Age-standardized Incidence Rates for Leukemia Associated with Consanguineous Marriages in 68 Countries, an Ecological Study

Parametric Models for Survival Analysis of Childhood Cancer Patients' Data

Background: The rate of childhood cancer death has dropped steadily over the past 50 years. The pediatric cancer risk has remained under investigation. Objectives: This study aims at investigating the associated factors with the survival of pediatric patients with retinoblastoma, sarcoma, brain tumor, and leukemia cancer. Methods: The cohort study of 1879 children with retinoblastoma, sarcoma, brain tumor, and leukemia aged < 1, 1 - 5, 6 - 10, 11 - 15, and > 15 years in Mahak Hospital and Rehabilitation Complex from 2007 to 2016 were enrolled in the study. Median survival time was reported for each cancer. Parametric survival models including Gompertz, Weibull, lognormal, and log‑logistic models were fitted. Then, the model with almost minimum Akaike information criterion (AIC) was chosen. The hazard ratio (HR) and the analysis were performed by R3.5.1. Results: Totally, 270 (14.37%) patients with Retinoblastoma, 667 (35.5%) with leukemia, 625 (33.26%) with a Brain tumor, and 317 (16.87%) with Sarcoma were included in this study; 815 (43.37%) patients were female. Gompertz's model was chosen to fit the data due to the minimum AIC. The associated factors with the survival of childhood cancers were as follows: age < 1 year, parental relation, loco-regional relapse and chemotherapy alone (HR: 7.63, 1.56, 4.61, 1.12) in leukemia, other nationalities, metastasis or metastasis and loco-regional relapse and chemotherapy alone (HR = 3.74, 5.75, 2.12) in retinoblastoma, loco-regional relapse and metastasis (HR = 2.40, 3.71) in brain tumor, other ages except for 5 - 10 years, parental relation, chemotherapy alone, and metastasis (HR = 33.3, 1.80, 3.57, 3.8) in sarcoma. Conclusions: Age, parental familial relationships, combination therapy, and metastasis of primary cancer were the risk factors for survival of children with 4 common cancers of leukemia, retinoblastoma, brain tumors, and sarcoma, using the Gompertz model.

CONSANGUINEOUS MARRIAGES AMONG IRANIAN MANDAEANS LIVING IN SOUTH-WEST IRAN

Several studies have indicated that consanguineous marriages (unions between biologically related persons) are associated with increased risk of autosomal recessive diseases and several multifactorial traits. Mandaeans are a closed ethno-religious community living in areas of southern Iraq and Iran (Khuzestan Province). There are currently no data on the prevalence of consanguineous marriages among Mandaeans. The present study was carried out in 2016 to determine the prevalence of consanguinity among Iranian Mandaeans living in Khuzestan Province, south-west Iran. A total of 137 couples (urban areas: 79 couples; rural areas: 58 couples) were included in the study. Information on the consanguineous marriages of the subjects was collected through direct interviews. Marriages were classified by the degree of relationship between couples as double first cousins, first cousins, first cousin once removed, second cousins and unrelated marriages. The coefficient of inbreeding (F) was calculated for each couple and the mean coefficient of inbreeding (α) estimated for the population, stratified by rural and urban areas. The overall frequency of consanguinity was found to be 50.7% in urban and 86.2% in rural areas. There was a significant difference between rural and urban areas in types of marriages (χ 2=24.8, df=4, p<0.001) and first cousin marriages (51.8%) were the most common type. The overall α-value was estimated to be 0.0363 for the Iranian Mandaean population.