Mapping the Relative Risk of Congenital Hypothyroidism Incidence via Spatial Zero-Inflated Poisson Model in Guilan Province, Iran

Bahare Gholami Chaboki; Manijeh Tabrizi; Maryam Heydarpour Meymeh; Hojjat Alaei; Alireza Akbarzadeh Baghban

doi:10.4103/ijpvm.IJPVM_299_19

Mapping the Relative Risk of Congenital Hypothyroidism Incidence via Spatial Zero-Inflated Poisson Model in Guilan Province, Iran

Int J Prev Med. 2021 May 27:12:53. doi: 10.4103/ijpvm.IJPVM_299_19. eCollection 2021.

Authors

Bahare Gholami Chaboki¹, Manijeh Tabrizi², Maryam Heydarpour Meymeh³, Hojjat Alaei¹, Alireza Akbarzadeh Baghban⁴

Affiliations

¹ Department of Biostatistics, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
² Pediatric Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran.
³ English Language Department, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
⁴ Department of Biostatistics, Proteomics Research Center, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

Background: Congenital hypothyroidism (CH) is one of the most prevalent preventable causes of mental retardation. Studies show that the incidence rate of CH is very high in Iran. Disease mapping is a tool for visually expressing the frequency, incidence, or relative risk of illness. The present study aimed to model CH counts considering the effects of the neighborhood in towns and perform mapping based on the relative risk.

Methods: In this historical cohort study, data of all neonates diagnosed with CH with TSH level ≥5 mIU/L between March 21, 2017, and March 20, 2018, in health centers in Guilan, Iran were used. The number of neonates with CH was zero in most towns of Guilan Province. The Bayesian spatial zero-inflated Poisson (ZIP) regression model was employed to investigate the effect of the town's neighborhood on the relative risk of CH incidence. Then, the map of the posterior mean of the relative risk for CH incidence was provided. The analysis was performed using OpenBUGS and Arc GIS software programs.

Results: The relative risk of CH incidence was high in the West of Guilan. Moreover, the goodness-of-fit criterion indicated that it is more appropriate to fit the Bayesian spatial ZIP model to these data than the common model.

Conclusions: Considering the high relative risk of CH in the Western towns of Guilan Province, it is better to check important risk factors in this region.

Keywords: Bayes theorem; Poisson distribution; congenital hypothyroidism; neonates; spatial analysis.