Underweight Versus Obesity and Gastrointestinal Cancer Mortality in Type 2 Diabetes: A Nationwide Cohort Study.
4 affiliations
- 1Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
- 2Department of Statistics and Actuarial Science, Soongsil University, Seoul, Republic of Korea.
- 3Division of Endocrinology and Metabolism, Department of Internal Medicine, Hallym University Dongtan Sacred Heart Hospital, Hwaseong, Republic of Korea.
- 4Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Abstract
Background
Underweight is a well-established risk factor for cancer mortality, yet its impact relative to obesity remains unclear in individuals with type 2 diabetes mellitus (T2DM), where current guidelines focus primarily on obesity management with limited guidance on underweight-related risks. We evaluated the association between body mass index (BMI) and gastrointestinal (GI) cancer mortality across the full BMI spectrum in individuals with T2DM.Methods
This nationwide population-based cohort study utilized the Korean National Health Insurance Service database. We included 2 507 976 adults with T2DM screened in 2015-2016 and followed through 2022, with a 1-year lag period applied to minimize reverse causality. BMI was categorized into eight groups: severe underweight (< 16.0 kg/m²), moderate underweight (16.0-16.9 kg/m²), mild underweight (17.0-18.4 kg/m²), normal weight (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), Class I obesity (25.0-29.9 kg/m²), Class II obesity (30.0-34.9 kg/m²) and Class III obesity (≥ 35.0 kg/m²). Multivariable-adjusted hazard ratios (aHRs) for GI cancer mortality were estimated using Cox proportional hazards models adjusting for clinical variables.Results
During 5.75-year mean follow-up, 10 978 GI cancer deaths occurred (975 oesophageal, 4391 gastric, 5317 colorectal and 295 other GI cancers including small intestine and anal cancer). A reverse J-shaped association was observed with mortality nadir at BMI 25.0-29.9 kg/m², which served as the reference group. Underweight was consistently associated with increased mortality across all severity categories: mild underweight aHR 2.54 (95% CI 2.26-2.85), moderate underweight aHR 2.51 (95% CI 1.96-3.20) and severe underweight aHR 2.96 (95% CI 2.14-4.09), with the highest risk observed in severe underweight. Notably, all underweight categories were associated with substantially higher mortality risk than Class III obesity (aHR 1.35, 95% CI 1.05-1.73). Cancer-specific analyses revealed that underweight was associated with the highest mortality risk for oesophageal cancer (aHR 13.23 [95% CI 6.77-25.85] for severe underweight), followed by gastric and colorectal cancers, whereas obesity significantly increased mortality only for colorectal cancer (aHR 1.52 [95% CI 1.10-2.08] for Class III obesity). Underweight was not significantly associated with GI cancer incidence after adjustment, and associations remained largely robust in 2-, 3-, and 4-year lag and competing risk analyses, except for colorectal cancer.Conclusions
In individuals with T2DM, underweight status is associated with substantially higher GI cancer mortality risk than obesity, with severe underweight showing nearly threefold higher risk compared to the reference group (BMI 25.0-29.9 kg/m²). These findings suggest that underweight, rather than obesity alone, warrants greater clinical attention as a determinant of GI cancer mortality in this population.
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BibTeX
@article{park2026underweight,
title = {{Underweight Versus Obesity and Gastrointestinal Cancer Mortality in Type 2 Diabetes: A Nationwide Cohort Study.}},
author = {Ji-Hong Park and Kyungdo Han and Hun Jee Choe and Se Eun Park and Won-Young Lee and Sun-Joon Moon and Eun-Jung Rhee},
journal = {Journal of cachexia, sarcopenia and muscle},
year = {2026},
month = oct,
doi = {10.1002/jcsm.70408},
url = {https://europepmc.org/article/MED/42908126},
note = {CC BY},
}
RIS
TY - JOUR
TI - Underweight Versus Obesity and Gastrointestinal Cancer Mortality in Type 2 Diabetes: A Nationwide Cohort Study.
AU - Ji-Hong Park
AU - Kyungdo Han
AU - Hun Jee Choe
AU - Se Eun Park
AU - Won-Young Lee
AU - Sun-Joon Moon
AU - Eun-Jung Rhee
PY - 2026
DA - 2026/10/01
JO - Journal of cachexia, sarcopenia and muscle
DO - 10.1002/jcsm.70408
UR - https://europepmc.org/article/MED/42908126
AB - Background Underweight is a well-established risk factor for cancer mortality, yet its impact relative to obesity remains unclear in individuals with type 2 diabetes mellitus (T2DM), where current guidelines focus primarily on obesity management with limited guidance on underweight-related risks. We evaluated the association between body mass index (BMI) and gastrointestinal (GI) cancer mortality across the full BMI spectrum in individuals with T2DM.Methods This nationwide population-based cohort study utilized the Korean National Health Insurance Service database. We included 2 507 976 adults with T2DM screened in 2015-2016 and followed through 2022, with a 1-year lag period applied to minimize reverse causality. BMI was categorized into eight groups: severe underweight (< 16.0 kg/m²), moderate underweight (16.0-16.9 kg/m²), mild underweight (17.0-18.4 kg/m²), normal weight (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), Class I obesity (25.0-29.9 kg/m²), Class II obesity (30.0-34.9 kg/m²) and Class III obesity (≥ 35.0 kg/m²). Multivariable-adjusted hazard ratios (aHRs) for GI cancer mortality were estimated using Cox proportional hazards models adjusting for clinical variables.Results During 5.75-year mean follow-up, 10 978 GI cancer deaths occurred (975 oesophageal, 4391 gastric, 5317 colorectal and 295 other GI cancers including small intestine and anal cancer). A reverse J-shaped association was observed with mortality nadir at BMI 25.0-29.9 kg/m², which served as the reference group. Underweight was consistently associated with increased mortality across all severity categories: mild underweight aHR 2.54 (95% CI 2.26-2.85), moderate underweight aHR 2.51 (95% CI 1.96-3.20) and severe underweight aHR 2.96 (95% CI 2.14-4.09), with the highest risk observed in severe underweight. Notably, all underweight categories were associated with substantially higher mortality risk than Class III obesity (aHR 1.35, 95% CI 1.05-1.73). Cancer-specific analyses revealed that underweight was associated with the highest mortality risk for oesophageal cancer (aHR 13.23 [95% CI 6.77-25.85] for severe underweight), followed by gastric and colorectal cancers, whereas obesity significantly increased mortality only for colorectal cancer (aHR 1.52 [95% CI 1.10-2.08] for Class III obesity). Underweight was not significantly associated with GI cancer incidence after adjustment, and associations remained largely robust in 2-, 3-, and 4-year lag and competing risk analyses, except for colorectal cancer.Conclusions In individuals with T2DM, underweight status is associated with substantially higher GI cancer mortality risk than obesity, with severe underweight showing nearly threefold higher risk compared to the reference group (BMI 25.0-29.9 kg/m²). These findings suggest that underweight, rather than obesity alone, warrants greater clinical attention as a determinant of GI cancer mortality in this population.
SN - 2190-5991
SN - 2190-6009
ER -