Environmental Factors before the Onset of Type ۱ Diabetes Mellitus: A Case-Control Study

Objective: The role of environmental factors in the development of type۱ diabetes mellitus (T۱D) is inconclusive. This study aimed to investigate the associations between selected environmental factors and T۱D. Materials and Methods: This group matched case-control study included diabetic and healthy subjects younger than ۱۹ years old in ۲۰۱۷. Cases were diabetic subjects diagnosed before the age of ۱۹ years and controls were healthy subjects with similar distributions of age, sex, and place of living. Information including demographic characteristics, birth season, duration of breastfeeding and major psychological stressors was obtained by a parent-administered questionnaire. Data were analyzed using SPSS version ۱۶ and T-test and chi-square test. Statistical significance was defined as P< ۰.۰۵. Results: The mean age of cases was ۱۲.۵ (±۵.۲) years and ۱۳ (±۶.۷) in controls (P: ۰.۵۵). Compared to controls, children with T۱D had a higher chance of having a major psychological stressor in the family before the onset of diabetes (P: ۰.۰۰۰۱) with odds ratio (OR) ۳.۳, higher neonatal jaundice (P: ۰.۰۱, OR: ۲.۲۵), infection leading to hospitalization within the first year of life (P: ۰.۰۰۷, OR: ۶.۴۶), and lower family income (P: ۰.۰۱۸). Duration of breastfeeding was shorter inT۱D group (P: ۰.۰۱۸, OR: ۳.۴۶) and they had started cereals one month earlier (P: ۰.۰۱۵). Conclusion: Certain environmental factors including major psychological stressors, neonatal jaundice, infection leading to hospitalization within first year of birth and shorter duration of breastfeeding were associated with the development of T۱D.

Keywords:

Environmental factors , Diabetes Mellitus , Type ۱