We identified dietary patterns sepa

We identified dietary patterns separately for men and women using principal components factor analysis based on responses to the baseline questionnaire. The FFQ database provided information on 204 separate food items which we aggregated into 181 food groups. Variables indicating different ways of eating butter and margarines were collapsed into five variables (i.e., butter, stick margarine, tub margarine, butter-margarine mixture and diet margarine), and non-caloric sweeteners (i.e., aspartame and saccharine) were collapsed into one variable. Two of the original food variables (i.e., “other fruits” and “other vegetables”) were excluded due to low reported consumption. Using a caloric density approach, we divided each individual’s daily frequency of consumption of each of the 181 food groups by his or her total daily calorie
consumption in order to adjust for energy, and then we standardized the energy-adjusted frequency values to a mean of 0 and standard deviation of 1.0. Each of the standardized, energyadjusted, frequency variables entered the factor analysis (using PROC FACTOR in SAS statistical software, version 8.2) and based on inspection of scree plots, three factors were
retained. The factors were rotated using the varimax procedure to facilitate interpretability of the factors. For every subject we calculated factor scores on each of the three retained factors by summing frequency of consumption multiplied by factor loadings across all food items.