Validation of the IMMIDIET food frequency questionnaire in an adult Belgian population: a report from the Belgian case-control study on bladder cancer risk

We evaluated the performance of the IMMIDIET food frequency questionnaire (FFQ) used to collect dietary data for the Belgian case-control study on bladder cancer. Thirty-seven men and women aged 50 years and older were recruited from the University Hospital in Leuven, Belgium. Participants completed the IMMIDIET FFQ, a 7-day diet diary and a 24-hour diet recall. Median intakes and inter-quartile ranges were calculated for 27 foods and nutrients from each dietary assessment method. All dietary factors were log-transformed and adjusted for energy using the nutrient density method. Pearson correlation coefficients were used to compare the different dietary assessment methods. Bland-Altman plots were also used to assess levels of agreement between the dietary methods. Energy, fruit and vegetable intake estimates were higher from the IMMIDIET FFQ compared with the two reference methods.The highest deattenuated correlations between the FFQ and 7-day diary were meat (0.58), bread (0.44), fruit (0.38) and fish (0.38). The highest deattenuated correlations between the FFQ and 24-hour recall were for fruit (0.72), fat (0.48), alcohol (0.44), cholesterol (0.42), monounsaturated fatty acid (0.42) and polyunsaturated fatty acid (0.41). Generally, correlation was lower for the micro-nutrients except for phosphorus (0.42), vitamin C (0.41) and calcium (0.40). The IMMIDIET FFQ is an appropriate instrument to measure usual dietary intake for the Belgian case-control study on bladder cancer risk. Further investigation of nutritional assessment methods is necessary.

Consumption of animal products, their nutrient components and postmenopausal circulating steroid hormone concentrations

BACKGROUND/OBJECTIVES

Little is known about nutritional factors that influence circulating concentrations of steroid hormones, which are consistently associated with risk of breast cancer for postmenopausal women. We aimed to investigate the association between consumption of animal products and the plasma concentrations of steroid hormones and sex hormone-binding globulin (SHBG).

SUBJECTS/METHODS

Cross-sectional analysis was conducted on plasma from 766 naturally postmenopausal women. We measured plasma concentrations of steroid hormones and SHBG, and estimated dietary intakes using a 121-item food frequency questionnaire. Log-transformed values of hormone concentrations were regressed on quartiles of intake of meat and dairy products among food items, and fats, proteins and cholesterol among nutrient intake.

RESULTS

Total red and fresh red meat consumption was negatively associated with SHBG levels (P for trend=0.04 and <0.01, respectively). Mean SHBG concentrations were approximately 8% and 13% lower for women in the highest quartile compared with the lowest quartile of total red and fresh red meat consumption, respectively. Positive associations were observed between dairy product consumption and total and free estradiol concentrations (P for trend=0.02 and 0.03, respectively). Mean concentrations of total and free estradiol were 15 and 14% higher for women in the highest quartile of dairy product consumption than for those in the lowest quartile, respectively. No associations were observed with consumption of processed meat, chicken, fish, eggs, cholesterol, fats or protein.

CONCLUSIONS

Our study suggests that greater consumption of total red and fresh red meat and dairy products might influence circulating concentrations of SHBG and estradiol, respectively. Confirmation and further investigation is required.