Self-reported height and weight: timeliness and source of the participant information

Self-reported data on body height and weight have often been used as an alternative when standardized measurements in large population-based examination surveys were not feasible. The timeliness and source of self-reported body height and weight information is often unknown. The aim of this analysis was to understand how up-to-date the self-reported data on body height and weight are, and from which source this information is given.

Within the population based national health interview survey "German Health Update" (GEDA 2022) data were collected from 06 to 10/2022 from 1729 women and 1436 men aged 18 years and older (mean age: 58.8 years, SD: 17.6 years). Participants were asked when height and weight had last been measured, how this was obtained and if they possess a scale. For the response categories given for these questions, the proportions (%) with 95% confidence intervals (CI) were presented. A weighting factor was used to correct for different selection probabilities and for deviations of the sample from the German population. Differences were considered statistically significant if the calculated p-value is < 0.05.

Among adults in Germany, 45.9% (95% CI: 43.1-48.7%) of the population reported that their height had been measured in the last year, 35.0% (32.3-37.8%) more than a year ago and 19.1% (17.1-21.3%) more than 10 years ago. 54.8% (52.0-57.6%) stated that they had been measured by a doctor/medical staff, 19.8% (17.7-22.1%) reported the value on their identity card and 20.3% (18.1-22.6%) had measured themselves. 67.2% (64.5-69.7%) of the population responded that they had measured their weight in the last 4 weeks and 11.9% (10.2-13.8%) in the last 3 months. 84.0% (81.6-86.2%) had a scale at home, and of these 85.9% (83.5-88.1%) had also measured their weight with this scale.

Self-reported data on height measurements, on average are much less recent than weight measurements, which appear to be relatively up-to-date. This limitation should be considered when BMI analyses are based on self-reported data. More precise information on height and weight can only be determined with standardized up-to-date measurements.