine. Their effect is mediated through their binding with specific receptors, though part of their biological action may also involve neural modulation. GIP and GLP-1 are both rapidly degraded into inactive metabolites by the enzyme dipeptidyl-peptidase-IV (DPP-IV). In addition to its effects on insulin secretion, GLP-1 exerts other significant actions, including stimulation of insulin biosynthesis, inhibition of glucagon secretion, inhibition of gastric emptying and acid secretion, reduction of food intake, and trophic effects on the pancreas. As the insulinotropic action of GLP-1 is preserved in type 2 diabetic patients, this peptide was a candidate as a therapeutic agent for this disease. A number of pharmacological strategies have been developed to provide continuous delivery of GLP-1 and to prevent degradation of GLP-1, including continuous administration of GLP-1, DPP-IV inhibitors and DPP-IV resistant GLP-1 analogues. Recent results of the most clinically advanced incretin mimetics confirmed their efficacy to improve glycemic control in type 2 diabetic patients. Further results are expected to confirm the efficacy/safety profile of these compounds, and to find their place in the therapeutic strategy of type 2 diabetes.

Exposure over the life course to an urban environment and its relation with obesity, diabetes, and hypertension in rural and urban Cameroon

BACKGROUND

This study aimed to assess the association between lifetime exposure to urban environment (EU) and obesity, diabetes, and hypertension in an adult population of Sub-Saharan Africa.

METHODS

We studied 999 women and 727 men aged > or =25 years. They represent all the adults aged > or =25 years living in households randomly selected from a rural and an urban community of Cameroon with a 98% and 96% participation rate respectively. Height, weight, blood pressure, and fasting blood glucose were measured in all subjects. Current levels of physical activity (in metabolic equivalents [MET]) were evaluated through the Sub-Saharan African Activity Questionnaire. Chronological data on lifetime migration were collected retrospectively and expressed as the total (EUt) or percentage (EU%) of lifetime exposure to urban environment.

RESULTS

Lifetime EUt was associated with body mass index (BMI) (r = 0.42; P < 0.0001), fasting glycaemia (r = 0.23; P < 0.0001), and blood pressure (r = 0.17; P < 0.0001) but not with age. The subjects who recently settled in a city (< or =2 years) had higher BMI (+2.9 kg/m(2); P < 0.001), fasting glycaemia (+0.8 mmol/l; P < 0.001), systolic (+23 mmHg; P < 0.001) and diastolic (+9 mmHg; P = 0.001) blood pressure than rural dwellers with a history of 2 years EU. EU during the first 5 years of life was not, on its own, associated with glycaemia or BMI. However, both lifetime EUt and current residence were independently associated with obesity and diabetes. The association between lifetime EUt and hypertension was not independent of current residence and current level of physical activity.

CONCLUSIONS

This study suggests that for the study of obesity and diabetes, in addition to current residence, both lifetime exposure to an urban environment and recent migration history should be investigated.

Ketosis-prone type 2 diabetes in patients of sub-Saharan African origin: clinical pathophysiology and natural history of beta-cell dysfunction and insulin resistance

Nonautoimmune ketosis-prone diabetic syndromes are increasingly frequent in nonwhite populations. We have characterized a cohort of patients of sub-Saharan African origin who had ketosis-prone type 2 diabetes (n = 111), type 1 diabetes (n = 21), and type 2 diabetes (n = 88) and were admitted to a hospital for management of uncontrolled diabetes. We compared epidemiological, clinical, and metabolic features at diabetes onset and measured insulin secretion (glucagon-stimulated C-peptide) and insulin action (short intravenous insulin tolerance test) during a 10-year follow-up. Ketosis-prone type 2 diabetes shows a strong male predominance, stronger family history, higher age and BMI, and more severe metabolic decompensation than type 1 diabetes. In ketosis-prone type 2 diabetes, discontinuation of insulin therapy with development of remission of insulin dependence is achieved in 76% of patients (non-insulin dependent), whereas only 24% of patients remain insulin dependent. During evolution, ketosis-prone type 2 diabetes exhibit specific beta-cell dysfunction features that distinguish it from type 1 and type 2 diabetes. The clinical course of non-insulin-dependent ketosis-prone type 2 diabetes is characterized by ketotic relapses followed or not by a new remission. Progressive hyperglycemia precedes and is a strong risk factor for ketotic relapses (hazard ratio 38). The probability for non-insulin-dependent ketosis-prone type 2 diabetes to relapse is 90% within 10 years, of whom approximately 50% will become definitively insulin dependent. Insulin sensitivity is decreased in equal proportion in both ketosis-prone type 2 diabetes and type 2 diabetes, but improves significantly in non-insulin-dependent ketosis-prone type 2 diabetes, only after correction of hyperglycemia. In conclusion, ketosis-prone type 2 diabetes can be distinguished from type 1 diabetes and classical type 2 diabetes by specific features of clinical pathophysiology and also by the natural history of beta-cell dysfunction and insulin resistance reflecting a propensity to glucose toxicity.