Table 1.
Advantages and limitations of tools used to characterized obesity in achondroplasia patients
| Advantages | Limitations in achondroplasia patients | |
|---|---|---|
| Body mass Index (BMI): Weight/Height2 (kg/m2) |
Easy to measure and low cost Routinely used to evaluate obesity (its use has been standardized as a tool to diagnose overweight and obesity) Standards values available in children and adults in general population (Cole et al., 2000) Useful to epidemiological studies |
Height dependent: overestimated in short stature patients (Hecht et al., 1988) It is not a good predictor of obesity because it is not predictor of body fat and does not report on the distribution of fat (subcutaneous body fat / visceral body fat) No Standard values available in achondroplasia, only some reference curves from 0 to 16 years old (Hoover-Fong et al., 2008; Hoover-Fong et al., 2016) but nothing after 16 years old or in adults |
| Adipocyte rebound |
Easy to measure and low cost Standards references available Early predictive to adult obesity and associated complications in general population (Guo et al., 2000; Koyama et al., 2014) |
Based on the use of BMI (cf BMI limitations) No Standard values available in achondroplasia |
| Rohrer’s index: Weight/Height3 (kg/m3) |
Easy to measure and low cost Better estimator of obesity than the BMI in children between 6 to 18 years old (ref) Moderated correlation with height: the best index from age 6 to 18 years in achondroplasia patients (Hunter et al., 1996) |
No standard values available in achondroplasia |
| Weight/Height ratio (kg/m) |
Easy to measure and low cost Standards values available in general population |
No Standard values available in achondroplasia, only one reference curve (Hunter et al., 1996) |
| Waist circumference (cm) |
Easy to measure and low cost Height independent It offers complementary information to the waist / hip ratio and both are used as predictors of cardiovascular risk Standards values available in general population |
No standard values available in achondroplasia |
| Waist/hips ratio |
Easy to measure and low cost Height independent Correlated with total fat mass in general population Used as an index of cardiovascular risk prediction due to its relationship with visceral fat in general population |
No standard values available in achondroplasia |
| Skinfold thickness (mm) |
The measurements must be made by a qualified professional and low cost Height independent Correlated with total fat mass in general population Useful to determine the subcutaneous fat mass that could correlate with orthopedic complications |
No standard values available and no specific predictive models to estimate the percentage of body fat in achondroplasia They do not estimate visceral body fat, therefore, they do not serve as a tool that correlates body fat with the risk of suffering metabolic complications associated with obesity in achondroplasia patients Difficult to measure and unreliable in patients with morbid obesity |
| % body fat mass |
Body fat mass defined obesity and is directly correlated with it Gold standard techniques (DEXA and others) are expensive and not accessible for clinical use, but specific predictive models for gender and age are available that reliably estimate body fat percentage in general population |
No standard values available in achondroplasia All gold standard techniques (Dual-Energy X-ray absorptiometry technique) have important limitations as body fat estimators in achondroplasia (data on body density, body dimensions, etc.) |
| Androïd: gynoïd fat mass ratio (DEXA) |
The most appropriated technique for correlating android obesity (estimates visceral fat independently of subcutaneous fat) with associated metabolic complications such as type II diabetes in the general population (Aucouturier et al., 2009; Samsell et al., 2014; Walton et al., 1995) It can predict the development of obesity regardless of size Predictive models to estimate the percentage of body fat by measuring the skinfold can be determined in comparison to DEXA measurements. |
No standard values available in achondroplasia All gold standard techniques (Dual-Energy X-ray absorptiometry technique) have important limitations as body fat estimators in achondroplasia (data on body density, body dimensions, etc.) |