Some recent advances in non-communicable diseases in the tropics. 2. Diabetes mellitus in the tropics

Epidemiology of diabetes in Bucharest

An analysis of the last 20,000 newly diagnosed diabetic patients consecutively registered from 1 January 1981 to 6 June 1991 in the Bucharest Registry of Diabetes showed the following: (1) primary insulin-dependence (Type 1 diabetes) was encountered in only 7% of cases: the rest were Type 2 diabetic patients (8745:43.7% treated with diet alone and 9856:49.3% treated with diet and oral drugs); (2) low body weight (BMI < 25) was encountered in 81.7% of patients in the age group 0-20 years, while obesity (BMI > 27) was encountered in 75.7% of cases in the age group 41-65 years; (3) the overall annual incidence of the Type 1 diabetes for all ages was 5.7/100,000, lowest (1.3/100,000) in the age group 0-4 years and the highest 10.1/100,000) in the age group 65-69 years; (4) the overall annual incidence for the Type 2 diabetes was 76.3/100,000, the lowest (2.4/100,000) in the age group 20-24 years and the highest (261.4/100,000) in the age group 60-64 years. Studying the relationship between the onset of Type 1 diabetes mellitus and age, we did not observe the previously reported strong relationship, so that the distribution of Type 1 diabetes can be considered relatively uniform, with the exception of extreme ages. In conclusion, each year, about 1 in 1000 inhabitants of Bucharest are registered as having diabetes, the majority (93%) had type 2 and only 7% had Type 1 diabetes, one of the lowest incidence rates in Europe.

Interaction of insulin with Pseudomonas pseudomallei

Pseudomonas pseudomallei is the causative agent of melioidosis, a disease being increasingly recognized as an important cause of morbidity and mortality in many regions of the world. An intriguing observation regarding melioidosis is that a significant percentage of patients who develop the disease have preexisting diabetes mellitus. In this regard, we have tested the hypothesis that insulin may modulate the growth of P. pseudomallei. We have demonstrated that insulin markedly inhibits the growth of P. pseudomallei in vitro and in vivo. The growth rate of P. pseudomallei in minimal medium containing human recombinant insulin was significantly lower than that of control cultures containing no insulin. P. pseudomallei grew at an increased rate in serum samples obtained from diabetic rats compared with that in serum samples obtained from control animals. When the insulin level was restored by the addition of human recombinant insulin, the growth rate was reduced to a level similar to that seen in control serum. P. pseudomallei also grew significantly better in insulin-depleted human serum than control human serum. 125I-insulin binding studies demonstrated that P. pseudomallei possesses a specific, high-affinity binding site for human insulin. In in vivo studies, rats made diabetic by streptozotocin injection (80 mg/kg of body weight, intraperitoneally) were significantly more susceptible to P. pseudomallei septicemia than control rats. Thus, it appears that serum insulin levels may play a significant role in modulating the pathogenesis of P. pseudomallei septicemic infections.

Diabetes mellitus in The Gambia, west Africa

A register of diabetic patients attending the Royal Victoria Hospital, Banjul, The Gambia, was kept and data on hospital admissions recorded over a 1-year period. Two hundred and sixty-nine patients (110 men, 159 women) were registered of whom 66 (25%) were receiving insulin. Seventy-five patients (28%: 40 men, 35 women) were newly diagnosed. There were significant differences in age (p less than 0.001) and obesity (p less than 0.001) between men and women and between patients with different types of diabetes. There were 95 hospital admissions (5.2%) related to diabetes, as were a fifth of medical out-patient attendances. Ketoacidosis was the major cause of death while foot infections were more common (p less than 0.01) in women. Diabetes imposed a heavy burden on the health services of The Gambia, a small developing country in West Africa; more than 3.6% of the annual health budget was spent on the treatment of diabetic patients.