Long-term discordant fluctuation of chronic stress and immune biomarkers in children and adolescents affected by the Great East Japan earthquake

抄録

Although reconstruction from the 2011 Great East Japan earthquake and tsunami is proceeding, the environment of children living in the disaster area has not yet recovered. Anxiety among such children may have adverse effects on their future mental and physical health. The purpose of this study was to examine fluctuations in chronic stress and immune conditions in children and adolescents living in the disaster area. The participants were elementary and junior high school students living in the Pacific coastal area of northern Japan. This serial cross-sectional study performed five surveys in September 2011 (6 months, n = 391), March 2012 (1 year, n = 394), March 2013 (2 years, n = 281), March 2014 (3 years, n = 332), and March 2015 (4 years, n = 313). Stimulated whole saliva samples were collected, and saliva flow, secretory immunoglobulin A concentration, secretory immunoglobulin A secretion rate, and cortisol concentration were determined. Cortisol concentration significantly decreased from 6 months to year 2 of the study period, but increased between year 2 and year 4. Secretory immunoglobulin A concentration significantly increased between year 1 and year 4 compared to the first 6 months. Gender differences were observed in saliva flow and secretory immunoglobulin A concentration, and significant differences between elementary and junior high school students were observed in cortisol concentration. Therefore, fluctuation of cortisol concentration as a chronic stress biomarker and an increase in SIgA as an immune biomarker were observed during the 4 years after the disaster, but the changes in the two biomarkers did not correspond.