Direct and proxy recall of childhood socio-economic position and health.

BACKGROUND: The utility of proxy reporting within the life course framework has not been adequately assessed; therefore we sought to assess the magnitude and type of agreement that exists between index and proxy reports for bodyweight, health, and socio-economic position (SEP) in childhood.
METHODS: Participants were enrolled as part of an ongoing study of preterm birth in African American women in Metro Detroit. Post-partum women and their mothers (n = 333 pairs) provided retrospective reports about the woman's childhood bodyweight, health, and SEP. Agreement was assessed using kappa, weighted kappa (κ), and intraclass correlation coefficients (ICC). Log-linear models were used to describe the pattern of agreement for ordinal data.
RESULTS: Birthweight and weight at age 18 was reported with a high level of agreement (ICC = 0.86 and 0.71, respectively). Kappa indicated moderate agreement for early and late childhood/adolescent weight. Log-linear models suggested that there was diagonal agreement plus linear by linear association for early childhood weight and linear by linear association in late childhood/adolescence. Reports of childhood medical problems and hospitalisations had only moderate agreement. Agreement for SEP in both early (κ = 0.14) and late childhood/adolescence (κ = 0.20) was poor. Log-linear models suggest a linear by linear association, indicating a positive association between the responses.
CONCLUSIONS: Results suggest that proxy reports may be utilised in conjunction with an index report to provide an estimate of the accuracy of report or to more fully capture experiences over the life course. This may be particularly useful when multiple developmental periods are examined.