Smoothed Body Composition Percentiles Curves for Mexican Children Aged 6 to 12 Years

Abstract

Overweight children and childhood obesity are a public health problem in Mexico. Obesity is traditionally assessed using body mass index (BMI), but an excess of adiposity does not necessarily reflect a high BMI. Thus, body composition indexes are a better alternative. Our objective was to generate body composition percentile curves in children from Mexico City. A total of 2026 boys and 1488 girls aged 6 to 12 years old were studied in Mexico City. Body weight, height, and BMI calculation were measured. Total body fat percentage (TBFP) was derived from the skinfold thicknesses, and fat mass (FMI) and free fat mass indexes (FFMI) were calculated. Finally, age- and gender-specifıc smoothed percentile curves were generated with Cole’s Lambda, Mu, and Sigma (LMS) method. In general, height, weight, waist circumference (WC), and TBFP were higher in boys, but FFM was higher in girls. TBFP appeared to increase significantly between ages 8 and 9 in boys (+2.9%) and between ages 10 and 11 in girls (+1.2%). In contrast, FFM% decreased noticeably between ages 8 and 9 until 12 years old in boys and girls. FMI values peaked in boys at age 12 (P97 = 14.1 kg/m2) and in girls at age 11 (P97 = 8.8 kg/m2). FFMI percentiles increase at a steady state reaching a peak at age 12 in boys and girls. Smoothed body composition percentiles showed a different pattern in boys and girls. The use of TBFP, FMI, and FFMI along with BMI provides valuable information in epidemiological, nutritional, and clinical research.

Fat Mass Index (FMI) as a Trustworthy Overweight and Obesity Marker in Mexican Pediatric Population

“…All these results point to a main issue that is that Mexican pediatric populations (as said previously by Alpizar et al 2017) [7] have a high-fat mass component in body composition and this cannot be overlooked by only analyzing total weight because it means that most of these children will likely have obesity as an adult or otherwise have normal weight obesity and either way they will be at high risk for developing cardiometabolic diseases. Other authors have also arrived at this conclusion, basing their investigations on the published Hattori charts that compare Fat Mass Index and Lean Mass Index with the associated BMI values for every case.…”

“…The comparison is shown in Table 1 as well as Figures 5 and 6. However, results are different when we base our comparison on FM percentage (25% for boys, 30% for girls) vs. BMI [4,7].…”

“…The National Survey of Nutrition and Health (ENSANUT) conducts a census every few years to determine the health and nutritional status of the Mexican population. The results of 2016 show that children between 5 and 11 years old have a 33.2% prevalence of obesity, a percentage that remains unchanged since 2012 [7]. This may be due in part to the lack of general standards that could determine accepted cutoff points for weight, height, and anthropometric measures associated with a healthy child with optimal dietary habits.…”

“…Skinfold thickness was measured three times in the triceps and subscapular area on the left side always with a caliper Lange model C-130. This study was one of the first efforts to create smoothed body composition percentile curves in this age group, and it also helped strengthen the value of fat mass index over total body weight by correcting by height [7]. That being said, these results are not the ideal standard, nor was that the goal unlike in the WHO study, but instead to capture an actual representation of the population measured.…”

“…Pediatric population still does not have standard cutoff points to determine excess body fat, however, studies have reported the same 25% and 30% for boys and girls respectively to be associated with risk factors such as high cholesterol, blood pressure, and triglycerides as well as low HDL and cardiovascular disease [4,7].…”