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F Sitas

Publications and source records attributed to F Sitas.

At least 37 records · Page 2Linked to original sources
PubMed1997

Association between human immunodeficiency virus type 1 infection and cancer in the black population of Johannesburg and Soweto, South Africa.

A case-control study of 913 black cancer patients (aged 15-50 years) was undertaken to measure the association between human immunodeficiency (HIV) infection and cancers believed to have an infective aetiology. Controls were patients with cancers believed not to be infective in origin. The prevalence of HIV in the controls of 7.3% (24 of 325) was similar to the background HIV seropositivity in this population. Odds ratios (ORs) and 95% confidence intervals (CI) adjusted for age, year of diagnosis, marital status and sex were calculated. There was a strong association between HIV infection and Kaposi's sarcoma (KS), with 27 of 33 cases being HIV seropositive, OR = 61.8 (95% CI 19.7-194.2) and an elevated association with non-Hodgkin's lymphoma (NHL), with 27 of 40 cases being HIV seropositive [OR = 4.8 (95% CI 1.5-14.8)]. The elevated odds ratio for KS associated with HIV infection accords with the observed increases in the incidence of KS in several sub-Saharan African countries where the prevalence of HIV is high. The odds ratio for NHL associated with HIV infection was lower than that reported in developed countries, and the reason for this is not clear. No other cancers, including cervical and liver cancers, showed significantly elevated odds ratios associated with HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Thyroid cancer in South Africa--an indicator of regional iodine deficiency.

OBJECTIVE: Because follicular thyroid cancers predominate in iodine deficient and papillary cancers predominate in iodine-replete populations, we have analysed national and regional (former Transvaal) incidences of these cancer types as a surrogate measure of the population iodine nutritional status in South Africa. DESIGN: Statistical analysis, by race and sex, of differentiated thyroid cancers reported to the South African National Cancer Registry (1988), and of the computerised histology records of the Department of Anatomical Pathology, SAIMR (January 1990 to June 1994; Transvaal data). MAIN OUTCOME MEASURES: Relative frequencies of the two cancer types nationally and geographically in the Transvaal region. MAIN RESULTS: Thyroid cancer was underdiagnosed in populations other than white. Nationally, follicular histology accounted for 55% of all differentiated primary thyroid cancers, and predominated especially in black women. Follicular morphology predominated in blacks resident in the rural regions of the former Transvaal (58%), while papillary histology predominated in urban areas (of present-day Gauteng), irrespective of race (78%; P = 0.003). CONCLUSION: The national predominance of follicular thyroid cancer indicates that significant iodine deficiency exists in the country as a whole. The observed urban-rural differences in prevalences of follicular and papillary cancer types suggest regional differences in the severity of iodine deficiency. There is a need for a formal survey of the population iodine nutritional status in South Africa.

Adult↗
PubMed1996

Age standardized incidence rates of oral cancer in South Africa, 1988-1991.

While numbers of papers on oral cancer in South Africa have been published, there have been very few studies on standardized morbidity rates. This paper has developed data collected by the National Cancer Registry from the entire country for the four year period 1988-1991 to present frequency, age standardized incidence rates (ASIRs) and life-time risk (LR) for histologically-diagnosed intra-oral cancers in female and male Asian, black, coloured and white South Africans. During this period 5396 cases of oral cancer were diagnosed in a total number of 157,307 cancer cases (3.4 per cent) excluding squamous cell carcinoma (SCC) and basal cell carcinoma (BSC) of the skin. Intra-oral cancer in all South African females and males accounted, respectively, for 1.8 per cent and 5.0 per cent of all cancers. There was a male preponderance in black, coloured and white groups but females were affected more frequently than men among Asians. The incidence in Asian women (6.66) was higher than those of the women in any of the other population groups, whereas the lowest incidence was found in black women (1.75). The incidence rate in coloured men was particularly high (13.13) whereas the incidence in white males (8.06) was not substantially lower than among black males (9.05). Differences between the eight groups were not significant (X2 = 6.24, df = 3, p > 0.1). The Cumulative Life Time Risk (LR) of developing intra-oral cancer for males and females in the four population groups ranged from 1:65 in coloured males to 1:455 for black females. Gender differences in LR in both black and coloured groups, signals substantial differences in exposure to known carcinogens for this disease. It is disturbing to note that the incidence in the period 1988-1991 was higher in Indian women that it was in 1964-1966, and that educative preventive measures have failed. Similarly, the incidence of intra-oral cancer in coloured men of 13.13 is substantially higher than the figure of 8.8 reported in 1979. If this is an accurately reflected trend, then a major educative programme needs to be pursued in this direction if the relative risk of one in 65 is to be reduced.

Adolescent↗
PubMed1995

Geographical epidemiology of prostate cancer: is there an association with infection?

Incidence and mortality data from the 1960s, when screening for cancers of the cervix and prostate was minimal, reveal a positive but statistically nonsignificant geographical association between the two diseases. Data on cancer incidence from African cancer registries and from the South African National Cancer Registry also show weak but positive associations. To determine whether infection is a cause of prostate cancer, case-control studies need to be conducted on individuals with and without prostate cancer or prostate cancer precursors. The screening of serum for prostate specific antigen provides an excellent opportunity to test for sexually transmitted agents.

Africa↗
PubMed1994

Residual risk of transmission of HIV through blood transfusion in South Africa.

Despite the ongoing review of donor recruitment criteria by local blood transfusion services and the development of highly sensitive and specific testing for the presence of antibodies to HIV in blood and blood products, there remains a residue of HIV in donated blood. This is because of donors who are in the 'window period' between acquisition of HIV and seroconversion, human errors and limits to the sensitivity and specificity of current tests. Data available from a national survey of HIV seroprevalence in South African blood donors allowed for the estimation of the number of units screened negative but likely to be infected with HIV. Assuming window periods of 4.8 and 14 weeks, a test sensitivity of 99.9%, a specificity of 98.5% and a human error rate of 0.1%, the likely rate of HIV-infected blood in the South African blood transfusion supply ranges from 1.1 to 3.9/100,000 units, with a likely estimate of 2.2/100,000 units. In the current South African blood transfusion setting, between 8.1 and 28.2 units of blood per annum will be HIV-positive with a likely estimate of 15.9 units. This corresponds to an odds ratio of between 1:90 909 and 1:25 641 units infected with HIV. These data are comparable with the risk in developed countries. The expected increase in the incidence and prevalence of HIV infection in all adult South African populations necessitates additional measures to ensure a blood supply which is as safe as possible. Some of these measures have already been taken by local blood transfusion services.

Blood Donors↗
PubMed1994

Histologically diagnosed cancers in South Africa, 1988.

The National Cancer Registry (NCR) collects information on cancer diagnoses via a nation-wide network of public and private pathology laboratories. In 1988, 45,570 new laboratory-diagnosed cancer cases were reported to the NCR. Minimal age-standardised registration rates for black, white, coloured and Asian males were 112.2, 229.9, 192.2 and 91.6/100,000, respectively, and those for females 107.2, 201.3 148.1 and 118.0. About 40% of cancers in females and 31.3% in males occurred in potentially economically active adults aged 15-54 years. The top five cancers in males were: (i) basal cell skin cancer; (ii) cancer of the prostate gland; (iii) cancer of the oesophagus; (iv) lung cancer; and (v) squamous cell skin cancer. In females they were: (i) cancer of the cervix; (ii) breast cancer; (iii) basal cell skin cancer; (iv) squamous cell skin cancer; and (v) cancer of the oesophagus. Despite under-reporting, a number of cancers, especially those of the oesophagus and cervix in blacks and skin cancers in whites, rank among the highest in the world. Moreover, 40.4% of the cancers in adult males (15-64 years) and 15.2% of those in adult females were associated with tobacco use.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Radiation therapy services in South Africa.

A survey of both private and public sector radiation therapy facilities in South Africa shows that they are available in only 7 major urban centres. About 20,000 cases are treated yearly by 58 therapists and 190 therapy radiographers, with 37 megavoltage and 24 X-ray machines. Brachytherapy, imaging and planning equipment is also inadequate. With limited epidemiological data it appears that less than 50% of all patients appropriately treated with radiation therapy present for such treatment. Increased referrals from sub-Saharan Africa place further strains on the system.

Brachytherapy↗
PubMed1994

A national sentinel surveillance network for the measurement of ill-health in South Africa. A prerequisite for epidemiological research and health planning.

Data on births, on deaths by cause and on morbidity are essential in planning appropriate health interventions, but the scarcity of these data in South Africa is striking. Some of the limitations of national mortality and morbidity data collection systems are reviewed. In order to improve the usefulness of vital statistical information, it is proposed that active disease monitoring be introduced in a number of surveillance sites where the population has been properly enumerated. A network of these sites would routinely gather information on births and deaths by cause and on a list of conditions that are: (i) easy to identify clinically; (ii) would bring most people to the attention of health personnel; and (iii) would indicate failure of health service provision, environmental control or resource allocation. The measurement of the geographical variation of a number of conditions, coupled with geographical information on health care indicators and risk and health promotive factors in each site, would facilitate the planning of interventions in a rational manner.

Female↗
PubMed1993

A role for the ecological study in the developing world.

Retrospective case-control or prospective (follow-up) studies are important epidemiological tools and have provided useful information on exposure disease associations. Prospective studies would be the ideal option, but many countries (particularly in the developing world) do not have the necessary infrastructure to follow people up. Both retrospective and prospective studies are, however, sometimes conducted without due regard for their own limitations. These limitations are exacerbated when measures of exposure or disease are based on a single measurement and where the population under study is homogeneous with regard to exposure. The former is responsible for regression dilution bias and the latter for a lack of contrasts between exposure groups. Both factors would attenuate any relationship between exposure and disease. Ecological studies in epidemiology are weaker in design than case-control or prospective studies, but in some circumstances an ecological approach, which looks at the prevalence of an exposure or disorder in a number of areas of varying disease rates, may offer some advantages.

China↗
PubMed1992

Histologically diagnosed cancer in South Africa, 1987.

The National Cancer Registry collects information on cases of histologically diagnosed cancer via a country-wide network of private and public pathology laboratories. Minimal age-standardised incidence rates (ASIR, world standard) per 100,000, excluding basal and squamous cell skin cancers, for white, coloured and Asian males were 195.9, 76.2 and 82.9 respectively, and for females 161.8, 68.8 and 81.1 respectively. The oesophagus was the commonest site of cancer in black males, comprising 25.2% of all cancers in this group, and the cervix was the commonest site in black females (31.6%). Basal and squamous cell skin cancers were the leading cancers in white males (ASIR 191.9) and females (ASIR 96.9). Despite limitations, especially in data for blacks, rates for oesophageal, cervical and skin cancers rank among the highest in the world. The lung was the leading site of cancer in coloured males (ASIR 13.8) but this cancer is underestimated in all populations. Reasons for underestimation of cancer incidence include the use of non-histological methods for diagnosing cancer (cytology, radiographs, clinical examination) and variable access of populations, especially blacks and coloureds, to laboratory diagnostic facilities.

Female↗