The influence of hip circumference on the relationship between abdominal obesity and mortality

Background: Higherwaist circumference and lower hip circumference are both associated withincreased cardiovascular disease (CVD) risk, despite being directly correlated.The real effects of visceral obesity may therefore be underestimated when hipcircumference is not fully taken into account. We hypothesized that addingwaist and hip circumference to traditional risk factors would significantlyimprove CVD risk prediction.

 

Methods: In apopulation-based survey among South Asian and African Mauritians (n = 7978),1241 deaths occurred during 15 years of follow-up. In a model that includedvariables used in previous CVD risk calculations (a Framingham-type model), theassociation between waist circumference and mortality was examined before andafter adjustment for hip circumference. The percentage with an increase inestimated 10-year cumulative mortality of >25% and a decrease of >20%after waist and hip circumference were added to the model was calculated.

 

Results: Waistcircumference was strongly related to mortality only after adjustment for hipcircumference and vice versa. Adding waist and hip circumference to aFramingham-type model increased estimated 10-year cumulative CVD mortality by>25% for 23.7% of those who died and 15.7% of those censored. Cumulative mortalitydecreased by >20% for 4.5% of those who died and 14.8% of those censored.

 

Conclusions: Theeffect of central obesity on mortality risk is seriously underestimated withoutadjustment for hip circumference. Adding waist and hip circumference to aFramingham-type model for CVD mortality substantially increased predictivepower. Both may be important inclusions in CVD risk prediction models.