title: Comparing dietary patterns derived by two methods and their associations with obesity in Polish girls aged 13-21 years: the cross-sectional GEBaHealth study.
abstract: OBJECTIVE
  To compare dietary patterns (DPs) derived by two methods and their assessment as a factor of obesity in girls aged 13-21 years.
  
  
  METHODS
  Data from a cross-sectional study conducted among the representative sample of Polish females ( n = 1,107) aged 13-21 years were used. Subjects were randomly selected. Dietary information was collected using three short-validated food frequency questionnaires (FFQs) regarding fibre intake, fat intake and overall food intake variety. DPs were identified by two methods: a priori approach (a priori DPs) and cluster analysis (data-driven DPs). The association between obesity and DPs and three single dietary characteristics was examined using multiple logistic regression analysis.
  
  
  RESULTS
  Four data-driven DPs were obtained: 'Low-fat-Low-fibre-Low-varied' (21.2%), 'Low-fibre' (29.1%), 'Low-fat' (25.0%) and 'High-fat-Varied' (24.7%). Three a priori DPs were pre-defined: 'Non-healthy' (16.6%), 'Neither-pro-healthy-nor-non-healthy' (79.1%) and 'Pro-healthy' (4.3%). Girls with 'Low-fibre' DP were less likely to have central obesity (adjusted odds ratio (OR) = 0.36; 95% confidence interval (CI): 0.17, 0.75) than girls with 'Low-fat-Low-fibre-Low-varied' DP (reference group, OR = 1.00). No significant associations were found between a priori DPs and overweight including obesity or central obesity. The majority of girls with 'Non-healthy' DP were also classified as 'Low-fibre' DP in the total sample, in girls with overweight including obesity and in girls with central obesity (81.7%, 80.6% and 87.3%, respectively), while most girls with 'Pro-healthy' DP were classified as 'Low-fat' DP (67.8%, 87.6% and 52.1%, respectively).
  
  
  CONCLUSIONS
  We found that the a priori approach as well as cluster analysis can be used to derive opposite health-oriented DPs in Polish females. Both methods have provided disappointing outcomes in explaining the association between obesity and DPs. The cluster analysis, in comparison with the a priori approach, was more useful for finding any relationship between DPs and central obesity. Our study highlighted the importance of method used to derive DPs in exploring associations between diet and obesity.
authors.affiliation: Department of Human Nutrition, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
authors.forename: Lidia
authors.initials: L
authors.lastname: Wadolowska
authors.affiliation: Department of Human Nutrition, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kowalkowska
authors.affiliation: Department of Human Nutrition and Hygiene, Poznań University of Life Sciences, Poznań, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Czarnocinska
authors.affiliation: Department of Organization and Consumption Economics, Warsaw University of Life Sciences, Warszawa, Poland.
authors.forename: Marzena
authors.initials: M
authors.lastname: Jezewska-Zychowicz
authors.affiliation: Department of Trade and Services, Gdynia Maritime University, Gdynia, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Babicz-Zielinska
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004032:Diet / Q000706:statistics & numerical data*; D000072001:Diet, Healthy / Q000706:statistics & numerical data; D002149:Energy Intake; D015444:Exercise; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D011044:Poland; D012107:Research Design; D012959:Socioeconomic Factors; D055815:Young Adult
keywords: BMI; cluster analysis; data-driven; dietary patterns; hypothesis-driven; socio-economic factors