Measures of obesity and metabolic syndrome in Indian Americans in northern California.

BACKGROUND: In populations predisposed to cardiovascular disease, type 2 diabetes and visceral obesity, use of additional measurements of waist girth and waist/hip ratio (WHR) can help define risk levels associated with body mass index (BMI) for screening and clinical purposes.
PURPOSE: To investigate measures of obesity associated with presence of metabolic syndrome and its risk factors in asymptomatic American adults of Asian Indian origin between 29 and 59 years of age.
METHODS: Fifty-six apparently healthy men (43.7 years +/- 7.1, BMI 21-34 kg/m2) and women (43.1 years +/- 6.9, BMI 21-36 kg/m2) were recruited for participation in this cross-sectional study. Height, weight, hip girth, waist girth, and blood pressure were recorded by using standard procedures. Blood samples were taken after an overnight fast and analyzed for measures defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria for the metabolic syndrome.
RESULTS: Prevalence of the metabolic syndrome was 33.9% (29-59 years, average BMI 26.1 +/- 3.7 kg/m2). Risk factors most prevalent were low high-density lipoprotein cholesterol (HDL-C) (55%), hypertriglyceridemia (61%), and high blood pressure (50%) in men and low HDL-C (56%), high waist circumference (44%), and high blood pressure (32%) in women. Waist girth of 90.8 +/- 6.8 cm (men) and 75 +/- 3 cm (women), waist/hip ratios (WHRs) of .89 +/- .06 (men) and .76 +/- .03 (women), and BMI values of 24.8 +/- 2.5 kg/m2 (men) and 23.7 +/- 1 kg/m2 (women) were associated with absence of all risk factors associated with metabolic syndrome. Average waist girth (men: 99.6 +/- 8.1 cm, P < .05; women: 95.5 +/- 5.2 cm, P < .001) of those positive was significantly higher than those negative for the metabolic syndrome. Waist girth in women was significantly associated with fasting glucose (r = .40, P < .05), two-hour glucose (r = .57, P < .05), triglyceride (r = .42, P < 05), and HDL-C (r = -.47, P < .05). Waist/ hip ratio (WHR) for women with the metabolic syndrome was significantly higher (.87 +/- .07, P < .05) compared to those without (.79 +/- .05) and most significantly correlated with two-hour glucose (r = .51, P < .05). Body mass index (BMI) in the overweight range for men (28.3 +/- 3 kg/m2, P < .05) and women (30.0 +/- 3.5 kg/m2, P < .05) was associated with metabolic syndrome and significantly correlated with low HDL-C levels in men (r = -.49,
CONCLUSION: Prevalence of the metabolic syndrome in Indian Americans aged 29- 59 years using the NCEP ATP III criteria was similar to rates reported in urban populations in India. Low HDL-C, hypertriglyceridemia, high waist circumference, and high blood pressure were most prevalent risk factors in this study. Among obesity measures, waist girth was significantly associated with most risk factors for the syndrome; WHR was most significant for two-hour glucose in women, whereas BMI mostly correlated with HDL-C for men. While BMI < or = 24.9 was associated with absence of all risk factors, BMI in overweight range was associated with presence of metabolic syndrome. These results point to clinical significance of using additional measures of obesity in addition to BMI to determine health risk in this population, particularly in premenopausal Asian Indian women.