Study in Tanzania of impaired glucose tolerance. Methodological myth?

During a study of diabetes prevalence in six rural Tanzanian communities, a repeat oral glucose tolerance test (OGTT) was carried out in 514 subjects greater than or equal to 15 yr of age within 1 wk of an initial 75-g OGTT. In 498 subjects, blood glucose was measured 2 h after the glucose load on both occasions, and in 175 subjects, fasting blood glucose measurement was also repeated. Of the 498 subjects, 245 had normal glucose tolerance in the first test and were selected at random for further testing; 223 subjects had impaired glucose tolerance (IGT), and 30 had diabetic values. Diabetes and IGT were diagnosed on the basis of the 2-h blood glucose values. In the second test, 241 (98.4%) of the 245 subjects with normal tolerance continued in this category and 4 (1.6%) showed IGT. Of the 223 with IGT in the first test, 171 (76.2%) reverted to normal on the second test, 7 (3.1%) had diabetic values, and 45 (20.2%) persisted with IGT. Of the 30 subjects diagnosed as diabetic in the first test, 8 (26.7%) remained with diabetic values, 11 (36.7%) had IGT, and 11 (36.7%) were normal. Based on the second test, the population-prevalence rates of diabetes and IGT would have been 0.5 and 3.3% vs. 1 and 7.6% based on the first test. There was a significant downward trend in the mean 2-h blood glucose values in all three diagnostic groups. Regression toward the mean could not account for the downward shift in blood glucose values observed on retesting.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical features of HIV-seropositive and HIV-seronegative patients with tuberculous pleural effusion in Dar es Salaam, Tanzania.

In a prospective study, we investigated whether human immunodeficiency virus (HIV) infection alters the clinical presentation in patients with tuberculous pleuritis. One hundred twelve of 118 patients who presented with pleural effusion suffered from tuberculosis (TB); 65 patients (58%) were HIV seropositive. Evidence of disseminated TB was found more often in HIV-positive than in HIV-negative patients (30.8% vs 10.6%, p < 0.02). Dyspnea, fever, night sweat, fatigue, and diarrhea, severe tachypnea, hepatomegaly, splenomegaly, and lymphadenopathy were significantly more common in HIV-infected than in HIV-negative patients with TB. The same applied to a negative Mantoux reaction, lower hemoglobin, higher beta 2-microglobulin values, and in pleural fluid, lower albumin and higher gamma-globulin levels. Among HIV-infected patients, PPD skin test anergy was significantly associated with relative low albumin and gamma-globulin levels of pleural fluid. However, the radiographic features did not differ with respect to HIV status; they were predominantly those of primary pleuritis (78% in each group). We conclude that coexisting HIV infection affects clinical and laboratory features, but not the radiographic presentation of patients with TB pleuritis in Tanzania.

Low prevalence of risk factors for coronary heart disease in rural Tanzania.

A community-based survey was used to assess the prevalence of risk factors for coronary heart disease (CHD) in rural Tanzanians. In all, 8581 subjects (3705 men, 4876 women) aged > or = 15 years in eight villages in three regions in rural Tanzania representing a range of socioeconomic deprivation were studied. The main outcome measures were serum cholesterol and triglyceride level, blood pressure and prevalence of dyslipidaemia, hypertension, smoking, overweight, impaired glucose tolerance (IGT) and diabetes; as well as ECG changes. Mean serum cholesterol levels in men were 4.2, 3.4 and 3.7 mmol/l, and in women 4.4 3.6 and 3.9 mmol/l in Kilimanjaro, Morogoro and Mara regions respectively. In Kilimanjaro region 17.4% of men and 19.0% of women had values above 5.2 mmol/l compared with only 5.0% and 6.7% in Morogoro region and 4.8% and 6.9% respectively in Mara region. Systolic and diastolic blood pressures increased with age in both men and women in all three regions with the most marked increase in Kilimanjaro region and the smallest rise in Mara region. Mean age-adjusted values were highest in Kilimanjaro region (124/75 mm Hg, and 125/76 mm Hg in men and women respectively) and lowest in Mara region (120/70 mm Hg in men and 118/68 mm Hg in women). Hypertension was found in 6.6% of men and 7.5% of women in Kilimanjaro region, 3.3% and 4.7% in Morogoro, and 2.6% and 3.4% in Mara region. Cigarette smoking was found in 42.6% of men in Kilimanjaro region, 28.2% of Morogoro region and 8.6% in Mara region. Less than 4% of women smoked in all three regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes and impaired glucose tolerance in an Asian community in Tanzania.

The prevalence of diabetes and impaired glucose tolerance has been determined in an Asian Muslim community in Dar-es-Salaam, Tanzania. Two-h oral glucose (75 g) tolerance tests were performed on 1049 subjects over 14 years old, who were fasting, from a random sample of families. The overall age and sex-adjusted prevalence of diabetes was 7.1% (4.4% known, 2.7% previously undiagnosed) with a steady increase from 0.8% at 15-24 years and 3.0% at 25-34 years, to 24.9% for 65 years and over. Impaired glucose tolerance (IGT) rates ranged from 11.4% (15-24 years) to 22.3% (over 64 years). The overall age-adjusted prevalence of IGT was 21.5%. The mean body indices (BMIs) were 24.3 and 26.4 for males and females, respectively, but age-adjusted diabetes rates were similar in the two sexes (7.0% and 7.6%, respectively). Diabetes and IGT were commoner in those with BMI greater than 25 only in the older age groups. Diabetes and IGT were commoner in those with a family history of diabetes. Increasing parity was also associated with a higher diabetes prevalence. Diabetes and IGT are thus common in Asians in Tanzania, in contrast to the indigenous community. Rates are indeed higher than in most other immigrant Asian communities.

Urinary stone disease in Dar es Salaam.

Forty four adult patients, 34 males and 10 females, with urinary stones were seen over a six-month-period at Muhimbili Medical Centre, Dar es Salaam. Most patients were peasants and semiskilled workers. 8 of the patients were Arabs, which suggests a high predisposition for this race. 12 of the patients had a history of having suffered from bilharzia. There was a high proportion of bladder (and urethral) stones (30%) but upper urinary tract stones were still predominant (70%). Of 20 patients whose stones were available for analysis, 8 were composed of calcium oxalate, 7 of calcium phosphate and 5 of mixed composition. The ratio of stone patients to all hospital admissions of 243 per 100,000 suggests the prevalence of urinary stone disease is comparable to that found in Western countries.

Serum iron, zinc, copper and bromine in malnourished children in Dar es Salaam, Tanzania.

We measured the serum concentration of iron, zinc, copper and bromine in fifty malnourished children and twenty one healthy controls using energy dispersive X-ray fluorescence spectrometry. The mean ages for the study group and controls were 27.06 and 29 months respectively. The mean weights of the study and control groups were 7.32 and 12.05 +/- 3.07 kilogrammes respectively. The serum iron, zinc, copper and bromine mean levels in the study and control groups were Fe 14.6 (9.9) Zn 12.5 (11.9) Cu 16.5 (21.2) and Br 59.1 (63.0) micromoles per litre. Analysis of variance between the study group and controls showed a significant fall in copper levels even when adjusted for age sex and weight differences (F = 4.6586 p < 0.05). The wide distribution of concentrations of Iron noted in the malnourished children is probably due to haemolysis and rapid catabolism. The role of bromine in nutrition is yet to be established.

Screening for diabetes: does measurement of serum fructosamine help?

The diagnostic sensitivity and specificity for diabetes of serum fructosamine levels and fasting venous blood glucose concentrations were compared in 613 subjects during a diabetes community screening programme of 1049 adult Muslim Asians in Dar es Salaam, Tanzania. Using WHO (1985) criteria 228 had impaired glucose tolerance (IGT), 41 had previously been diagnosed as having diabetes while 32 had newly recognized diabetes. The mean (+/- SD) serum fructosamine levels were 20.9 +/- 3.2, 21.6 +/- 3.2, 23.9 +/- 4.9, and 30.1 +/- 7.9 (mumol g-1 albumin) in subjects with normal glucose tolerance, IGT, newly diagnosed diabetes, and previously diagnosed diabetes, respectively (p less than 0.001 for differences between groups). The specificity of values above the mean +2SD normal was 99% for abnormal glucose tolerance with a sensitivity of only 22% for diabetes. The predictive values were 44% and 97% for positive and negative results, respectively. Very little difference from normal was found for IGT subjects. Expressing fructosamine values in absolute terms or per gram albumin made little difference to sensitivity and specificity. The sensitivity was only 32% for fasting blood glucose greater than or equal to 6.7 mmol l-1, 73% for values greater than or equal to 5.5 mmol l-1, and 100% for fasting blood glucose greater than or equal to 4.5 mmol l-1. It is concluded that both serum fructosamine and fasting blood glucose are poor screening and diagnostic tests for diabetes and for IGT, and that glucose loading is required.

Specificity of hypoglycaemia for cerebral malaria in children.

Glycaemic status on hospital admission was compared in 97 children with severe falciparum malaria (36 with cerebral malaria) and 89 children with other serious illnesses (32 in coma; 57 with acute pneumonia, not in coma). The frequency of hypoglycaemia (blood glucose below 2.2 mmol/l) did not differ significantly between malarial and control patients (5.2% vs 11.2%) nor between the comatose (11.1% vs 18.8%) and conscious (1.6% vs 7.0%) malarial and control subgroups. Compared with normoglycaemic patients, hypoglycaemic patients had appropriately low serum insulin (3.0 vs 8.2 mU/l) and C-peptide (0.13 vs 0.42 mmol/l) and high plasma non-esterified fatty acids (1.42 vs 0.83 mmol/l). Hypoglycaemia, the level of consciousness, and death were all significantly associated with the time since the last meal. Hypoglycaemia is not a specific complication of malaria but is found in severely ill fasted children, resulting from glycogen depletion and perhaps impaired hepatic gluconeogenesis. It should be sought in all severely sick children. A single bolus dose of glucose may not be enough to correct it.

Diagnosis of tuberculosis in patients with pleural effusion in an area of HIV infection and limited diagnostic facilities.

In a prospective study of 118 patients with pleural effusion, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Löwenstein-Jensen medium) in pleural fluid or pleural tissue (obtained by closed biopsy) or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%) and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 patients and dissemination of TB to other sites in 25 patients of whom 20 were HIV positive. By logistic regression analysis we identified 2 independent diagnostic markers for TB pleuritis: pleural fluid protein > 50 g/l (Odds ratio 12.1, 95% confidence interval (CI): 1.1-128.3) and adenosine deaminase of > 10 U/l (Odds ratio 11.08, 95% CI: 1.3-96.4). We conclude that conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, for regions with overstretched health services and high prevalences of tuberculous pleurisy in patients with pleural effusion we suggest a simplified diagnostic approach based on exclusion of other causes of pleural effusion by simple means and use of these diagnostic markers.

PIP: In a prospective study of 118 patients with pleural effusion admitted to four medical wards in Muhimbili Medical Center between January and August 1991, Dar es Salaam, Tanzania, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Lowenstein-Jensen medium) in pleural fluid or pleural tissue obtained by closed biopsy or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. In the remaining 6 non-TB patients adenocarcinoma (1), bacterial infection (2), and aspecific inflammation (3) were diagnosed. 58% of the TB and 3 of the non-TB patients were infected with HIV. The diagnostic procedures were evaluated in 75 patients. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%), and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 (4 HIV-positive) patients and dissemination of TB to other sites in 25 patients, of whom 20 were HIV-positive. By logistic regression analysis, two independent diagnostic markers for TB pleuritis were identified: pleural fluid protein 50 g/l (odds ratio [OR] 12.1) and pleural fluid adenosine deaminase level of 10 U/l (OR 11.08). The sensitivity of these two diagnostic tests was 82% and 97.3%, and the specificity was 83.6% and 50%, respectively. TB was the underlying cause in nearly all patients who presented with pleural effusion (94.9%). TB was confirmed in 75% of these using the referral hospital. Conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, in regions with overburdened health facilities and high prevalence of tuberculous pleurisy in patients with pleural effusion, a simplified diagnostic approach is suggested based on exclusion of other causes of pleural effusion by simple use of these diagnostic markers.

Chronic cyanide poisoning in relation to blindness and tropical neuropathy.

Within a group of 20 patients showing optic atrophy and macula degeneration, 14 patients could be examined for neurological and audiometric defects. In 6 patients neurological signs and symptoms were observed. Nine patients reported loss of hearing and in 3 of them a severe perceptive deafness was seen in the audiogram. In 3 of the 14 patients a combination of severe neurologic and audiologic symptoms developed and in two of them a high thiocyanate concentration in serum was observed. The occurrence of perceptive deafness and posterior column sensory loss in the lower extremities in four of the patients made the diagnosis of polyneuropathy the most plausible. Although a similarity to chronic myelopathies caused by nutritional cyanide poisoning cannot be denied, the mean thiocyanate concentration in plasma 24 mumol/L (1.39 mg/L), and the cyanide levels in the blood 0.09 mumol/L (2.3 micrograms/L) were substantially lower than those found in other individuals during periods of extreme drought in which food only consisted of the bitter variety of cassava. The role of cyanide in the etiopathology of this polyneuropathy is unknown.

Prevalence of diabetes and impaired glucose tolerance in rural Tanzania.

The prevalence of diabetes mellitus and impaired glucose tolerance (IGT) was assessed by use of WHO diagnostic criteria in 6299 Africans aged 15 years and above living in six villages in Tanzania. 0.87% (1.1% male, 0.68% female) had diabetes and 7.8% (6.9% male, 7.7% female) had IGT. Prevalence rates were 1.1% and 8.4%, respectively, when age-adjusted to the USA population. Only 7 (13.5%) of the 53 individuals with diabetes had been known to have the disorder; 34 (74%) of the other 46 were symptom-free. Mean age was 54 (SD 20) for diabetic subjects and 37 (17) years for the whole population. Diabetes and IGT rates did not differ significantly between villages despite geographical, socioeconomic, and dietary differences. Diabetes rates increased modestly with age and body mass index (BMI). Fasting blood glucose (FBG) levels did not rise significantly with age but correlated positively with systolic blood pressure (BP) and negatively with haemoglobin concentration (Hb) and BMI. The 2 hour post-glucose load blood glucose values correlated positively with age, sex, and systolic BP and negatively with Hb. Diabetes is less prevalent in rural Africa than in developed countries, even when age has been corrected for. This difference is probably related to body weight, diet, and exercise.