OBJECTIVE: To investigate the association between reproductive factors and the risk of ovarian cancer among southern Chinese women. METHODS: A hospital-based case-control study was undertaken in Guangzhou, Guangdong Province, between 2006 and 2008. A structured questionnaire was used to obtain information on parity, oral contraceptive use and other reproductive factors in a sample of 500 incident ovarian cancer patients and 500 controls (mean age, 59 years). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression models. RESULTS: High parity was inversely associated with ovarian cancer, with an adjusted OR 0.43 (95% CI, 0.30 to 0.62) for women who had given birth to 3 or more children compared to women who had given no more than one birth. Ever use of oral contraceptives was also protective against ovarian cancer; adjusted OR 0.56 (95% CI, 0.40 to 0.78). No association was found for hormone replacement therapy, menopausal status, hysterectomy and family history of ovarian and/or breast cancer. CONCLUSION: High parity and oral contraceptive use are associated with a lower risk of ovarian cancer in southern Chinese women.
Asian Continental Ancestry Group ; Breast ; Case-Control Studies ; Child ; China ; Contraceptives, Oral ; Female ; Hormone Replacement Therapy ; Humans ; Hysterectomy ; Logistic Models ; Odds Ratio ; Ovarian Neoplasms ; Parity ; Parturition ; Surveys and Questionnaires

Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.
Humans ; Lung Neoplasms/*etiology/prevention & control ; Risk Assessment ; Tea/*adverse effects

OBJECTIVE: To assess the association between condom use and oral contraceptive consumption and the risk of cervical intraepithelial neoplasia (CIN). METHODS: A cross-sectional study was conducted in Perth clinics. A total of 348 women responded to the structured questionnaire. Information sought included demographic and lifestyle characteristics such as the use of condom for contraception, consumption of oral contraceptive, and duration of oral contraceptive usage. Crude and adjusted odds ratio (OR) and associated 95% confidence interval (CI) were calculated using unconditional logistic regression models and reported as estimates of the relative risk. RESULTS: The prevalence of CIN was found to be 15.8%. The duration of oral contraceptive consumption among women with abnormal Papanicolaou (Pap) smear result indicating CIN was significantly shorter than those without abnormal Pap smear result (mean+/-SD, 5.6+/-5.2 years vs. 8.2+/-7.6 years; p=0.002). Comparing to < or =3 years usage, prolonged consumption of oral contraceptive for > or =10 years reduced the risk of CIN (p=0.012). However, use of condom for contraception might not be associated with a reduced risk of CIN after accounting for the effects of confounding factors (adjusted OR, 0.52; 95% CI, 0.05 to 5.11; p=0.577). CONCLUSION: Use of oral contraceptives, but not condoms, for contraception appeared to be inversely associated with CIN. Prolonged use of oral contraceptive demonstrated its benefits of reducing the risk of CIN.
Adult ; Cervical Intraepithelial Neoplasia/epidemiology/*prevention & control ; Condoms/*utilization ; Contraception Behavior/*statistics & numerical data ; Contraceptives, Oral/*administration & dosage ; Cross-Sectional Studies ; Drug Administration Schedule ; Drug Utilization/statistics & numerical data ; Female ; Humans ; Middle Aged ; Prevalence ; Risk Assessment/methods ; Socioeconomic Factors ; Western Australia/epidemiology