Agreement Between Self-Reported And Measured Weight Among Older Adults In Southern Brazil

Abstract

OBJECTIVE: To evaluate the agreement between self-reported and measured weight among older adults living in the city of Pelotas, southern Brazil. METHODS: Cross-sectional analyses using data from the second follow-up of "COMO VAI?", a longitudinal population-based study that included community-dwelling older adults from the urban region of Pelotas. Weight was self-reported and measured at the same visit. Standing height was estimated based on knee height, which was measured at the first follow-up (2014). Body mass index was categorized as normal (< 24.9 kg/m2), overweight (between 25.0 and 29.9 kg/m2) or obese (≥ 30 kg/ m2). Agreement between self-reported and measured weight and between body mass index based on self-reported and measured weight was evaluated using Lin’s concordance correlation coefficient and a Bland-Altman plot. The kappa coefficient was used to evaluate the agreement between body mass index according to self-reported and measured weight. RESULTS: Ninety-nine participants were visited at home, where their weight was self-reported and directly measured. The mean difference between measured and self-reported weight was 1.8 kg (95%CI 0.5; 3.1) in men and -0.1 kg (95%CI -1.1; 0.8) in women. Nutritional status according to self-reported and measured weight showed good agreement (81% of the elderly correctly classified themselves) with a kappa of 0.71 in men and 0.68 in women, and a weighted kappa of 0.75 in men and 0.72 in women. CONCLUSIONS: There was good agreement between self-reported and measured weight in women, but strong agreement for nutritional status according to self-reported and measured weight in both sexes, thus self-reported weight can be used to monitor nutritional status in older adults.

Keywords

• self report
• body weight
• nutritional status
• aged