Detection of cardiovascular risk factors by anthropometric measures in Tehranian adults: receiver operating characteristic (ROC) curve analysis
Objective: To determine optimal cutoff points of anthropometric measures as cardiovascular indicators in an Iranian adult population. Design: Population-based cross-sectional study. Setting: Tehran, the capital of Iran. Subjects: A total of 10522 subjects (4449 men and 6073 women) aged 18-74 y. Methods: Demographic data were collected and anthropometric indices were measured. Blood pressure was evaluated and hypertension was defined based on JNC VI. Biochemical measurements were done. Diabetes was considered as FBSgreater than or equal to126 mg/dl (greater than or equal to7.0 mmol/l) and dyslipidemia was defined according to ATP II. Risk factors were considered as: hypertension, diabetes, dyslipidemia, 'hypertension or diabetes', 'hypertension and diabetes', 'hypertension or dyslipidemia', 'hypertension and dyslipidemia', 'diabetes or dyslipidemia', 'diabetes and dyslipidemia', 'at least one risk factor' and 'at least two risk factors'. ROC curve analysis was performed to determine optimal cutoff values-where the sensitivity approximates specificity. Results: Younger men (the age category of 18-34 y) had higher WC than women. Men had higher waist-to-hip ratio (WHpR) and lower waist-to-height ratio (WHtR) than women in all age categories. Dyslipidemia, 'hypertension or dyslipidemia', 'diabetes or dyslipidemia' and 'at least one risk factor' were more prevalent risk categories in both genders. Range of areas under ROC curves for BMI and WC was 0.55-0.94 and 0.56-0.93 for men and 0.41-0.94 and 0.53-0.92 for women in various age groups, respectively. Range of areas for WHpR and WHtR in men was between 0.58-0.87 and 0.56-0.94, respectively, and for women varied between 0.53-0.91 and 0.53-0.90 in various age groups, respectively. Cutoff points of BMI for various risk factors were between 24 and 29 kg/m(2) in men and 25-31 kg/m(2) in women. Range of WHpR was between 0.86 and 0.97 in men and between 0.78 and 0.92 in women. Cutoff points for WC and WHtR were between 80 and 93 cm and 0.47 and 0.56 for men and between 79 and 96 cm and 0.50 and 0.63 for women in different age groups to detect various risk factors, respectively. In general, values were lowest for the most prevalent risk factors and highest for less prevalent conditions. Conclusion: The results suggested cutoff points of anthropometric measures as indicators of cardiovascular risk factors. It seems that these cut-points are higher for Iranians than for other Asian populations. Sponsorship: Endocrine Research Center, Shaheed Beheshti University of Medical Sciences.