Expansion of a food composition database for the food frequency questionnaire in the Korean Genome and Epidemiology Study (KoGES): a comprehensive database of dietary antioxidants and total antioxidant capacity.

Objectives: This study constructed a comprehensive database of dietary antioxidants and total antioxidant capacity (TAC) to facilitate the estimation of daily antioxidant intake using a food frequency questionnaire (FFQ). This database was applied to 3 general population-based cohorts (n=195,961) within the Korean Genome and Epidemiology Study (KoGES). Methods: To establish a database of 412 foods derived from recipes of a 106-item FFQ, we followed a pre-established standardized protocol. This included the selection of source databases, matching of foods, substitution of unmatched items with identical foods and input of values, and assessment of coverage. For each food, the TAC was estimated by summing the individual antioxidant capacities, calculated by multiplying the amount of each antioxidant by its vitamin C equivalent antioxidant capacity. Results: We identified 48 antioxidants across 5 classes: retinol, carotenoids, vitamins C and E, and flavonoids, with flavonoids divided into 7 subclasses. TAC values were then established. Coverage exceeded 90.0% for retinol, carotenoids, vitamin C, and vitamin E, while coverage for flavonoids was 60.9%. The daily intakes of 4 antioxidant classes-all but vitamin E-were higher in women than in men. The Ansan-Ansung cohort exhibited the highest levels of dietary TAC, vitamin E, and flavonoids, while the Health Examinees Study cohort displayed the highest values for retinol, carotenoids, and vitamin C. Conclusion: We customized a comprehensive antioxidant database for the KoGES FFQ, achieving relatively high coverage. This expansion could support research investigating the impact of dietary antioxidants on the development of chronic diseases targeted by the KoGES.

Habitual intake of iron, copper, and zinc and the risk of type 2 diabetes in a prospective cohort: The CAVAS (Cardiovascular Disease Association Study).

BACKGROUND AND AIMS: Unlike iron, evidence of the association between dietary copper and zinc intake and type 2 diabetes (T2D) risk is limited. This study aimed to examine the prospective associations of dietary intake of iron (total, plant-based, and animal-based), copper, and zinc with T2D risk among adults aged ≥40 years. METHODS AND RESULTS: For 16,666 participants, dietary intakes (baseline, cumulative average, and most recent) of iron, copper, and zinc were calculated from repeated food frequency questionnaires; a modified Poisson regression model with a robust error estimator was conducted. In men, positive associations between T2D and baseline dietary intake of Cu and Zn, cumulative average dietary intake of Fe (total and animal-based), Cu and Zn, and most recent dietary intake of Fe (total, plant-based, and animal-based), Cu, and Zn [most recent diet: for total Fe, IRR(95%CI) = 1.93 (1.41-2.64); for plant-based Fe, 1.56 (1.15-2.11); for animal-based Fe, 1.44 (1.09-1.90); for Cu, 3.17 (2.33-4.30); for Zn, 2.18 (1.64-2.89)] were observed, where as in women, there were positive associations of only cumulative average dietary Zn intake and most recent dietary intake of plant-based Fe, Cu, and Zn [most recent diet: for plant-based Fe, 1.30 (1.01-1.68); for Cu, 1.62 (1.27-2.08); for Zn, 2.07 (1.61-2.66)]. CONCLUSION: Dietary intakes of iron (total, plant-based, and animal-based), copper, and zinc may be positively associated with T2D risk. These positive associations are predominantly observed in most recent diet and appear to be stronger compared to baseline and cumulative average diet.

Associations of cumulative average dietary total antioxidant capacity and intake of antioxidants with metabolic syndrome risk in Korean adults aged 40 years and older: a prospective cohort study (KoGES_CAVAS).

OBJECTIVES: Limited and inconsistent prospective evidence exists regarding the relationship of dietary total antioxidant capacity (dTAC) and antioxidant intake with metabolic syndrome (MetS) risk. We evaluated the associations of the cumulative averages of dTAC and antioxidant intake (in 5 classes: retinol, vitamin C, vitamin E, carotenoids, and flavonoids, as well as 7 flavonoid subclasses) with the risk of MetS. METHODS: This study included 11,379 participants without MetS, drawn from the Korean Genome and Epidemiology Study_CArdioVascular disease Association Study (KoGES_CAVAS). The cumulative average consumption was calculated using repeated food frequency questionnaires. Incidence rate ratios were estimated using a modified Poisson regression model with a robust error estimator. RESULTS: The median follow-up period was 5.16 years, and 2,416 cases of MetS were recorded over 58,750 person-years. In men, significant inverse associations were observed in all 5 antioxidant classes, except for the highest quartile of dTAC. In women, dTAC and total flavonoids were not significantly associated with MetS; however, significant L-shaped associations were found for the remaining 4 antioxidant classes. Of the 7 flavonoid subclasses, only flavones in the highest quartile for men and flavan-3-ols in women lacked significant associations with MetS. The inverse associations were not sex-specific, but they were particularly pronounced among participants with a body mass index (BMI) of 23 kg/m2 or higher. CONCLUSIONS: The findings suggest that most antioxidant classes and flavonoid subclasses, unlike dTAC, exhibit a clear beneficial association with MetS in an L-shaped pattern in both men and women, particularly those with a high BMI.

Positive association of alcohol consumption with incidence of hypertension in adults aged 40 years and over: Use of repeated alcohol consumption measurements.

BACKGROUND & AIMS: Managing alcohol consumption may be an effective way of preventing hypertension, which is an important modifiable risk factor for cardiovascular diseases. However, there is little evidence on the temporal relationship between alcohol consumption and incidence of hypertension. We investigated the prospective association between repeated measures of alcohol consumption and hypertension incidence among Korean adults aged 40 and over. METHODS: This study included a total of 4989 participants that were not taking antihypertensive drugs and had normal blood pressure (BP) (systolic < 140 mmHg and diastolic < 90 mmHg). We used three measures of alcohol consumption (baseline, most recent, and average) as exposures and compared the three approaches. Using a modified Poisson regression model with a robust error estimator, we estimated incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for hypertension. RESULTS: Over a total of 17,689 person-years (average 3.5 years of follow-up), 574 incident cases of hypertension were identified. In multivariable models, consuming ≥30 ml/d of alcohol was associated with a risk of hypertension among men (IRR = 1.72, 95% CI = 1.20-2.48, p trend = 0.017 for baseline alcohol consumption; IRR = 1.69, 95% CI = 1.23-2.33, p trend = 0.005 for the most recent alcohol consumption; IRR = 1.49, 95% CI = 1.09-2.03, p trend = 0.014 for average alcohol consumption). After additional adjustment for baseline BP the positive association remained only when the most recent alcohol consumption measure was used. There was no significant association between alcohol consumption and hypertension among women, and no interaction effect between alcohol consumption and baseline BP levels on incidence of hypertension (all p interaction > 0.05) existed. CONCLUSIONS: Alcohol consumption, especially consuming ≥30 ml/d, may be positively linked with incidence risk of hypertension among men.