Breakfast habits and differences regarding abdominal obesity in a cross-sectional study in Spanish adults: The ANIBES study

RESEARCH ARTICLE Breakfast habits and differences regarding abdominal obesity in a cross-sectional study in Spanish adults: The ANIBES study Beatriz Navia 1☯ , Ana M. Lo ´pez-Sobaler 1☯ , Tania Villalobos 1 , Javier Aranceta-Bartrina 2,3‡ , A ´ngel Gil 3,4‡ , Marcela Gonza ´lez-Gross 3,5‡ , Lluis Serra-Majem 3,6‡ , Gregorio VarelaMoreiras 7,8‡ , Rosa M. Ortega 1 * 1VALORNUT Research Group, Department of Nutrition, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain, 2Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Spain, 3CIBER: CB12/03/30038 Fisiopatologı ´a de la Obesidad y la Nutricio ´n, CIBERobn, Instituto de Salud Carlos III (ISCIII), Madrid, Spain, 4Department of Biochemistry and Molecular Biology II, Institute of Nutrition and Food Sciences, University of Granada, Granada, Spain, 5ImFINE Research Group, Department of Health and Human Performance, Technical University of Madrid, Madrid, Spain, 6Research Institute of Biomedical and Health Sciences & Medical School, University of Las Palmas de Gran Canaria, Las Palmas, Spain, 7Department of Pharmaceutical and Health Sciences, Faculty of Pharmacy, CEU San Pablo University, Madrid, Spain, 8Spanish Nutrition Foundation (FEN), Madrid, Spain ☯These authors contributed equally to this work. ‡ These authors also contributed equally to this work. *[email protected] Abstract Background Previous studies have indicated that breakfast has a protective effect against obesity. The aim of this study was to describe the breakfast habits of the Spanish adult population and to assess the possible association between breakfast frequency and the presence of abdominal obesity, in a cross-sectional analysis of the ANIBES Study. Methods A representative sample of 1655 Spanish adults (aged 39±12 y; (mean±sd)) from the ANIBES Study was investigated. The final field work was carried out from mid-September to November (three months) 2013. Collected data included a dietary data collected by a 3days food record, and health, socioeconomic, physical activity and anthropometric (weight, height and waist circumference) data. Abdominal obesity was defined as having a waist-toheight ratio 0.5. The adults were also classified into three groups based on the number of days they ate breakfast (never (0/3 days), sometimes (1-2/3 days) and always (3/3 days)). Logistic regression analyses were used to evaluate the association between breakfast and abdominal obesity. Results In total, 3.6% of adults skipped breakfast and 14.1% ate breakfast sometimes. Having always breakfast was negatively associated with abdominal obesity [OR = 0.738 (0.558– PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 1 / 15 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Navia B, Lo ´pez-Sobaler AM, Villalobos T, Aranceta-Bartrina J, Gil A ´, Gonza ´lez-Gross M, et al. (2017) Breakfast habits and differences regarding abdominal obesity in a cross-sectional study in Spanish adults: The ANIBES study. PLoS ONE 12 (11): e0188828. https://doi.org/10.1371/journal. pone.0188828 Editor: Cristina Vassalle, Fondazione Toscana Gabriele Monasterio, ITALY Received: February 28, 2017 Accepted: November 14, 2017 Published: November 30, 2017 Copyright: ©2017 Navia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Due to ethical restrictions and participant confidentiality, data cannot be made publicly available. Data are restricted under the Clinical Research ethics Committee Regional Madrid (CEIC-R). However, data from the ANIBES Study are available upon request from the Spanish Nutrition Foundation (FEN), for researchers who meet the criteria for access to confidential data. Data requests can be sent to FEN through the President and ANIBES study coordinator (Gregorio Varela-Moreiras: 0.975) p= 0.033]. The odds of abdominal obesity after full adjustment (age, gender, and educational and activity level) were 1.5 times higher for those who skipped breakfast when compared to those who always have breakfast. By correcting the model considered for other variables, the odds among smokers decreased when they have breakfast sometimes [OR = 0.032 (0.003–0.387) p = 0.007] and always [OR = 0.023 (0.002–0.270) p = 0.003] comparing with smokers who skip breakfast. Conclusion Breakfast frequency could be negatively associated with abdominal obesity, especially among smokers. Introduction Breakfast is considered the most important meal of the day [1]. Different studies have shown that eating breakfast improves daily food selection [2,3], the intake of many nutrients [2,3] and diet quality [1,3,4]. Regular breakfast consumption has also been associated with improved cardiovascular risk factors [5,6] and weight/adiposity measures [4,7–10]. Regarding obesity, previous research has shown that children and adolescents who eat breakfast regularly have a lower BMI and better long-term weight management than breakfast skippers [10]. In adults, it has also been observed that eating breakfast regularly decreased the prevalence of overweight and obesity [4,7–9]. BMI is widely used to estimate the prevalence of obesity within a population and the risks associated with it; however, BMI does not account for the wide variation in body fat distribution [11] and individuals with excess fat in the intra-abdominal depots are at particular risk of the adverse health consequences [12–14]. However, there is limited information about the breakfast patterns of adults with abdominal obesity and how they may differ from their counterpart controls, as well as whether breakfast frequency influences abdominal obesity. In addition, most previous studies on breakfast habits have included children and adolescents [10,15,16], and data in the adult population [4, 17]. Therefore, the aim of the present study was to report the breakfast habits of a sample of the Spanish adult population and to assess the possible association between breakfast frequency and abdominal obesity as part of the ANIBES (Anthropometry, Intake, and Energy Balance in Spain) Study. Material and methods The data used in this study were obtained as part of the ANIBES Study, a nationally representative survey conducted in the Spanish population aged 9–75 years; the design and methodology of the ANIBES Study have been described in detail elsewhere [18–22]. The final protocol was approved by the Ethical Committee for Clinical Research of the Region of Madrid (Spain). Written informed consent was obtained from all subjects. All data were collected by trained interviewers. Briefly, ANIBES study was performed to record food and beverage intake, dietary habits, and anthropometric data, as well as energy expenditure and physical activity patterns of the Spanish population. The target population consisted of all inhabitants living in Spain (excluding the autonomous cities of Melilla and Ceuta in the north of Africa), aged 9 to 75 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 2 / 15 [email protected]/[email protected]) or non-author General Director Spanish Nutrition Foundation (FEN): (Jose ´Manuel A ´vila: [email protected]). Funding: ANIBES Study was financially supported by Coca Cola Iberia through an agreement with the Spanish Nutrition Foundation (FEN). The funding sponsors had no role in the study design, data collection, analysis or interpretation of the data; the writing of the manuscript; or the decision to publish the results. Competing interests: ANIBES Study was financially supported by Coca Cola Iberia through an agreement with the Spanish Nutrition Foundation (FEN). There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials. years and living in municipalities of at least 2,000 inhabitants. The sample for the ANIBES Study was based on the 2012 census data published by the INE (Instituto Nacional de Estadı ´stica/Spanish Bureau of Statistics) for gender, age, habitat size and region. The total sample size was calculated based on a 0.05 probability of Type I error (rejecting a null hypothesis when it is true) and 0.1 probability of Type II error (accepting a null hypothesis when it is wrong) in the main outcome of the study (energy intake). No previous pre-recruitment was considered to minimize the risk of bias in responses. The final study sample included 2009 individuals aged 9 to 75 years. The present paper focused on the adult population (18–64 years, n= 1655). Data were collected between mid-September and mid-November 2013. Survey component included a dietary study, data from the habitat, level of education, socioeconomic level, percentage of immigrant population, tobacco consumption, physical activity, and anthropometric measures. Dietary data Dietary intake was assessed via face-to-face 24-hour recall (1-day intake, not included in the final data) and a 3-day food record using a tablet device (Samsung Galaxy Tab 27.0, Korea) on 2 weekdays and one weekend day, including information on all food and beverages consumed at home and away, as well as eating habits (e.g., recipes, brands, types of milk and fat spread usually consumed, among other data). Participants who declared or demonstrated that they were unable to use the tablet device were offered other options, such as using a digital camera and paper record and/or telephone interviews. A manual of procedures to facilitate food collection was provided to participants, in addition to a toll-free telephone number in case they had any questions regarding the software, use of the device, or food and beverage records. Food, beverages, and energy and nutrient intake were calculated using software (VD-FEN 2.1, Madrid, Spain) that was newly developed for the ANIBES study by the Spanish Nutrition Foundation and is based mainly on expanded and updated Spanish food composition tables [23]. Breakfast was defined by self-report and included consumption of any food or beverage at a meal occasion named by the respondent as breakfast. Subjects who consumed no food or beverages at breakfast, excluding water, coffee or other noncaloric beverages, were categorized as breakfast skippers [24]. We also calculated the energy provided by breakfast regarding total energy intake. An energy intake of 15–25% of total energy was considered adequate [24]. Participants were also asked about the time spent on breakfast, and the food variety at breakfast was calculated considering only the consumption of foods within the cereal, dairy, fruits and protein-rich food groups. The adults were classified into three groups based on the number of days they ate breakfast: never (0/3 days), sometimes (1-2/3 days) and always (3/3 days). Anthropometric data Weight, height, and waist circumference were measured using standardized procedures by well-trained interviewers to minimize the inter-observer coefficients of variation [25]. Weight was measured once with a Seca model 804 weighing scale (Medizinische Messsysteme und Waagen seit 1840, Hamburg, Germany; range 0.1–150 kg, precision 100 g). Height was assessed in triplicate using a Seca model 206 Stadiometer (range 70–205 cm, precision 1 mm). Waist circumference was measured in triplicate using a Seca 201 tape measure (Seca, Hamburg, Germany; range 0–150 cm, precision 1 mm). BMI was calculated as weight to height squared (kg/m 2 ), and abdominal obesity was defined as having a waist to height ratio (WHtR) 0.5 in both men and women, as others authors have reported [14,26,27]. Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 3 / 15 Personal, socioeconomic and lifestyle data A questionnaire was administered face-to-face in order to record the following data: age in completed years (which were later classified in 18–40/41–65 years), gender, habitant size (rural, semi-urban, or urban populations of 2,000–30,000, 30,000–200,000, and over 200,000 inhabitants, respectively), place of birth (no immigrant/immigrant), educational level according to years and type of education (primary or less/secondary/university). Smoking habits were grouped as smoker or non-smoker. Subjects were classified into two levels of physical activity based on two questions, one about the time spent in physical activity of daily life, and the second about time spent in structured physical exercise. “Active” subjects were those who performed at least 30 min per day of physical activity of daily life or at least 2 h per week of structured physical exercise; otherwise subjects were classified as “Inactive”. Statistical analysis Data are presented as the means, standard deviations and percentages. Analyses were performed using SPSS version 22.0 (SPSS, Inc, Chicago, Illinois, USA). The Kolmogorov-Smirnoff test was used to test whether the variables followed a normal distribution to decide between a parametric or non-parametric analysis. Gender and abdominal obesity differences were assessed using T-test (normal distributions) or tests and Mann-Whitney test (non-normal distributions) tests. When comparing proportions, z-test was used. Kruskal-Wallis test was used to determine the differences between the three breakfast groups. Comparisons of the percentages of the categorized variables were conducted using Pearson’s Chi-square test. Backward stepwise logistic regression was conducted to examine the association of breakfast frequency and abdominal obesity, after controlling for confounders (gender, age, education level, smoking and physical activity level). The dependent variable was WHtR. Reference groups comprised individuals without abdominal adiposity (WHtR<05). Logistic regression analysis results from the reduced model were expressed as odds ratios (OR) and their respective 95% CI. We used the Hosmer-Lemeshow test to determine the model fit p<0.05 was considered statistically significant. Results Personal, anthropometric, sociodemographic and lifestyle factors of the studied sample have been described previously [21,22,28] but are presented again for simple characterization (Table 1). Some 58.4% of the population had abdominal obesity and the percentage is significantly higher in men. Most participants had a high school diploma (48.9%). Approximately a third were smokers and two thirds were physicaly inactive. In total, 3.6% of the study population skipped breakfast, including significantly more men than women (Table 2); 2% did not eat anything for breakfast, and 1.6% had only coffee or tea for breakfast (Table 3). Skipping breakfast occurred more frequently in young adults (5.8% in 18–29 y versus 1.2% in 60–64 y, p<0.05), in males (4.8% versus 2.5% in females, p<0.05), in rural populations (5.2% versus 1.6% in semiurban and 4.0% in urban, p<0.05), in immigrant populations (7.6% versus 3.4%, p<0.05), in smokers (5.3% versus 2.7%, p<0.05) and in those less physically active (6.9% versus 2.7%, p<0.05). Breakfast represented 16.7% of total daily energy intake, and intake from breakfast was inadequate in 59.2% of the adults, being more frequently insufficient (<15%) than excessive (>25%) (Table 2). The most frequently consumed food groups at breakfast were dairy products with cereals (34.6%); dairy products with cereals and fruit (16.8%) and dairy products with cereals, fruit and protein-rich foods (10.4%), whereas 10% of adults only had some dairy product for breakfast (Table 3). Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 4 / 15 The most consumed food groups were dairy products (88.9%) (Table 4), especially semiskimmed milk (43.8%) and less frequently whole milk (28.2%) and skimmed milk (22.3%). There were more men who consumed whole milk at breakfast than women (p<0.05), whereas there were more women who chose skimmed milk and soya drinks more often than men (p<0.05) (S1 Table). In the study population, cereals were the second most chose food group at breakfast (84.2%), in particular bread (51.6%), and in lower proportions, cookies (25.7%), cakes and pastries (20.6%), and Ready-to-eat-cereals (RTEC) (12.9%). Furthermore, 38.8% of the population included fruit or fruit juice, and 26.3% included protein-rich foods, especially charcuterie and other meat products (20%) and eggs (7.2%). Regarding to fats, 29.2% included oils, mainly olive oil (25.3%), while 22.9% used other fats (butter, margarine, etc.). Butter, margarine and other solid fats were also significantly more consumed by women than men, similar to jam consumption. Sugar was the most widely used sweetener (46.9%), with no gender differences, although saccharin was more frequently used in women than men (p<0.05) (S1 Table). In food variety at breakfast, we just have been taking into account foods that belong to one of this Table 1. Characteristics of the study population. Total Men Women n 1655 798 857 Age (y) (m±sd) 40.0±12.2 39.6±12.2 40.3±12.2 18–40 (%) 53.4 54.5 52.3 41–64 (%) 46.6 45.5 47.7 Weight (kg) (m±sd) 74.2±16.48 82.4±15.34 *66.6±13.62 * Height (cm) (m±sd) 167.7±9.35 174.5±6.95 *161.3±6.37 * BMI (kg/m 2 ) (m±sd) 26.3±5.15 27.1±4.87 *25.6±5.3 * Waist circumference (cm) (m±sd) 88.1±14.5 93.8±13.61 *82.7±13.19 * WHtR (m±sd) 0.53±0.08 0.54±0.08 *0.51±0.09 * WHtR >0.5 (%) 58.4 64.7 *52.5 * Habitat size a (%) Rural 34.1 33.3 34.8 Semi-urban 33.9 35.6 32.3 Urban 32.0 31.0 32.9 Level of education (%) Primary or less 26.8 26.6 27.0 Secondary 48.9 49.6 48.3 University 24.3 23.8 24.7 Immigrant population (%) 6.4 7.3 5.6 Smoking status (%) Non smoker 65.0 60.2 *69.5 * Smoker 35.0 39.8 *30.5 * Physical Activity level (%) Active 32.6 39.8 *25.8 * Inactive 67.4 60.2 *74.2 * m: mean; sd: standard deviation; BMI: Body mass index; WHtR: Waist to height ratio (a) Habitat size: rural populations: 2,000–30,000; semi-urban: 30,000–200,000; urban population: over 200,000 inhabitants. Student’s t test for normally distributed variables and Mann Withney test for variables with non-normal distribution. Z test proportions for categorical variables. (*) Significant differences regarding gender. https://doi.org/10.1371/journal.pone.0188828.t001 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 5 / 15 food groups: cereals, dairy, fruits and protein-rich foods. The variety at breakfast was 2.20 ±0.94 foods per day and was significantly higher in men than in women; however, women spent more time on breakfast than men (p<0.05) (Table 2). Table 2. Breakfast habits in the study population. Total Men Women n 1655 798 857 Age (y) (m±sd) 40.0±12.2 39.6±12.2 40.3±12.2 18–40 (%) 53.4 54.5 52.3 41–64 (%) 46.6 45.5 47.7 Breakfast (%): Never 3.6 4.8*2.5* Sometimes 14.1 16.9*11.6* Always 82.3 78.3*86.0* Total energy intake (kcal/day) (m±sd) 1.816±512 1.966±543*** 1.675±437*** (MJ/day) (m±sd) 7.6±2.1 8.2±2.3*** 7.0±1.8*** Breakfast energy intake (kcal/day) (m±sd) 301.5±164.3 313.5±178.3** 290.5±149.7** (MJ/day) (m±sd) 1.3±0.7 1.3±0.8** 1.2±0.6** Breakfast energy intake (% total energy intake) (m±sd) 16.7±8.3 15.94±8.3*** 17.4±8.2*** Individuals whose breakfast provides: (%) 15–25% total energy intake 40.8 39.0 42.5 <15% total energy intake 44.0 47.9*40.4* >25% total energy intake 15.2 13.0*17.1* Food variety at breakfast (number of foods at breakfast/day) (m±sd) 2.20±0.94 2.21±1.01*2.19±0.87* Time used for breakfast (minutes/day) (m±sd) 12.48±8.86 11.94±9.39*12.96±8.33* m: mean; sd: standard deviation; Student’s t test for normally distributed variables and Mann Withney test for variables with non-normal distribution. Z test proportions for categorical variables. *p<0.05 ** p<0.01 *** p<0.001. https://doi.org/10.1371/journal.pone.0188828.t002 Table 3. More frequently consumed breakfasts (% consumers). Total Men Women Only coffee or tea 1.6 1.8 1.4 Only dairy products 10.0 10.6 9.6 Only cereals 0.4 0.1 0.6 Only fruit 1.1 1.7*0.6* Dairy products + Cereals 34.6 34.9 34.4 Dairy products + Fruit 1.3 1.6 1.1 Cereals + Fruit 1.4 1.7 1.1 Dairy products + Cereals + Fruit 16.8 12.4*20.8* Protein-rich foods + Cereals + Dairy products 8.0 8.1 7.8 Dairy products + Cereals + Fruit + Protein-rich foods 10.4 11.0 9.8 Other breakfasts 14.5 16.2 13.4 None of the above 5.5 6.5 4.6 Z test proportions. *p<0.05. https://doi.org/10.1371/journal.pone.0188828.t003 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 6 / 15 The prevalence of breakfast consumption among adults with abdominal obesity compared to those without abdominal obesity is presented in Table 5. We found no difference in the prevalence of breakfast skippers regarding WHtR categories (Table 5), but men who never had Table 4. Food groups consumed at breakfast (% consumers). Total Men Women Dairy products 88.9 86.7*90.9* Cereals 84.2 81.7*86.4* Fruit + Juice 38.8 37.6 40.0 Protein-rich foods 26.3 28.8*24.1* Other foods 5.8 6.0 5.6 Beverages 8.3 6*10.5* Fats 43.3 38.7*47.6* Other products 88.6 85.5*91.5* Z test proportions. *p<0.05. https://doi.org/10.1371/journal.pone.0188828.t004 Table 5. Breakfast habits regarding WHtR categories. WHtR <0.5 WHtR 0.5 Total Men Women Total Men Women N 689 282 407 966 516 450 Age (y) (m±sd) 34.0 ±11.0*** 32.5±11.2*** 35.0 ±10.7*** 44.2 ±11.2*** 43.5±10.9*** 45.0 ±11.5*** 18–40 (%) 73.4*78.4*70*39*41.5*36.2* 41–64 (%) 26.6*21.6*30*61*58.5*63.8* Breakfast (%): Never 2.9 3.6 2.5 4.1 5.5 2.4 Sometimes 16.4*20.9*13.3 12.5*14.7*10 Always 80.7 75.5 84.3 83.4 79.8 87.5 Total energy intake (kcal/day) (m±sd) 1886 ±543*** 2102±581*** 1736 ±460*** 1765 ±482*** 1892±507*** 1620 ±407*** (MJ/day) (m±sd) 7.9±2.3*** 8.8±2.4*** 7.3±1.9*** 7.4±2.0*** 7.9±2.1*** 6.8±1.7*** Breakfast energy intake (kcal/day) (m±sd) 310.8±169.3 339.3 ±189.0** 291.2±151.6 294.9±169.3 299.4 ±170.8** 289.9±148.1 (MJ/day) (m±sd) 1.3±0.7 1.4±0.8** 1.2±0.6 1.2±0.7 1.3±0.7** 1.2±0.6 Breakfast energy intake (% total energy intake) (m±sd) 16.6±8.0 16.1±8.0 16.8±8.5*16.8±8.5 15.8±8.5 18.0±8.3* Individuals whose breakfast provides: (%) 15–25% energy total 39.3 36.3 41.4 41.9 40.5 43.4 <15% energy total 45.7 49.5 43.1 42.8 47.1 38.1 >25% de la energy total 15 14.3 15.5 15.3 12.4 18.5 Food variety at breakfast (number of foods at breakfast/day) (m±sd) 2.25±1.00*2.33±1.12*2.20±0.91 2.16±0.89*2.13±0.93*2.18±0.84 Time used for breakfast (minutes/day) (m±sd) 12.12±8.72 11.72±9.75 12.40±7.95 12.73±8.96 12.07±9.19 13.47±8.63 m: mean; sd: standard deviation; Student’s t test for normally distributed variables and Mann Whitney test for variables with non-normal distribution. Z test proportions for variables expressed in proportions. Significant differences between adults with WHtR <0.5 and WHtR 0.5. *p<0.05 ** p<0.01 *** p<0.001. https://doi.org/10.1371/journal.pone.0188828.t005 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 7 / 15 breakfast had a higher waist circumference and WHtR than men who sometimes ate breakfast (Table 6). In food variety at breakfast, we just have been taking into account foods that belong to one of this food groups: cereals, dairy, fruits and protein-rich foods. An inverse association was observed between breakfast frequency and abdominal obesity by Chi-square test (p = 0.046). Binary logistic regression analysis also showed that breakfast was negatively associated with abdominal obesity (Table 7). After adjusting for age, the odds of abdominal obesity decreased in those who ate breakfast sometimes and always, compared to those who skipped breakfast. When adjusting also by other variables (gender, smoking, educational level and physical activity), the odds of abdominal obesity decreased only in those who always ate breakfast. There was a significant interaction between breakfast frequency and smoking, and the odds of abdominal obesity (adjusted by age, gender, educational level and physical activity) decreased among smokers when they ate breakfast sometimes [OR = 0.032 (0.003–0.387) p= 0.007] and always [OR = 0.023 (0.002–0.270) p= 0.003] comparing with smokers who skipped breakfast. We have also found significant differences in breakfast composition regarding abdominal obesity (Table 8). Comparing with adults without abdominal obesity, there were more consumers of coffee, tea, saccharin (men and women) and skimmed milk (women) with abdominal obesity, while there were less consumers of cocoa, chocolate and juice (men and women), cakes and pastries, RTEC, fruit and eggs (men). (S2 Table). We did not observe differences in Table 6. Anthropometric parameters regarding the pattern of breakfast intake. Never Sometimes Always Total Men Women Total Men Women Total Men Women Age (y) (m±sd) 37.1±11.7 b 37.6±12.8 36.2±12.2 b 35.4±12.9 c 36.2±12.8 c 34.3±13.0 c 40.9±11.9 b, c 40.5±12.0 c 41.2±11.9 b, c Weight (kg) (m±sd) 76.2±17.4 83.6±16.5 62.7±9.2 74.1±16.6 81.1±15.4 64.7±13.3 74.0±16.4 82.5±15.4 66.9±13.7 Height (cm) (m±sd) 169.4±9.8 174.3±7.0 160.6±7.8 169.7±9.5 c 174.7±6.8 160.6±6.0 167.4±9.3 c 174.5±7.0 161.5±6.4 BMI (kg/m 2 ) (m±sd) 26.5±5.2 27.6±5.6 24.4±3.8 25.9±4.9 26.6±4.8 25.1±5.1 26.4±5.2 27.1±4.9 25.7±5.4 Waist circumference (cm) (m ±sd) 90.3±15.2 96.2±14.1 a 79.4±10.6 86.8±14.2 91.5±13.7 a, c 80.3±12.2 88.1±14.5 94.1±13.6 c 83.1±13.3 WHtR (m±sd) 0.53±0.08 0.55±0.08 a 0.50±0.07 0.51±0.08 0.52±0.08 a, c 0.50±0.08 0.53±0.09 0.54±0.08 c 0.52±0.09 m: mean; sd: standard deviation; WHtR: Waist to height ratio; Kruskal Wallis Test. The differences are according to breakfast frequency a: differences between “never” vs “sometimes” b: differences between “never” vs “always” c: differences between “sometimes” vs “always”. p<0.05. https://doi.org/10.1371/journal.pone.0188828.t006 Table 7. Association of breakfast frequency and abdominal obesity in Spanish adults. Logistic regression analysis. OR (95%CI) p OR 1 p OR 2 p Never 1 1 1 Sometimes 1.355 (0.782–2.349) 0.279 0.145 (0.030–0.710) 0.017 1.397 (0.704–2.771) 0.338 Always 0.738 (0.558–0.975) 0.033 0.122 (0.026–0.576) 0.008 0.662 (0.464–0.946) 0.024 OR 1 : Odds ratio adjusted for age OR 2 : Odds ratio adjusted for age, gender, smoking, educational level and activity. https://doi.org/10.1371/journal.pone.0188828.t007 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 8 / 15 the type of breakfast regarding WHtR categories (Table 9) but, for both total sample and males, the variety of foods at breakfast was lower among those with abdominal obesity (Table 5). Finally, in our study we found 16.9% of regular exercises in the group who did not have breakfast versus 33.9% (p<0.05) and 33.1% (p<0.05) in the groups who ate breakfast sometimes and always, respectively. Moreover, we also found that 6.9% of inactive men skipped breakfast while do it 3.5% of active men (p<0.05). Discussion In several studies, breakfast has been considered the most important meal of the day, in part because of its nutritional benefits, as well as its associations with other positive outcomes [29]. In the present study, 82.3% of the sample reported consuming breakfast daily, whereas 14.1% did not always have breakfast, and 3.6% (more men than women) skipped this meal. Awareness campaigns conducted in Spain about the importance of improving breakfast habits [30–33] may be the cause of the lower percentage of individuals who skipped their first meal of the day, compared with the results of other studies. Specifically, Reeves et al. [34] in a Table 8. Foods consumed at breakfast regarding WHtR categories (% consumers). WHtR <0.5 WHtR 0.5 Total Men Women Total Men Women Dairy products 89.9 88.6 90.7 88.2 85.6 91.1 Cereals 84.1 83.2 84.7 84.2 80.8 88.0 Fruit + Juice 41.8*42.9*41.1 36.7*34.7*39.0 Protein-rich foods 26.2 30.0 23.6 26.4 28.1 24.5 Other foods 5.7 7.4 4.4 5.9 5.2 6.7 Beverages 9.4 6.0 11.8 7.6 6.0 9.3 Fats 40.9 37.2 43.5 45.0 39.5 51.3 Other products 86.8 84.0 88.7 89.9 86.2 94.0 Z test proportions. The differences are between groups of the same gender. *p<0.05 https://doi.org/10.1371/journal.pone.0188828.t008 Table 9. More frequently consumed breakfasts regarding WHtR categories (% consumers). WHtR <0.5 WHtR 0.5 Total Men Women Total Men Women Only coffee and tea 0.4 0.4 0.5 2.4 2.6 2.2 Only dairy products 11.2 11.0 11.3 9.3 10.4 8.0 Only cereals 0.6 0 1.0 0.2 0.2 0.2 Only fruit 1.3 1.8 1.0 0.9 1.6 0.2 Dairy products + Cereals 33.3 34.1 32.8 35.6 35.3 35.9 Dairy products + Fruit 1.3 1.5 1.3 1.3 1.6 0.9 Cereals + Fruit 1.8 2.6 1.3 1.1 1.2 0.9 Dairy products + Cereals + Fruit 18.0 13.2 21.3 15.9 12.0 20.3 Protein-rich foods + Cereals + Dairy products 7.6 7.3 7.8 8.2 8.6 7.8 Dairy products + Cereals + Fruit + Protein-rich foods 10.4 12.1 9.3 10.3 10.4 10.2 Other breakfasts 9.1 11.4 7.5 8.9 8.8 9.1 None of the above 4.9 4.8 5.0 5.9 7.4 4.2 https://doi.org/10.1371/journal.pone.0188828.t009 Breakfast habits and abdominal obesity in Spanish adults PLOS ONE | https://doi.org/10.1371/journal.pone.0188828 November 30, 2017 9 / 15