Prevalence of Skeletal Fluorosis in Northern Tanzania: A Follow-Up Study.

OBJECTIVES: Skeletal fluorosis is a metabolic bone disease caused by excessive exposure to fluoride, predominantly through contamination of drinking water. This study aimed to identify all cases of skeletal fluorosis in Tindigani village situated in Northern Tanzania. This was done following changes in drinking water sources after a previous prevalence study in 2009 in this population. METHODS: In a door-to-door cross-sectional study of Tindigani village, a sample of residents was assessed for skeletal fluorosis and dental fluorosis. Diagnosis of skeletal fluorosis was based on pre-defined angles of deformity of the lower limbs. Dental fluorosis was diagnosed and graded using the Thylstrup and Fejerskov Index. Samples from current drinking water sources underwent fluoride analysis. RESULTS: Tindigani village had a population of 1,944 individuals. Of the 1,532 individuals who were screened, 45 had skeletal fluorosis, giving a prevalence of 3.3% (95% CI=2.4, 4.3). Dental fluorosis was present in 82.5% of those examined (95% CI=79.8, 85.3). Dental fluorosis was present in all individuals with skeletal fluorosis and at higher grades than in the rest of the population. Drinking water samples were collected from 28 sources. These included piped, surface, well, and borehole water sources. Fluoride concentrations ranged from 0.45-38.59 mg/L of fluoride. CONCLUSIONS: Skeletal fluorosis is an ongoing but preventable health problem in the current population. The delivery of sustainable low fluoride piped water to this community would be of clear health benefit. This has been addressed at a local level.

Comparison of two village primary schools in northern Tanzania affected by fluorosis.

High fluoride levels in drinking water sources are a problem throughout the East African Rift Valley and can lead to dental fluorosis (DF) and skeletal fluorosis (SF) in exposed local populations. Two villages in the Hai District of northern Tanzania in which fluoride has been identified as a problem were investigated in a pilot study. Fluoride levels in drinking water sources were measured and the prevalence of DF and deformities due to SF were assessed in children attending school in the two villages. The assessment also recorded the source of drinking water as well as children's height, weight and 3-day food diaries. Over one-quarter of the children in both villages had skeletal deformities, despite one village having much higher levels of fluoride in its drinking water sources. More than 90% of children in both villages had DF. SF and DF are major problems in this area. Deformities relating to SF are common, but the reasons for individual susceptibility remain unclear and may include a low calcium diet, ingestion of magadi (local salt) with high fluoride, or genetic factors.

The prevalence of Parkinson's disease in rural Tanzania.

The prevalence of Parkinson's disease (PD) varies worldwide from 7 to 450 per 100,000, and appears low in sub-Saharan Africa (SSA) but few data exist. We conducted a prevalence study of PD in rural Tanzania. A door-to-door study was conducted in the Hai district project area (population 161,071), using a screening questionnaire followed by structured history and examination of positive responders. Diagnosis was based on the UK PD Society Brain Bank Criteria. 33 (23 men) cases of PD were detected, with mean age 74 years (range 38-94). One patient died before the prevalence date. 78% were previously undiagnosed and untreated. Mean duration of symptoms was 5 years, and median Hoehn and Yahr stage 3. Crude prevalence rates were 30/100,000 (men), 11/100,000 (women) and 20/100,000 (combined). The direct age-standardized prevalence rates compared with the UK population were 64/100,000 (men), 20/100,000 (women) and 40/100,000 (combined). These rates are higher than previously reported from SSA, but still lower than the developed world. Many PD patients in SSA may never be diagnosed or treated, with consequent reduction in their life expectancy and quality of life. With the world population ageing PD is predicted to become an increasing problem.