1.Vitamin B6 intake and health effects:associations with chronic diseases and adverse effects of long-term highdose intake
Min Young UM ; Kyung Hee HONG ; Eun Young CHOI
Journal of Nutrition and Health 2026;59(2):192-201
Vitamin B6 is an essential water-soluble vitamin involved in amino acid metabolism, neurotransmitter synthesis, heme biosynthesis, and one-carbon metabolism. Its active form, pyridoxal-5′-phosphate (PLP), serves as a coenzyme in more than 100 enzymatic reactions and is critical for maintaining metabolic homeostasis, immune regulation, and nervous system function. Epidemiological studies have reported inverse associations between vitamin B6 intake or the circulating PLP concentrations and the risk of cardiovascular disease, certain cancers, and diabetes-related metabolic dysfunction. The proposed mechanisms include the modulation of inflammation, oxidative stress, and homocysteine metabolism. Nevertheless, most available evidence is derived from observational studies conducted in Western or non-Korean populations, limiting generalizability and precluding revisions to current intake recommendations based on the chronic disease outcomes. Relevant epidemiological studies, mechanistic evidence, and recent international and national risk assessment reports were reviewed. Although excessive intake from habitual diets is uncommon, the increasing use of dietary supplements has raised concerns regarding chronic high-dose exposure. Accumulating human evidence suggests that long-term supplementation with high pyridoxine doses may induce sensory peripheral neuropathy, even at lower intake levels than previously assumed. Accordingly, recent international risk assessments, including the 2023 re-evaluation by the European Food Safety Authority, have proposed substantially lower Tolerable Upper Intake Level (UL) using benchmark dose modeling based on human data. In the 2025 Dietary Reference Intakes for Koreans, the UL for adults was set at 50 mg/day, reflecting the updated safety evidence and domestic supplement use patterns, while the recommended intake levels were maintained based on the established metabolic requirements. Further population-specific prospective studies and long-term safety data are needed to refine intake guidance and strengthen evidence-based risk management strategies in Korea.
2.Machine Learning Models to Identify Individuals With Imminent Suicide Risk Using a Wearable Device: A Pilot Study
Jumyung UM ; Jongsu PARK ; Dong Eun LEE ; Jae Eun AHN ; Ji Hyun BAEK
Psychiatry Investigation 2025;22(2):156-166
Objective:
We aimed to determine whether individuals at immediate risk of suicide could be identified using data from a commercially available wearable device.
Methods:
Thirty-nine participants experiencing acute depressive episodes and 20 age- and sex-matched healthy controls wore a commercially available wearable device (Galaxy Watch Active2) for two months. We collected data on activities, sleep, and physiological metrics like heart rate and heart rate variability using the wearable device. Participants rated their mood spontaneously twice daily on a Likert scale displayed on the device. Mood ratings by clinicians were performed at weeks 0, 2, 4, and 8. The suicide risk was assessed using the Hamilton Depression Rating Scale’s suicide item score (HAMD-3). We developed two predictive models using machine learning: a single-level model that processed all data simultaneously to identify those at immediate suicide risk (HAMD-3 scores ≥1) and a multilevel model. We compared the predictions of imminent suicide risk from both models.
Results:
Both the single-step and multi-step models effectively predicted imminent suicide risk. The multi-step model outperformed the single-step model in predicting imminent suicide risk with area under the curve scores of 0.89 compared to 0.88. In the multi-step model, the HAMD total score and heart rate variability were most significant, whereas in the single-step model, the HAMD total score and diagnosis were key predictors.
Conclusion
Wearable devices are a promising tool for identifying individuals at immediate risk of suicide. Future research with more refined temporal resolution is recommended.
3.Risk of Diabetes Mellitus in Adults with Intellectual Disabilities: A Nationwide Cohort Study
Hye Yeon KOO ; In Young CHO ; Yoo Jin UM ; Yong-Moon Mark PARK ; Kyung Mee KIM ; Chung Eun LEE ; Kyungdo HAN
Endocrinology and Metabolism 2025;40(1):103-111
Background:
Intellectual disability (ID) may be associated with an increased risk of diabetes mellitus (DM). However, evidence from longitudinal studies is scarce, particularly in Asian populations.
Methods:
This retrospective cohort study used representative linked data from the Korea National Disability Registration System and the National Health Insurance Service database. Adults (≥20 years) who received a national health examination in 2009 (3,385 individuals with ID and 3,463,604 individuals without ID) were included and followed until 2020. ID was identified using legal registration information. Incident DM was defined by prescription records with relevant diagnostic codes. Multivariable-adjusted Cox proportional hazards regression models were used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for DM risks in individuals with ID compared to those without ID.
Results:
Over a mean follow-up of 9.8 years, incident DM occurred in 302 (8.9%) individuals with ID and 299,156 (8.4%) individuals without ID. Having ID was associated with increased DM risk (aHR, 1.38; 95% CI, 1.23 to 1.55). Sensitivity analysis confirmed a higher DM risk in individuals with ID (aHR, 1.39; 95% CI, 1.24 to 1.56) than those with other disabilities (aHR, 1.11; 95% CI, 1.10 to 1.13) or no disability (reference). Stratified analysis showed higher DM risk in non-hypertensive subjects (aHR, 1.63; 95% CI, 1.43 to 1.86) compared to hypertensive subjects (aHR, 1.00; 95% CI, 0.80 to 1.26; P for interaction <0.001).
Conclusion
Adults with ID have an increased risk of developing DM, highlighting the need for targeted public health strategies to promote DM prevention in this population.
4.Machine Learning Models to Identify Individuals With Imminent Suicide Risk Using a Wearable Device: A Pilot Study
Jumyung UM ; Jongsu PARK ; Dong Eun LEE ; Jae Eun AHN ; Ji Hyun BAEK
Psychiatry Investigation 2025;22(2):156-166
Objective:
We aimed to determine whether individuals at immediate risk of suicide could be identified using data from a commercially available wearable device.
Methods:
Thirty-nine participants experiencing acute depressive episodes and 20 age- and sex-matched healthy controls wore a commercially available wearable device (Galaxy Watch Active2) for two months. We collected data on activities, sleep, and physiological metrics like heart rate and heart rate variability using the wearable device. Participants rated their mood spontaneously twice daily on a Likert scale displayed on the device. Mood ratings by clinicians were performed at weeks 0, 2, 4, and 8. The suicide risk was assessed using the Hamilton Depression Rating Scale’s suicide item score (HAMD-3). We developed two predictive models using machine learning: a single-level model that processed all data simultaneously to identify those at immediate suicide risk (HAMD-3 scores ≥1) and a multilevel model. We compared the predictions of imminent suicide risk from both models.
Results:
Both the single-step and multi-step models effectively predicted imminent suicide risk. The multi-step model outperformed the single-step model in predicting imminent suicide risk with area under the curve scores of 0.89 compared to 0.88. In the multi-step model, the HAMD total score and heart rate variability were most significant, whereas in the single-step model, the HAMD total score and diagnosis were key predictors.
Conclusion
Wearable devices are a promising tool for identifying individuals at immediate risk of suicide. Future research with more refined temporal resolution is recommended.
5.Risk of Diabetes Mellitus in Adults with Intellectual Disabilities: A Nationwide Cohort Study
Hye Yeon KOO ; In Young CHO ; Yoo Jin UM ; Yong-Moon Mark PARK ; Kyung Mee KIM ; Chung Eun LEE ; Kyungdo HAN
Endocrinology and Metabolism 2025;40(1):103-111
Background:
Intellectual disability (ID) may be associated with an increased risk of diabetes mellitus (DM). However, evidence from longitudinal studies is scarce, particularly in Asian populations.
Methods:
This retrospective cohort study used representative linked data from the Korea National Disability Registration System and the National Health Insurance Service database. Adults (≥20 years) who received a national health examination in 2009 (3,385 individuals with ID and 3,463,604 individuals without ID) were included and followed until 2020. ID was identified using legal registration information. Incident DM was defined by prescription records with relevant diagnostic codes. Multivariable-adjusted Cox proportional hazards regression models were used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for DM risks in individuals with ID compared to those without ID.
Results:
Over a mean follow-up of 9.8 years, incident DM occurred in 302 (8.9%) individuals with ID and 299,156 (8.4%) individuals without ID. Having ID was associated with increased DM risk (aHR, 1.38; 95% CI, 1.23 to 1.55). Sensitivity analysis confirmed a higher DM risk in individuals with ID (aHR, 1.39; 95% CI, 1.24 to 1.56) than those with other disabilities (aHR, 1.11; 95% CI, 1.10 to 1.13) or no disability (reference). Stratified analysis showed higher DM risk in non-hypertensive subjects (aHR, 1.63; 95% CI, 1.43 to 1.86) compared to hypertensive subjects (aHR, 1.00; 95% CI, 0.80 to 1.26; P for interaction <0.001).
Conclusion
Adults with ID have an increased risk of developing DM, highlighting the need for targeted public health strategies to promote DM prevention in this population.
6.Machine Learning Models to Identify Individuals With Imminent Suicide Risk Using a Wearable Device: A Pilot Study
Jumyung UM ; Jongsu PARK ; Dong Eun LEE ; Jae Eun AHN ; Ji Hyun BAEK
Psychiatry Investigation 2025;22(2):156-166
Objective:
We aimed to determine whether individuals at immediate risk of suicide could be identified using data from a commercially available wearable device.
Methods:
Thirty-nine participants experiencing acute depressive episodes and 20 age- and sex-matched healthy controls wore a commercially available wearable device (Galaxy Watch Active2) for two months. We collected data on activities, sleep, and physiological metrics like heart rate and heart rate variability using the wearable device. Participants rated their mood spontaneously twice daily on a Likert scale displayed on the device. Mood ratings by clinicians were performed at weeks 0, 2, 4, and 8. The suicide risk was assessed using the Hamilton Depression Rating Scale’s suicide item score (HAMD-3). We developed two predictive models using machine learning: a single-level model that processed all data simultaneously to identify those at immediate suicide risk (HAMD-3 scores ≥1) and a multilevel model. We compared the predictions of imminent suicide risk from both models.
Results:
Both the single-step and multi-step models effectively predicted imminent suicide risk. The multi-step model outperformed the single-step model in predicting imminent suicide risk with area under the curve scores of 0.89 compared to 0.88. In the multi-step model, the HAMD total score and heart rate variability were most significant, whereas in the single-step model, the HAMD total score and diagnosis were key predictors.
Conclusion
Wearable devices are a promising tool for identifying individuals at immediate risk of suicide. Future research with more refined temporal resolution is recommended.
7.Machine Learning Models to Identify Individuals With Imminent Suicide Risk Using a Wearable Device: A Pilot Study
Jumyung UM ; Jongsu PARK ; Dong Eun LEE ; Jae Eun AHN ; Ji Hyun BAEK
Psychiatry Investigation 2025;22(2):156-166
Objective:
We aimed to determine whether individuals at immediate risk of suicide could be identified using data from a commercially available wearable device.
Methods:
Thirty-nine participants experiencing acute depressive episodes and 20 age- and sex-matched healthy controls wore a commercially available wearable device (Galaxy Watch Active2) for two months. We collected data on activities, sleep, and physiological metrics like heart rate and heart rate variability using the wearable device. Participants rated their mood spontaneously twice daily on a Likert scale displayed on the device. Mood ratings by clinicians were performed at weeks 0, 2, 4, and 8. The suicide risk was assessed using the Hamilton Depression Rating Scale’s suicide item score (HAMD-3). We developed two predictive models using machine learning: a single-level model that processed all data simultaneously to identify those at immediate suicide risk (HAMD-3 scores ≥1) and a multilevel model. We compared the predictions of imminent suicide risk from both models.
Results:
Both the single-step and multi-step models effectively predicted imminent suicide risk. The multi-step model outperformed the single-step model in predicting imminent suicide risk with area under the curve scores of 0.89 compared to 0.88. In the multi-step model, the HAMD total score and heart rate variability were most significant, whereas in the single-step model, the HAMD total score and diagnosis were key predictors.
Conclusion
Wearable devices are a promising tool for identifying individuals at immediate risk of suicide. Future research with more refined temporal resolution is recommended.
8.Risk of Diabetes Mellitus in Adults with Intellectual Disabilities: A Nationwide Cohort Study
Hye Yeon KOO ; In Young CHO ; Yoo Jin UM ; Yong-Moon Mark PARK ; Kyung Mee KIM ; Chung Eun LEE ; Kyungdo HAN
Endocrinology and Metabolism 2025;40(1):103-111
Background:
Intellectual disability (ID) may be associated with an increased risk of diabetes mellitus (DM). However, evidence from longitudinal studies is scarce, particularly in Asian populations.
Methods:
This retrospective cohort study used representative linked data from the Korea National Disability Registration System and the National Health Insurance Service database. Adults (≥20 years) who received a national health examination in 2009 (3,385 individuals with ID and 3,463,604 individuals without ID) were included and followed until 2020. ID was identified using legal registration information. Incident DM was defined by prescription records with relevant diagnostic codes. Multivariable-adjusted Cox proportional hazards regression models were used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for DM risks in individuals with ID compared to those without ID.
Results:
Over a mean follow-up of 9.8 years, incident DM occurred in 302 (8.9%) individuals with ID and 299,156 (8.4%) individuals without ID. Having ID was associated with increased DM risk (aHR, 1.38; 95% CI, 1.23 to 1.55). Sensitivity analysis confirmed a higher DM risk in individuals with ID (aHR, 1.39; 95% CI, 1.24 to 1.56) than those with other disabilities (aHR, 1.11; 95% CI, 1.10 to 1.13) or no disability (reference). Stratified analysis showed higher DM risk in non-hypertensive subjects (aHR, 1.63; 95% CI, 1.43 to 1.86) compared to hypertensive subjects (aHR, 1.00; 95% CI, 0.80 to 1.26; P for interaction <0.001).
Conclusion
Adults with ID have an increased risk of developing DM, highlighting the need for targeted public health strategies to promote DM prevention in this population.
9.Risk of Diabetes Mellitus in Adults with Intellectual Disabilities: A Nationwide Cohort Study
Hye Yeon KOO ; In Young CHO ; Yoo Jin UM ; Yong-Moon Mark PARK ; Kyung Mee KIM ; Chung Eun LEE ; Kyungdo HAN
Endocrinology and Metabolism 2025;40(1):103-111
Background:
Intellectual disability (ID) may be associated with an increased risk of diabetes mellitus (DM). However, evidence from longitudinal studies is scarce, particularly in Asian populations.
Methods:
This retrospective cohort study used representative linked data from the Korea National Disability Registration System and the National Health Insurance Service database. Adults (≥20 years) who received a national health examination in 2009 (3,385 individuals with ID and 3,463,604 individuals without ID) were included and followed until 2020. ID was identified using legal registration information. Incident DM was defined by prescription records with relevant diagnostic codes. Multivariable-adjusted Cox proportional hazards regression models were used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for DM risks in individuals with ID compared to those without ID.
Results:
Over a mean follow-up of 9.8 years, incident DM occurred in 302 (8.9%) individuals with ID and 299,156 (8.4%) individuals without ID. Having ID was associated with increased DM risk (aHR, 1.38; 95% CI, 1.23 to 1.55). Sensitivity analysis confirmed a higher DM risk in individuals with ID (aHR, 1.39; 95% CI, 1.24 to 1.56) than those with other disabilities (aHR, 1.11; 95% CI, 1.10 to 1.13) or no disability (reference). Stratified analysis showed higher DM risk in non-hypertensive subjects (aHR, 1.63; 95% CI, 1.43 to 1.86) compared to hypertensive subjects (aHR, 1.00; 95% CI, 0.80 to 1.26; P for interaction <0.001).
Conclusion
Adults with ID have an increased risk of developing DM, highlighting the need for targeted public health strategies to promote DM prevention in this population.
10.Machine Learning Models to Identify Individuals With Imminent Suicide Risk Using a Wearable Device: A Pilot Study
Jumyung UM ; Jongsu PARK ; Dong Eun LEE ; Jae Eun AHN ; Ji Hyun BAEK
Psychiatry Investigation 2025;22(2):156-166
Objective:
We aimed to determine whether individuals at immediate risk of suicide could be identified using data from a commercially available wearable device.
Methods:
Thirty-nine participants experiencing acute depressive episodes and 20 age- and sex-matched healthy controls wore a commercially available wearable device (Galaxy Watch Active2) for two months. We collected data on activities, sleep, and physiological metrics like heart rate and heart rate variability using the wearable device. Participants rated their mood spontaneously twice daily on a Likert scale displayed on the device. Mood ratings by clinicians were performed at weeks 0, 2, 4, and 8. The suicide risk was assessed using the Hamilton Depression Rating Scale’s suicide item score (HAMD-3). We developed two predictive models using machine learning: a single-level model that processed all data simultaneously to identify those at immediate suicide risk (HAMD-3 scores ≥1) and a multilevel model. We compared the predictions of imminent suicide risk from both models.
Results:
Both the single-step and multi-step models effectively predicted imminent suicide risk. The multi-step model outperformed the single-step model in predicting imminent suicide risk with area under the curve scores of 0.89 compared to 0.88. In the multi-step model, the HAMD total score and heart rate variability were most significant, whereas in the single-step model, the HAMD total score and diagnosis were key predictors.
Conclusion
Wearable devices are a promising tool for identifying individuals at immediate risk of suicide. Future research with more refined temporal resolution is recommended.

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