Normal-weight obesity and adverse health outcomes in women: a systematic review and meta-analysis of observational studies.
- 1School of Human Medicine, Faculty of Health Sciences, Universidad Nacional Jorge Basadre Grohmann, Tacna, Peru.
- 2Hospital Daniel Alcides Carrión, EsSalud, Tacna, Peru.
- 3Hospital Hipólito Unanue de Tacna, Tacna, Peru.
Abstract
Background
Normal body mass index (BMI) can coexist with excess adiposity, a phenotype termed normal-weight obesity (NWO). Female-specific evidence remains fragmented; we synthesized associations between NWO and female adverse health outcomes.Methods
This was a systematic review and meta-analysis of observational studies. PubMed/MEDLINE, Embase, Scopus, and Web of Science were searched from inception to May 28, 2026, for eligible female-specific studies comparing NWO with normal-weight lean/non-obese controls. Odds ratios (OR) and other effect ratios were synthesized separately; continuous outcomes were pooled as mean differences (MDs). Outcomes reported in ≥3 studies were pooled with random-effects models using Paule-Mandel between-study variance and Hartung-Knapp confidence intervals (CIs) with an ad hoc correction. Risk of bias was assessed using the Risk Of Bias In Non-randomized Studies of Exposures tool and the Joanna Briggs Institute cross-sectional checklist.Results
Twenty studies (200,461 women with normal BMI) were included; 17 were cross-sectional. NWO was associated with metabolic syndrome (number of studies [k] = 4; OR 2.02, 95% CI 1.60 to 2.55), abdominal obesity (k = 3; OR 3.62, 95% CI 1.22 to 10.70), higher triglycerides (k = 7; MD 10.99 mg/dL, 95% CI 2.03 to 19.94), total cholesterol (k = 6; MD 6.86 mg/dL, 95% CI 2.60 to 11.11), and total cholesterol-to-high-density lipoprotein cholesterol (HDL-C) ratio (k = 3; MD 0.76, 95% CI 0.11 to 1.42). Associations with fasting glucose, diabetes, low-density lipoprotein cholesterol (LDL-C), HDL-C, fasting insulin, homeostatic model assessment of insulin resistance, and blood pressure were uncertain. Hard clinical outcomes were sparse, and two of three longitudinal studies had high risk of bias.Conclusion
Among women with normal BMI, excess adiposity is associated with a less favorable cardiometabolic phenotype, most consistently metabolic syndrome and selected lipid measures. Evidence for diabetes, blood pressure, cardiovascular events, mortality, cancer, and reproductive or functional outcomes remains limited. Standardized NWO definitions and prospective female-specific studies are needed. (PROSPERO: CRD420261408853).
Related
- Multi-site metabolomics reveals one-carbon and placental steroid disruption in maternal pre-pregnancy obesity linked to adverse pregnancy outcomes
- Association Between Pre-pregnancy Obesity and Adverse Obstetric Outcomes: A Retrospective Cohort Study at a Secondary Care Center in Tbilisi, Georgia
- Urinary organophosphate flame retardants and risk of sarcopenia and sarcopenic obesity among middle-aged and older adults: a systematic investigation integrating epidemiological and adverse outcome pathway analyses
- Incidence of adverse events following COVID-19 vaccination in observational studies
- Maternal Obesity and Outcomes During Pregnancy and the Puerperium: A Single-Center Retrospective Observational Study
BibTeX
@article{florespalacios2026normalweight,
title = {{Normal-weight obesity and adverse health outcomes in women: a systematic review and meta-analysis of observational studies.}},
author = {Rodrigo Flores-Palacios and Danna Velasquez-Mamani and Alexis Ramos-Vilca and Victor Chara-Saenz},
journal = {Obesity pillars},
year = {2026},
month = oct,
doi = {10.1016/j.obpill.2026.100343},
url = {https://europepmc.org/article/MED/42898729},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Normal-weight obesity and adverse health outcomes in women: a systematic review and meta-analysis of observational studies.
AU - Rodrigo Flores-Palacios
AU - Danna Velasquez-Mamani
AU - Alexis Ramos-Vilca
AU - Victor Chara-Saenz
PY - 2026
DA - 2026/10/08
JO - Obesity pillars
DO - 10.1016/j.obpill.2026.100343
UR - https://europepmc.org/article/MED/42898729
AB - Background Normal body mass index (BMI) can coexist with excess adiposity, a phenotype termed normal-weight obesity (NWO). Female-specific evidence remains fragmented; we synthesized associations between NWO and female adverse health outcomes.Methods This was a systematic review and meta-analysis of observational studies. PubMed/MEDLINE, Embase, Scopus, and Web of Science were searched from inception to May 28, 2026, for eligible female-specific studies comparing NWO with normal-weight lean/non-obese controls. Odds ratios (OR) and other effect ratios were synthesized separately; continuous outcomes were pooled as mean differences (MDs). Outcomes reported in ≥3 studies were pooled with random-effects models using Paule-Mandel between-study variance and Hartung-Knapp confidence intervals (CIs) with an ad hoc correction. Risk of bias was assessed using the Risk Of Bias In Non-randomized Studies of Exposures tool and the Joanna Briggs Institute cross-sectional checklist.Results Twenty studies (200,461 women with normal BMI) were included; 17 were cross-sectional. NWO was associated with metabolic syndrome (number of studies [k] = 4; OR 2.02, 95% CI 1.60 to 2.55), abdominal obesity (k = 3; OR 3.62, 95% CI 1.22 to 10.70), higher triglycerides (k = 7; MD 10.99 mg/dL, 95% CI 2.03 to 19.94), total cholesterol (k = 6; MD 6.86 mg/dL, 95% CI 2.60 to 11.11), and total cholesterol-to-high-density lipoprotein cholesterol (HDL-C) ratio (k = 3; MD 0.76, 95% CI 0.11 to 1.42). Associations with fasting glucose, diabetes, low-density lipoprotein cholesterol (LDL-C), HDL-C, fasting insulin, homeostatic model assessment of insulin resistance, and blood pressure were uncertain. Hard clinical outcomes were sparse, and two of three longitudinal studies had high risk of bias.Conclusion Among women with normal BMI, excess adiposity is associated with a less favorable cardiometabolic phenotype, most consistently metabolic syndrome and selected lipid measures. Evidence for diabetes, blood pressure, cardiovascular events, mortality, cancer, and reproductive or functional outcomes remains limited. Standardized NWO definitions and prospective female-specific studies are needed. (PROSPERO: CRD420261408853).
SN - 2667-3681
ER -