A new body shape index predicts mortality hazard independently of body mass index


Krakauer NY, Krakauer JC. PLoS One. 2012;7(7):e39504. 

BACKGROUND Obesity, typically quantified in terms of Body Mass Index (BMI) exceeding threshold values, is considered a leading cause of premature death worldwide. For given body size (BMI), it is recognized that risk is also affected by body shape, particularly as a marker of abdominal fat deposits. Waist circumference (WC) is used as a risk indicator supplementary to BMI, but the high correlation of WC with BMI makes it hard to isolate the added value of WC. 

METHODS AND FINDINGS We considered a USA population sample of 14,105 non-pregnant adults ([Formula: see text]) from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 with follow-up for mortality averaging 5 yr (828 deaths). We developed A Body Shape Index (ABSI) based on WC adjusted for height and weight:[Formula: see text] ABSI had little correlation with height, weight, or BMI. Death rates increased approximately exponentially with above average baseline ABSI (overall regression coefficient of [Formula: see text] per standard deviation of ABSI [95% confidence interval: [Formula: see text]-[Formula: see text), whereas elevated death rates were found for both high and low values of BMI and WC. [Formula: see text] ([Formula: see text]-[Formula: see text]) of the population mortality hazard was attributable to high ABSI, compared to [Formula: see text] ([Formula: see text]-[Formula: see text]) for BMI and [Formula: see text] ([Formula: see text]-[Formula: see text]) for WC. The association of death rate with ABSI held even when adjusted for other known risk factors including smoking, diabetes, blood pressure, and serum cholesterol. ABSI correlation with mortality hazard held across the range of age, sex, and BMI, and for both white and black ethnicities (but not for Mexican ethnicity), and was not weakened by excluding deaths from the first 3 yr of follow-up.

CONCLUSIONS Body shape, as measured by ABSI, appears to be a substantial risk factor for premature mortality in the general population derivable from basic clinical measurements. ABSI expresses the excess risk from high WC in a convenient form that is complementary to BMI and to other known risk factors. 

 

August 2012 

Last Modified: 12/12/2012