Stressful life events in childhood and risk of infectious disease hospitalization

Individuals exposed to high levels of stress might have an increased risk of infectious diseases. However, most of the previous studies have been conducted among adults. To examine the effect of childhood stress, we conducted a nationwide cohort study including all Danish children born from 1977 to 2004. Stressful life events (SFLE) included parental death, death of sibling or parental divorce. Outcome was defined as hospitalizations due to less severe (LSID) or severe infectious diseases (SID). Children were followed until the age of 15 years. The association between SFLE and risk of infections was evaluated through rate ratios (RR) comparing infectious disease incidence ratios in children with and without a history of SFLE. Overall, children exposed to SFLE were at 13% increased risk of LSID (RR=1.13 (1.10– 1.15)), but at no increased risk of SID hospitalization (RR= 1.05 (0.97–1.14)). Looking at the specific type of SFLE, parental divorce increased the risk of LSID (RR=1.11 (1.09– 1.14)) and SID hospitalization (1.11 (1.02–1.21)) by 11%, whereas no increased risk of LSID and SID hospitalization was observed following parental death. Finally, a 34% increased risk of LSID hospitalization (RR=1.34 (1.23– 1.45)) was observed following death of sibling, in contrast to no increased risk of SID hospitalization. Conclusion: Childhood exposure to SFLE, especially parental divorce seems to increase the risk of infectious disease hospitalization. Although we cannot determine whether our observations are the result of a biological effect of stress, adoption of unhealthy behaviours or increased likelihood of hospitalization, our findings do have public health relevance as a considerable proportion of the children today will be exposed to SFLE, the majority to parental divorce.