INTERVIEWER VARIABILITY IN ANTHROPOMETRIC MEASUREMENTS AND ESTIMATES OF BODY-COMPOSITION

Objective. The extent of intra- and inter-interviewer variability both in anthropometric measurements and in estimates of body composition w as assessed and the possibility of systematic Variation due to intervi ewer differences investigated. Design and subjects. Seventeen intervie wers trained in the anthropometric measurement technique and 10 health y volunteers (4 men, 6 women) participated in the study on measurement variability. To ensure participation of all interviewers the study wa s carried out on three different days. On each of these days interview ers got randomly allocated to the subjects being present. Each intervi ewer took 12 measurements-body weight, body height, sitting height, ci rcumferences of waist, hip, and midarm, skinfolds (biceps, triceps, su bscapular, and suprailiac), chest breadth and depth-per subject on two occasions. From these measurements, body mass index, waist-to-hip rat io, percentage of body fat, fat mass, fat free mass and metric index w ere determined. For ail anthropometric variables variance components, reliability coefficients (R) and coefficients of variation (CV) were e stimated and systematic differences of measurements between interviewe rs were assessed. Results. Measurement reliability in basic anthropome tric measures expressed as variance components, reliability coefficien ts and coefficients of variation was influenced to a greater extent by inter-interviewer variability (R : 0.858-0.998; CV : 0.1-20.9) than i ntra-interviewer variability (R : 0.979-0.999; CV : 0.0-6.4). The resp ective estimates of body composition exhibited comparatively higher re liability (R(inter): 0.975-0.999; R(intra):0.995-0.999). Measurements more prone to subjectivity, e.g. skinfolds showed lower reliability (C Vinter : 9.3-20.9; CVintra : 3.6-6.4). Although the absolute variation in measures due to interviewers was small, systematic differences amo ng interviewers were clearly evident in all measurements and estimates except sitting height in this group of subjects. Conclusion. Anthropo metric measures and estimates of body composition obtained in the curr ent study show the feasibility of detailed anthropometric data collect ion by multiple interviewers in large-scale epidemiological studies.