[Metabolic risks in individuals with normal body mass index and normal waist circumference]

ABSTRACT

It seems that the risk of cardiovascular diseases increases adults of the Middle-Eastern region within the normal limits of BMI and WC, as defined for universal application by the WHO. This study was conducted to determine a point of BMI and WC above which the chances of having cardiovascular risk factors increased. In this population-based cross-sectional study, a representative sample of 3447 subjects [1781 males and 1666 females] with normal body mass index [BMI = 19-<25 kg/m2 for both genders] and normal waist circumference [WC] [<102 cm for men and <88 cm for women] were included. Demographic data was collected anthropometric indices and blood pressure were measured according to standard protocol. Hypertension was defined based on Joint National Committee VI [JNC VI]. Biochemical analysis was conducted on fasting blood samples. Diabetes was defined as fasting plasma glucose [FPG] >/= 126 mg/dl or 2-hour plasma glucose [2hPG] >/= 200 mg/dl. Dyslipidemia was considered based on Adult Treatment Panel III [ATP III]. The presence of "at least one risk factor" and "at least two risk factors" of the three major risk factors for cardiovascular disease [hypertension, dyslipidemia, diabetes] were also evaluated. Men had higher WC than women [79.6 +/- 6.5 vs. 74.7 +/- 6.2 cm, P<0.001], while their BMIs was not statistically different [22.4 +/- 1.6 vs.22.4 +/- 1.6, P=0.224]. The prevalence of all metabolic risk factors increased with BMI and WC in both genders such that those in the highest category of BMI and WC had the highest prevalence of all metabolic abnormalities. Individuals in the highest category of BMI [24 -< 25 kg/m2] had significantly higher odds for being at risk for metabolic risk factors [odds ratios ranging from 1.3 to 1.6 for men and 1.36 to 2.0 for women for different risk factors] compared to those of the first category [19 -< 20 kg/m2]. Also, individuals in the highest category of waist circumference [95 -< 102 cm for men and 85-88cm for women] had significantly higher chances for having metabolic abnormalities [odds ratios ranging from 2.6 to 4.5 for men and 2.1 to 2.6 for women for different risk factors] compared to those in the first category [62-<70 cm for men and 60 -< 65 cm for women] in both genders. It is concluded that the cut-points of BMI and WC suggested by WHO are inappropriate for the Tehranian urban population and that the appropriate cut-points of BMI and WC should be lower in this population