Alterações clínicas, metabólicas e resistência à insulina entre adolescentes

Prevalence of overweight and obesity among Brazilian adolescents over time: a systematic review and meta-analysis

OBJECTIVE

To estimate the burden of excess weight in Brazilian adolescents.

DESIGN

Systematic review with meta-analysis.

SETTING

We searched the literature in four databases (MEDLINE/PubMed, EMBASE, SciELO and LILACS). Studies were included if they had cross-sectional or cohort design and enrolled Brazilian adolescents. Studies based on self-reported measures were excluded. Random effect models were used to calculate prevalence estimates and their 95 % CI.

PARTICIPANTS

Brazilian adolescents (10 to 19 years old).

RESULTS

One hundred and fifty-one studies were included. Trend analyses showed a significant increase in the prevalence of excess weight in the last decades: 8·2 % (95 % CI 7·7, 8·7) until year 2000, 18·9 (95 % CI 14·7, 23·2) from 2000 to 2009, and 25·1 % (95 % CI 23·4, 26·8) in 2010 and after. A similar temporal pattern was observed in the prevalence of overweight and obesity separately. In sensitivity analyses, lower prevalence of excess weight was found in older adolescents and those defined using International Obesity Task Force cut-off points. The Southeast and South regions had the highest prevalence of excess weight, overweight and obesity. No significant difference in prevalence by sex was found, except for studies before the year 2000.

CONCLUSIONS

The prevalence of overweight and obesity in Brazilian adolescents is high and continues to rise. Public policies on an individual level and targeting modifications in the obesogenic environment are necessary.

Identification of neck circumference cut-off points for insulin resistance as a marker in adolescents

ABSTRACT Objective To identify cut-off points of neck circumference measurement to predict insulin resistance in adolescents. Methods Cross-sectional analysis with data derived from the Study of Cardiovascular Risks in Adolescents, nationwide, multicenter, school-based survey. We evaluated 901 adolescents, aged 12 to 17, from public and private schools in two cities of Sergipe state in Brazil. We measured demographic, anthropometric, and biochemical data, and insulin resistance using Homeostasis Model Assessment-Insulin Resistance. We used multiple linear regression and logistic analysis to evaluate the association between dependent variables (biochemical) and independent variables (anthropometric) controlled by body mass index, age, gender, and Tanner’s stage. We used the Receiver operating characteristic curve to determine cut-off points of neck circumference that can identify insulin resistance. Results The multiple linear regression analysis showed a positive association between neck circumference measurement with fasting glycemia and glycated hemoglobin (p<0.001) and a negative association with insulin (p<0.024). Furthermore, in logistic regression, the measurement of neck circumference was the only anthropometric indicator positively correlated with homeostasis model assessment-insulin resistance. The cut-off points of neck circumference for predicting insulin resistance were: 30.55cm for female pubertal and 32.10cm for post-pubertal adolescents; 35.90cm for male pubertal adolescents and 36.65cm for post-pubertal adolescents. Conclusions The measurement of neck circumference is a simple, practical anthropometric indicator and can be used as a screening tool to identify insulin resistance in adolescents.