Dietary factors and endometrial cancer risk. Results of a case-control study in Mexico.

Daily diet factors that could potentially be related to endometrial cancer (EC) in Mexico are still unknown. This study aims to evaluate the association between EC and Mexican dietary factors. A case-control study in Mexico City was conducted during 1995-1997 in a social security hospital, using 85 incident cases of EC and 629 controls. A validated questionnaire with 116 items about the frequency and type of food intake was used. The analysis of nutrients was performed using the residual method, adjusting by predictor variables through logistic regression methods. In addition, partitional models estimated total caloric intake for other sources. We found no association between EC risk and consumption of animal or vegetable proteins, saturated, monounsaturated, or polyunsaturated fat, although high intake of nutrients such as lactose (odds ratio [OR], 0.46; 95% confidence interval [CI], 0.21-1.01, P for trend = 0.004), vitamin D (OR, 0.38; 95% CI, 0.18-0.82, P= 0.003), and calcium (OR, 0.39; 95% CI, 0.17-0.89, P= 0.02) were inversely associated with EC. Our results suggest that dietary vitamin D and calcium play an important role in the development of EC, although the mechanisms postulated should be explained with additional studies with large populations.

Factors associated with non-epithelial ovarian cancer among Mexican women: a matched case-control study.

The purpose of this study was to identify risk factors associated with the development of non-epithelial ovarian cancer in Mexican women. A case-control study was carried out on women registered with the Mexican Institute of Social Security in Mexico City over a period of two years (1995-97). Twenty-eight new cases were recruited from the Gynecology and Obstetrics Hospital no. 4, "Luis Castelazo Ayala", and were matched by age with 84 controls selected randomly. Eighteen (64.3%) cases of germ cell tumors and 10 (35.7%) stromal sex cord tumors were found. The number of full term pregnancies was associated inversely to development of stromal sex cord tumors with lower risk in women with more than three full term pregnancies (odds ratio, 0.02: 95% confidence interval, 0.001-0.56) compared to nulliparous women. No associations were found respecting to germ cell tumors. Parity was inversely associated to development of stromal sex cord tumors, probably as a result of the endocrine system's influence on the ovaries. The development of germ cell tumors could be associated to factors not evaluated in this study.

Call and recall for cervical cancer screening in a developing country: a randomised field trial.

A randomised field trial was used to assess Mexican women's response to a mailed invitation for a Papanicolaou test. A sample of 4,802 women, 20 to 64 years old, chosen at random from the Mexican Social Security Institute Register were randomly assigned to an intervention and to a control group. A letter of invitation and a reminder were sent to the intervention group. A letter was also sent to the control group at the end of the follow-up period (8.5 weeks) in order to compare the response among women who received a letter in both groups. Cumulative incidence and incidence rates were used to determine the response and the speed of response, respectively. The response among women who had received the letter was 33.5% (efficacy) in the intervention group, while 5.9% (p<0.001) in the control group attended a Papanicolaou test. For the total of women invited, the response was 20.1% (effectiveness) and 3.3% (p<0.001), respectively. The response was greater in rural areas (rural vs. urban/suburban; p = 0.002) and eldest women (50-64 vs. 20-49; p = 0. 02). The response rate was 7 times grater in the intervention than in the control group (RR = 7.1; 95% CI 5.4-9.4; p < 0.001). A mailed invitation to have a Papanicolaou test substantially increases attendance by women who receive it. A mailed reminder improves results. This strategy could be implemented in addition to the ones already in use, mainly among rural and elderly women.

The cervical cancer screening program in Mexico: problems with access and coverage.

A cross-sectional study was carried out in two geographic regions of Mexico - Oaxaca (rural area) and Mexico City (urban area) - to determine the main factors for predicting participation in Cervical Cytology Screening Programs (CCSP), in populations with high mortality due to cervical cancer. We included 4,208 women aged between 15 and 49 years, randomly selected through a national household-sample frame. Knowledge of what the Pap test is used for strongly predisposes use of CCSP in Mexico City (odds ratio [OR] = 46.1, 95 percent confidence interval [CI] = 33.1-64.1) and Oaxaca state (OR = 61.5, CI = 42.0-89.9), as well as high socioeconomic level (Mexico: OR = 2.0, CI = 1.1-7.6; Oaxaca: OR = 4.1, CI = 3.1-5.3), high education level (Mexico: OR = 3.6, CI = 1.5-8.8; Oaxaca: OR = 5.3, CI = 2.8-10.0), and access to social security (Mexico: OR = 1.7, CI = 1.4-2.2; Oaxaca: OR = 2.2, CI = 1.8-2.7). Low coverage of the CCSP is confirmed as an important problem in Mexico.

[Cost-benefit analysis of the Program for Early Screening of Cervico-uterine Cancer]. / Análisis costo beneficio del Programa de Detección Oportuna del Cáncer Cervicouterino.

OBJECTIVE: Previous researches pointed out the critical changes needed to increase the efficiency of the National Screening Programme of Cervical Cancer in Mexico. These changes were assessed through a cost-benefit analysis. This paper presents the results of that appraisal. Figures are presented as US Dollars of 1996 valued as 7.5 pesos for each dollar. RESULTS: The operational unitary cost of the integral process of the cytology-the obtention of the Pap smear, its transportation to the interpretation centre, its analysis, and the notification of results to users-was estimated in US$ 11.6. If the proposed changes are operated, the cost of each citology would increase by 32.7%. The benefit/cost ratio would be 2 and the net benefit of 88 millions of US dollars for the next five years. CONCLUSIONS: The operation of the proposed changes is socially desirable, but should be supported the training activities of the personnel, the increase of the coverage of women at risk, the quality control activities, the monitoring of the program and the communication with women detected as positive cases.

[Epidemiologic panorama of cancer mortality in the Mexican Institute of Social Security: 1991-1995]. / Panorama epidemiológico de la mortalidad por cáncer en el Instituto Mexicano del Seguro Social: 1991-1995.

OBJECTIVE: This paper describes the global cancer mortality and the specific mortality patterns for the main neoplasms among adult members of the Mexican Institute of Social Security (IMSS). MATERIAL AND METHODS: Using official death certificates and information about the population of the IMSS members during 1991-1995, national and regional annual global cancer mortality as well as specific mortality rates for the 10 most important malignant neoplasms by sex were estimated among people older than 20 years of age. The trends for these neoplasms during the study period were estimated by means of Poisson regression. The rate differences in specific cancer mortality by region and sex, for the two major neoplasms, were calculated subtracting specific regional rates from the respective national rate in 1995. RESULTS: The global mortality rate for cancer among men increased from 76.2 in 1991 to 94.8 x 100000 IMSS' members in 1995; and among women from 85.6 to 105.8 x 100000 IMSS' members, representing an increment of 24.4 and 24% men and women, respectively, during the study period. Among men, neoplasm of kidney, leukemia, pancreas, prostate and lung showed the major increment; among women, neoplasm of colon, breast, pancreas, leukemia and liver showed the most significant increment. CONCLUSIONS: In the IMSS it is necessary the integration of a population based cancer registry. The registry will play a main role in disease surveillance and control; will give basic information over incidence and temporal variation, and could be the main source of information for epidemiologic research, as well as planning and evaluation of the quality of medical attention services such as prevention and early diagnosis and treatment.

Validity and reproducibility of cytologic diagnosis in a sample of cervical cancer screening centers in Mexico.

OBJECTIVE: To evaluate the diagnostic precision of the cervical cytology (smear) in a sample of 16 cervical cancer screening centers (CCSCs) from the Mexican Ministry of Health and Mexican Institute for Social Security CCSCs distributed across the country. STUDY DESIGN: Each center received a batch of 90 cytologic specimens with a random positive prevalence of 1.5-36%. Positive cases were always histologically confirmed. The "gold standard" was an expert pathologist certified by the Mexican Board of Pathology. RESULTS: Our results show that cytologic diagnosis validity and reproducibility vary greatly within and between institutions. The false negative rate (FNR) varied between 10% and 54%, independent of the prevalence of positive cases. CONCLUSION: Quality control of diagnostic precision is central to the consistency of results obtained at CCSCs. In Mexico the high FNR calls for governmental regulation of cytopathology policies and methods, such as through national and international accreditation of cytotechnology programs. In order to decrease the FNR, developing countries must frame managerial development strategies to streamline the cervical cancer screening program, including continuing education, improvement of operation processes in CCSCs, internal and external quality control of cytopathology laboratories and cervical sampling procedures, and standardization of diagnostic criteria.

Factors associated with Mexican women's familiarity with the purpose of the Pap test.

Use of health services is usually associated with a variety of factors, including the socioeconomic characteristics of the users, their familiarity with the usefulness of the services provided, and the acceptability and accessibility of those services. To study the factors associated with women's familiarity with the Pap test, a population-based study was carried out in Mexico City and two rural areas in the state of Oaxaca by means of household interviews. The sample consisted of 4208 women 15 to 49 years of age. Univariate, bivariate, and multivariate analyses were done using unconditional logistic regression; the independent variables were access to social security health services, age, education, housing quality, and place of residence (urban or rural); the dependent variable was the interview subject's familiarity with the purpose of the Pap test. The results were expressed as odds ratios with 95% confidence intervals. It was found that 41.5% of the women surveyed did not know the purpose of the Pap test, and that within this latter group, 97% had never had one. Factors found to be associated with not knowing the test's purpose were lack of access to the social security health services (OR = 1.9; 95% CI: 1.5-2.3); illiteracy (OR = 36.1; 95% CI: 17.9-72.7); and low socioeconomic level (OR = 2.9; 95% CI: 2.3-3.7). Also, rural dwellers had less familiarity with the Pap test than urban dwellers (OR = 0.5; 95% CI: 0.4-0.7). These results highlight the need to develop strategies for making the benefits of the Pap test known, bearing in mind the socioeconomic and cultural diversity of the populations involved.

Age of natural menopause among women in Mexico City.

OBJECTIVES: The average age of menopause among women in Mexico City was calculated, considering their reproductive and socio-demographic characteristics. The information was obtained from a population-based control group from a case-controlled study of gynecologic cancer. METHODS: Interviews were carried out with 1005 women resident in Mexico City chosen at random from a sample using the housing sample framework of the Mexico General Directorate of Epidemiology, 472 of whom had undergone a natural menopause. RESULTS: The most important results include an average age for menopause in this population of 46.5 +/- 5 years (95% C.I. 46-48) with a median of 47. Groups of women with an average early menopause were those with no formal education (1.6 years), low socio-economic level (1.3 years, P < 0.05), nulliparas (2.6 years, P < 0.05), those who had never breastfed (2.2 years, P < 0.05) and those who had not used contraceptive hormones (1.7 years, P < 0.05). CONCLUSION: This phenomenon must be documented in Mexico because of its strong links with the morbidity and mortality of the growing number of women who are reaching advanced ages and whose survival is calculated at 30 years after menopause.

[Reproductive risk factors and sexual history associated with cervical cancer in Mexico]. / Factores de riesgo reproductivo e historia de vida sexual asociados a cáncer cervical en México.

Uterine cervical cancer is one of the principal public health problems in Mexico. The national mortality rate for cervical cancer in 1991 is estimated at 9.5 per 100,000 women, representing 4,194 deaths. In the period from August 1990 to December 1992, a case-control study was carried out that included 630 cases of histologically confirmed cervical cancer in eight Mexico City hospitals (two for people with no social security cover, four of the social security system and two private). As controls, 1,005 women were chosen from a random sampling of houses in the Mexico City metropolitan area. The main cervical cancer risk factors found in this study, adjusted for a multivariate model, were multiple normals births (with five births OR of 1.93 and 95% C.I. of 1.22-2.73) and a history of two or more sex partners (the OR with four or more sex partners was 5.56 and a C.I. of 2.3-13.4). In addition, there was an estimated lower risk of disease related to starting a sex life after 25 years of age (OR 0.41 with C.I. of 0.25-0.69) and to having cesareans as compared versus one normal birth (OR 0.28 and C.I. of 0.13-0.61). The information obtained is relevant since it identifies Mexican women with a high-risk of developing cervical cancer which can be used in planning programs for the early detection of cancer in this population.