title: Evaluating the Applicability of Data-Driven Dietary Patterns to Independent Samples with a Focus on Measurement Tools for Pattern Similarity.
abstract: Diet is a key modifiable risk for many chronic diseases, but it remains unclear whether dietary patterns from one study sample are generalizable to other independent populations.
  
  
  
  The primary objective of this study was to assess whether data-driven dietary patterns from one study sample are applicable to other populations. The secondary objective was to assess the validity of two criteria of pattern similarity.
  
  
  
  Six dietary patterns-Western (n=3), Mediterranean, Prudent, and Healthy- from three published studies on breast cancer were reconstructed in a case-control study of 973 breast cancer patients and 973 controls. Three more internal patterns (Western, Prudent, and Mediterranean) were derived from this case-control study's own data.
  
  
  
  Applicability was assessed by comparing the six reconstructed patterns with the three internal dietary patterns, using the congruence coefficient (CC) between pattern loadings. In cases where any pair met either of two commonly used criteria for declaring patterns similar (CC ≥0.85 or a statistically significant [P<0.05] Pearson correlation), then the true similarity of those two dietary patterns was double-checked by comparing their associations to risk for breast cancer, to assess whether those two criteria of similarity are actually reliable.
  
  
  
  Five of the six reconstructed dietary patterns showed high congruence (CC >0.9) to their corresponding dietary pattern derived from the case-control study's data. Similar associations with risk for breast cancer were found in all pairs of dietary patterns that had high CC but not in all pairs of dietary patterns with statistically significant correlations.
  
  
  
  Similar dietary patterns can be found in independent samples. The P value of a correlation coefficient is less reliable than the CC as a criterion for declaring two dietary patterns similar. This study shows that diet scores based on a particular study are generalizable to other populations.
authors.forename: Adela
authors.initials: A
authors.lastname: Castelló
authors.forename: Brian
authors.initials: B
authors.lastname: Buijsse
authors.forename: Miguel
authors.initials: M
authors.lastname: Martín
authors.forename: Amparo
authors.initials: A
authors.lastname: Ruiz
authors.forename: Ana M
authors.initials: AM
authors.lastname: Casas
authors.forename: Jose M
authors.initials: JM
authors.lastname: Baena-Cañada
authors.forename: Roberto
authors.initials: R
authors.lastname: Pastor-Barriuso
authors.forename: Silvia
authors.initials: S
authors.lastname: Antolín
authors.forename: Manuel
authors.initials: M
authors.lastname: Ramos
authors.forename: Monserrat
authors.initials: M
authors.lastname: Muñoz
authors.forename: Ana
authors.initials: A
authors.lastname: Lluch
authors.forename: Ana
authors.initials: A
authors.lastname: de Juan-Ferré
authors.forename: Carlos
authors.initials: C
authors.lastname: Jara
authors.forename: Virginia
authors.initials: V
authors.lastname: Lope
authors.forename: María A
authors.initials: MA
authors.lastname: Jimeno
authors.forename: Esperanza
authors.initials: E
authors.lastname: Arriola-Arellano
authors.forename: Elena
authors.initials: E
authors.lastname: Díaz
authors.forename: Vicente
authors.initials: V
authors.lastname: Guillem
authors.forename: Eva
authors.initials: E
authors.lastname: Carrasco
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pérez-Gómez
authors.forename: Jesús
authors.initials: J
authors.lastname: Vioque
authors.forename: Marina
authors.initials: M
authors.lastname: Pollán
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D016208:Databases, Factual; D000072001:Diet, Healthy; D038441:Diet, Mediterranean; D066273:Diet, Western; D005260:Female; D006801:Humans; D008962:Models, Theoretical; D012307:Risk Factors; D013030:Spain
keywords: Breast cancer; Congruence coefficient; Dietary patterns; Mediterranean/Western patterns; Pattern similarity