Deriving an optimal threshold of waist circumference for detecting cardiometabolic risk in sub-Saharan Africa.

BACKGROUND: Waist circumference (WC) thresholds derived from western populations continue to be used in sub-Saharan Africa (SSA) despite increasing evidence of ethnic variation in the association between adiposity and cardiometabolic disease and availability of data from African populations. We aimed to derive a SSA-specific optimal WC cut-point for identifying individuals at increased cardiometabolic risk. METHODS: We used individual level cross-sectional data on 24 181 participants aged ⩾15 years from 17 studies conducted between 1990 and 2014 in eight countries in SSA. Receiver operating characteristic curves were used to derive optimal WC cut-points for detecting the presence of at least two components of metabolic syndrome (MS), excluding WC. RESULTS: The optimal WC cut-point was 81.2 cm (95% CI 78.5-83.8 cm) and 81.0 cm (95% CI 79.2-82.8 cm) for men and women, respectively, with comparable accuracy in men and women. Sensitivity was higher in women (64%, 95% CI 63-65) than in men (53%, 95% CI 51-55), and increased with the prevalence of obesity. Having WC above the derived cut-point was associated with a twofold probability of having at least two components of MS (age-adjusted odds ratio 2.6, 95% CI 2.4-2.9, for men and 2.2, 95% CI 2.0-2.3, for women). CONCLUSION: The optimal WC cut-point for identifying men at increased cardiometabolic risk is lower (⩾81.2 cm) than current guidelines (⩾94.0 cm) recommend, and similar to that in women in SSA. Prospective studies are needed to confirm these cut-points based on cardiometabolic outcomes.International Journal of Obesity advance online publication, 31 October 2017; doi:10.1038/ijo.2017.240.

Body fat estimation in black South Africans: a pilot study.

OBJECTIVE: To estimate and compare the percentage of body fat in Black South Africans by underwater weighing (using three different equations), skinfold thicknesses measurements and bioelectrical impedance, in order to ascertain whether existing equations for body fat estimation apply to this racial group. DESIGN: Blind comparison of techniques. SETTING: Academic hospital. SUBJECTS: 22 (11 female and 11 male) healthy Black South African volunteers were studied, for hydration reasons, we present the data of 14 (six female and eight male) with a Body Mass Index between 20 and 30 kg/m2. MAIN OUTCOME MEASURE: Percentage of body fat. RESULTS: The comparisons indicated that the different methods give results which are in the same direction (all correlations were 0.69 or higher), but apart from the three underwater weighing equations, the methods do not give results which are the same. The 95% limits of agreement indicated a difference of no larger than four units between the underwater weighing equations, whereas the skinfold estimate could differ from the underwater weighing estimates by as much as 14 units, and bio-impedance could differ from the underwater weighing estimates by as much as 18 units. CONCLUSION: From this pilot study we conclude that skinfold thickness measurements and bioelectrical impedance are unproblematic means for estimating percentage of body fat. Existing equations for body fat estimation by underwater weighing and skinfold thickness measurements seem to be applicable to this racial group, but we suggest that further research should be conducted to develop, ethnic-specific equations within racial parameters.

Diabetes mellitus, pulmonary tuberculosis and chronic calcific pancreatitis revisited.

The prevalence of chronic calcific pancreatitis (CCP) was determined in 25 successive patients with both diabetes mellitus and newly diagnosed pulmonary tuberculosis. Twenty patients (80%) were alcoholics and all were black. Of these, 9 (45%) had CCP. In only 3 of these 9 patients was the history compatible with the condition diagnosed. Clinical steatorrhoea was absent in the patients with CCP. Pulmonary tuberculosis was extensive with major involvement of three or more lung zones in 36% of patients. Mainly basal involvement of the lungs was present in 8% of patients.

Ophthalmoscopy versus non-mydriatic fundus photography in the detection of diabetic retinopathy in black patients.

The contribution of non-mydriatic fundus photography in the detection of diabetic retinopathy before and after dilatation of the pupils in black diabetics was investigated and compared with direct ophthalmoscopy. Eighty-six patients were examined and good-quality photographs were obtained for 54.7% of eyes before and 86.6% of eyes after dilatation. Photographically documented retinopathy was detected by ophthalmoscopy in only 64.7% of eyes. The two methods were concordant for the presence of retinopathy in 62.2% of eyes before and 56.9% of eyes after dilatation. Photography through dilated pupils also improved the rate of detection of diabetic retinopathy from 24% to 30%. The 45 degrees non-mydriatic fundus camera was found to be a valuable adjunct in the detection of diabetic retinopathy in a busy diabetic clinic.

Humalog Mix25 improves 24-hour plasma glucose profiles compared with the human insulin mixture 30/70 in patients with type 2 diabetes mellitus.

OBJECTIVE: To compare the effects of Humalog Mix25 (Humalog Mix75/25 in the USA) (Mix25) and human insulin 30/70 (30/70) on the 24-hour inpatient plasma glucose (PG) profile in patients with type 2 diabetes mellitus (T2DM). DESIGN: A randomised, open-label, 8-week crossover study. Study insulins were injected twice daily, 5 minutes before breakfast and dinner. SETTING: Four-week outpatient (dose-adjustment) treatment phase, and 3-day inpatient (test) phase. PATIENTS: Twenty-five insulin-treated patients with T2DM (ages 40-66 years), mean (+/- standard error of the mean) (SEM) HbA1c 7.7% +/- 0.23%, and body mass index (BMI) 29.3 +/- 0.83 kg/m2. OUTCOME MEASURES: 24-hour PG profiles, PG excursions after meals, PG area under the curve (AUC), and 30-day hypoglycaemia rate. RESULTS: The 2-hour PG excursions following breakfast (5.5 +/- 0.34 v. 7.2 +/- 0.34 mmol/l, p = 0.002) and dinner (2.4 +/- 0.27 v. 3.4 +/- 0.27 mmol/l, p = 0.018) were smaller with Mix25 than with 30/70. PG AUC between breakfast and lunch was smaller with Mix25 than with 30/70 (77.6 +/- 3.8 v. 89.5 +/- 4.3 mmol/h/ml, p = 0.001). PG AUC between lunch and dinner, dinner and bedtime, and bedtime and breakfast did not differ between treatments. Pre-meal and nocturnal PG were comparable. The postprandial insulin requirement for lunch meals was supplied equally by the two insulin treatments. The thirty-day hypoglycaemia rate was low (Mix25 0.049 +/- 0.018 v. 30/70 0.100 +/- 0.018 episodes/patient/30 days, p = 0.586) for both treatments. CONCLUSION: In patients with T2DM, Mix25 improved the 24-hour PG profile with lower postprandial PG excursions than with human insulin 30/70.

Early thyroidectomy for medullary thyroid carcinoma in children and young adults with the multiple endocrine neoplasia type 2A (MEN 2A) syndrome.

A South African family, at risk for the multiple endocrine neoplasia type 2A (MEN 2A) syndrome, was identified. The Bloemfontein MEN Study Group was founded, inter alia, to study the effects of early detection of medullary carcinoma of the thyroid (MTC) and treatment by total thyroidectomy in children and young adults with MEN 2A. Genotypes were identified by DNA probe and MTC diagnosed by basal and stimulated calcitonin levels. Between 1986 and 1989, 10 members of the family underwent total thyroidectomy and central lymph node dissection for MTC. There were 6 female and 4 male patients (mean age 22,0 years; range 10 - 35 years). Histological examination of the resected thyroid revealed MTC in all patients; 8 had bilateral disease and 2 unilateral. Lymph nodes were negative for MTC in all patients. None of the patients suffered injury to the recurrent nerve, while 1 experienced transient hypoparathyroidism postoperatively. Replacement therapy is maintaining thyroid hormone levels in all patients. Screening should probably begin at the age of 1 year, and total thyroidectomy should be performed when an elevated calcitonin level is observed.

Experience with a provocative test of calcitonin release as a prospective screening for preclinical medullary thyroid carcinoma in MEN type 2A family members.

We report our experience with a provocative test of calcitonin (CT) release using a combined stimulus of intravenous 10% CaCl2 solution and pentagastrin on 34 normal adults (15 females: age 41 +/- 12.3 years and range 22-65 years; and 19 males: age 43 +/- 9.1 years and range 23-60 years) and in 44 family members of three proven multiple endocrine neoplasia type 2A syndrome (MEN 2A) patients. A commercial radioimmunoassay was used to determine the serum CT levels. Peak CT levels were reached within 2 to 5 minutes after administration of the stimulus in all subjects tested. In the group of normal subjects there was no significant difference in the mean basal CT levels between males (54.8 +/- 21.7 pg/ml) and females (56.5 +/- 34.8 pg/ml), whilst the mean peak response values for males was 146.3 +/- 120.6 pg/ml, which was significantly different from the mean value of females, namely 71.6 +/- 39.0 pg/ml. We did not find significant correlations between the basal CT level, peak CT response, and age. Of the 44 family members tested, 9 showed an exaggerated CT response to the combined stimulus and subsequently had a total thyroidectomy. Histological examination confirmed C-cell hyperplasia (CCH) in one and medullary thyroid carcinoma (MTC) in the other 8. Three of the 9 had high basal plasma CT levels. The 9 patients were retested postoperatively and all showed a flat response to the combined stimulus. Those family members with histological proof of MTC or CCH were screened for genetic linkage to the disease gene for MEN 2A using probe MCK2, and showed correlation in each instance.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary heart disease risk factors in a rural and urban Orange Free State black population.

OBJECTIVE: To determine and compare the prevalence of ischaemic heart disease (IHD) risk factors in a rural and an urban black population. DESIGN: A survey to determine the prevalence of hypertension, diabetes mellitus, smoking, obesity, central obesity and dyslipidaemia in black subjects 25 years and older. SETTING: The indigenous black populations of QwaQwa and Mangaung. PARTICIPANTS: A random sample of 950 households was selected from each area. From each household an unrelated male and/or female subject was selected in a standardised way. From QwaQwa 853 subjects (279 men and 574 women) and from Mangaung 758 subjects (290 men and 468 women) participated in the study. The response rate was 68% and 62% respectively for QwaQwa and Mangaung. MAIN OUTCOME MEASURES: Few urban-rural differences in the prevalence of IHD risk factors were found in this study. A low prevalence of clustering of major IHD risk factors was noted. RESULTS: The age- and sex-adjusted prevalences of hypertension were 29% in QwaQwa and 30.3% in Mangaung. Diabetes was present in 4.8% of the QwaQwa sample and 6% of the Mangaung sample. The prevalence of heavy smoking in the Mangaung sample was almost double that of the QwaQwa sample and mostly confined to men. High-risk hypercholesterolaemia was present in 12.5% of QwaQwa and 6% of Mangaung men in the 25-34-year age group. The corresponding figures for moderate-risk hypercholesterolaemia were 34% and 44.8% and both levels of risk declined with increasing age. The mean body mass index of women in both samples exceeded 25 kg/m2. CONCLUSION: All the elements for a potential epidemic of atherosclerotic cardiovascular disease are present in the study populations. The similarity of findings in the two samples may be indicative of the advanced stage of urbanisation and westernisation of the rural group. It is alarming that subjects in the younger age groups tended to have the highest prevalences of moderate and even high-risk hypercholesterolaemia.

Multiple endocrine neoplasia type 2A (MEN 2A) syndrome in a South African family. Biochemistry and molecular genetics.

Multiple endocrine neoplasia type 2A (MEN 2A), an uncommon heritable disease, was investigated in an Afrikaner kindred. Serum calcitonin levels after combined pentagastrin and calcium chloride stimulation were measured to determine thyroid involvement, as were urinary metadrenalin levels to determine adrenal gland involvement. MEN 2A genotype status was determined using the DNA probe MCK2 (D10S15). The index patient, who showed both thyroid and adrenal gland involvement, died of phaeochromocytoma complications. Thirty-four of his 114 family members, in 4 generations, were investigated. Nine had positive histological and calcitonin tests and were predicted to be MEN 2A genotypes by DNA analysis. One asymptomatic individual had a positive calcitonin test after being predicted to be a MEN 2A genotype with the probe MCK2. In 3 DNA-positive cases calcitonin stimulation tests were negative. Preclinical detection of the heritable form of MEN 2A will be facilitated by utilising the DNA probe MCK2 to determine carrier status in this large South African family. It is also the first South African family in which biochemical and molecular genetic techniques were used to facilitate diagnosis.

Evaluation of a family at risk for the multiple endocrine neoplasia type 2A (MEN 2A) syndrome.

A multidisciplinary group was formed to advise on strategy and to co-ordinate the management of a family at risk for the multiple endocrine neoplasia type 2A (MEN 2A) syndrome. A proposed strategy is outlined in which DNA analysis and provocative calcitonin testing is central.

Application of the new ADA criteria for the diagnosis of diabetes to population studies in sub-Saharan Africa. American diabetes association.

AIMS: To examine the implications for epidemiological studies of the American Diabetes Association (ADA) recommendation that the fasting blood glucose at a lowered level becomes the main diagnostic test for diabetes on cross-sectional-based data from sub-Saharan Africa. METHODS: Data from 11 surveys conducted in rural, peri-urban and urban Cameroon (n = 1804), South Africa (n = 3799) and Tanzania (n = 10013) which measured fasting (ADA criteria) and 2-h blood glucose concentrations during a standard 75 g OGTT (old WHO criteria) were analysed. RESULTS: The prevalence of diabetes was higher in eight of the 11 surveys when applying the new ADA compared to the old WHO criteria. With the exception of one population (Mara, Tanzania) the absolute difference in prevalence between the two classifications tended to be small (< 2%). There was considerable variation in the categorization of individuals using the ADA and old WHO criteria. The level of agreement between the two ranged from fair to good (Kappa statistic 0.17-0.86). The prevalence of impaired fasting glycaemia (IFG) was lower than that of impaired glucose tolerance (IGT) in 10 of the surveys and the agreement between the two was fair, < or = 0.26 in all the surveys. CONCLUSIONS: Although the use of the new ADA fasting criteria for prevalence surveys is an attractive and practical option, particularly in Africa, further information is required on the characteristics and prognosis of individuals classified as IFG or diabetic by the fasting criteria, prior to wide adoption of the ADA criteria. Ideally measurement of both fasting and two low glucose concentrations should remain the standard for epidemiological studies.