Psychometric evaluation of a Brazilian version of the impact of weight on quality of life (IWQOL-Lite) instrument.
OBJECTIVE
The impact of weight on quality of life (IWQOL-Lite) is a self-administered instrument that assesses quality of life in obesity. It is composed of 31 items and five domains (physical function, self-esteem, sexual life, public distress, and work). The aim of the present study was to evaluate reliability (test-retest), internal structure, construct validity and discriminant validity.


METHODS
IWQOL-Lite scores were obtained from 89 people in a Weight Watchers institution (clinical sample) and 156 community volunteers (community sample). The participants were selected based on the same criteria: gender (female) and age (> 24 years), except for BMI. The community sample also completed the SF-36, a generic measure of health-related quality of life.


RESULTS
The Brazilian IWQOL-Lite demonstrated good test-retest reliability, internal consistency, discriminative validity and convergent validity.


CONCLUSIONS
The IWQOL-Lite is the first specific instrument validated in Brazil for assessing quality of life in obesity. The results reveal that IWQOL-Lite is an instrument with good psychometric properties. Nevertheless, in some cases results were dissimilar to those reported in earlier studies using the original American English.
de A Mariano
M H
MH
Health Sciences and Biomedicine Pernambuco State University, Rheumatologist Oswaldo Cruz University Hospital of the State University of Pernambuco, Brazil. mhz@hotlink.com.br
Kolotkin
R L
RL
Petribú
K
K
de N L Ferreira
M
M
Dutra
R F
RF
Barros
M V G
MV
Almeida
N C
NC
de L Filho
L E
LE
Rabelo
P J
PJ
Monteiro
V
V
da Silva
B F
BF
D000328:Adult; D001938:Brazil; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000523:psychology*; D018579:Patient Selection; D011594:Psychometrics / Q000592:standards*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012649:Self Concept; D011795:Surveys and Questionnaires / Q000592:standards*