Association between risk of breast cancer and fertility factors--a latent variable approach.

BACKGROUND: Breast cancer is the most common malignant tumor in females. Many studies have been carried out in order to assess the reproductive risk factors. Particular attention has focused on information regarding fertility, including breastfeeding, age at first birth and number of live births. These factors are highly correlated with each other. The objective of this study was to employ latent variables to reduce the confounding effect of this correlation with a logistic regression analysis. METHODS: The investigation drew upon results from a dataset belonged to a hospital based case-control study covering 303 breast cancer patients and 303 hospital controls. Data were collected through interview and reproductive variables included age at first full-term pregnancy and live birth, number of pregnancies and live births, and total length of breast feeding. Latent variables were generated using factor analysis and principal components analysis. RESULTS: The study revealed that for both latent variable approaches the odds ratios of two latent variables significantly indicated a protective impact of number of pregnancy and live birth and breastfeeding and a prognostic relation with age at first pregnancy or live birth. CONCLUSION: The findings suggest that breastfeeding and decreasing age at first live birth have protective influences on breast cancer risk. Also using statistical model with latent variables in the presence of collinear data leads to reliable results.

An epidemiological analysis of cancer data in an Iranian hospital during the last three decades.

Cancer is the third leading cause of death in Iranian population. Descriptive epidemiology provides a better understanding of the etiology of cancer and the development strategies. The objective of this study was to collect analysis of data and discuss certain epidemiologic features of neoplasm using data from hospital. Records of 14,540 patients diagnosed for cancer during the time period 1973-2003, who were referred to the department of radiation oncology were studied. The tumors were coded and classified according to the International Classification of Diseases 10th revision and ICD-O. SPSS version 10 was used for statistical analysis. In this study the frequency distribution of cancer patients were computed by age of diagnosis, gender, and anatomical sites. There were 8,178 male patients (56%) and 6,365 females (44%) with a male female ratio of 1.29. Mean age was 44.5?21.6 with a median of 47 years. The mean age of diagnosis for females (43.8.?.19.7) was significantly lower than that of males (45.0?23.1) (P<0.05). The ten most frequent cancer sites among patients were breast (13.6%), brain &CNS (13.6%), skin(13.5%), haemapoitic system(9.7%), lymphoid (7.1%), esophagus (7.1%), colon & rectum (4%), male genital organs (1.3%), bladder (1.3%), lung (1.2%), and stomach (1%). These accounted for 81% of all cases. It was found that 41% of women's cancers were in the breast, female genital organs compared to 7.3%in male genital organs and breast. All tumors except the breast, female genital organs, thyroid, gallbladder and kidney cancers, were more frequent in males compared to women. The frequency of patients with cancers increased with age in both sexes. Overall 53% of cases were between 40-63 years of age. For those aged 54 and below the male to female ratio was 0.99, while after this age the ratio rose to 1.61. About 16.6% of tumors occurred in children aged 15 years or younger. More than four fifths (81%) of patients with cancer of haematopoeitic system were under age of 15 years. In conclusion, the results of this study present an important epidemiological understanding of patients with tumors. It emphasizes that gender plays an important role in the frequency of primary tumors, and how much the sex ratio varies with some types of tumors. We also noted that certain tumor types show a prediction for certain decades of life in our series.

Socioeconomic factors association with knowledge and practice of breast self-examination among Iranian women.

BACKGROUND: Breast cancer is the leading type of cancer in women and is one of the most frequent cancers among Iranian women. Delay in diagnosis and treatment of breast cancer diminishes a women's chance of survival. Breast self- examination (BSE) may be effective in early detection. The purpose of this study was to identify the relationship between Iranian women's socioeconomic status and their knowledge and practice of BSE. METHODS: Data were from a hospital-based case-control study among women diagnosed with breast cancer. Control subjects were matched to patients on age. 303 breast cancer patients and 303 control women were interviewed. Socioeconomic status and information including knowledge and practices of breast self examination and clinical breast examination were recorded and compared. RESULTS: The mean +/- SD age of cases and controls was 48.2 +/- 9.8 and 50.2 +/- 11.1 (range 24-84 years), respectively. The study revealed that there were significant relationships between education level and knowledge and practices of breast self examination in both cases and controls, increase in usage being observed with the level of education (P<0.05). CONCLUSION: The findings suggest that the knowledge and practices of women toward breast cancer early detection are inadequate in women with a lower level of education. Mass media cancer education should promote widespread access to information about early detection behavior.

Epidemiology of primary intracranial tumors in Iran, 1978-2003.

The pattern of primary brain tumors have not been reported in Iran and the etiology remains largely unknown. The need for current estimation of geographical and secular variation is clear. The purpose of this study was to review cases of brain tumors treated in Shariatti hospital, a neurosurgical center, over the twenty five years from 1978 to 2003. A descriptive, retrospective study was made of 3,437 cases who were hospitalized with brain tumors. Data abstracted from the patients' clinical records included age at the time of admission , sex, histological diagnosis and tumor location. The frequency distribution of brain tumors by age and sex, and histology was calculated for comparison with the literature. There is a preponderance of males over females, the overall ratio of male/female cases was 55.4% to 44.6% (P< 0.05). The average age of the patients at the diagnosis was 33.9 years (SD = 18.1) with a median of 34 years and a ranged from 1 to 95 years. The mean age did not significantly differ between the genders. Of recorded series cases, 20.1% brain tumors occurred in children 15 years and younger, with a mean + sd of 8.7 + 3.9 years, and 79.9 % of cases in adults with the mean + sd of 40.2 + 14.4. The five most common histological types in both sexes were meningioma in 892 cases (26%) followed by astrocytoma in 805 cases (23.4%), pituitary adenoma in 488 cases (14.2%), glioblasomaoma in 278 cases (5.1%) and ependymoma in 166 cases (4.8%). These accounted for 84 % of all brain tumors. The 10 most frequent brain tumors were ranked separately by sex and age groups. Male predominance was observed for the astrocytoma group, craniopharyngiomas, ependymomas, glioblastomas, medulloblastomas, and pituitary adenomas. Meningiomas were the only tumors with a significant excess in females (p<0.05)-- some 28% of cases occurred in patients younger than 20 years of age; 45% cases 21- 45 years of age; 25% cases 46-65 years of age, and 2% cases in patients older than 65 years of age. In conclusion, the results present an important epidemiological basis for understanding of the brain tumor burden in Iran. Wider epidemiological studies of a prospective nature are now required .

Comparison of cancer incidence in Iran and Iranian immigrants to British Columbia, Canada.

Migrant studies provided strong evidence about the role of environment and life style in cancer risk. Iran has experienced many immigrants to other countries with different cultures and environment. This study compares cancer incidence rates in Iran, Iranian immigrants to British Columbia (BC), Canada, and the BC general population. Cancer incidence rates were computed from two population-based cancer registries in Iran and from the BC cancer registry. A listing of common Iranian surnames and given names was produced to identify Iranian immigrants within the BC cancer registry. Age-standardized rates (ASRs) were calculated using mid year census data. The overall cancer incidence rate for Iranian female immigrants was intermediate between rates for Iran and the BC general population, and the rate for Iranian male immigrants was lower as compared to the other population groups. For female Iranian immigrants, the incidence of breast cancer was increased four-fold, and for colorectal cancer two-fold, as compared to Iranian rates. A dramatic decrease was found in the incidence of both stomach and oesophageal cancers for Iranian immigrants of both sexes. For male Iranian immigrants, the incidence of prostate cancer was increased as compared to Iranian rates. Differences in incidence rates of specific cancers were observed between BC Iranian immigrants and Iran, with cancer patterns in Iranian immigrants being more similar to the BC general population. This warrants further investigation into differences in lifestyle and cancer detection.

Methodology to identify Iranian immigrants for epidemiological studies.

Determining ethnic differences in cancer patterns using administrative databases is often a methodological challenge for information on ethnicity or place of birth is commonly lacking. This paper describes the approach we used to identify Iranians residing in British Columbia (BC), Canada and who were registered within the BC Cancer Registry. A listing of common Iranian surnames and given names was generated from two sources: a residential telephone book (with a high density of Iranians) and a provincial breast cancer screening program (which allowed for the selection of women born in Iran). Surnames and given names were reviewed manually and the Iranian names were identified and coded as 'highly probable' and 'probable' Iranian. A name directory was then created and linked with the BC Cancer Registry to identify Iranian cancer cases. Using this method, 1729 surnames and 737 given names were selected from the telephone book, and 1881 surnames and 757 given names from the screening program. The majority of these names were coded as 'highly probable' Iranian (98% and 96% for surnames and given names, respectively). 12% of surnames and 10% of given names were common to both sources. A listing of the most common Iranian surnames and given names is provided. In conclusion, in the absence of other ethnicity data, surnames and given names can be very helpful to identify persons of specific ethnicities when these ethnic groups have distinctive names.