and a considerable number of subjects, both males and females, will not be classified as obese based on their BMI alone[19].
The disagreement became impressive in the classification of obese women: in the class of age 30-40 the proportion of obese women according to BMI is 30% reaching about 82% if the classification is based on PBF. Notably, among women that were classified as normal according to their observed PBF, the median BMI was 20.1, ranging from 15.6 to 26.7.
For the Italian population, the percentage of obese women according to PBF classification increases as age increases, ranging from 63.17% in women younger than 20 years to 87.39% in women older than 60[20].
Moreover, values corresponding to normal weight, overweight, and various subgroups of obesity are confounded by body frame and muscularity, fluid retention, sarcopenia in aging or disease, spinal deformities, physical disabilities, and transcultural differences. A person with the same BMI, may have a large proportion of total body fat mass and be obese, or may have a considerable muscle mass and be a weight-lifter. Moreover, PBF at a given BMI will tend to vary across gender, age, and race-ethnicity[21-23].
Moreover, it is recommended to measure waist circumference (WC) in adults with BMIs below 35 kg/m2, to further assess disease risk[24].
Anyway, obese individuals differ not only in the amount of excess fat mass, but also in the regional distribution of the fat within the body. The fat distri¬bution affects the risk associated with obesity. It is useful therefore, to be able to distinguish between those at increased risk as a result of abnormal fat distribution or android obesity from those with the less serious gynoid fat distribution, in which fat is more evenly and peripherally distributed around the body[2].
On the hand even if there are some obese people are prone to develop alterations in fat distribution and metabolic disease, others are protected from the adverse metabolic effects of weight gain and increased adiposity[25].
Some studies suggested that the main issue to explain the metabolic abnormalities in normal weight individuals was fat distribution.
Certain attributes of visceral fat, the adipose tissue surrounding abdominal organs, make its accu¬mulation more worrisome than the accumulation of subcutaneous fat, which resides below the skin[26-28].
Other markers for excess body fat evaluation have to be used in clinical practice and investigation (e.g., WC, skin fold thickness, waist-to-hip ratio, waist-to-height ratio).
WC or waist-to-hip ratio has been used as a proxy measure for body fat distribution when investigating the health risk increased with an increasing ratio. Some studies have suggested that WC, either singly or in combination with BMI, may have a stronger relation to some health outcomes than BMI alone[29]. Moreover, progressively higher values of BMI and WC are associated with a progressive elevation in metabolic markers of