Risk factors and viruses associated with hospitalization due to lower respiratory tract infections in Canadian Inuit children : a case-control study.

Banerji, Anna; Greenberg, David; White, Laura Forsberg; Macdonald, W Alexander; Saxton, Audrey; Thomas, Eva; Sage, Douglas; Mamdani, Muhammad; Lanctôt, Krista L; Mahony, James B; Dingle, Mia; Roberts, Ann

OBJECTIVES To examine risk factors for lower respiratory tract infections (LRTI) hospital admission in the Canadian Arctic. METHODS This was a case-control study during a 14-month period among children less than 2 years of age. Cases were admitted to the Baffin Regional Hospital in Iqaluit, Nunavut with LRTI. Controls were age matched and came from Iqaluit and 2 communities. Odds ratios (ORs) of hospital admission for LRTI were estimated through multivariate conditional logistic regression modeling for following risk factors: smoking in pregnancy, Inuit race, prematurity, adoption status, breast-feeding, overcrowding, and residing outside of Iqaluit. Viruses in nasophayngeal aspirates were sought at the time of each hospital admission. RESULTS There were 101 age-matched cases and controls. The following risk factors were significantly associated with an increased risk of admission for LRTI (adjusted OR): smoking in pregnancy (OR = 4.0; 95% CI: 1.1-14.6), residence outside of Iqaluit (OR = 2.7; 95% CI: 1.0 -7.2), full Inuit race (OR = 3.8; 95% CI: 1.1-12.8), and overcrowding (OR = 2.5, 95% CI: 1.1- 6.1). Non-breast-fed children had a 3.6-fold risk of being admitted for LRTI (95% CI: 1.2-11.5) and non-breast-fed adopted children had a 4.4-fold increased risk (95% CI: 1.1-17.6) when compared with breast-fed, nonadopted children. Prematurity was not associated with an increased risk of admission. Viruses were identified in 88 (72.7%) of admissions, with respiratory syncytial virus being identified in the majority of admissions, 62 (51.2%). Multiple viruses were isolated in 19 (15.7%) admissions. CONCLUSIONS Smoking during pregnancy, place of residence, Inuit race, lack of breast-feeding, and overcrowding were all independently associated with increased risk of hospital admission for LRTI among Inuit children less than 2 years of age. Future research on the role of adoption and genetics on the health of Inuit children are required.