Health Behavior and Metabolic Risk Factors Associated with Normal Weight Obesity in Adolescents

<div><p>Objective</p><p>To explore health behaviors and metabolic risk factors in normal weight obese (NWO) adolescents compared with normal weight lean (NWL) peers.</p><p>Design and Methods</p><p>A cross-sectional study of 18-year-old students (n = 182, 47% female) in the capital area of Iceland, with body mass index within normal range (BMI, 18.5–24.9 kg/m²). Body composition was estimated via dual energy X-ray absorptiometry, fitness was assessed with maximal oxygen uptake (VO₂max) during treadmill test, dietary intake through 24-hour recall, questionnaires explained health behavior and fasting blood samples were taken. NWO was defined as normal BMI and body fat >17.6% in males and >31.6% in females.</p><p>Results</p><p>Among normal weight adolescents, 42% (n = 76) were defined as NWO, thereof 61% (n = 46) male participants. Fewer participants with NWO were physically active, ate breakfast on a regular basis, and consumed vegetables frequently compared with NWL. No difference was detected between the two groups in energy- and nutrient intake. The mean difference in aerobic fitness was 5.1 ml/kg/min between the groups in favor of the NWL group (p<0.001). NWO was positively associated with having one or more risk factors for metabolic syndrome (Odds Ratio OR = 2.2; 95% confidence interval CI: 1.2, 3.9) when adjusted for sex. High waist circumference was more prevalent among NWO than NWL, but only among girls (13% vs 4%, p = 0.019).</p><p>Conclusions</p><p>High prevalence of NWO was observed in the study group. Promoting healthy lifestyle with regard to nutrition and physical activity in early life should be emphasized regardless of BMI.</p></div

Daily energy and nutrient intake using 24-hour dietary recall among 18-year-old students.

<p>Daily energy and nutrient intake using 24-hour dietary recall among 18-year-old students.</p

Prevalence of metabolic syndrome and its components among 18-year-old students who are normal weight obese or normal weight lean.

<p>Prevalence of metabolic syndrome and its components among 18-year-old students who are normal weight obese or normal weight lean.</p

Characteristic of the 18-year-old participants and lifestyle factors.

<p>Characteristic of the 18-year-old participants and lifestyle factors.</p

Normal weight obesity according to anthropometric, fitness and metabolic parameters– 18-year-old students.

<p>Normal weight obesity according to anthropometric, fitness and metabolic parameters– 18-year-old students.</p

Difference between the observed and the weighed amount by serving method (country)—Modified Bland-Altman.

<p>a) Total energy (kcal) content in served meal, Iceland (served by canteen staff); b) Total energy (kcal) content in leftovers, Iceland; c) Total energy (kcal) content in served meal, Sweden (selfserving); d) Total energy (kcal) content in leftovers, Sweden.</p

Study design–procedure in each country.

<p>Study design–procedure in each country.</p

Agreement¹ of amount (g) and energy content (kcal) estimated by photomethod with weighed method—by country.

<p>Agreement<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163970#t001fn001" target="_blank">¹</a> of amount (g) and energy content (kcal) estimated by photomethod with weighed method—by country.</p

Example of served and leftover plates of the same meal.

<p>Serving left, leftovers right.</p