Risk factors of breast cancer in north of Iran: a case-control in Mazandaran Province.

INTRODUCTION: Breast cancer is the most common cancer among Iranian women. This study aimed to determine risk factors for breast cancer in the north of Iran. METHOD: A matched case-control study was conducted in Mazandaran province of Iran in 2004 of 250 biopsy proven cases of breast cancer and 500 neighbor controls that were matched by age within a 3 year period. Statistical analysis was carried out using conditional logistic regression with the backward elimination method and crude and adjusted odds ratios with related 95% CIs were estimated with Stata 8.0 software RESULTS: Multivariate analysis showed that higher education (OR=4.70, 95%CI: 1.71-12.88), late menopause (OR=4.18, 95%CI: 2.54-6.88), history of induced abortion (OR=1.62, 95%CI: 1.13-2.31), positive first-degree family history of breast cancer (OR=3.14, 95%CI: 1.37-7.20), and BMI (OR=1.02, 95%CI: 1.01-1.03) were risk factors for breast cancer. Furthermore, having more episodes of full term pregnancy (OR=0.87, 95%CI: 0.80-0.95), longer duration of breast feeding (OR=0.993, 95%CI: 0.989-0.997) and parity more than 2 were shown to be protective factors. CONCLUSIONS: Our study revealed the role of some modifiable determinants of breast cancer that can be focused by public health intervention in the northern community of Iran. Accordingly, the women who have one or more of the following risk factors should take the special attention to risk of breast cancer: obesity, being menopause, positive family history of breast cancer and history of induced abortion. The protective effect of longer duration of breast feeding should be encouraged too.

Time trends in the occurrence of major GI cancers in Iran.

OBJECTIVE: The aim of this study was to study the changes in occurrence of esophageal, stomach and colon cancers (cancers of interest) over the last 30 years in Iran. MATERIAL AND METHODS: Cancer cases referred to two main cancer centers in the country (the Shiraz cancer center and the Tehran cancer center) during last 30 years and published by the two centers were utilized. Morbidity odds ratios (MOR) were used to study trend in the occurrence of each cancer site in each center. For this purpose the cancers of interest were considered as cases; childhood cancers as controls; and calendar year as exposure. A regression line was fitted to morbidity odds ratios over years and the slope of the regression line was considered to indicate the overall trend. MORs and 95% CIs comparing the last five and first five years were computed to measure the magnitude of the change over time. RESULT: The overall trend for esophageal cancer was decrease (slopes = -0.02 for Shiraz and -0.03 for Tehran); for stomach was increase (slopes = 0.04 for Shiraz and 0.08 for Tehran), and for colon cancer was sharp increase (slopes = 0.02 for Shiraz and 0.10 for Tehran). The magnitude of changes showed stomach cancer to increase by 35% in Shiraz (MOR = 1.35 with 95% CI 1.1, 1.65) and 13% in Tehran (MOR = 1.13 with 95% CI 0.96, 1.38), esophageal cancer to decrease by 20% in Shiraz (MOR = 0.82 with 95% CI 0.62, 1.11) and 50% in Tehran (MOR = 0.52 with 95% CI 0.45, 0.60), and colon cancer to increase by 65% in Shiraz (MOR = 1.65 with 95% CI 1.26, 2.16) and 82% in Tehran (MOR = 1.82 with 95% CI 1.52, 2.25). CONCLUSION: During the last thirty years the occurrence of major GI cancers has changed in Iran with sharp increase in colon cancer, slight to moderate increase in stomach cancer and sharp decrease in esophageal cancer.