The waist-hip ratio: a flawed index.

The waist-hip ratio, namely waist circumference (WC) divided by hip circumference (HC), has been referred to in thousands of articles, generally as a correlate and predictor either of health conditions such as cardiovascular disease and diabetes, or of amounts of visceral and subcutaneous abdominal fat. It has been argued that combining WC and HC as a ratio is inappropriate, and yet their individual roles can only be fully elucidated if considered jointly. Whereas WC is positively associated with cardiovascular disease, diabetes and premature mortality, the opposite is true of HC.

When is sitting height a better measure of adult body size than total height, and why? The contrasting examples of body mass, waist circumference, and lung volume.

Objectives: We aimed to establish which of sitting height (SH) and total height (Ht) is most appropriately used in the scaling of adult body mass (BM), waist circumference (WC), and forced vital capacity (FVC), considering likely explanations and proposing a suitable index for each.

Methods: Data were from the US Third National Health and Nutrition Survey for white and black American women and men aged 20 to 50 years. Statistical analysis involved mainly correlation coefficients, the multiple regression of BM, WC, or FVC on SH and leg length (LL), and fitting of allometric regression equations relating each of BM, WC, and FVC to SH or Ht.