Reproducibility and validity of the Toronto-modified Harvard food frequency questionnaire in a multi-ethnic sample of young adults

Reproducibility and Relative Validity of a Short Food Frequency Questionnaire for Chinese Older Adults in Hong Kong

Changes in an individual's digestive system, hormones, senses of smell and taste, and energy requirement accompanying aging could lead to impaired appetite, but older adults may not notice their risk of nutrient deficiency. When assessing the dietary intake of older adults, it was found that they had more difficulties with short-term recall and open-ended recall and would experience greater fatigue and frustration when compared to younger individuals when completing a lengthy questionnaire. There is a need to develop a brief dietary assessment tool to examine the nutritional needs of older adults. In this study, we aimed to assess the diet of Hong Kong older adults using the short FFQ and examine its reproducibility and relative validity as a dietary assessment tool. Dietary data of 198 older adults were collected via FFQs and three-day dietary records. Correlation analyses, cross-tabulation, one-sample t-tests, and linear regression analyses were used to evaluate the relative validity of the short FFQ. In general, the short FFQ was accurate in assessing the intake of phosphorus, water, grains, and wine, as shown by a significant correlation (>0.7) between values reported in the FFQs and dietary records; good agreement (more than 50% of observations belonged to the same quartile) and insignificant differences detected with the one-sample t-tests and linear regression analyses were observed for the above four variables. Additionally, the intake of proteins, carbohydrates, total fat, magnesium, and eggs in terms of the values reported in the FFQs and dietary records showed good agreement.

A validation study comparing energy and nutrient intake between a web-based food frequency questionnaire and a 4-d dietary record

OBJECTIVE

Reliable assessments of dietary intake is crucial when examining associations between dietary factors and different outcomes. Today, web-based instead of paper-based food frequency questionnaires (FFQs) are common. A web-based FFQ implies a different experience (including design differences, the possibility only to show relevant questions, and automatic checks for completeness) and may capture dietary intake differently. The aim of this study was to validate a well-used paper-based FFQ transferred to a web-based version against a 4-d dietary record.

METHODS

Baseline data from a dietary intervention study comprising women and men with type 2 diabetes were used. Diet was assessed with the web-based FFQ and a 4-d dietary record. Energy intake and energy-adjusted nutrient intakes were assessed and compared using Spearman's rank correlation and Bland-Altman analysis. The analysis included 101 participants.

RESULTS

The average energy intake with the FFQ was 2068 kcal, 157 kcal higher than the average from the dietary record. Significant deattenuated correlations were found for intake of energy (r = 0.37; 95% confidence interval [CI],0.19-0.53), carbohydrates (r = 0.85; 95% CI, 0.78-0.89), protein (r = 0.53; 95% CI, 0.38-0.66) and fat (r = 0.59; 95% CI, 0.44-0.70). Significant deattenuated correlations (ranging r = 0.26-0.73) were found for intake of alcohol, whole grain, fiber, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, vitamins A, B12, C, D, and E, folate, iron, potassium, magnesium, and calcium. Bland-Altman analyses showed no clear trends but wide limits of agreement.

CONCLUSION

Overall, the web-based FFQ performed well and is similar to the paper-based version. It can be a useful tool for dietary assessments.

Dietary and plasma retinoids are not associated with fatty acid desaturase indices in healthy young adults

Past research in rodents suggests that fatty acid (FA) desaturase expression and activity may be modified by vitamin A; however, this has not been investigated in humans. The primary objective of this study was to examine associations between dietary retinoid intakes, plasma retinoid concentrations, and FA desaturase indices in young adults. As a secondary objective, biological sex and estrogen-containing contraceptive (EC) use were investigated due to prior evidence demonstrating that both can influence plasma retinol concentration and FA desaturase indices. Dietary retinoid intake (food frequency questionnaire), plasma retinoid concentrations (high-performance liquid chromatography-tandem mass spectrometry), plasma FA (gas chromatography), and FA desaturase indices (product-to-precursor ratios) from 945 adults recruited for the cross-sectional Toronto Nutrigenomics and Health study were analyzed. Participants were stratified into quartiles based on plasma retinol concentration and data analyzed by one-way analysis of covariance. Dietary retinoid intakes were not associated with the overall n-3 pathway, overall n-6 pathway, delta-5 desaturase, delta-6 desaturase, or delta-9 desaturase indices (all r < 0.10, p > 0.05). The overall n-6 pathway index was significantly higher (p = 0.0004) and the delta-5 desaturase index was significantly lower (p = 0.0003) in individuals with higher plasma retinol levels; however, these differences were lost when participants were grouped by biological sex and EC use. Although weak relationships were observed between plasma retinol and some FA desaturase indices in the total population, these associations appear to be driven by biological sex and EC usage rather than retinoids. We therefore find little evidence of a relationship between retinoids and FA desaturase indices in young, healthy adults.

Associations Between Dietary Vitamin C, Serum Ascorbic Acid, and GSTT1 Genotype and Premenstrual Symptoms

OBJECTIVE

Premenstrual symptoms are a cyclically occurring combination of adverse psychological and somatic symptoms that impact the quality of life for most females of childbearing age. Growing evidence suggests that diet may attenuate premenstrual symptoms; however, the relationship between vitamin C and premenstrual symptoms remains unclear. The aim of the research was to determine the association between different measures of vitamin C status and premenstrual symptoms.

METHOD

Females (n = 555) aged 20 to 29 years from the Toronto Nutrigenomics and Health Study completed a General Health and Lifestyle Questionnaire, capturing 15 premenstrual symptoms. Dietary intake was measured using a 196-item Toronto-modified Harvard food frequency questionnaire. Serum ascorbic acid concentrations were measured, and participants were categorized into deficient (<11 µmol/L), suboptimal (11-28 µmol/L), and adequate (>28 µmol/L) ascorbic acid levels. DNA was genotyped for the GSTT1 (Ins/Del) polymorphism. Using logistic regression, odds of experiencing premenstrual symptoms were compared between vitamin C intake levels above and below the recommended daily allowance (75 mg/d) between ascorbic acid levels and between GSTT1 genotypes.

RESULTS

Increased vitamin C intake was associated with premenstrual appetite changes (OR, 1.65; 95% CI, 1.01-2.68). Compared to deficient ascorbic acid levels, suboptimal levels were associated with premenstrual appetite changes (OR, 2.59; 95% CI, 1.02-6.58) and bloating/swelling (OR, 3.00; 95% CI, 1.09-8.22). Adequate serum ascorbic acid levels were not associated with premenstrual appetite changes (OR, 1.69; 95% CI, 0.73-3.94) or bloating/swelling (OR, 1.92; 95% CI, 0.79-4.67). Those with the GSTT1 functional variant (Ins*Ins) had an increased risk of premenstrual bloating/swelling (OR, 1.96; 95% CI, 1.10-3.48); however, the interaction between vitamin C intake and GSTT1 was not significant for any premenstrual symptoms.

CONCLUSIONS

Our findings suggest that indicators of higher vitamin C status are associated with increased premenstrual appetite changes and bloating/swelling. The observed associations with GSTT1 genotype suggest that these observations are not likely due to reverse causation.