RAZONABILIDAD DEL PRECIO OFERTA #1

Obesity is independently associated with cardiovascular disease and increased morbidity and mortality (45). It is widely accepted that atherosclerosis begins in

childhood and progresses slowly into adulthood and is influenced by excess weight (46, 47). Obese children have an increased carotid itima-media thickness, a measure of atherosclerosis, compared to non-obese children (48). The American Academy for

Pediatrics states that overweight children belong to a special risk category of children and are in need of cholesterol screening regardless of family history or other risk factors (49). Several studies provide information regarding cardiovascular disease risk in children indicating that body fatness is correlated with an increase in the prevalence of blood lipid levels and an increased risk of developing cardiovascular disease (47, 50-59). However, few studies have been conducted in U.S. children and adolescents.

Markers of cardiovascular disease include total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride levels, and C-reactive protein levels. Brazilian children and adolescents assessed for BMI, blood pressure and blood lipid levels had significant associations between BMI and increased blood pressure, decreased HDL cholesterol, and increased triglyceride levels (47).Similar results were found in a sample of 780 Greek children (50). In a large study of 26,008 overweight and obese European children, the

degree of overweight classified by BMI was inversely associated with HDL-cholesterol levels and related to an increase in blood pressure and triglyceride levels (51). BMI was also associated with increased triglyceride levels and decreased HDL-cholesterol levels in Iranian adolescents aged 10-19 years (52).

Researchers in India examined a small sample of 49 overweight and obese

children aged 6-11. Obese children had a significantly higher rate of high triglyceride and low HDL-cholesterol levels (53). In addition to blood lipid levels, C-reactive protein levels, a marker of inflammation associated with cardiovascular disease, were found to be higher in overweight and obese children compared to their normal weight counterparts (53, 54).

Researchers examining the relationship between excess body fat, defined by BMI, in samples of non-U.S. children and adolescents reported significant positive correlations between BMI and markers of cardiovascular disease. Children and adolescents with an increased BMI had an increase in triglyceride, C-reactive protein, and blood pressure levels as well as a decrease in HDL-cholesterol levels. Studies examining these relationships in U.S. children and adolescents are limited to a few studies.

Chen et al. (55) examined the relationship of BMI to blood pressure in a sample of U.S. children aged 8-10, limited to only Chinese Americans. BMI was positively associated with systolic blood pressure. Williams and Strobino (56) assessed associations between body mass index and lipid levels in young children with a mean age of 3.9. Lipid levels and BMI were assessed at baseline and four years later in 519 children. Increasing BMI levels over the four year period were significantly inversely associated with HDL-

cholesterol levels and children at higher BMI levels had higher total cholesterol and triglyceride levels.

Similar results were found in a study utilizing data from a nationally

representative sample. Masters (57) analyzed lipid concentrations in relation to body fat indicators in U.S. children aged 6-11. Data came from the 2001-2004 NHANES and multiple linear regression analyses adjusted for age, gender, survey period, and race- ethnicity were conducted. HDL cholesterol levels were significantly inversely associated with BMI, subscapular skinfold measures, and triceps skinfold measures. In addition, total cholesterol levels were positively associated with subscapular skinfold and triceps skinfold measures.

The correlation between body fat and lipid levels in adolescents also exists. Lamb et al. (58) analyzed associations between body fat percentage and lipid concentrations in both children and adolescents from the NHANES 1999-2004. Body fat percentage measured by dual-energy X-ray absorptiometry was utilized and triglycerides, total, HDL, and LDL cholesterol were assessed for youth with or without high adiposity. A significantly higher prevalence of adverse triglyceride, total, HDL, and LDL cholesterol levels was found in youth with high adiposity compared to those without high adiposity. Body fat percentage explained 2-20% of the variance in lipid values.

Camhi et al. (59) assessed body fat and blood lipid levels in adolescents 12-18 years of age using data from the 2001-2008 NHANES. BMI was used as the marker of overweight/obese and markers of cardiovascular disease were clustered. Prevalence of risk factor clustering was defined as having two or more of the following: high

triglycerides, low HDL-cholesterol, high blood pressure, and high fasting glucose. Adolescents with risk factor clustering were more likely to have a higher BMI.

No published studies have utilized the most recent 2009-2010 NHANES data and only one study has examined the relationship between body fat and blood lipid levels in children 6-11 years of age (57). It is important to examine these relationships using the most recent data and for both children and adolescents due to the fact that

overweight/obese youth with unfavorable blood lipids have an increased risk of carrying these risk factors into adulthood. Juhola et al. (60) tracked childhood lipid levels, blood pressure, and body mass over a 27 year period. Participants were ages 3-18 when the study started in 1980 and 30-45 year old adults at the time of the 27-year follow-up in 2007. Unfavorable blood lipid, blood pressure, and BMI levels correlated strongly with unfavorable levels in middle age suggesting that obese children are setting the stage for disease development earlier in adulthood. Research examining the associations between body fat and adverse lipid concentrations in a recent sample of U.S. children and