Identification of dietary patterns using factor analysis in an epidemiological study in São Paulo.
OBJECTIVE
Diet and nutrition are environmental factors in health/disease relationships. From the epidemiological viewpoint, diet represents a complex set of highly correlated exposures. Our objective was to identify patterns of food intake in a group of individuals living in São Paulo, and to develop objective dietary measurements for epidemiological purposes. DESIGN AND LOCAL: Exploratory factor analysis of data in a case-control study in seven teaching hospitals in São Paulo.


METHODS
The participants were 517 patients (260 oral cancer cases and 257 controls) admitted to the study hospitals between November 1998 and March 2001. The weekly intake frequencies for dairy products, cereals, meat, processed meat, vegetables, pulses, fruits and sweets were assessed by means of a semi-quantitative food frequency questionnaire. Dietary patterns were identified by factor analysis, based on the intake of the eight food groups, using principal component analysis as an extraction method followed by varimax rotation.


RESULTS
Factor analysis identified three patterns that accounted for 55% of the total variability within the sample. The first pattern ("prudent") was characterized by vegetable, fruit and meat intake; the second ("traditional") by cereals (mainly rice) and pulses (mainly beans); and the third ("snacks") by dairy products and processed meat.


CONCLUSIONS
This study identified food intake patterns through an a posteriori approach. Such analysis may be useful for nutritional intervention programs and, after computing scores for each individual according to the patterns identified, for establishing a relationship between diet and other epidemiological measurements of interest.
Marchioni
Dirce Maria Lobo
DM
Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil.
Latorre
Maria do Rosário Dias de Oliveira
Mdo R
Eluf-Neto
José
J
Wünsch-Filho
Victor
V
Fisberg
Regina Mara
RM
D000328:Adult; D001938:Brazil; D016022:Case-Control Studies; D004034:Diet Surveys; D005163:Factor Analysis, Statistical; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000209:etiology*; D010610:Pharyngeal Neoplasms / Q000209:etiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires