OBJECTIVES: Most cohort studies used food frequency questionnaires (FFQ) to evaluate coffee consumption as it assesses habitual dietary patterns, whereas some studies have used the 24-hour recalls (24HR) as it elicits in-depth description of foods and the amount eaten. The aim of this study was to compare FFQs and 24HR to assess the consumption of various types of coffee.METHODS: We included 25,904 participants aged 40 years or older from the Health Examinees (HEXA) Study of the Korean Genome and Epidemiologic Study (KoGES). Each participant completed one FFQ and one-day (n=11,280) or two-day 24HR (n=14,624). We classified coffee types into: black coffee, coffee with sugar and cream, and coffee with sugar alone or cream alone. We compared the proportions of nondrinkers, black coffee, and coffee with sugar and cream through FFQ and 24HR.RESULTS: Among those who completed one FFQ and one-day 24HR, 39.4% of “nondrinkers” on one-day 24HR reported that they did not drink coffee on their FFQs. Whereas among those who complete two-day 24HR, 71.2% of “nondrinkers” on two-day 24HR said that they did not drink coffee on their FFQs. Among those who completed one FFQ and oneday 24HR, 58.3% marked “black coffee” on one-day 24HR said that they drank black coffee on their FFQs. Among those who complete two-day 24HR, 58.8% marked “black coffee” on two-day 24HR said that they drank black coffee on their FFQs. The kappa coefficients and percent agreements were 0.4 and 59.6%, respectively, for the comparison of coffee intake between FFQ and one-day 24HR, and 0.6 and 72.8%, respectively, for the comparison of coffee intake between FFQ and two-day 24HR.CONCLUSIONS: We found discrepancies between FFQs and 24HR in the types of coffee consumed. Such limitations should be considered when using the 24HR data to examine the effect of coffee consumption on disease development.
Coffee ; Cohort Studies ; Epidemiologic Studies ; Genome

BACKGROUND/OBJECTIVES: Habitual coffee consumption was inversely associated with type 2 diabetes (T2D) and hyperglycemia in observational studies, but the causality of the association remains uncertain. This study tested a causal association of genetically predicted coffee consumption with T2D using the Mendelian randomization (MR) method. SUBJECTS/METHODS: We used five single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) associated with habitual coffee consumption in a previous genome-wide association study among Koreans. We analyzed the associations between IVs and T2D, fasting blood glucose (FBG), 2h-postprandial glucose (2h-PG), and glycated haemoglobin (HbA1C) levels. The MR results were further evaluated by standard sensitivity tests for possible pleiotropism. RESULTS: MR analysis revealed that increased genetically predicted coffee consumption was associated with a reduced prevalence of T2D; ORs per one-unit increment of logtransformed cup per day of coffee consumption ranged from 0.75 (0.62–0.90) for the weighted mode-based method to 0.79 (0.62–0.99) for Wald ratio estimator. We also used the inverse-variance-weighted method, weighted median-based method, MR-Egger method, and MR-PRESSO method. Similarly, genetically predicted coffee consumption was inversely associated with FBG and 2h-PG levels but not with HbA1c. Sensitivity measures gave similar results without evidence of pleiotropy. CONCLUSIONS A genetic predisposition to habitual coffee consumption was inversely associated with T2D prevalence and lower levels of FBG and 2h-PG profiles. Our study warrants further exploration.

BACKGROUND/OBJECTIVES: Weight loss via a mobile application (App) or a paper-based diary (Paper) may confer favorable metabolic and anthropometric changes. SUBJECTS/METHODS: A randomized parallel trial was conducted among 57 adults whose body mass indices (BMIs) were 25 kg/m 2 or greater. Participants randomly assigned to either the App group (n = 30) or the Paper group (n = 27) were advised to record their foods and supplements through App or Paper during the 12-week intervention period. Relative changes of anthropometries and biomarker levels were compared between the 2 intervention groups.Untargeted metabolic profiling was identified to discriminate metabolic profiles. RESULTS: Out of the 57 participants, 54 participants completed the trial. Changes in body weight and BMI were not significantly different between the 2 groups (P = 0.11). However, body fat and low-density lipoprotein (LDL)-cholesterol levels increased in the App group but decreased in the Paper group, and the difference was statistically significant (P = 0.03 for body fat and 0.02 for LDL-cholesterol). In the metabolomics analysis, decreases in methylglyoxal and (S)-malate in pyruvate metabolism and phosphatidylcholine (lecithin) in linoleic acid metabolism from pre- to post-intervention were observed in the Paper group. CONCLUSIONS In the 12-week randomized parallel trial of weight loss through a App or a Paper, we found no significant difference in change in BMI or weight between the App and Paper groups, but improvement in body fatness and LDL-cholesterol levels only in the Paper group under the circumstances with minimal contact by dietitians or health care providers.Trial Registration: Clinical Research Information Service Identifier: KCT0004226