Rural South African Community Research Articles

The use of low density lipoprotein receptor activity of lymphocytes to determine the prevalence of familial hypercholesterolaemia in a rural South African community.

The diagnosis of heterozygous familial hypercholesterolaemia in three rural South African communities in which hypercholesterolaemia is very prevalent could be confirmed by the measurement of low density lipoprotein (LDL) receptor activity in circulating lymphocytes. A nominal cut off point could be proposed which separated the LDL receptor activity of 24 clinically diagnosed heterozygous FH patients and 31 healthy people. LDL receptor activity was measured as total degradation of 125I-LDL and expressed as ng LDL/mg cell protein/6 hours. The cut off point was set at 970 ng/mg protein/6 hours. This proposed cut off point was tested by assaying the LDL receptor of three homozygous FH patients and seven of their obligate heterozygous FH first degree relatives. The three homozygous FH patients showed no receptor activity and the activity of the seven obligate heterozygous first degree relatives fell below the proposed cut off point. To determine the prevalence of FH in the study population, all persons aged 15 to 24 years whose total cholesterol levels fell above the 80th centile for their age and sex, as well as their families, were approached (n = 114). The LDL receptor activity in lymphocytes of 77 of these persons aged 15 to 24 years was determined after applying the exclusion criteria. Ten of the 77 participants had LDL receptor activity below 970 ng LDL/mg protein/6 hours and were therefore diagnosed as being heterozygous FH patients. The calculation of the prevalence (corrected for exclusions) revealed that one in 71 of the 15 to 24 year old permanent residents in the predominantly Afrikaans speaking community suffered from heterozygous FH. This is higher than any FH prevalence previously reported for any group.

The prevalence of ischaemic heart disease in three rural South African communities

In a population reportedly excessively prone to ischaemic heart disease (IHD) i.e. South African (SA) whites, a 3-community study of 7188 subjects aged 15–64 showed a high prevalence of chest pain by questionnaire (9.5% of males, 7.7% of females) or by ECG findings suggestive of IHD (12.8% males, 6.7% females). In the oldest decile (55–64 years) the prevalence of chest pain and/or ECG findings was 33.4% of males and 26.1% of females. For all ages, 18.4% of males and 13.1% of females were apparently affected. Though females were as likely as males to have a history of chest pain they had fewer ECG findings suggestive of IHD and the history was less likely to have been confirmed by a doctor. The significance of individual findings, assessed by the strength of their associations with symptomatic history and age, appeared to differ between the sexes; though very common, medium S-T depression was not classed as suggestive of IHD in females, while left ventricular hypertrophy was unimpressive in males. Large and medium Q waves, large S-T depression, large and medium T wave inversion were positive in both sexes, but left and right bundle branch block only in males. There was little overlap between a history of chest pain and suggestive ECG findings; however, a previous diagnosis of IHD by the family doctor increased the overlap by up to 6 times.

Trachoma in a rural South African community.

The prevalence of trachoma was studied in a representative sample of family units from a rural community. Evidence of current or previous infection was found in 82% of the total population, but there was a relatively low prevalence of intense upper tarsal disease. Most children acquire the disease within the first 3 yr of life, these primary infections having a tendency towards spontaneous cure without complications. The prevalence of active disease and potentially blinding sequelae is higher in elderly females than in males of the same age. Clinical and microbiological evidence suggests that trachoma is transmitted primarily within households in this community, the main source of infection appearing to be children of pre-school age. Chlamydiae were isolated from the eyes of children with intense upper tarsal disease, but not from elderly persons with similar clinical signs.