Effect of exposure to poverty, biological vulnerability, and early psychosocial vulnerability on the occurrence of asthma attacks among seven year olds in the Quebec birth cohort

Background: Asthma is one of the most common childhood diseases. Early exposure to stressful situations such as material deprivation, biological vulnerability, and psychosocial hardship are hypothesized to increase the occurrence and severity of asthma. This study examined the role of biological and psychosocial vulnerabilities, and poverty in explaining the occurrence of asthma attacks among children of the Quebec Longitudinal Study of Child Development (QLSCD).

Method: We used data from the first eight waves of the QLSCD an ongoing birth cohort study. A representative sample of 2120 singleton infants was recruited at the age of 5 months and followed-up annually. Mothers reported the occurrence of asthma attacks between the ages of six and seven years. Main exposure variables: living in poverty before four years old and at age seven years; biological vulnerability (male, second born or over, preterm); psychosocial hardship in the first four years of life (single parenthood, maternal depression, unsafe neighborhood, difficult temperament). Poverty was operationalized as having a household annual income below the Canadian low-income cut-off. Logistic regressions were used to assess main effects of exposure to variables and interactions between poverty and respectively psychosocial and biological vulnerabilities.

Results: There were 1528 participants at age seven years. Among them, 15% were living within poverty and 14% spent most of their first four years of life in poverty. In the final model, exposure to poverty at age 6-7 years (OR=2.13, 95% CI: 1.03, 4.44) or chronic exposure since birth (OR=1.63, 95% CI: .99-2.68) increased the likelihood of experiencing at least one asthma attack in the preceding 12 months. Concurrent poverty and biological vulnerability interact to increase the likelihood of experiencing asthma attacks at ages 6-7 years old.

Conclusion: Poverty may act jointly with biological vulnerabilities in producing poor child health outcomes.