Medical Journal of the Islamic Republic Of Iran

en Analysis of Birth Growth: Using a Mixture Cure Frailty Model Biostatistics and Epidemiology Biostatistics and Epidemiology Original Research Original Research Background: The birth rate is important in population growth. Concerns are growing over declining birth rates in Iran, as a developing country in the past decade. The present study aimed to examine population growth in Hamadan and the factors influencing the birth rate.    Methods: This retrospective cohort study utilized data from 633 families with their first child in 2012 in Hamadan—information updated in 2022. The Kaplan-Meier plateau indicates a curing pattern; therefore, a mixture cure frailty model was employed to estimate the probability and hazard rate of having different numbers of children. This model comprises 2 components: the first estimates the probability of birth (or nonbirth, indicating cure), while the second component calculates the birth hazard rate for having different number of children.    Results: Mothers with high school diploma (odds ratio [OR], 0.049; P = 0.004) and under diploma (OR,  0.449; P < 0.001) education levels and fathers with  under diploma (OR, 0.802; P = 0.021) education levels were linked to a lower risk of birth and a higher chance of a cure. Moreover, high school diploma (hazard ratio [HR] = 0.668; P < 0.001) and under diploma (HR = 0.821; P < 0.001) education levels in mothers significantly decreased the birth hazard rate. The shape parameter in the hazard function (μ =  0.933; SE = 0.049) indicates that the hazard rate of birth was decreasing during the follow-up time.    Conclusion: The study found that the mixture cure frailty model was effective in analyzing birth rates, with couples showing a decreased inclination to have more than 2 children. One contributing factor to this trend is the mothers’ education and employment. Recurrent Event, Mixture Cure Model, Frailty, Birth 1154 1159 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-8843-1&slc_lang=en&sid=1 Azadeh Naderi azad.stat.2@gmail.com 200319475328460087461 0009-0004-2319-4685 No Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran Hadis Najafimehr najafi.mehr@yahoo.com 200319475328460087462 200319475328460087462 No Kamal Azam kazam@tums.ac.ir 200319475328460087463 200319475328460087463 No Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran Abbas Rahimi Foroushani rahimifo@tums.ac.ir 200319475328460087464 200319475328460087464 No Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran Ali Moghaddas Jafari a.moghaddasjafari@iautmu.ac.ir 200319475328460087465 0009-0003-9138-4053 No Farhikhtegan Hospital, Azad University of Medical Sciences, Tehran, Iran Mohammed I M Gubari mohammed.jubari@gmail.com 200319475328460087466 200319475328460087466 No Community Medicine, College of Medicine, University of Sulaimani, Sulaimani, Iraq Hende Sadeghi h.sadeghi0808@gmail.com 200319475328460087467 200319475328460087467 No Department of Health Information Management, Tehran University of Medical Sciences, Tehran, Iran Mostafa Hosseini Mhossein110@yahoo.com 200319475328460087468 200319475328460087468 Yes Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran Mehdi Yaseri m.yaseri@gmail.com 200319475328460087469 200319475328460087469 No Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran