Seasonal incidence of diabetes mellitus in tropical Africa

Seasonality in diabetes in Yaounde, Cameroon: a relation with precipitation and temperature

Background

Diabetes is a growing health concern in developing countries, with Cameroon population having an estimated 6% affected. Of note, hospital attendees appear to be increasing all over the country, with fluctuating numbers throughout the annual calendar. The aim of the study was to investigate the relationship between diabete hospitalization admission rates and climate variations in Yaounde.

Methods

A retrospectively designed study was conducted in four health facilities of Yaounde (Central Hospital, University teaching hospital, Biyem-Assi and Djoungolo District Hospitals), using medical records from 2000 to 2008. A relationship between diabetes (newly diagnosed diabetes patients or decompensated diabetics) hospitalization admissions and climate variations was determined using the “2000–2008” national meteorological database (precipitation and temperature).

Results

The monthly medians of precipitation and temperature were 154mm and 25 °C, respectively. The month of October received 239mm of precipitation. The monthly medians of diabetic admissions rates (newly diagnosed or decompensated diabetes patients) were 262 and 72 respectively. October received 366 newly diagnosed diabetics and 99 decompensated diabetics. Interestingly, diabetic hospitalization admissions rates were higher during the rainy (51 %, 1633/3232) than the dry season, though the difference was non-significant. The wettest month (October) reported the highest cases (10 %, 336/3232) corresponding to the month with the highest precipitation level (239mm). Diabetes hospitalization admissions rates varied across health facilities [from 6 % (189/3232) in 2000 to 15 % (474/3232) in 2008].

Conclusion

Diabetes is an important epidemiological disease in the city of Yaounde. The variation in the prevalence of diabetes is almost superimposed to that of precipitation; and the prevalence seems increasing during raining seasons in Yaoundé.

A systematic overview of prospective cohort studies of cardiovascular disease in sub-Saharan Africa

Background

Cardiovascular diseases (CVDs) are becoming increasingly significant in sub-Saharan Africa (SSA). Reliable measures of the contribution of major determinants are essential for informing health services and policy solutions.

Objective

To perform a systematic review of all longitudinal studies of CVDs and related risk factors that have been conducted in SSA.

Data source

We searched electronic databases from 1966 to October 2009. Published studies were retrieved from PubMed and Africa EBSCO. Reference lists of identified articles were scanned for additional publications.

Study selection

Any longitudinal study with data collection at baseline on major cardiovascular risk factors or CVD, including 30 or more participants, and with at least six months of follow up were included.

Data extraction

Data were extracted on the country of study, year of inception, baseline evaluation, primary focus of the study, outcomes, and number of participants at baseline and final evaluation.

Results

Eighty-one publications relating to 41 studies from 11 SSA countries with a wide range of participants were included. Twenty-two were historical/prospective hospital-based studies. These studies focused on risk factors, particularly diabetes mellitus and hypertension, or CVD including stroke, heart failure and rheumatic heart disease. The rate of participants followed through the whole duration of studies was 72% (64–80%), with a significant heterogeneity between studies (for heterogeneity, p < 0.001). Outcomes monitored during follow up included trajectories of risk markers and mortality.

Conclusions

Well-designed prospective cohort studies are needed to inform and update our knowledge regarding the epidemiology CVDs and their interactions with known risk factors in the context of common infectious diseases in this region.

Type 2 diabetes management in nurse-led primary healthcare settings in urban and rural Cameroon

AIMS

To implement a protocol-driven primary nurse-led care for type 2 diabetes in rural and urban Cameroon.

METHODS

We set-up three primary healthcare clinics in Yaounde (Capital city) and two in the Bafut rural health district. Participants were 225 (17% rural) patients with known or newly diagnosed type 2 diabetes, not requiring insulin, referred either from a baseline survey (38 patients, 17%), or secondarily attracted to the clinics. Protocol-driven glucose and blood pressure control were delivered by trained nurses. The main outcomes were trajectories of fasting capillary glucose and blood pressure indices, and differences in the mean levels between baseline and final visits.

RESULTS

The total duration of follow-up was 1110 patient-months. During follow-up, there was a significant downward trend in fasting capillary glucose overall (p<0.001) and in most subgroups of participants. Between baseline and final visits, mean fasting capillary glucose dropped by 1.6 mmol/L (95% CI: 0.8-2.3; p< or =0.001). Among those with hypertension, blood pressure also decreased significantly for systolic and marginally for diastolic blood pressure. No major significant change was noticed for body weight.

CONCLUSIONS

Nurses may be potential alternatives to improve access to diabetes care in settings where physicians are not available.

Absence of seasonal variation in Graves disease

PURPOSE

To determine whether there is an identifiable pattern of seasonal variation in the onset of symptoms of orbitopathy and thyrotoxicosis in patients with Graves disease.

METHODS

This retrospective, noncomparative case series reviewed 305 randomly selected office records of patients referred to one author (M.K.) for evaluation of Graves orbitopathy between July 1990 and June 1998. All patients met inclusion criteria for the diagnosis of Graves orbitopathy. During initial evaluation for orbitopathy, patients identified the date of onset of orbital symptoms as well as the earliest date of either onset of thyroid symptoms or documented thyroid abnormality. Patients were excluded from analysis of seasonal variation if they could not recall the month of symptom onset or were euthyroid. The onset of orbital symptoms and identification of dysthyroid state were analyzed by calendar month and season. The chronological relationship of the development of orbital and thyroid symptoms was evaluated.

RESULTS

No significant seasonal variation appeared in the onset of orbital symptoms or identification of dysthyroidism. Out of 148 patients, 115 (78%) developed symptoms of orbital disease within 18 months of the identification of dysthyroidism. The most common presenting orbital symptoms were swelling of the lid or prominence of the globe.

CONCLUSIONS

This study fails to provide evidence for a seasonal influence on the incidence of Graves disease and the associated orbitopathy.

Prospective study of incidence of juvenile diabetes mellitus over 10 years in Dar es Salaam, Tanzania

OBJECTIVE

To ascertain the annual incidence of diabetes requiring treatment with insulin in children and adolescents aged 0-19 years in Dar es Salaam, Tanzania, during a 10 year period from 1 January 1982 to 31 December 1991.

DESIGN

Prospective registration at a major urban hospital of all patients with newly diagnosed diabetes who were resident in Dar es Salaam.

SETTING

Muhimbili Medical Centre, Dar es Salaam, Tanzania.

PATIENTS

86 patients: 45 male, 41 female.

RESULTS

The annual incidence of juvenile diabetes for both sexes was 1.5 per 100,000 population aged 0-19 years (95% confidence interval 1.3 to 1.7). Incidence per 100,000 population per year increased with age: 0.6 (0.0 to 0.13) in the age group 0-4 years, 0.5 (0.3 to 0.7) at 5-9 years, 2.2 (1.8 to 2.6) at 10-14 years, and 3.4 (2.9 to 3.9) at 15-19 years.

CONCLUSION

Juvenile diabetes mellitus is fairly rare in sub-Saharan Africa. If environmental factors such as infection and material deprivation were important determinants of insulin dependent diabetes in Africans, as they may be in Europeans, much higher rates would have been expected unless genetic factors possibly exert a protective role. The eightfold greater incidence in African Americans than in Tanzanians may be related to greater genetic admixture in African Americans with people from countries in Europe with a high incidence.

Relation between early introduction of solid food to infants and their weight and illnesses during the first two years of life

OBJECTIVE

To assess the relations between early introduction of solid food and infant weight, gastrointestinal illness, and allergic illnesses during the first two years of life.

DESIGN

Prospective observational study of infants followed up for 24 months after birth.

SETTING

Community setting in Dundee.

PATIENTS

671 newborn infants, of whom 455 were still available for study at 2 years of age.

MAIN OUTCOME MEASURES

Infants' diet, weight, and incidence of gastrointestinal illness, respiratory illness, napkin dermatitis, and eczema at 2 weeks and 2, 3, 4, 6, 9, 12, 15, 18, 21, and 24 months of age.

RESULTS

The infants given solid food at an early age (at < 8 weeks or 8-12 weeks) were heavier than those introduced to solids later (after 12 weeks) at 4, 8, 13, and 26 weeks of age (p < 0.01) but not at 52 and 104 weeks. At their first solid feed those given solids early were heavier than infants of similar age who had not yet received solids. The incidence of gastrointestinal illness, wheeze, and nappy dermatitis was not related to early introduction of solids. There was a significant but less than twofold increase in respiratory illness at 14-26 weeks of age and persistent cough at 14-26 and 27-39 weeks of age among the infants given solids early. The incidence of eczema was increased in the infants who received solids at 8-12 weeks of age.

CONCLUSION

Early introduction of solid food to infants is less harmful than was previously reported. Longer follow up is needed, but, meanwhile, a more relaxed approach to early feeding with solids should be considered.

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

Diabetes mellitus occurs in all parts of the world, but with striking differences in prevalence and mode of presentation. This article considers the epidemiology of diabetes world-wide and specifically the pattern of diabetes in the tropics which appears to differ from that seen in Europe and the USA. Detailed epidemiological studies will help both in understanding diabetes pathogenesis and in rational management of this very important and common disease.

Diabetes in tropical Africa: a prospective study, 1981-7. I. Characteristics of newly presenting patients in Dar es Salaam, Tanzania, 1981-7

OBJECTIVE

To study the clinical characteristics of newly diagnosed diabetic patients in tropical Africa.

DESIGN

Prospective study of all newly diagnosed diabetic patients registered at a major urban hospital between 1 June 1981 and 31 May 1987.

SETTING

Muhimbili Medical Centre, Dar es Salaam, Tanzania.

PATIENTS

1250 Patients: 874 men, 376 women.

RESULTS

272 (21.8%) Patients had diabetes requiring insulin, 825 (66.0%) had diabetes not requiring insulin, and 153 (12.2%) had diabetes of uncertain type. Most patients (1103, 88.2%) presented with the classic symptoms of diabetes. The peak time of presentation of diabetic patients requiring insulin was at age 15 to 19 years. Male manual workers and peasant farmers with diabetes not requiring insulin presented at a significantly older age and had a lower body mass index than sedentary office workers. Forty six (18.1%) of the patients requiring insulin diabetes and 111 (14.4%) not requiring insulin had first degree relative with diabetes. Twenty seven per cent of patients were underweight (body mass index less than 20 kg/m2) and 14.6% were obese (body mass index greater than 30 kg/m2). Hypertension was diagnosed in 211 (26.7%) of 791 patients not requiring insulin. Nine (3.3%) of those requiring insulin may have had the protein deficient type of diabetes related to malnutrition. The fibrocalculous variety of diabetes related to malnutrition was not observed.

CONCLUSIONS

Newly presenting diabetic patients in Tanzania with diabetes requiring insulin are older at presentation than those in Britain; most diabetic patients present with diabetes not requiring insulin and a smaller proportion of Tanzanian patients are obese. Most have a lower socioeconomic state than diabetic patients in Britain. There are often delays in diagnosis in Tanzania, and there is a higher incidence of death shortly after presentation.