Women (n 160) aged 50 to 65 years were asked to weigh their food for 4 d on four occasions over the period of 1 year, using the PETRA (Portable Electronic Tape Recorded Automatic) scales. Throughout the year, they were asked to complete seven other dietary assessment methods: a simple 24 h recall, a structured 24 h recall with portion size assessments using photographs, two food-frequency questionnaires, a 7 d estimated record or open-ended food diary, a structured food-frequency (menu) record, and a structured food-frequency (menu) record with portion sizes assessed using photographs. Comparisons between the average of the 16 d weighed records and the first presentation of each method indicated that food-frequency questionnaires were not appreciably better at placing individuals in the distribution of habitual diet than 24 h recalls, due partly to inaccuracies in the estimation of frequency of food consumption. With a 7 d estimated record or open-ended food diary, however, individual values of nutrients were most closely associated with those obtained from 16 d weighed records, and there were no significant differences in average food or nutrient intakes. Dietary assessment methods: Weighed intake : Nutritional epidemiologyRecognition of the need for prospective investigation of future individual risk of cancer, and other diseases of middle life, in relation to present day diet is one of the factors that has prompted the search for accurate measures of habitual diet. However, the methodological aims of nutritional epidemiology are inevitably tempered by two opposing interests: that of accuracy in the dietary assessment, and that of feasibility for use in large numbers of individuals, in order to have sufficient power to detect modest relative risks and to demonstrate doseresponse relationships (Bingham, 1987). As part of the preparation for a large European collaborative study of diet and cancer risk (EPIC, European Prospective Investigation of Cancer) we have therefore assessed the accuracy of various methods commonly used in epidemiological studies of diet in large numbers of subjects. We assessed the accuracy of each method by comparison with 16 d of weighed records kept over 1 year.

Results from analysis of 24 h urine collections, verified for completeness with para-amino benzoic acid, and blood samples collected over 1 year were compared with 16 d weighed records of all food consumed collected over the year, and with results from 24 h recalls, food-frequency questionnaires and estimated food records in 160 women. Using the weighed records, individuals were sorted into quintiles of the distribution of the urine N excreti0n:dietary N intake ratio (UN:DN). UN exceeded DN in the top quintile of this ratio; mean ratio UN:DN = 1.13. Individuals in this top quintile were heavier, had significantly greater body mass indices, were reportedly more restrained eaters, had significantly lower energy intake:basal metabolic rate ratios (EI:BMR), and had correlated ratios of UN:DN and EI : BMR (r -0.62). Those in the top quintile reported lower intakes of energy and energy-yielding nutrients, Ca, fats, cakes, breakfast cereals, milk and sugars than individuals in the other quintiles but not lower intakes of non-starch polysaccharides, vitamin C, vegetables, potatoes or meat. Correlations between dietary intake from weighed records and 24 h urine K were 0.74 and 0.82, and between dietary vitamin C and &carotene and plasma vitamin C and &carotene 0.86 and 0.48. Correlations between dietary N intake from weighed records and 24 h urine excretion were high (0-78-0.87). Those between N from estimated food records and urine N were r 0-60-0.70. Correlations between urine N and 24 h recalls and food-frequency questionnaires were in the order of 0.01 to 0.5. Despite problems of underreporting in overweight individuals in 20% of this sample, weighed records remained the most accurate method of dietary assessment, and only an estimated 7 d diary was able to approach this accuracy. Dietary assessment methods: Urine nitrogen: Dietary nitrogenThe validity of measurements of dietary intake in free-living individuals is difficult to assess because all methods rely on information given by the subjects themselves, which may not be correct. In an attempt to determine objective measures for validating dietary assessments, the search has begun for analytes of biological specimens that closely reflect dietary intake, but which do not rely on reports of food consumption (Isaksson, 1980;Bingham, 1987). In individuals in energy and N balance, urine N as assessed from 8 d of complete 24 h urine available at https://www.cambridge.org/core/terms. https://doi

Abbreviations: CAD = Coronary artery disease; SNPs = Single-nucleotide polymorphisms; E2 = 17β-estradiol; T = Testosterone; A = Aromatase ABSTRACT Background: The relationship between CYP19A1 genetic polymorphisms and coronary artery disease (CAD) remains unclear. Thus, the aim of the present study was to investigate the association of CYP19A1 genetic polymorphisms with CAD in Han and Uygur populations and to characterize the association between the levels of sex hormones and aromatase with single-nucleotide polymorphisms (SNPs) in CYP19A1 genes in Chinese women. Results: There were significant differences in the genotype distributions of rs2236722 and rs4646 between CAD patients and control subjects in the Uygur population. The rs4646 was found to be associated with CAD in the dominant model (CC vs. CA + AA) and the additive model (CA vs. CC + AA) (both P ≤ 0.001). The difference remained statistically significant after multivariate adjustment (OR = 0.483, 95% CI: 0.338-0.690, P = 0.000; and OR = 1.844, 95% CI: 1.300-2.617, P = 0.001, respectively). In normal Uygur postmenopausal women, there were significant differences in the genotype distributions of rs4646 and the circulating hormone and aromatase levels between CAD patients and control subjects. The differences in estradiol and aromatase levels remained statistically significant after multivariate adjustment (OR = 0.889, 95% CI: 0.817-0.969, P = 0.007; and OR = 0.947, 95% CI: 0.936-0.957, P = 0.000, respectively). Additionally, there were differences in sex hormone levels between the different ethnicities among the Xinjiang Chinese population. Materials and Methods: Among a total of 1,064 Han individuals (614 men and 450 women) and 790 Uygur individuals (484 men and 306 women), 498 postmenopausal women (265 Han and 233 Uygur individuals) were selected. Four SNPs (rs2236722, rs2304463, rs4646, and rs4275794) were genotyped using the improved multiplex ligation detection reaction (iMLDR) technique. The estradiol and testosterone levels were determined using a radioimmunoassay based on GC-2016γ. In addition, an enzyme-linked immunosorbent assay (ELISA) was performed to determine the serum P450 aromatase levels. Conclusions: The results of this study indicate that the rs2236722 and rs4646 of the CYP19A1 gene are associated with CAD and circulating sex hormone levels in the Xinjiang population of China.

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