Obesity is a worldwide public health problem, also affecting the pediatric population.¹ For example, between 1989 and 2010, an 82% increase in obese individuals was observed in this population, calling attention to the association of childhood obesity with high blood pressure (BP),² similar to dyslipidemia and Type 2 Diabetes Mellitus.³

The Bogalusa study showed that risk factors during childhood could result in cardiovascular diseases in one'sadult life. Berenson et al. demonstrated that increases in body mass index (BMI), systolic BP, low-density lipoprotein (LDL), triglycerides (TG), and smoking are related to the extent of atherosclerotic lesions, determined after performing autopsies on 204 young people.⁴

The European Childhood Obesity Surveillance Initiative (COSI) study, which is in its fourth round, through the prevalence of thinness, obesity, and severe obesity in 203,323 children, aged 6 to 9 years, living in different regions of Europe and Asia, including 36 participating countries, demonstrated that excess weight and obesity are more common among children of in the European Region, identified in 28.7% among boys and 26.5% among girls.⁵ The ERICA (Studies of Cardiovascular Risks in Adolescents), conducted with Brazilian children and adolescents, described the prevalence of excess weight and obesity at 17.1% and 8.4%, respectively, as well as other disorders, such as hypercholesterolemia (20.1%), metabolic syndrome (2.6%), and high BP (9.6%).^6–10

Thus, the present study aimed to evaluate the prevalence of excess weight (overweight/obesity) and its association with BP, lipid profile, and area of residence (rural vs. urban) in the pediatric population of a Brazilian semiarid region (Sertão).

The sample consisted of 138 schoolchildren, aged 6 to 10 years, 76 (55.07%) female, and 81 (58.7%) from the urban area.

None of the lipid, anthropometric, WC, SBP, and DBP variables showed differences in terms of sex.

As for region (rural or urban area), children from rural areas had higher levels of TC and SBP than did those living in urban areas, and higher than desirable TC values (≥ 170 mg/dl) among rural children. However, no differences were observed for the other clinical and laboratory variables (Table 1).

The frequency of children classified as eutrophic was 84.8% and excess weight, 15.2%, including overweight (8.7%), obesity (5.1%), and severe obesity (1.4%). No schoolchildren were classified as thin or excessively thin. The frequency of these groups was analyzed in rural and urban areas, defining the "excess weight" group as children who fit the overweight, obesity, and severe obesity groups. In the urban area, the frequency of the excess weight group was higher (17 children, 8 overweight, 7 with obesity, and 2 with severe obesity, corresponding to 12.31%) than in the rural area (04 children, 3 overweight, and 01 with obesity, corresponding to 2.89%) (p = 0.024).

No differences were observed between groups when considering the students with high cholesterol (≥ 170 mg/dL), low HDL (≤ 45 mg/dl), high LDL (≥ 110 mg/dL), high TGs (from 0 to 9 years ≥ 75 mg/dl and 10 to 19 years ≥ 90 mg/dL), and a high TG/HDL ratio (≥2.73), when assessing data from the population of children who reside in rural and urban areas regarding the lipid profile.

Table 2 compares averages of SBP and DBP measurements, WC, and lipid variables. The SBP, WC, TG, and TG/HDL ratio presented higher averages in the excess weight group.

Regarding 117 eutrophic children, 111 schoolchildren (94.9%) were normotensive, and 6 (5.1%) presented high BP, while 20 children (95.2%) of the excess weight group were normotensive and one child (4.8%) presented high BP, with no difference between the groups (p = 0.944).

The percentage of the students in the eutrophic group with high cholesterol was 38.8% (n = 47), and in the excess weight group, 47.6% (n = 10). Regarding low HDL, in the eutrophic group, the percentage was 5% (n = 6), and 4.8% in the excess weight group (n = 1). As for the high LDL, 18% (n = 21) of the children were from the eutrophic group and 33.3% (n = 7) were from the excess weight group. As for high TG, 37.6% (n = 44) of the students belonged to the eutrophic group, while 61.9% (n = 13) belonged to the excess weight group. Concerning high TG/HDL, 3.4% (n = 4) were in the eutrophic group and 14.3% (n = 3) in the excess weight group. The TG and TG/HDL ratio variables were higher in the excess weight group (p = 0.037).

Among the families of the evaluated students, 73.19% had a history of hypertension, and 31.9% presented obesity.

In the group of 117 eutrophic students, 84 (71.8%) children did not present a family history of obesity, while 33 (28.2%) had a positive history of obesity. Among the excess weight children, 10 (47.6%) had no family history of obesity (FHO), and 11 (52.4%) presented a positive FHO, showing an association between FHO and excess weight (p = 0.029).

According to this study, the WC values for the excess weight group reached the 75 percentile values for children in each age group of 6, 7, 8, 9, and 10 years, as compared to Eutrophic Group¹¹ (Chart 1a).

Graph 1b describes the eutrophic and excess weight groups and waist/stature ratio values. Again, the excess weight group shows values close to the reference value (≥ 0.55).¹³

Figure 1a simultaneously evaluated: (1) nutritional status (eutrophic and excess weight); TG classification (standard or high); (2) HDL (≤ 45 mg/dl or> 45 mg/dl); (3) LDL (≤ 110 mg/dl or > 110 mg/dl); (4) TC risk (≤ 170 mg/dl or > 170 mg/dL), and TG/HDL risk (< 2.73 or ≥ 2.73). This perceptual map shows the association between eutrophic, regular TG, normal HDL, normal LDL, and regular TC, while the excess weight group is closer to the low and high TG, high LDL, high TC, high HDL groups, and high TG/HDL.

Figure 1b shows another perceptual map showing the characteristics of nutritional status (eutrophic or excess weight), BP classification (high BP or normal BP), and location (rural or urban area).

This study demonstrated that the prevalence of the excess weight group (overweight, obesity, and severe obesity) totaled 15.2% (view Central Figure). The study describes a population of schoolchildren, aged 6 to 10 years. Oliveira et al.¹⁴ evaluated children, aged 5 to 9 years, and found a lower prevalence of overweight and obesity, corresponding to 9.3% and 4.4%, respectively. WHO¹⁵ data indicate that overweight and obesity prevalence in children and adolescents, aged 5 to 19, calculated at 4% in 1975, increased to 18% for girls and 19% for boys in 2016.

In the ERICA study,⁶ the prevalence of overweight and obesity was 17.1% and 8.4%, involving adolescents, aged 12 to 17 years. Santos et al.¹¹ recorded the prevalence of obesity in each age group, which ranged from 17% (6 years of age) to 21.6% (9 years old) among boys, and from 14.1% (7 years old) to 17.3% (9 years old) among girls. Pereira et al.,¹⁶ among 911 schoolchildren, aged 6 to 10 years, found a prevalence of overweight of 17.7% and obesity of 16.2%, which is similar to that found in the present study.

The COSI⁵ study found that the percentages of overweight children reached 28.7% for boys and 26.5% for girls. In the study conducted by Bont et al.,¹⁷ the prevalence of excess weight, including overweight and obesity, was 39.9% for children aged 10.8 years. Boys were more likely to be overweight/obese when compared to girls (42.2% vs. 36.9%). According to the WHO, being overweight and obese have been considered a serious problem in high-income countries and, for some years, have been on the rise in low- and medium-income countries, particularly in urban environments.¹⁵ In the present study, the most significant percentage of children with excess weight (overweight, obesity, and severe obesity) was found in the metropolitan area (12.31%), when compared to the countryside (2.89%). These data agree with the study of Garibaldi et al.,¹⁸ which evaluated 174 children, aged 7 to 17 years; 16.66% of the urban children were overweight, while in the countryside, this number was 12.64%. Some considerations can explain these results; urban regions have an easy supply of more caloric foods associated with reduced physical activity and greater access to electronic devices without using time controls.¹⁹ It is essential to highlight that children in the countryside often walk to school transportation or to school, and participate in working activities with their parents, which can increase physical activity.²⁰

Dyslipidemic children presented a change in at least one of the lipid fractions, given that the present study shows that the rural children had a higher level of TC (p=0.041),as well as higher levels of SBP (p=0.028), when compared to urban schoolchildren. One of the possible causes of dyslipidemic changes is becoming more present in the countryside. This may well be due to this population's greater access of to fat-rich foods. Costa et al.,²¹ in the adjusted analysis of healthy and unhealthy food consumption markers, observed a higher bean consumption (OR = 1.20; 95% CI: 1.14-1.26) and excessive meat or chicken fat (OR = 1.48; 95% CI: 1.42-1.55), as well as fewer fruits and vegetables (OR = 0.89; 95% CI: 0.85-0.96), fish (OR = 0.88; 95% CI: 0.84-0.92), soft drinks (OR = 0.55; 95% CI: 0.52-0.59), and snack meal replacement (OR = 0.59; 95% CI: 0.51-0.66) in rural areas. The same study states that Brazilian residents in rural areas are more likely to maintain a traditional food pattern, consuming minimally processed foods, especially beans, and less ultra-processed food consumption, but with less consumption of fruits, vegetables, and fish.

Due to globalization and urbanization, residents of rural areas may be accompanying the eating patterns of urban areas, including more sedentary habits, the consumption of processed foods, and access to the most diverse forms of electronic entertainment, which make children exercise less, causing a decrease in HDL levels.²²

For Oliveira et al.,¹² the TG/HDL ratio helps identify insulin resistance in overweight young people. Iwani et al.²³ also associated this marker with obesity, and the TG/HDL ratio was indicated as a possible marker to replace fasting blood glucose in the diagnosis of insulin resistance. In this study, an association was found between the TG/HDL ratio and the excess weight group, reinforcing the role of the TG/HDL ratio as a cardiovascular risk marker.

In the present study, no difference was observed between eutrophic and excess weight groups in the frequency of high BP, with a general prevalence of 5.07%. By contrast, Pereira et al.¹⁶ evaluated 911 schoolchildren (6 to 10 years), finding a prevalence of 34% high BP, and no statistical difference between the sexes, with excess weight associated with high BP in the group of schoolchildren aged 8 to 9 years (p =0.004), while obesity was associated in both groups of schoolchildren aged 6-7 years (p = 0.004) and 8-9 years (p = 0.001). Moreover, in the study of Brandão-Souza et al.,²⁴ which evaluated 899 schoolchildren, aged 7 to 10 years, excess weight (overweight + obesity) was associated with increased BP, and the latter was more commonly related to schoolchildren from rural schools.

Our study found a prevalence of 31.9% FHO in the studied population. This data becomes relevant, since studies address heredity as a risk factor for obesity in the pediatric population. Frutoso et al.⁸ demonstrated maternal obesity is also a risk factor for obesity in adolescence.⁸

Graph 1 (1a) of the present study demonstrates that the excess weight group reaches the values of P75, suggesting that this group is at a greater risk of developing cardiovascular disease. Graph 1 (1b) also describes the waist/height ratio values of both the eutrophic and excess weight groups, and the excess weight group shows a more unfavorable profile, with values close to the reference (≥ 0.55),¹³ indicating the presence of abdominal adiposity and, consequently, more significant risk of cardiometabolic disease.

These data reinforce the knowledge that obesity in the pediatric population involves a complex web of genetic, hormonal, nutritional, physical, environmental, and social factors. In addition, obesity is different in ethnic groups and monogenic obesity types differ from each other.²⁵ This sheds new light on the molecular mechanisms of obesity, opening the door to new forms of treatment.

The present study demonstrated that overweight and obesity indicators among schoolchildren, aged 6 to 10 years, in the Brazilian semiarid region the state of Bahia (Serrinha Region), were significantly associated with cardiometabolic risk factors such as WC, TG, and the TG/HDL ratio. A higher prevalence of excess weight was found in schoolchildren from urban areas as compared to rural areas. A higher prevalence of lipid alterations was also observed in rural areas, calling attention to a possible unfavorable pattern in this population (according to Central Figure attached).

The present study reinforces the importance of monitoring and controlling cardiovascular risk factors directly related to excess weight, opening the door to more comprehensive studies involving the monitoring of diet quality and levels of physical activity, as well as measurements of anthropometric data, lipid profiles, and the BP of these students over time.