Association between Cardiovascular Risk in Adolescents and Daily Consumption of Soft Drinks: a Brazilian National Study

Background: Cardiovascular risk in adolescence is a public health problem that has grown along with the increase in soft drink consumption. Objective: To investigate the association between cardiovascular risk factors and daily consumption of soft drinks in Brazilian adolescents. Methods: We conducted a cross-sectional, national, school-based study of 36,956 Brazilian adolescents aged 12 to 17 years. Daily soft drink consumption was estimated using a 24-hour dietary recall. Cardiovascular risk was categorized as overweight, obesity, hypertension, hyperglycemia, and dyslipidemia. The survey command of Stata 14.0® was used to analyze data from a complex sample. The chi-square test was used to assess differences in soft drink consumption and other variables in the descriptive analysis. The odds ratio of cardiovascular risk factors and their respective 95% confidence intervals were estimated, considering sociodemographic and behavioral variables in the Mantel-Haenszel model. Statistical significance was set at p < 0.05. Results: Daily consumption of soft drinks was common among adolescents. A daily serving ≥ 450 mL was significantly associated with overweight and hypertension. Results associated with the consumption of regular soft drinks show the possibility of reverse causality. Consumption of diet soft drinks in adolescence should be considered a cardiovascular risk factor. Conclusion: Daily consumption of soft drinks can be understood as a relevant risk factor in the epidemiological scenario. Improper eating habits are multifactorial in nature and need to be better understood in the context of adolescent health and further explored in national surveys.

Food consumption was estimated based on 24-HDR data, collected using ERICA-REC24h, a computerbased direct data collection platform. The software was developed from a database consisting of 1626 food items, including preparation methods and units of predefined serving sizes. The database was developed by the Brazilian Institute of Geography and Statistics and used in the 2008-2009 National Diet Survey. 13,14 Reported foods that were not included in ERICA-REC24h were incorporated by the researchers.
Beverages reported by the adolescents in 24-HDRs were divided into 6 groups: flavored dairy drinks, soybased beverages, juices and fruit drinks, regular soft drinks, diet soft drinks, and other (beverages that did not fit any of the previous groups). 15 Participants' sex, age group, and Brazilian region were treated as sociodemographic variables. Eating habits (calories consumed daily and the percentage of sugar in the diet) and sedentary lifestyle (screen time > 2 hours/ day) were treated as behavioral variables. Cardiovascular risks were investigated by a n t h r o p o m e t r i c a s s e s s m e n t , b l o o d p r e s s u r e measurement, and biochemical blood tests using fasting blood samples. [16][17][18] Cardiovascular risk factors in adolescence were defined as follows: overweight and obesity, classified according to body mass index; hypertension, when systolic or diastolic blood pressure corresponded to the 95th percentile or higher; hyperglycemia, defined as fasting blood glucose ≥ 126 mg/dL; and dyslipidemia, defined as total cholesterol ≥ 170 mg/dL, LDL-cholesterol ≥ 130 mg/dL, HDLcholesterol < 45 mg/dL, and/or triglycerides ≥ 130 mg/dL. Sex, age, geographic region, and screen time (> 2 hours/ day) were used as adjustment variables.

Statistical analysis
Data were analyzed in Stata 14.0®, and the effect of sample design and expansion based on sample weight were considered by using the survey command. A 95% CI was adopted, and the level of statistical significance was set at p < 0.05.
The chi-square test was used to assess the association between variables in the descriptive analysis. For inferential analyses, soft drink consumption was categorized by using the median daily consumption of regular soft drinks (450 mL) as a cutoff point. The odds ratio of cardiovascular risk was calculated b y a s s o c i a t i n g s o f t d r i n k c o n s u m p t i o n with interval [CI], 26.1%-28.4%) of the adolescents surveyed consume soft drinks 5 or more days per week. 5 Limiting soft drink consumption can contribute to reducing weight gain and associated chronic diseases, such as cardiometabolic diseases. Public policies have been adopted to promote health and to reduce soft drink consumption especially in childhood and adolescence, but compensation mechanisms have limited the benefits of these actions. [6][7][8] Early interventions have been successful in reducing CVD with the potential to change the current epidemiological scenario. 9 Adolescent exposure to unhealthy habits, such as high consumption of soft drinks, is associated with increased cardiovascular risk and greater lifetime accumulation of exposure. Cardiovascular risk factors include overweight and obesity, dyslipidemia, hypertension, insulin resistance, sedentary lifestyle, and atherogenic diet. 10 Great human potentialities are developed during adolescence and may have repercussions in adulthood. A better understanding of risk factors common to this age group can strengthen public policies and guide more effective health actions for changes in the epidemiological profile. Therefore, this study aimed to investigate the association between cardiovascular risk factors and daily consumption of soft drinks in Brazilian adolescents.

Methods
This study analyzed data from the Brazilian Study of Cardiovascular Risks in Adolescents (ERICA), whose methodological approach was based on conglomerate sampling, minutely described in preliminary studies. 11,12 We conducted a cross-sectional, multicenter, national, school-based study that covers the population of adolescents aged 12 to 17 years enrolled in public or private schools in Brazilian municipalities with more than 100,000 inhabitants.
The data were collected between March 2013 and December 2014. A total of 1251 schools in 124 Brazilian municipalities were selected, for a total sample of 36,956 adolescents with complete data from a self-report questionnaire, 24-hour dietary recall (24-HDR), and physical and biochemical examinations. The sample is representative of the population of Brazilian adolescents at the national and regional levels, for the capital cities and the Federal District. Only adolescents who agreed in writing and whose guardians signed the informed consent form participated in the study. The confidentiality and anonymity of the participants were preserved in this study.

Results
The consumption of sugar-sweetened beverages was high among adolescents attending schools in Brazilian cities with more than 100,000 inhabitants. The mean age of the participants was 14.7 years (range, 12 to 17 years), and 60% were female. Geographic region was a determinant of soft drink consumption (p = 0.000). Table 1, beverages in the groups 'juices and fruit drinks,' 'regular soft drinks,' and 'flavored dairy drinks' were the most frequently reported in the 24-HDR by Brazilian adolescents. As measured by the median, the highest daily servings were found in the groups 'regular soft drinks' (450 mL) and 'juices and fruit drinks' (300 mL). Flavored dairy drinks, soy-based beverages, and diet soft drinks had values of 240 mL/day.

As shown in
The ratio of the amount of added sugar to the total daily energy value, in calories, was checked for the different groups. The groups 'regular soft drinks' and 'juices and fruit drinks' had a ratio of 8.06% and 6.78%, respectively. Diet soft drinks do not contain sugar, which is why the ratio was zero. Daily servings of sugar-sweetened beverages were high and often positively correlated with daily energy (calorie) increase in adolescents, probably because of the added sugar from these drinks (Table 1). Table 2 presents the distribution of sociodemographic, behavioral, and cardiometabolic characteristics of adolescents in the ERICA study according to the consumption of regular and diet soft drinks. Only 1.06% (n = 391) of the sample reported consuming diet soft drinks in the 24-HDR. In contrast, 45.21% (n = 16,708) reported consuming regular soft drinks. The consumption of soft drinks varied according to the different independent variables ( Table 2).
Soft drink consumption was significantly associated with overweight, obesity, and hypertension (p < 0.05), as shown in Tables 3 and 4. Adolescents who consumed more regular soft drinks had a lower odds ratio for overweight, obesity, and hypertension ( Table 3). The odds ratio for overweight, obesity, and hypertension increased with increasing servings of diet soft drinks ( Table 4). The distribution of associations remained constant after adjustments.

Discussion
Data from the 2017-2018 Brazilian Household Budget Survey show that soft drinks are the beverages with the highest average daily per capita consumption in Brazil (67.1 g/day). The average daily per capita soft drink consumption in the South is twice as high as in the North and Northeast. 19 Considered a marker of an unhealthy dietary pattern, soft drink is a beverage made from carbonated water  Liquid calories do not produce the same level of satiety as solid calories, and the consumption of soft drinks is often associated with excessive calorie intake and increased risk of obesity. 6,22 The World Health Organization recommends that sugar consumption should be reduced to 5% of the calories ingested daily, but consuming diet soft drinks, as a substitute for regular soft drinks, has also been associated with cardiovascular risk and should be considered in the development of public health policies. 23,24 The association between sugar-sweetened beverages and chronic diseases is complex and can be confused by several factors. 25 Ambrosini et al., 26 identified that the daily serving size of soft drinks influenced the increase in cardiometabolic risk, overweight, and obesity in girls. Among boys, there was a reduction in HDL-cholesterol levels, regardless of weight gain. All adolescents, both female and male, who increased their intake to more than 325 mL/day showed increased triglyceride levels.
In our study, soft drink consumption was negatively associated with overweight and hypertension in adolescents. A possible explanation for these results is the reverse causality effect, considering the cross-sectional design of the study, as restrictions on the consumption of sugar-sweetened beverages have been incorporated into recommendations for dietary changes to prevent cardiovascular risk. 22,23 Replacing sugar-sweetened beverages by diet/light soft drinks has been pointed out as an alternative  to reduce sugar in the diet. Diet soft drinks are lowcalorie beverages, but the artificial sweeteners in their composition can increase the storage of calories from other foods consumed. An increased consumption of diet soft drinks has been associated with increased risk of type 2 diabetes, CVD, and metabolic syndrome. 27 Also, diet soft drinks have more sodium than regular soft drinks, and the increased amount of sodium in the diet may be associated with higher blood pressure in adolescents who consume diet soft drinks than in those who consume regular soft drinks. This possibility should be considered by people on a recommended low-sodium diet. 28 Hypertension is strongly associated with adverse cardiovascular events, including heart failure, ischemic heart disease, and cerebrovascular diseases. 29 It is important to highlight that the health-disease process is not associated simply with the presence or absence of a certain food in the diet, but rather with the set of foods consumed, their quantity and servings. Therefore, other independent pathways should be considered in the investigation of cardiovascular risk factors in adolescence. 25 For example, high screen time favors physical inactivity and greater consumption of obesogenic foods, in addition to causing distractions that interfere with the physiological signals of hunger and satiety. The media can negatively influence eating behaviors in adolescents, and high screen time contributes to both a sedentary lifestyle and excessive soft drink consumption. 30 Regional specificities should be considered in the development of public policies aimed at promoting health and reducing cardiovascular risk in adolescents. It is known that the current epidemiological scenario is multifactorial and that social, demographic, and behavioral variables are associated with the development of cardiovascular risk factors in this population. Therefore, in-depth scientific studies on sociodemographic, behavioral, and epidemiological factors associated with soft drink consumption are essential, since the daily consumption of these beverages is high in adolescence. Associations between dietary habits and epidemiological risk factors need to be carefully observed.
One of the limitations of this study is the inability to establish a cause-and-effect relationship between soft drink consumption and cardiovascular risk, as the crosssectional design makes it impossible to determine the time interval between the variables. However, there are few Brazilian population-based studies of adolescents on this topic with the amount of information provided in this study. The sample size and the standardization of methods and instruments used in data collection reinforce the reliability of the data reported in this study.

Conclusions
Population-based studies investigating the consumption of sugar-sweetened beverages using a 24-HDR are still incipient, and the association of regular and diet soft drinks with cardiovascular risk factors in adolescents was a relevant finding in the present study.
Brazilian adolescents who are overweight and have hypertension may be realizing the importance of reducing the consumption of regular soft drinks, resulting in lower intake or greater underreporting of soft drink consumption in this group. In contrast, adolescents consuming larger servings of diet soft drinks were at greater risk of being overweight, obese, and hypertensive.
These data highlight the need to expand scientific research and strengthen health actions focused on soft drink consumption among adolescents, considering the susceptibilities and specific characteristics of this population. Adolescents' consumption of sugarsweetened beverages needs to be explored as an important cardiovascular risk factor for the Brazilian epidemiological scenario and should not be ignored in the development of public policies within the environments in which adolescents live.