Читать книгу Clinical Obesity in Adults and Children - Группа авторов - Страница 48

In both clinical practice and public health surveillance, children’s weight status is routinely assessed according to body mass index (BMI), calculated as weight in kilograms divided by height (or recumbent length in children under age 2 years) in meters squared, and categorized compared with a reference population of the same age and sex. The World Health Organization Child Growth Standard, which provides standards for weight, length, and BMI‐for‐age and sex for children from birth to age 18 years, is used as the reference in most settings [3,4]. With this tool, obesity is defined as BMI above the 97.7th percentile. In the United States, many continue to calculate BMI percentiles from growth charts developed by the Centers for Disease Control and Prevention (CDC), which provide reference data based on US‐specific, population‐based norms for children 2 years and older [5]. Within the CDC reference, obesity is defined as BMI at or above the 95th percentile for age and sex, and overweight as a BMI between the 85th and 95th percentiles. While the two different references yield slightly different thresholds and thus slightly different obesity prevalence values within a population, they are equally predictive of obesity and adverse cardiometabolic risk in later childhood and adolescence [6,7].

BMI is not a direct assessment of body composition, and thus some caution is appropriate as it is composed of both lean mass and fat mass. Nevertheless, BMI is strongly correlated with other more direct measures of adiposity such as skinfold thickness, dual‐x‐ray absorptiometry (DXA), and bioimpedance, especially at the higher end of the distribution [8]. Obesity, measured using BMI, often persists from childhood or adolescence into adulthood; therefore, children with obesity are more likely to become adults with obesity, further highlighting the importance of early interventions [9]. While multiple other techniques exist that more directly assess fat and lean mass, there is no evidence to suggest that any measure is better than BMI for diagnosing obesity in childhood or predicting adult obesity and morbidity [10]. Thus, evidence‐based guidelines recommend using BMI to clinically screen children and adolescents for obesity to allow for subsequent referral and multidisciplinary treatment [11]. In parallel, most researchers continue to use BMI as the primary measure of obesity in their studies.