Prediction of Areal Bone Mineral Density and Bone Mineral Content in Children and Adolescents Living With HIV Based on Anthropometric Variables

Abstract

Children and adolescents living with HIV have low bone mass for age. There are reliable and accurate methods for evaluation of bone mass, however, alternative methods are necessary, especially, for application in limited-resource scenarios. Anthropometry is a noninvasive and low cost method that can predict bone mass in healthy youths. The aim of the study was to develop predictive equations for bone mineral content and bone mineral density in children and adolescents living with HIV based on anthropometric variables. Forty-eight children and adolescents of both sexes (24 females) from 7 to 17 years, living in greater Florianopolis area, Santa Catarina, Brazil, who were under clinical follow-up at “Hospital Infantil Joana de Gusmão”, participated in the study. Dual-energy X-ray absorptiometry was used to evaluate whole-body bone mineral content (BMC) and areal bone mineral density (aBMD). Height, body weight, bone diameters, arm circumference, and triceps skinfold were measured and the body mass index and arm muscle area were calculated. Multiple regression models were fitted to predict BMC and aBMD, using backward selection (p ≥ 0.05). Two predictive models with high R² values (84%–94%) were developed. Model 1 to estimate aBMD [Y = −0.1450124 + (height × 0.0033807) + (age × 0.0146381) + (body mass index × 0.0158838) + (skin color × 0.0421068)], and model 2 to estimate BMC [Y = 1095.1 + (body weight × 45.66973) + (age × 31.36516) + (arm circumference × −53.27204) + (femoral diameter × −9.594018)].The predictive models using anthropometry provided reliable estimates and can be useful to monitor aBMD and BMC in children and adolescents living with human immunodeficiency virus where limited resources are available.

Introduction

Human immunodeficiency virus (HIV) itself and highly active antiretroviral therapy (HAART) are associated with adverse morphological, metabolic, cardiovascular, nervous system, and renal events (1). The available information suggests low bone mineral content (BMC) and areal bone mineral density (aBMD) in children and adolescents infected with HIV (2). The main concern regarding seropositive individuals infected by vertical transmission are the long-term effects of exposure to HIV and to the drugs used for its treatment, particularly during puberty, a critical period of bone mineral accrual when about 80% of the adult bone mass is deposited. Low peak bone mass during this phase is related to an increased risk of osteoporosis and fractures (3).

Bone mass can be measured by quantitative computed tomography, quantitative ultrasound, and dual-energy X-ray absorptiometry (DXA) (4). These methods are usually used to assess BMC, BMD, and aBMD, but they require sophisticated equipment, adequate physical structure, and are expensive in most of settings where HIV is more prevalent. Anthropometry could be alternative method for the predicting bone mass because it is noninvasive and of low cost. Body weight, height, circumference measurements, and bone diameters, combined with age, gender, and skin color, have been used for the prediction of bone mass in healthy children and adolescents (5). These variables can be measured with portable devices which are frequently available in primary care centers, although trained personnel are necessary for reliable measurement.

In this respect, predictive equations would permit valid and accurate data that could be applied in clinical practice and in field studies (6). These predictive equations are particularly relevant to middle- and low-income countries where resources for bone health monitoring are limited. Despite these advantages, there are few studies designed to elaborate prediction models of bone mass for populations with altered clinical conditions 7, 8. Therefore, the objective of the present study was to develop predictive equations of BMC and aBMD based on anthropometric measures in children and adolescents living with HIV using DXA as the reference method.