Risk factors for goiter in primary school girls in Qom city of Iran

Abstract

Goiter is endemic in Iran. The iodine deficiency disorders program was begun a few years ago in Iran, and the coverage of iodized salt is sufficient now. But, in a periodic yearly medical examination of primary school girls in Qom, the prevalence of goiter was above 30% in 2002. This survey was designed to study the risk factors of goiter in those students. The study was a randomized (multistage, proportional simple random sampling) case-control study. We selected and performed thyroid examinations in 1050 girl students in primary schools in Qom city of Iran in 2002. We found 284 cases: girls in primary schools had goiter in accordance with the clinical exam of World Health Organization classification. Among students who did not present with goiter in the clinical exam, we randomly selected 288 students as the control group. We used a questionnaire to evaluate them for the risk factors of goiter. The mean+/-s.d. ages of cases and controls were 8.7+/-1.3 and 8.9+/-1.3 years, respectively. There is no significant difference between the two groups regarding history of soya, kale, turnip, fish, daily iodized salt usage, education and job of mothers, monthly family income, nationality, immigration and residential situation. By using multinomial logistic regression, we found that storage of iodized salt in open containers, odds ratio (OR): 2.201 (1.412-3.428); P-value <0.0001, medium socioeconomic situation (SES) of family, OR: 2.099 (1.029-4.282), P-value=0.041, district 2 of Qom city, OR: 2.880 (1.376-6.027), P-value=0.005, and district 3 of Qom city, OR: 2.051(1.032-4.078), P-value=0.041, were the major risk factors for goiter in this population. In this study, the main risk factors for goiter were storage of iodized salt in open containers, medium SES and also living in specific districts of Qom city. As the coverage of iodinized salt is over 95% in Iran, we advise the education of the family about storage of iodized salt in closed containers. We also recommend the study of the other risk factors of goiter in the different geographical areas of Iran, because of differences in the SES and nutritional habits. This study was supported by issuing permission letters for our activities: (not funding support) Qom Health Network and Medical Services, Qom Medical University, Qom Primary School Education Office, Fathemieh Medical University.