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A rate ratio (RR) is an important metric for comparing cancer risks among different subpopulations. Inference for RR becomes complicated when populations used for calculating age-standardized cancer rates involve sampling errors, a situation that arises increasingly often when sample surveys must be used to obtain the population data. We compare a few strategies of estimating the standardized RR and propose bias-corrected ratio estimators as well as the corresponding variance estimators and confidence intervals that simultaneously consider the sampling error in estimating populations and the traditional Poisson error in the occurrence of cancer case or death. Performance of the proposed methods is evaluated empirically based on simulation studies. An application to immigration disparities in cancer mortality among Hispanic Americans is discussed. Our simulation studies show that a bias-corrected RR estimator performs the best in reducing the bias without increasing the coefficient of variation; the proposed variance estimators for the RR estimators and associated confidence intervals are fairly accurate. Finding of our application study are both interesting and consistent with the common sense as well as the results of our simulation studies. [ABSTRACT FROM AUTHOR]

Introduction: The promotion of a positive birth experience has been a main goal of the World Health Organization's (WHO) recent work on improving maternity care. The purpose of this study was to assess the cesarean rates, the prevalence of birth practices, perinatal outcomes, and maternal satisfaction, in women involved with the respectful maternity care (RMC) support groups in Sao Paulo, Brazil. Methods: This was a cross‐sectional study of women with low‐risk pregnancies who were assisted by professionals recommended by the RMC groups. An online questionnaire was administered. Variables to assess birth practices were classified as positive, negative, or unspecified according to the WHO guidelines. The Pearson chi‐square tests and odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were computed to assess differences between the groups. Results: Five‐hundred and eighty women completed the questionnaire. The cesarean rate was 14.7%, and the operative vaginal birth rate was 9.5%. The VBAC rate was 87.1%, and there was no significant difference in risk for cesarean between women with or without a prior cesarean. Of all women, 83.1% had a midwife's assistance and 75.5% hired a doula; 81.4% gave birth in a nonlithotomic position. The practices of enema, fasting and episiotomy were all under 2%. All 5‐minute Apgar scores were ≥7. Most (83.1%) women reported having a positive birth experience. Conclusions: Woman's engagement with the birth support groups and a transdisciplinary team focused on RMC are key elements to achieve positive perinatal outcomes and high women's satisfaction. [ABSTRACT FROM AUTHOR]