Associations of multiple unhealthy lifestyle behaviors with overweight/obesity and abdominal obesity among Brazilian adolescents: A country-wide survey.

BACKGROUND AND AIMS: Physical inactivity, unhealthy diet, smoking and heavy drinking are four key unhealthy lifestyle behaviors (ULB) that may influence body weight and obesity development. More recently, sedentary time has been recognized as another potentially emerging ULB related to obesity. We therefore investigated the association of multiple ULB with overweight/obesity and abdominal obesity among Brazilian adolescents. METHODS AND RESULTS: This cross-sectional study involved 62,063 students (12-17 years). Physical inactivity, high screen time, low fiber intake, binge drinking and smoking were self-reported and combined to a ULB risk score, ranging from zero to five. Participants were classified as overweight/obese or with abdominal obesity using sex and age-specific cut-off points for BMI and waist circumference, respectively. Poisson regression models were used to examine the associations between ULB with overweight/obesity and abdominal obesity, adjusted for socio-demographic variables. Overall, 2.3%, 18.9%, 43.9%, 32.3% and 2.6% of participants reported zero, one, two, three and four/five ULB, respectively. Higher ULB risk score was associated with overweight/obesity and abdominal obesity in a dose-response gradient. Among 32 possible combinations of ULB, the three most prevalent combinations (physical inactivity + low fiber intake; high screen time + low fiber intake; physical inactivity + high screen time + low fiber intake) were positively associated with general and abdominal obesity. CONCLUSIONS: Our findings suggest a synergistic relationship between ULB and general and abdominal obesity. Preventive efforts targeting combined ULB should be sought to reduce the prevalence of general and abdominal obesity in Brazilian youth.

C-reactive protein in Brazilian adolescents: distribution and association with metabolic syndrome in ERICA survey.

BACKGROUND/OBJECTIVES: C-reactive protein (CRP) is a marker of inflammation that has been shown to be predictive of cardiovascular diseases in adults. To evaluate the distribution of CRP as well as its association with metabolic syndrome and its components. SUBJECTS/METHODS: This is a cross-sectional study on adolescents aged 12-17, participants in the Study of Cardiovascular Risk in Adolescents (ERICA). Anthropometric, biochemical and blood pressure data were collected from 6316 adolescents, selected from a random sample of students in the cities of Brasilia, Fortaleza, João Pessoa, Manaus, Porto Alegre and Rio de Janeiro. Metabolic syndrome was defined by the criteria proposed by International Diabetes Federation for adolescent. Poisson regression model with robust variance, taking into consideration the study's complex sampling design, was used to determine multivariate-adjusted prevalence rate ratios expressing the relationship of metabolic syndrome with CRP. RESULTS: In adolescents with metabolic syndrome, CRP concentrations were five times higher (1.01 mg/l; interquartile range (IQR): 0.54-3.47) compared with those without metabolic syndrome (0.19 mg/l; IQR: 0.10-0.78). In multivariate Poisson regression analysis adjusted by sex, age and skin color, the prevalence of elevated CRP (>3.0 mg/l) was almost three times higher in adolescents with metabolic syndrome than in those without this condition (prevalence ratio (PR): 2.9; 95%CI: 2.0-4.3; P<0.001). Of the metabolic syndrome components, elevated waist circumference, low high-density lipoprotein-cholesterol and high triglycerides were significantly related to CRP in a graded (dose-response) manner. CONCLUSIONS: The association of CRP with metabolic syndrome and its components suggests that inflammation may be useful in assessing cardiovascular risk in adolescents.

Does body mass index modify the association between physical activity and screen time with cardiometabolic risk factors in adolescents? Findings from a country-wide survey.

BACKGROUND: Moderate and vigorous physical activity (MVPA) and screen time (ST) have been associated with cardiometabolic health in youth. However, previous studies are conflicting whether these associations are independent of each other and it is unknown if they are modified by adiposity. We aimed to examine the independent and joint associations between MVPA and ST with cardiometabolic risk across body mass index (BMI) categories. METHODS: A total of 36 956 Brazilian adolescents (12-17 years) from the Study of Cardiovascular Risks in Adolescents were included. Information on time spent in MVPA and ST were assessed by self-reports. Blood pressure, Homeostasis Model Assessment of Insulin Resistance, triglycerides, high-density lipoprotein-cholesterol and waist circumference were used to calculate a cardiometabolic risk score (sex-age-specific top-risk quintile for each biomarker). Ordered logistic regression was used to examine the associations. RESULTS: In final adjusted models, both higher MVPA (proportional odds ratio (POR)=0.80; 95% confidence interval (CI): 0.67-0.95) and ST (POR=1.23; 95% CI: 1.10-1.37) were independently associated with cardiometabolic risk. After stratification by normal weight vs overweight/obese, the inverse independent association for MVPA remained unchanged, whereas ST was positively associated with cardiometabolic risk only in overweight/obese adolescents (POR=1.62; 95% CI: 1.18-2.22). Participants who met the recommendations for both MVPA and ST had lower odds for cardiometabolic risk, especially if they were overweight/obese (POR=0.46; 95% CI: 0.31-0.68). CONCLUSIONS: MVPA and ST are independently associated with cardiometabolic risk; the association with ST, however, appears modified by BMI. Normal-weight adolescents should be encouraged to increase MVPA, whereas a combination of increasing MVPA and decreasing ST is recommended in those who are overweight or obese.