Adjusting diet-outcome associations for random error: comparison of associations based on observed and estimated usual intakes

    loading  Checking for direct PDF access through Ovid



To compare linear regression coefficients adjusted for random errors with true coefficients.


Three hundred and two individuals from the city of Rio de Janeiro, Brazil answered 20 non-consecutive 24-hr. Means of 20 24-hr were used as an approximation of the usual dietary intakes. It was simulated outcomes with pre-defined linear regression coefficient (β = 1.0, referred as ‘true coefficient’) for usual coffee and soft-drink intakes as explanatory variables controlled for sex and age. Regression calibration was applied in each 1000 random combinations of j days of intake (j = 2, 4 and 6), and adjusted coefficients were compared with true one.


Mean-adjusted coefficients were 1.06 to 1.03 (coffee) and 1.17 to 1.11 (soft drink). The association was not detected (95% CI included zero) in 33 to 23% (coffee) and 37 to 23% (soft drink) when using two and six collection days, respectively, compared with 20% when using observed usual intake. Frequency of consumption as covariate in the regression calibration model increased the precision of the adjusted coefficients.


Adjustment for random errors de-attenuates the association but its precision depends mainly on the number of collection days and sample size.

Related Topics

    loading  Loading Related Articles