Background: Variation in cancer incidence in geographical locations is due to different lifestyles and risk factors. Diet and socio-economic position (SEP) have been identified as important for the etiology of cancer but patterns are changing and inconsistent. The aim of this study was to investigate correlations of the incidence of common cancers with food groups, total energy, smoking, and SEP. Materials and Methods: In an ecological study, disaggregated cancer data through the National Cancer Registry in Iran (2008) and dietary intake, smoking habits and SEP obtained through a population based survey within the Urban Health Equity Assessment (Urban-HEART) project were correlated across 22 districts of Tehran. Results: Consumption of fruit, meat and dairy products adjusted for energy were positively correlated with bladder, colorectal, prostate and breast and total cancers in men and women, while these cancers were adversely correlated with bread and fat intake. Also prostate, breast, colorectal, bladder and ovarian cancers had a positive correlation with SEP; there was no correlation between SEP and skin cancer in both genders and stomach cancer in men. Conclusions: The incidence of cancer was higher in some regions of Tehran which appeared to be mainly determined by SEP rather than dietary intake. Further individual data are required to investigate reasons of cancer clustering.

Although many people became infected and recovered during the Covid-19 epidemic, the immunity duration and reinfection in recovered patients has recently attracted many researchers. The aim of this study was to evaluate the recurrence of the infection in recovered individuals over a 9 month period after onset of the Covid-19 epidemic.In this study, data related to Covid-19 patients in Shahroud city were collected using the electronic system for registering suspicious patients and also by checking patients' hospital records. In this study, from March 20, 2020 to November 20, 2020 (9 months) a total of 8734 suspected patients with respiratory symptoms were observed and followed up. RT-PCR was positive for 4039 patients. During this period, out of the total number of positive cases of Covid-19, 10 cases became re-infected after complete recovery. The risk of reinfection was 2.5 per thousand (0.95 CI:1.2-4.5). The mean time interval between the first infection and re-infection was 134.4±64.5 days (range: 41 to 234 days). The risk of reinfection between male and females was not statistically different (1.98 per 1,000 women and 2.96 per 1,000 men). Exposure to COVID-19 may not establish long-term protective immunity to all patients and may predispose them to re-infection. This fact can be reminded that the use of masks, social distancing and other preventive measures are very important in recovered patients and should be emphasized especially in health care personnel who are more exposed to the virus.

The aim of this study was to estimate the basic reproduction number (R0) of COVID-19 in the early stage of the epidemic and predict the expected number of new cases in Shahroud in Northeastern Iran. The R0 of COVID-19 was estimated using the serial interval distribution and the number of incidence cases. The 30-day probable incidence and cumulative incidence were predicted using the assumption that daily incidence follows a Poisson distribution determined by daily infectiousness. Data analysis was done using ‘earlyR’ and ‘projections’ packages in R software. The maximum-likelihood value of R0 was 2.7 (95% confidence interval (CI): 2.1−3.4) for the COVID-19 epidemic in the early 14 days and decreased to 1.13 (95% CI 1.03–1.25) by the end of day 42. The expected average number of new cases in Shahroud was 9.0 ± 3.8 cases/day, which means an estimated total of 271 (95% CI: 178–383) new cases for the period between 02 April to 03 May 2020. By day 67 (27 April), the effective reproduction number (Rt), which had a descending trend and was around 1, reduced to 0.70. Based on the Rt for the last 21 days (days 46–67 of the epidemic), the prediction for 27 April to 26 May is a mean daily cases of 2.9 ± 2.0 with 87 (48–136) new cases. In order to maintain R below 1, we strongly recommend enforcing and continuing the current preventive measures, restricting travel and providing screening tests for a larger proportion of the population.

Background: The effect of related factors on recovery or death rates may vary from country to country. Therefore, we aimed to investigate the relationship between demographic, clinical, laboratory factors on the survival rates of confirmed cases of COVID-19 in Shahroud, Iran. Methods: This is an analytical study of the estimation of the survival of patients with COVID-19. Patients who had positive PCR test were considered as COVID-19 cases, and the 2-month survival of these patients was estimated. Among the diseases, heart disease and diabetes were considered as separate variables, and the patients' histories of other diseases were included in the model as comorbidities. Results: Of 396 confirmed patients hospitalized, 109 patients (27.5%) had a history of heart disease, 100 (25.3%) were diabetic, and 80 (20.2%) had a history of other comorbidities. The number of deaths due to the disease was 59 (14.9%). The median age of those who died was 76 years. The multivariate Cox regression analysis shows that heart disease increases hazard ratio more than two times (HR=2.37, 95% CI: 1.33-4.23). The neutrophil-to-lymphocyte ratio (NLR) factor, (HR=1.15, 95% 1.08-1.22), and older age (HR=1.06, 95% CI: 1.03-1.08) increases the risk of death significantly. Conclusion: The heart disease history, NLR factor and older age are associated with death of COVID-19 and may be helpful for the early warning and prediction of disease progression.

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