Measurement of waist circumference at different sites affects the detection of abdominal obesity and metabolic syndrome among psychiatric patients

There is a lack of understanding about the impact of different waist circumference (WC) measurements on the detection of abdominal obesity and metabolic syndrome in psychiatric patients. This cross-sectional study included a total of 382 inpatients with schizophrenia-related disorders to assess each component of metabolic syndrome. WC was measured at the lowest rib, midpoint between the iliac crest and lowest rib, iliac crest, minimal waist, and umbilicus. Logistic regression analysis was performed to examine the ability of WC at each site to predict the presence of metabolic risk clustering. The mean WC values for all sites were significantly different from each other. The measurement site had an influence on the prevalence of abdominal obesity (30-38.2% in men and 53.9-86.3% in women). The influence on the prevalence of metabolic syndrome was greater with the International Diabetes Federation (IDF) criteria (19.3-23.9% in men and 29.4-43.1% in women) than with the Adult Treatment Panel III (ATP III) criteria (26.1-28.6% in men and 37.3-44.1% in women). The areas under the receiver operating characteristic curve for metabolic risk clustering were highest at the umbilicus and midpoint. Given that the WC measurement protocol has substantial influence on the prevalence of abdominal obesity and metabolic syndrome, a predefined measurement site is required for all psychiatric studies.