Validation of an easy questionnaire on the assessment of salt habit: the MINISAL-SIIA Study Program

A representation and interpretation of the area under a receiver operating characteristic (ROC) curve obtained by the "rating" method, or by mathematical predictions based on patient characteristics, is presented. It is shown that in such a setting the area represents the probability that a randomly chosen diseased subject is (correctly) rated or ranked with greater suspicion than a randomly chosen non-diseased subject. Moreover, this probability of a correct ranking is the same quantity that is estimated by the already well-studied nonparametric Wilcoxon statistic. These two relationships are exploited to (a) provide rapid closed-form expressions for the approximate magnitude of the sampling variability, i.e., standard error that one uses to accompany the area under a smoothed ROC curve, (b) guide in determining the size of the sample required to provide a sufficiently reliable estimate of this area, and (c) determine how large sample sizes should be to ensure that one can statistically detect differences in the accuracy of diagnostic techniques.

The current paper aims to present the main results of the Italian National Food Consumption Survey INRAN-SCAI 2005-06. A cross-sectional study was performed. Households were randomly selected after geographical stratification of the national territory. Food consumption was assessed on three consecutive days through individual estimated dietary records. Italy. The final study sample comprised 3323 subjects (1501 males and 1822 females) aged 0.1 to 97.7 years belonging to 1329 households: fifty-two infants (0-2.9 years), 193 children (3-9.9 years), 247 teenagers (10-17.9 years), 2313 adults (18-64.9 years) and 518 elderly (65 years and above). Participation rate was 33 %. The mean ratio of estimated energy intake to estimated BMR was 1.41 in adults. Indicators of mean and high individual consumption are presented for fifteen large categories and fifty-one subcategories of foods and beverages, in the total population and in consumers, by age and sex categories. The overall consumption of fruit and vegetables was 418 g/d. The consumption of red meat was approximately 700 g/week, expressed as raw weight. Some specific aspects of the Italian food consumption pattern were confirmed: a large contribution from bread, pasta and pizza to cereals, from olive oil to fats and from wine to alcoholic beverages. The database obtained from the survey will be the key reference for Italian food consumption during the coming years and will be utilized for a variety of purposes including the assessment of nutrient intakes and risk analysis.