Determinants of sexual activity and its relation to cervical cancer risk among South African women.

BACKGROUND: Invasive cervical cancer is the commonest cause of cancer morbidity and mortality in South African women. This study provides information on adult women's sexual activity and cervical cancer risk in South Africa. METHODS: The data were derived from a case-control study of hormonal contraceptives and cervical cancer risk. Information on age of sexual debut and number of lifetime sexual partners was collected from 524 incident cases and 1541 hospital controls. Prevalence ratios and adjusted prevalence ratios were utilised to estimate risk in exposures considered common. Crude and adjusted relative risks were estimated where the outcome was uncommon, using multiple logistic regression analysis. RESULTS: The median age of sexual debut and number of sexual partners was 17 years and 2 respectively. Early sexual debut was associated with lower education, increased number of life time partners and alcohol use. Having a greater number of sexual partners was associated with younger sexual debut, being black, single, higher educational levels and alcohol use. The adjusted odds ratio for sexual debut < 16 years and >/= 4 life-time sexual partners and cervical cancer risk were 1.6 (95% CI 1.2 - 2.2) and 1.7 (95% CI 1.2 - 2.2), respectively. CONCLUSION: Lower socio-economic status, alcohol intake, and being single or black, appear to be determinants of increased sexual activity in South African women. Education had an ambiguous effect. As expected, cervical cancer risk is associated with increased sexual activity. Initiatives to encourage later commencement of sex, and limiting the number of sexual partners would have a favourable impact on risk of cancer of the cervix and other sexually transmitted infections.

Risk of invasive cancer of the cervix in relation to the use of injectable progestogen contraceptives and combined estrogen/progestogen oral contraceptives (South Africa).

BACKGROUND: Cervical cancer is caused by specific types of the human papilloma virus (HPV), but not all infected women develop cancer. It has been hypothesized that hormonal contraceptives may potentiate the oncogenicity of HPV infection. METHODS: In a case-control study of colored and black women in the Western Cape Province, South Africa, 524 incident cases of clinically evident invasive cervical cancer (stages 1b-1V) were compared with 1541 controls, and with a subgroup of 254 HPV-positive controls. FINDINGS: For injectable progestogen contraceptives (95% of which were depot medroxyprogesterone acetate) the overall relative risk, adjusted for confounding, was 1.0 (95% confidence interval 0.8-1.3); for combined estrogen/progestogen oral contraceptives the corresponding estimate was 0.8 (0.7-1.1). When the data were divided into categories of duration of use extending to > or = 15 years, or according to age, ethnic group, or recency of use, there was no consistent evidence of an increased risk. The findings were unchanged when the cases were compared with the HPV-positive controls. INTERPRETATION: The present findings suggest that neither injectable progestogen-only nor combined estrogen/ progestogen oral contraceptives increase the risk of clinically evident invasive cancer of the cervix.