Weight changes may bean important indicator of an ongoing pathological process.Retrospective self-report might be the only possibility to capture prior weight. The objective of the study was to evaluate the accuracy of retrospective recallof body weight in old age and factors that might predict accuracy.
Design and Methods:
In 2007, 646 participants (mean age, 71.6 years) of the Swedish Adoption/Twin Study of Aging (SATSA)answered questions about their present weight and how much they weighed 20-years ago. Of these, 436 had self-reported their weighttwenty years earlier and among these 134 had also had their weight assessed at this time point.
Twenty yearretrospectively recalled weight underestimated the prior assessed weight by -1.89 ± 5.9 kg and underestimatedprior self-reported weight by -0.55 ±5.2 kg.Moreover, 82.4% of the sample were accurate within 10%, and 45.8% were accurate within 5% of their prior assessed weights;similarly, 84.2% and 58.0 %were accurate within 10% and 5% respectively, forprior self-reported weight. Current higher body mass index and preferences of reporting weights ending with zero or five was associated with an underestimation of prior weight, while greater weight change over 20 year, and low Mini-Mental State Scores (MMSE) (<25) led to an overestimation of prior weight.
Recalled weight comes close to the assessed population mean, but at the individual level there is a large variation. The accuracy is affected by current BMI, changes in weight, end-digit preferences, and current cognitive ability. Recalled weight should be used with caution.