Life Cycle

About Life Cycle

Life Cycle is an international, peer-reviewed, open access general medical journal and invites submissions of any original contribution that broadens, advances, or brightens medical science or practice, or that educates or delights the Journal’s readers. Building on the foundation of Life Cycle as the best science for medical health research, the Journal is committed to publishing high-quality and cutting-edge Original Research Articles, State-of-the-Art Reviews, and Letters that contribute to the advancement of healthy life from birth to senescence.

CURRENT ISSUE: Sep 2024, Vol. 4

A National trends in type 2 diabetes in South Korea, including the COVID-19 pandemic, 1998-2021: A nationally representative survey study

Yejun Son, Jaeyu Park, Hyejun Kim, Jiseung Kang, Masoud Rahmati, Selin Woo

Life Cycle 2024;4:e7
https://doi.org/10.54724/lc.2024.e7

ABSTRACT

Objective: The COVID-19 pandemic has been associated with worse outcomes for people with diabetes, including increased mortality, while the long-term impact of the pandemic on diabetes prevalence is still underestimated. Thus, we aimed to analyze long-term prevalence trends of type 2 diabetes in South Korea from 1998 to 2021, encompassing the befor...

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Are citation counts of articles related to outcomes and legacies of authors and journal editors? (CAROL): a cohort study

Wonwoo Jang, Seokjun Kim, Jaehyun Kong, Hanseul Cho, Jiyeon Oh, Jiseung Kang, Lee Smith, Yejun Son

Life Cycle 2024;4:e8
https://doi.org/10.54724/lc.2024.e8

ABSTRACT

Objective: To investigate the association between the number of citations each article received and quantitative factors of journal editors or corresponding authors. Methods: We performed retrospective cohort study using corresponding author and editor information of articles published in PLOS Medicine. The number of citations for each article and ...

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Machine-learning prediction of kidney failure occurrence based on regular health check-up data: a nationwide cohort dataset in South Korea

Gahee Lee, Seokjun Kim, Seohyun Hong, Soo-Young Yoon, Hyeon Seok Hwang, Ai Koyanagi, Lee Smith, Hayeon Lee, Jinseok Lee

Life Cycle 2024;4:e6
https://doi.org/10.54724/lc.2024.e6

ABSTRACT

Objective: While prior research developed numerous machine learning (ML) models for disease prediction and demonstrated their potential, there has yet to be research on models concerning the prediction of kidney failure and its associated risk factors using simple, regular health check-up data. Thus, this study aimed to develop a ML model capable o...

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Nationwide trends in the prevalence of cataract, glaucoma, and macular degeneration among Korean adults amid the COVID-19 pandemic, 2015-2021: A representative study in South Korea

Hyeri Lee, Jun Hyuk Lee, Jaeyu Park, Hans Oh, Jiseung Kang, Louis Jacob, Lee Smith, Yejun Son

Life Cycle 2024;4:e5
https://doi.org/10.54724/lc.2024.e5

ABSTRACT

Objective: Understanding the impact of the COVID-19 pandemic on the prevalence of key ocular diseases—cataracts, glaucoma, and macular degeneration—in the general population remains a critical yet understudied area. This study aimed to assess the long-term national prevalence of cataract, glaucoma, and macular degeneration in South Korea, consi...

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National trends in the prevalence of tuberculosis before and during the COVID-19 pandemic, 1998-2021: a nationwide representative study in South Korea

Jaeyu Park, Ann Nguyen, Mafaz Kattih, Jiseung Kang, Ai Koyanagi, Masoud Rahmati, Seong H. Cho

Life Cycle 2024;4:e4
https://doi.org/10.54724/lc.2024.e4

ABSTRACT

Objective: In this study, we investigate changes in the prevalence of tuberculosis (TB) before and during the COVID-19 pandemic in South Korea, analyzing the effects of age, socioeconomic, and environmental variables on TB trends over a period of 24 years. Investigation into the association between TB and the COVID-19 pandemic can accelerate advanc...

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Association between dietary circadian rhythms and metabolic dysfunction-associated steatotic liver disease risk

Hyeseung Lee, Sang Youl Rhee

Life Cycle 2024;4:e3
https://doi.org/10.54724/lc.2024.e3

ABSTRACT

Irregular or late eating patterns have been increasingly associated with a higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD), which stands as the most prevalent hepatic disorder globally. These eating habits are believed to disrupt the body’s circadian rhythm, a critical factor involved in regulating lipid...

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Association of transitioning from combustible cigarettes to noncombustible nicotine or tobacco products with subsequent cancer risk: a nationwide cohort study in South Korea

Ho Geol Woo, Yejun Son, Sunyeup Kim, Jongnam Kim, Jiseung Kang, Seung Won Lee

Life Cycle 2024;4:e2
https://doi.org/10.54724/lc.2024.e2

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Trends in prevalence of asthma and COVID-19 pandemic-related factors in South Korea: a post-hoc analysis

Ann Nguyen, Jaeyu Park, Mafaz Kattih, Ai Koyanagi, Lee Smith, Min Seo Kim, Masoud Rahmati, Seong H. Cho, Nikolaos G. Papadopoulos

Life Cycle 2024;4:e1
https://doi.org/10.54724/lc.2024.e1

ABSTRACT

Objective: There are only a few studies investigating the effects of the COVID-19 pandemic on the prevalence of asthma, especially between different age groups. Thus, we aimed to examine the trends of age-stratified asthma prevalence in South Koreans before and during the COVID-19 pandemic. Methods: This study utilized data derived from the Korea N...

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MOST READ ARTICLES

Propensity score matching for causal inference and reducing the confounding effects: statistical standard and guideline of Life Cycle Committee

Seung Won Lee, Krishna Prasad Acharya

Life Cycle 2022;2:e18
https://doi.org/10.54724/lc.2022.e18

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Last 3 months views: 2843

Regression analysis for continuous independent variables in medical research: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2022;2:e3
https://doi.org/10.54724/lc.2022.e3

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Last 3 months views: 2663

Methods for testing statistical differences between groups in medical research: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2022;2:e1
https://doi.org/10.54724/lc.2022.e1

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Last 3 months views: 2382

Kaplan-Meier and Cox proportional hazards regression in survival analysis: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2023;3:e8
https://doi.org/10.54724/lc.2023.e8

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Last 3 months views: 1324

Global, regional, and national incidence and mortality of COVID-19 in 237 countries and territories, January 2022: a systematic analysis for World Health Organization COVID-19 Dashboard

So Young Kim, Abdullah Özgür Yeniova

Life Cycle 2022;2:e10
https://doi.org/10.54724/lc.2022.e10

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Last 3 months views: 872

PRISMA 2020 statement and guidelines for systematic review and meta-analysis articles, and their underlying mathematics: Life Cycle Committee Recommendations

Seung Won Lee, Min Ji Koo

Life Cycle 2022;2:e9
https://doi.org/10.54724/lc.2022.e9

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Last 3 months views: 746

Global Burden of Disease study at the World Health Organization: research methods for the most comprehensive global study of disease and underlying health policies

Lee Smith, Jae Il Shin, Soo Young Hwang, Kalthoum Tizaoui, Elena Dragioti, Louis Jacob, Karel Kostev, Seung Won Lee, Ai Koyanagi

Life Cycle 2022;2:e8
https://doi.org/10.54724/lc.2022.e8

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Last 3 months views: 732

Machine-learning prediction of kidney failure occurrence based on regular health check-up data: a nationwide cohort dataset in South Korea

Gahee Lee, Seokjun Kim, Seohyun Hong, Soo-Young Yoon, Hyeon Seok Hwang, Ai Koyanagi, Lee Smith, Hayeon Lee, Jinseok Lee

Life Cycle 2024;4:e6
https://doi.org/10.54724/lc.2024.e6

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Last 3 months views: 501

The emerging pandemic recent: SARS-CoV-2

Yoojin Cha, Wondong Jung, Minjae Seo, Masoud Rahmati

Life Cycle 2023;3:e2
https://doi.org/10.54724/lc.2023.e2

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Last 3 months views: 492

N-Nitrosodimethylamine-contaminated ranitidine and risk of cancer in South Korea: a nationwide cohort study

In Kyung Yoo, Dominic C. Marshall, Joo Young Cho, Hae Won Yoo, Seung Won Lee

Life Cycle 2021;1:e1
https://doi.org/10.54724/lc.2021.e1

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Last 3 months views: 471

MOST CITED ARTICLES

Methods for testing statistical differences between groups in medical research: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2022;2:e1
https://doi.org/10.54724/lc.2022.e1

ABSTRACT

In medical research, when independent variables are categorical (i.e., dividing groups), statistical analysis is often required. This situation mostly occurs on randomized controlled trials and observational studies that have multiple patient groups. Also, when analyzing continuous independent variables in a single patient group, breakpoints can be...

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Cited by 159

Regression analysis for continuous independent variables in medical research: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2022;2:e3
https://doi.org/10.54724/lc.2022.e3

ABSTRACT

Variables measured in medicine are usually continuous, such as blood pressure, serum glucose, and drug dosage. There are statistical methods to confirm whether these variables act as independent variables that cause an outcome. Most of these methods are types of regression analysis. In this article, starting with a simple correlation coefficient, l...

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Cited by 88

PRISMA 2020 statement and guidelines for systematic review and meta-analysis articles, and their underlying mathematics: Life Cycle Committee Recommendations

Seung Won Lee, Min Ji Koo

Life Cycle 2022;2:e9
https://doi.org/10.54724/lc.2022.e9

ABSTRACT

The paper discussed the overall aspects of systematic review and meta-analysis and explored the main mathematical context of meta-analysis. This included various methods of analyzing the effect size and obtaining the average effect size depending on the variable type. In doing so, methods of obtaining effect sizes in continuous outcome variables, c...

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Cited by 57

Global, regional, and national incidence and mortality of COVID-19 in 237 countries and territories, January 2022: a systematic analysis for World Health Organization COVID-19 Dashboard

So Young Kim, Abdullah Özgür Yeniova

Life Cycle 2022;2:e10
https://doi.org/10.54724/lc.2022.e10

ABSTRACT

Objective: To estimate global, regional, and national incidences and mortality of the coronavirus disease 2019 (COVID-19) in 237 countries and territories since the outbreak of the COVID-19 pandemic to 31 January, 2022. Methods: Comprehensive estimates were produced through global, regional, and national studies of cumulative severe acute respirato...

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Cited by 31

N-Nitrosodimethylamine-contaminated ranitidine and risk of cancer in South Korea: a nationwide cohort study

In Kyung Yoo, Dominic C. Marshall, Joo Young Cho, Hae Won Yoo, Seung Won Lee

Life Cycle 2021;1:e1
https://doi.org/10.54724/lc.2021.e1

ABSTRACT

Objective: On September 2019, the United States Food and Drug Administration announced that some ranitidine products were contaminated with unacceptable levels of N-nitrosodimethylamine (NDMA). We aimed to determine whether the use of ranitidine that was potentially contaminated with NDMA, rather than another histamine H2-receptor antagonist (H2 bl...

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Cited by 24

Nationwide COVID-19 vaccination coverage and COVID-19 incidence in South Korea, January 2022: a national official report

So Young Kim

Life Cycle 2022;2:e2
https://doi.org/10.54724/lc.2022.e2

ABSTRACT

Objective: To reduce the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, severe coronavirus disease 2019 (COVID-19) illness, and COVID-19 related death, all persons in South Korea should stay up to data with recommended COVID-19 vaccinations. This study investigated the rates and effectiveness of the COVID-19 vaccina...

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Cited by 20

Global Burden of Disease study at the World Health Organization: research methods for the most comprehensive global study of disease and underlying health policies

Lee Smith, Jae Il Shin, Soo Young Hwang, Kalthoum Tizaoui, Elena Dragioti, Louis Jacob, Karel Kostev, Seung Won Lee, Ai Koyanagi

Life Cycle 2022;2:e8
https://doi.org/10.54724/lc.2022.e8

ABSTRACT

The Global Burden of Disease (GBD) is a compass that navigates researchers and clinicians in discovering the latest knowledge and the current status of health for populations and countries worldwide. The GBD helps to present various methods in evaluating health-related quality of life and assess the health burden, economic burden, years of life los...

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Cited by 19

Propensity score matching for causal inference and reducing the confounding effects: statistical standard and guideline of Life Cycle Committee

Seung Won Lee, Krishna Prasad Acharya

Life Cycle 2022;2:e18
https://doi.org/10.54724/lc.2022.e18

ABSTRACT

Since the development of research methodology, there has always been keen interest in developing the accuracy of the research by comparing covariates. Propensity score is useful when the research covers many variables which are not intended to be included as independent variables, thus allowing the removal of certain covariates from the model. This...

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Cited by 16

Age, ethnic, and sex disparity in body mass index and waist circumference: a bi-national large-scale study in South Korea and the United States

Seounghyun Eum, Sang Youl Rhee

Life Cycle 2023;3:e4
https://doi.org/10.54724/lc.2023.e4

ABSTRACT

The study investigated age, ethnic, and sex disparities in body mass index (BMI) and waist circumference (WC) in South Korea and the United States. We conducted a bi-national large-scale study and analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES) and the National Health and Nutrition Examination Survey in the U...

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Cited by 14

Kaplan-Meier and Cox proportional hazards regression in survival analysis: statistical standard and guideline of Life Cycle Committee

Seung Won Lee

Life Cycle 2023;3:e8
https://doi.org/10.54724/lc.2023.e8

ABSTRACT

In medical research, analyzing the time it takes for a phenomenon to occur is sometimes crucial. However, various factors can contribute to the length of survival or observation periods, and removing specific data can lead to bias results. In this paper, we discuss the Kaplan-Meier analysis and Cox proportional hazards regression model, which are t...

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Cited by 13