Selection of anthropometric indicators for classification of abdominal fatness--a critical review.

In the literature, a variety of anthropometric indicators for abdominal obesity have been suggested. The criteria for their selection vary, and they have been justified mainly on the basis of being correlated with other risk factors, with morbidity and mortality, or to be predictors of the amount of visceral fat. Many of the studies, however, suffer from methodological limitations: they are based on a small number of subjects, often derived from cross-sectional data, based on indirect measurement of risk, or the indicators are complicated to interpret biologically or difficult to use in a public health context. The literature lacks a systematic evaluation of the proposed indicators taking into account possible differences between genders, age categories and ethnic groups and different diseases and mortality. Similar considerations relate to the cut-off points based on the indicators of abdominal obesity. The suggested cut-off points for waist-hip ratio have been based on rather arbitrary criteria, and the studies where cut-off points for waist circumference have been suggested have methodological shortcomings as well, such as being based on cross-sectional data and arbitrary cut-off points for other variables. It is also a reason for concern that so far all suggested cut-off points for abdominal obesity have been based on results obtained in Caucasian populations. Moreover, they are based on assessment of risk and their appropriateness in the use of intervention has not been evaluated. Therefore, no consensus about the appropriateness of the different cut-off points has been reached. We conclude that there is an apparent lack of consistency in the field and therefore a more scientifically and theoretically solid basis for the selection and use of anthropometric indicators of abdominal obesity and cut-off points based on them should be a high priority in this research field in the near future.