To treat or not to treat: comparison of different criteria used to determine whether weight loss is to be recommended

Ottavia Colombo¹ , Simona Villani¹ , Giovanna Pinelli¹ , Claudia Trentani¹ , Maurizia Baldi² , Orazio Tomarchio² and Anna Tagliabue¹

¹Department of Applied Health Sciences – University of Pavia, via A. Bassi 21, I-27100 Pavia, Italy

²IRCCS Salvatore Maugeri Foundation, via Maugeri, I-27100 Pavia, Italy

author email corresponding author email

Nutrition Journal 2008, 7:5doi:10.1186/1475-2891-7-5


Published:	29 January 2008

Abstract

Background

Excess body fat is a major risk factor for disease primarily due to its endocrine activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless, treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI), calculated as body weight (in kg) divided by height in m². The aim of our study was to determine whether application of the BMI, compared to adiposity-based criteria, results in underestimation of the number of subjects needing lifestyle intervention.

Methods

We compared treatment need based on BMI classification with four adiposity-based criteria: percentage body fat (%BF), considered both alone and in relation to metabolic syndrome risk (MS), waist circumference (WC), as an index of abdominal fat, and Body Fat Mass Index (BFMI, calculated as fat mass in kg divided by height in m²) in 63 volunteers (23 men and 40 women, aged 20 – 65 years).

Results

According to the classification based on BMI, 6.3% of subjects were underweight, 52.4% were normal weight, 30.2% were overweight, and 11.1% were obese. Agreement between the BMI categories and the other classification criteria categories varied; the most notable discrepancy emerged in the underweight and overweight categories. BMI compared to almost all of the other adiposity-based criteria, identified a lower percentage of subjects for whom treatment would be recommended. In particular, the proportion of subjects for whom clinicians would strongly recommend weight loss on the basis of their BMI (11.1%) was significantly lower than those identified according to WC (25.4%, p = 0.004), %BF (28.6%, p = 0.003), and MS (33.9%, p = 0.002).

Conclusion

The use of the BMI alone, as opposed to an assessment based on body composition, to identify individuals needing lifestyle intervention may lead to unfortunate misclassifications. Population-specific data on the relationships between body composition, morbidity, and mortality are needed to improve the diagnosis and treatment of at-risk individuals.