Abstract

Objectives:

To describe food consumption frequency in adolescents in the context of the financial crisis in 2012, and to analyse potential fluctuations in excess body weight between 2008 and 2012.

Method:

A cross-sectional study of eating habits and excess body weight was conducted in adolescents aged 13 to 19 years old from public, subsidised and private secondary schools in Barcelona, Spain. The FRESC lifestyle risk factors survey was used, and food frequency consumption, food recommendations and body mass index were analysed according to gender, year of education and socioeconomic status.

Results:

Girls ate vegetables and fruits more frequently than boys, while the prevalence of junk food consumption was higher in boys. The prevalence of compliance with food recommendations was lower than 50% for all foods, and gender and socioeconomic differences were found for eggs, red meat and soft drinks. Regarding excess body weight, boys had a higher prevalence than girls in the 2 years analysed. Furthermore, a reduction in excess body weight was observed among girls in secondary education in the highest socioeconomic groups (28.7% [95% CI: 24.8-32.6%] in 2008 to 20.5% [95% CI: 17.1-23.8%] in 2012).

Conclusions:

The prevalence of adolescents following food recommendations is low, and gender differences were found in terms of food consumption frequency, even in the context of financial crisis. There is a need to promote programmes and policies to reduce inequalities related to eating habits and excess body weight in adolescents.

Keywords:
Adolescent; Food consumption; Overweight; Economic recession; Diet surveys

Resumen

Objetivos:

Describir la frecuencia de consumo de alimentos en adolescentes en un contexto de crisis económica en el año 2012, y analizar los potenciales cambios en el exceso de peso entre los años 2008 y 2012.

Diseño:

Estudio transversal de los hábitos alimentarios y el exceso de peso en adolescentes de entre 13 y 19 años de edad pertenecientes a escuelas públicas, concertadas y privadas de Barcelona. Se utilizó la encuesta FRESC sobre factores de riesgo asociados a estilos de vida y se analizaron, según sexo, curso académico y nivel socioeconómico, las frecuencias de consumo, recomendaciones alimentarias e índice de masa corporal.

Resultados:

Las chicas realizaban un mayor consumo de frutas y verduras, mientras que los chicos consumían comida no saludable con mayor frecuencia. La prevalencia de cumplimiento de las recomendaciones alimentarias es inferior al 50% para todos los alimentos, y se encontraron diferencias según el sexo y el nivel socioeconómico en el consumo de huevos, carne roja y refrescos. En relación al exceso de peso, la prevalencia fue mayor en los chicos que en las chicas en los 2 años analizados. Además, se observó una reducción del exceso de peso en las chicas cursando Educación Secundaria Obligatoria y de nivel socioeconómico alto (de 28,7% [IC95%: 24,8-32,6%] en 2008 a 20,5% [IC95%: 17,1-23,8%] en 2012).

Conclusiones:

La prevalencia de adolescentes que siguen las recomendaciones de consumo es baja. Hay diferencias de sexo en las frecuencias de consumo de los alimentos, incluso en un contexto de crisis económica. Existe una necesidad de promover programas y políticas para reducir las desigualdades relacionadas con los hábitos alimentarios y el exceso de peso en los adolescentes.

Palabras clave:
Adolescente; Ingestión de alimentos; Sobrepeso; Recesión económica; Encuestas sobre dietas

Introduction

Excess weight (overweight and obesity) in adolescents is a major concern in Spain due to the high prevalences of overweight and obesity at 17% and 8.5% respectively in 2012.¹1. Sánchez-Cruz J-J, Jiménez-Moleón JJ, Fernández-Quesada F, et al. Prevalence of child and youth obesity in Spain in 2012. Rev Esp Cardiol. 2013;66: 371-6. Moreover, adolescents with excess weight are more likely to be overweight or obese in adulthood²2. Power C, Lake JK, Cole TJ. Measurement and long-term health risks of child and adolescent fatness. Int J Obes Relat Metab Disord. 1997;21:507-26. and to have a higher risk of cardiovascular diseases³3. Park MH, Falconer C, Viner RM, et al. The impact of childhood obesity on morbidity and mortality in adulthood: a systematic review. Obes Rev Off J Int Assoc Study Obes. 2012;13:985-1000. which are one of the main causes of death in Spain.⁴4. Instituto Nacional de Estadística. Defunciones según la causa de Muerte;2014. [Accessed November 2015]. Available at: http://www.ine.es/prensa/np830.pdf
http://www.ine.es/prensa/np830.pdf... Excess weight is influenced by multiple factors, with eating habits playing a key role.

The “food recommendation pyramid” graphically represents the recommended frequency of food consumption according to their properties.⁵5. Agència de Salut Pública de Barcelona. Programa CANVIS. [Accessed November 2015]. Available at: http://www.aspb.cat/quefem/escoles/canvis.htm
http://www.aspb.cat/quefem/escoles/canvi... In general, a healthy diet should include daily consumption of cereals or potatoes, vegetables, fruits and dairy products; meat, fish and eggs a few times per week; and sausages, sweets and manufactured products only occasionally.⁵5. Agència de Salut Pública de Barcelona. Programa CANVIS. [Accessed November 2015]. Available at: http://www.aspb.cat/quefem/escoles/canvis.htm
http://www.aspb.cat/quefem/escoles/canvi... Eating habits are especially important during adolescence due to the physical and mental development that takes place at this period of life.⁶6. Story M, Stang J. Guidelines for Adolescent Nutrition Services. Minneapolis: Center for Leadership, Education and Training in Maternal and Child Nutrition, Division of Epidemiology and Community Health, School of Public Health, University of Minnesota. 2005. [Accessed November 2015]. Available at: http://www.epi.umn.edu/let/pubs/adol_book.shtm
http://www.epi.umn.edu/let/pubs/adol_boo... Moreover, in adolescence, some lifestyles can be established and last until later stages, and therefore the acquisition of healthy habits, including eating habits, is especially important.⁷7. Wang Y, Bentley ME, Zhai F, et al. Tracking of dietary intake patterns of Chinese from childhood to adolescence over a six-year follow-up period. J Nutr. 2002;132:430-8.

The Spanish population has been experiencing an economic crisis since the third trimester of 2008. It is known that economic recessions can modify eating habits and,⁸8. Fröjd S, Marttunen M, Pelkonen M, et al. Perceived financial difficulties and maladjustment outcomes in adolescence. Eur J Public Health. 2006;16:542-8.^,99. Widome R, Neumark-Sztainer D, Hannan PJ, et al. Eating when there is not enough to eat: eating behaviors and perceptions of food among food-insecure youths. Am J Public Health. 2009;99:822-8. despite the lack of scientific published data, the available information from some organizations and non-governmental organizations show that there might be increasing food insecurity.¹⁰10. Centro de Investigaciones Sociológicas. Ficha del estudio 2923, Barómetro de Diciembre 2011. [Accessed November 2015]. Available at: http://www.cis.es/cis/opencm/ES/1_encuestas/estudios/ver.jsp?estudio=12104
http://www.cis.es/cis/opencm/ES/1_encues...

11. Síndic de Greuges de Catalunya. La malnutrició infantil a Catalunya 2013. [Accessed November 2015]. Available at: http://www.sindic.cat/site/unitFiles/3506/Informe%20malnutricio%20infantil%20catala.pdf
http://www.sindic.cat/site/unitFiles/350... ^-1212. González-Bueno G, Bello A, Arias M. La infancia en España 2012-2013: El impacto de la crisis en los niños. Madrid: UNICEF comité Español; 2012 [Accessed November 2015]. Available at: http://www.unicef.es/sites/www.unicef.es/files/Infancia_2012_2013_final.pdf
http://www.unicef.es/sites/www.unicef.es... The Sociologic Investigation Center of Spain and UNICEF reported that eating habits in families might be changing, especially by reducing fresh food consumption, due to families’ limited economic resources.¹⁰10. Centro de Investigaciones Sociológicas. Ficha del estudio 2923, Barómetro de Diciembre 2011. [Accessed November 2015]. Available at: http://www.cis.es/cis/opencm/ES/1_encuestas/estudios/ver.jsp?estudio=12104
http://www.cis.es/cis/opencm/ES/1_encues... ^,1212. González-Bueno G, Bello A, Arias M. La infancia en España 2012-2013: El impacto de la crisis en los niños. Madrid: UNICEF comité Español; 2012 [Accessed November 2015]. Available at: http://www.unicef.es/sites/www.unicef.es/files/Infancia_2012_2013_final.pdf
http://www.unicef.es/sites/www.unicef.es... The Sindic de Greuges, a public organization that defends the fundamental rights of the Catalan population, warned that 2,800 children in Catalonia could have food security problems, and around 50,000 might have insufficient protein intake.¹¹11. Síndic de Greuges de Catalunya. La malnutrició infantil a Catalunya 2013. [Accessed November 2015]. Available at: http://www.sindic.cat/site/unitFiles/3506/Informe%20malnutricio%20infantil%20catala.pdf
http://www.sindic.cat/site/unitFiles/350...

Published studies on food consumption frequency in adolescents in Spain are limited,¹³13. Aranceta Bartrina J, Serra-Majem L, Pérez-Rodrigo C, et al. Nutrition risk in the child and adolescent population of the Basque country: the enKid Study. Br J Nutr. 2006;96(Supl 1):S58-66.^,1414. Serra-Majem L, Aranceta Bartrina J, Pérez-Rodrigo C, et al. Prevalence and determinants of obesity in Spanish children and young people. Br J Nutr. 2006;96 Suppl. 1:S67-72. or focus on other eating behaviours.¹⁵15. Rampersaud GC, Pereira MA, Girard BL, et al. Breakfast habits, nutritional status, body weight, and academic performance in children and adolescents. J Am Diet Assoc. 2005;105:743-60.^,1616. Gómez-Martínez S, Martínez-Gómez D, Pérez de Heredia F, et al. Eating habits and total and abdominal fat in Spanish adolescents: influence of physical activity. The AVENA study. J Adolesc Health. 2012;50:403-9. Since 1987 a lifestyle risk-factor survey (FRESC) has been administered periodically to the adolescent population in Barcelona. The main objectives of this study were to describe eating habits in terms of food consumption frequency and compliance with food recommendations among adolescents in 2012 (in an economic crisis setting), and to analyse changes in the prevalence of excess weight as a health indicator between 2008 (before the economic crisis) and 2012.

Methods

A cross-sectional study based on two representative samples of students from Barcelona was carried out using the 2008 and 2012 FRESC surveys (lifestyle risk-factor survey for secondary school students [FRESC]). Both surveys were administered to adolescents enrolled in the 8^th year of education (13-14 years old), 10^th year (15-16 years old) and 12^thyear (17-18 years old) in secondary schools in the city of Barcelona, Spain.¹⁷17. Agència de Salut Pública de Barcelona. Enquesta FRESC 2008. [Accessed November 2015]. Available at: http://www.aspb.cat/quefem/docs/FRESC_4ESO_16anys_2008.pdf.
http://www.aspb.cat/quefem/docs/FRESC_4E... ^,1818. Agència de Salut Pública de Barcelona. Enquesta FRESC 2012. [Accessed November 2015]. Available at: http://www.aspb.cat/quefem/docs/FRESC_2012_4t-ESO.pdf.
http://www.aspb.cat/quefem/docs/FRESC_20...

Samples were obtained following the same procedure in each edition of the survey. The sample size was calculated to obtain a 3% precision and assuming 95% confidence for a proportion of 0.5. The sample assessed for each year of education and edition was 1,250 adolescents, taking into account a 20% loss. Classrooms were used as the sample unit and were randomly selected for each year, stratifying by the family economic capacity index (low, medium and high −FECI-96−) and type of school (state, subsidized or private).

The FRESC questionnaire includes sociodemographic information and questions on different health risk factors, such as addictive substances, physical activity, emotional relationships, and food consumption frequency. The questionnaire was anonymous and was administered, with the prior permission of the schools’ headmasters, by professionals from the Public Health Agency of Barcelona (ASPB, Agència de Salut Pública de Barcelona) between the first and second trimester of the year. In 2008 and 2012 editions, students’ weight and height were objectively measured with their prior consent at the end of the questionnaire by the same professionals.

Principals and teachers of selected schools were properly informed about the objectives of the study. Furthermore, they gave their verbal informed consent and arranged a meeting with trained personnel of the ASPB and students for the administration of the questionnaire during regular school hours at classrooms. Students were also informed about the study and that their participation was absolutely voluntary, being free of not answering any question they did not consider appropriate. Students were also guaranteed that their responses were anonymous and would not be treated individually in any case. They were told not to write down their names or other personal identifiers in the questionnaire to assure anonymity. The study was approved by the Research Committee of the ASPB and parental informed consent was not considered necessary given the nature of the questionnaire.

Food consumption frequency was described using the food frequency questionnaire included in the 2012 FRESC survey, which provided data from a context of economic crisis. It was studied in terms of “food consumption frequency” and “compliance with the food recommendations”. Food consumption questions included the following items: bread, rice and pasta, potato or yucca, cereals, raw vegetables, boiled vegetables, fruits, legumes, meat (white and red), sausage, fish, eggs, dairies, nuts, pastries, sweets, milk desserts, crisps, and soft drinks. The response options differed, depending on the food, and ranged from “never or less than once a month” to “at least once a day”. Food consumption frequency was analysed by categorizing the food questions of the survey into “never”, “weekly” and “daily”. “Never” included the answers “never or less than once a month”; “weekly” included between “1 and 3 times a month” and “4 and 6 times a week”; and “daily” included between “once a day” and “3 or more times a day”. Compliance with food recommendations was analysed according to the “food recommendation pyramid”.⁵5. Agència de Salut Pública de Barcelona. Programa CANVIS. [Accessed November 2015]. Available at: http://www.aspb.cat/quefem/escoles/canvis.htm
http://www.aspb.cat/quefem/escoles/canvi... The food answers from the questionnaire which contained the recommended frequency were classified as the “recommended” category for each food. The other categories were classified in “more than recommended” when the frequency was higher than recommended and “less than recommended” when the frequency was lower than recommended when possible. Since the recommendations for bread, rice and pasta, potato or yucca and cereals is for the entire group together, a variable called “carbohydrate” was created by pooling them together. The same was done for the variable “fruit and vegetables”, which included cooked and raw vegetables and fruits. “Junk food” included crisps, milk desserts, sweets and pastries.

Body mass index (BMI) information was extracted from the 2008 (before the economic crisis) and 2012 FRESC surveys. Weight and height were used to calculate the adolescents’ Quetelet index or BMI. The variable created weight status was defined using the age- and sex-specific cut-offs proposed by the World Health Organisation Z-score.¹⁹19. Onis M, Onyango AW, Borghi E, et al. Development of a WHO growth reference for school-aged children and adolescents. Bulletin of the World Health Organization. 2007;85:660-7. The categories given were “low weight”, “normal weight”, “overweight” and “obesity” and were recategorized in two categories: “excess weight”, which included “overweight” and “obesity”, and “non-excess weight”, which included low and normal weight.

The sociodemographic variables analysed were age, sex, school year (8^th, 10^th or 12^th year), which was categorized in compulsory education (8^th and 10^th years) and postcompulsory education (12^th year), type of school (state, private or subsidized) and socioeconomic status (SES) based on the family affluence scale (FAS), which is an individual socioeconomic index that reflects family expenditure and consumption by asking for the number of holidays per year, the number of computers and cars at home and the availability of a private bedroom at home.²⁰20. Currie C, Molcho M, Boyce W, et al. Researching health inequalities in adolescents: the development of the Health Behaviour in School-Aged Children (HBSC) family affluence scale. Soc Sci Med. 2008;66:1429-36. The result is a scale that goes from 0 to 9 points, and it can be categorized in three groups: low affluence (0 to 3 points), middle affluence (4 or 5) and high affluence (6 to 9).

Bivariate analyses stratified by sex and year were conducted for “food consumption frequency”. Food consumption recommendations were analysed by FAS and sex (no stratification analysis by year was applied since there were no significant differences between them). In both cases, the chi-squared test with a significance level of 0.05 was used for comparison. Neither food frequency nor food recommendations were possible to compare between 2008 and 2012, since food frequency records differed between both editions. Excess weight data from the 2008 and 2012 FRESC surveys were analysed by comparing the prevalences of the two editions and stratifying them by sex, FAS and year, and using 95% confidence intervals (95%CI) for comparison. All statistical analysis were performed using the software STATA/IC11.2.

Results

Table 1 shows the main characteristics of the sample. A total of 3,089 students were analysed in the 2008 survey and 3,492 students in the 2012 survey. Around 48% of the students were boys and the median age was 15.7 years in 2008 and 15.8 years in 2012.

Table 2 shows that boys from the 8^th to 10^th years ate eggs (4.2%) in a significantly higher daily frequency than girls (2.3%). Boys also showed higher junk food consumption, reporting never eating “milk desserts” (14.8%), “pastries” (9.5%) and “soft drinks” (8.7%) in a lower frequency than girls (29.6%, 13.0% and 16.0% respectively). In contrast, girls showed a significantly higher daily consumption frequency of raw vegetables (34.9%), cooked vegetables (15.2%) and fruits (58.7%) than boys (25.1% ate raw vegetables, 13.1% ate cooked vegetables and 51.9% ate fruits).

Among adolescents in the 12^th year (Table 3), significant differences in daily consumption frequencies were found between boys and girls for raw vegetables (35.5% girls and 26.5% boys), cooked vegetables (15.6% girls 11.2% boys) and fruits (54.8% girls 45.6% boys). As in the group in the 8^th to 10^th years, boys also showed lower prevalences of “never eating” “milk desserts” (16.5%), “pastries” (8.5%) and “soft drinks” (8.9%) than girls (30.6%, 14.1% and 20.8%, respectively).

Regarding eating red meat, boys and girls in the lowest FAS level showed the highest prevalence of complying with food recommendations (12% in boys and 15% in girls) compared to the adolescents in the medium FAS (9.8% and 10.8%, respectively) and the highest FAS (7.6% and 12.6%). Furthermore, adolescents in the highest FAS showed a higher prevalence of eating red meat “more than recommended” (90.6% in boys and 84.2% in girls) than adolescents in the lowest FAS (76.3% in both sexes). Moreover, egg consumption in boys followed an SES gradient, with students from the lowest FAS being those who had the highest prevalence of complying with food recommendations (23.5%) compared with the medium (16.9%) and highest (14.2%) FAS. As for the recommended frequency of soft drinks, significant differences were observed among girls by FAS. Girls from the highest FAS had a higher prevalence of complying with the soft drink recommendations than girls in the lowest FAS (43.3% and 31.1% respectively) (p = 0.004) (Table 4).

According to the WHO cut-off points, differences in the prevalences of excess weight between 2008 and 2012 were found among girls in the 8^th and 10^th decreasing from 28.7% (95%CI: 24.8-32.6) to 20.5% (95%CI: 17.1-23.8) in girls in the highest FAS (Table 5).

Discussion

Food frequency differences in the economic crisis were observed between boys and girls, with girls eating fruits and vegetables more frequently. In addition, less than a half of the adolescents were currently following the recommendations of the “food recommendation pyramid”. Finally, excess weight is higher in boys than in girls, and decreased in girls from the highest SES and in the 8^th to 10^th years of education between 2008 and 2012.

The results of this study, showing that girls ate more fruit and vegetables than boys, are concordant with those in previous studies conducted in Madrid and the Balearic Islands²¹21. Diez-Gañan L. Hábitos de salud en la población juvenil de la comunidad de Madrid 2012. Resultados del sistema de vigilancia de factores de riesgo asociados a enfermedades no transmisibles en población juvenil (SIVFRENT-J). Boletín Epidemiológico de la Comunidad de Madrid. Madrid: Consejería de Sanidad. 2013. [Accessed November 2015]. Available at: http://www.madrid.org/cs/Satellite?blobcol=urldata&blobheader=application%2Fpdf&blobheadername1=Content-disposition&blobheadername2=cadena&blobheadervalue1=filename%3DSIVFRENT_J_2012.pdf&blobheadervalue2=language%3Des%26site%3DPortalSalud&blobkey=id&blobtable=MungoBlobs&blobwhere=1352851472259&ssbinary=true
http://www.madrid.org/cs/Satellite?blobc... ^,2222. Salas R, del Mar Bibiloni M, Zapata ME, et al. Balearic adults have low intakes of fruits and vegetables compared with the dietary guidelines for adults in Spain. Nutr Res. 2013;33:204-10. as well as in other European studies.²³23. Zaborskis A, Lagunaite R, Busha R, et al. Trend in eating habits among Lithuanian school-aged children in context of social inequality: three cross-sectional surveys 2002, 2006 and 2010. BMC Public Health. 2012;12:52. The results on food consumption in boys were also consistent with the SIVFRENT report, showing that adolescents in Madrid ate bread, crisps and biscuits in a higher frequency than girls.

The prevalence of compliance with food recommendations among adolescents was lower than 50%, independently of SES. Most adolescents consume more junk food, soft drinks and red meat than recommended and eat fewer fruits and vegetables than recommended, as described in other studies.²¹21. Diez-Gañan L. Hábitos de salud en la población juvenil de la comunidad de Madrid 2012. Resultados del sistema de vigilancia de factores de riesgo asociados a enfermedades no transmisibles en población juvenil (SIVFRENT-J). Boletín Epidemiológico de la Comunidad de Madrid. Madrid: Consejería de Sanidad. 2013. [Accessed November 2015]. Available at: http://www.madrid.org/cs/Satellite?blobcol=urldata&blobheader=application%2Fpdf&blobheadername1=Content-disposition&blobheadername2=cadena&blobheadervalue1=filename%3DSIVFRENT_J_2012.pdf&blobheadervalue2=language%3Des%26site%3DPortalSalud&blobkey=id&blobtable=MungoBlobs&blobwhere=1352851472259&ssbinary=true
http://www.madrid.org/cs/Satellite?blobc... ^,2323. Zaborskis A, Lagunaite R, Busha R, et al. Trend in eating habits among Lithuanian school-aged children in context of social inequality: three cross-sectional surveys 2002, 2006 and 2010. BMC Public Health. 2012;12:52.^,2424. Ortiz-Moncada R, Norte Navarro AI, Zaragoza Marti A, et al. Do the Spanish university students follow Mediterranean dietary patterns? Nutr Hosp. 2012;27:1952-9. In this regard, it is important that the “food recommendation pyramid” used in this study was based on the Mediterranean diet, while some studies report a shift towards more westernised diets and an abandonment of the Mediterranean diet, which could partially explain the results found in our study.

Differences in consumption by SES were not found for most of the types of food analysed, although red meat, eggs, junk food and soft drinks showed an SES gradient. It is well documented that people from lower SES groups consume more junk food than those from higher SES groups,²⁵25. Bruening M, MacLehose R, Loth K, et al. Feeding a family in a recession: food insecurity among Minnesota parents. Am J Public Health. 2012;102: 520-6. as indicated by our results. With reference to meat and eggs, Tatiana Andrayeva et al. pointed out that in the USA the demand for meat (especially beef) is related to the cost of the product (elastic demand) but the demand of eggs is not (inelastic demand). ⁽²⁶26. Andreyeva T, Long MW, Brownell KD. The impact of food prices on consumption: a systematic review of research on the price elasticity of demand for food. Am J Public Health. 2010;100:216-22. Additionally, these authors concluded that increasing food prices or reducing family incomes may influence family food purchasing. Indeed, a study with a representative sample of the Finnish population aimed to explore if the reasons of the food choice were related to income and education. Finnish with low SES reported that price and income were the main motivations in food purchasing decisions compared to those in the highest SES groups who prioritize healthy food.²⁷27. Konttinen H, Sarlio-Lähteenkorva S, Silventoinen K, et al. Socio-economic disparities in the consumption of vegetables, fruit and energy-dense foods: the role of motive priorities. Public Health Nutr. 2013;16:873-82. In our study, adolescents in the lowest FAS less frequently ate red meat and more often ate eggs than adolescents in the highest FAS, which could be explained by economic factors such as family income, which may influence the shopping basket. In contrast, no differences in fruit and vegetable consumption were observed by SES. Although it is generally believed that fruit and vegetable consumption follows an SES gradient,²⁶26. Andreyeva T, Long MW, Brownell KD. The impact of food prices on consumption: a systematic review of research on the price elasticity of demand for food. Am J Public Health. 2010;100:216-22.

27. Konttinen H, Sarlio-Lähteenkorva S, Silventoinen K, et al. Socio-economic disparities in the consumption of vegetables, fruit and energy-dense foods: the role of motive priorities. Public Health Nutr. 2013;16:873-82.^-2828. Stephens LD, McNaughton SA, Crawford D, et al. Longitudinal predictors of frequent vegetable and fruit consumption among socio-economically disadvantaged Australian adolescents. Appetite. 2014;78:165-71. the results of this study are concordant with the theory that the SES gradient depends on the availability/affordability of these products. In southern European countries, such as Spain, fruit and vegetables are widely available and affordable, so their consumption is not strongly associated with SES, as is sometimes the case in northern European countries.²⁹29. Prättälä R, Hakala S, Roskam A-JR, et al. Association between educational level and vegetable use in nine European countries. Public Health Nutr. 2009;12:2174-82.^,3030. Roos G, Johansson L, Kasmel A, et al. Disparities in vegetable and fruit consumption: European cases from the north to the south. Public Health Nutr. 2004;4:35-43. Although the study design does not allow us to attribute differences between SES in the eating frequencies to the economic crisis, these results are consistent with those reported in the SESPAS report.³¹31. Antenas JM, Vivas E. Impacto de la crisis en el derecho a una alimentación sana y saludable. Informe SESPAS 2014. Gac Sanit. 2014;28(Supl 1):58-61. Furthermore, some authors suggest that SES differences can be found in the variety and quality of the fruits consumed rather than in the quantity.³²32. Conklin AI, Forouhi NG, Suhrcke M, et al. Variety more than quantity of fruit and vegetable intake varies by socioeconomic status and financial hardship. Findings from older adults in the EPIC cohort. Appetite. 2014;83:248-55.

The prevalence of excess weight in boys was higher than in girls. These results confirm the findings observed in previous studies describing the same pattern.¹1. Sánchez-Cruz J-J, Jiménez-Moleón JJ, Fernández-Quesada F, et al. Prevalence of child and youth obesity in Spain in 2012. Rev Esp Cardiol. 2013;66: 371-6.^,3333. Morgenstern M, Sargent JD, Hanewinkel R. Relation between socioeconomic status and body mass index: evidence of an indirect path via television use. Arch Pediatr Adolesc Med. 2009;163:731-8.^,3434. Valdés Pizarro J, Royo-Bordonada MA. Prevalence of childhood obesity in Spaat: National Health Survey 2006-2007. Nutr Hosp. 2012;27:154-60. When 2008 and 2012 were compared, excess weight differences were only found among girls from the highest SES, showing a decrease in the prevalence. Different tendencies in excess weight in Spain have been observed depending on the definition taken.¹1. Sánchez-Cruz J-J, Jiménez-Moleón JJ, Fernández-Quesada F, et al. Prevalence of child and youth obesity in Spain in 2012. Rev Esp Cardiol. 2013;66: 371-6. Some tendencies show that excess weight is still increasing,¹1. Sánchez-Cruz J-J, Jiménez-Moleón JJ, Fernández-Quesada F, et al. Prevalence of child and youth obesity in Spain in 2012. Rev Esp Cardiol. 2013;66: 371-6. but others suggest that it has reached a plateau and even has decreased in girls.³⁵35. Moreno LA, Moliner-Urdiales D, Ruiz JR, et al. Five year trends on total and abdominal adiposity in Spanish adolescents. Nutr Hosp. 2012;27:731-8. The excess weight reduction among girls, especially in those in the 8^th to 10^th years in the highest SES, indicates that socioeconomic inequalities in excess weight among girls could be increasing in Barcelona.

This study has some limitations. Firstly, the study might be affected by information bias due to the use of self-reported questionnaires. However, the questionnaire was anonymous and eating habits are not a sensitive topic, so this bias is not expected to be relevant. Secondly, the FRESC survey is a generalist questionnaire, which was not exclusively designed to study eating habits. However, the questions on this topic were designed in concordance with the “food recommendation pyramid” and belonged to other food frequency questionnaires. In addition, the questionnaire has not been previously validated. Nevertheless, self-administered food frequency questionnaires for adolescents are a common tool in epidemiological studies and previous studies have shown that anonymous self-reported food frequency questionnaires have fair to moderate validity.³⁶36. Truthmann J, Mensink GBM, Richter A. Relative validation of the KiGGS Food Frequency Questionnaire among adolescents in Germany. Nutr J. 2011; 10:133. Finally, it was not possible to compare the food consumption between 2008 and 2012, since, unfortunately, the questionnaires differed from each other between FRESC editions.

One of the strengths of our study is that studies showing details on food consumption frequency in adolescents in an economic crisis context are scarce. Therefore, the results of this study provide the first data on this important topic. The sample used was representative of adolescents in Barcelona. Furthermore, both 2008 and 2012 FRESC surveys gathers objective information on height and weight. Consequently, comparison between 2008 and 2012 editions was possible.

This study observed a low prevalence of adolescents following food recommendations, as well as differences between sex in the food frequency consumption, even in an economic crisis. Importantly, excess weight was higher in boys than in girls, and SES differences between 2008 and 2012 among girls have been observed. Further studies should be conducted to monitor the eating habits of adolescents and meeting the food recommendations and to detect the key associated factors. According to our results, health promotion programs including a gender perspective seem to be needed to improve eating habits among adolescents. In addition, results on differences in excess weight related to adolescents’ SES clearly support the need of public policies focused on reducing social inequalities.

Acknowledgements

The authors would like to thank teachers and students for participating in this study. We would also like to thank the “community health service” and the “evaluation methods and intervention service” of the ASPB for their help in administering the questionnaire, taking weight and height measurements and creating the database.

References

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