Metabolically healthy obesity (MHO) is a disputed[1] medical condition characterized by obesity which does not produce metabolic complications.[2]
No universally accepted criteria exist to define putative MHO,[2] but definitions generally require the patient to be obese and to lack metabolic abnormalities such as dyslipidemia, impaired glucose tolerance,[1] or metabolic syndrome.[3]
MHO individuals display less visceral adipose tissue, smaller adipocytes, and a reduced inflammatory profile relative to metabolically unhealthy obese individuals.[3][4][5] As a result, it has been argued that cardiometabolic risk might not improve significantly as a result of weight loss interventions.[6]
Prevalence estimates of MHO have varied from 6 to 75 percent,[7] and it has been argued that between 10 and 25 percent of obese individuals are metabolically healthy.[8] One study found that 47.9% of obese people had MHO, while another found that 11% did.[3] It seems to be more prevalent in women than men, and its prevalence decreases with age.[9][10]
Some research suggests that metabolically healthy obese individuals are at an increased risk of several adverse outcomes when compared to individuals of a normal weight, including type 2 diabetes,[11] depressive symptoms,[12] and cardiovascular events.[13][14] Other research also suggests that although MHO individuals display a favorable metabolic profile, this does not necessarily translate into a decrease in mortality.[15] Research to date has produced conflicting results with respect to cardiovascular disease and mortality.[16] MHO individuals are at a higher risk of cardiovascular disease compared to metabolically healthy non-obese individuals, but they are also at a lower risk thereof than individuals who are both unhealthy and obese.[17][18] A 2016 meta-analysis found that MHO individuals were not at an increased risk of all-cause mortality (but were at an increased risk of cardiovascular events).[19] The relatively low risk of cardiovascular disease among people with MHO relative to metabolically unhealthy obese people has been attributed to differences in white adipose tissue function between the two groups.[20]
Stefan, Norbert; Häring, Hans-Ulrich; Hu, Frank B; Schulze, Matthias B (October 2013). "Metabolically healthy obesity: epidemiology, mechanisms, and clinical implications". The Lancet Diabetes & Endocrinology. 1 (2): 152–162. doi:10.1016/S2213-8587(13)70062-7. PMID 24622321.
Navarro, Estanislau; Funtikova, Anna N.; Fíto, Montserrat; Schröder, Helmut (November 2014). "Can Metabolically Healthy Obesity be explained by diet, genetics and inflammation?". Molecular Nutrition & Food Research. 59 (1): 75–93. doi:10.1002/mnfr.201400521. PMID 25418549.
Rey-López, JP; de Rezende, LF; Pastor-Valero, M; Tess, BH (October 2014). "The prevalence of metabolically healthy obesity: a systematic review and critical evaluation of the definitions used". Obesity Reviews. 15 (10): 781–90. doi:10.1111/obr.12198. PMID 25040597. S2CID 825441.
Blüher, Susann; Schwarz, Peter (September 2014). "Metabolically healthy obesity from childhood to adulthood — Does weight status alone matter?". Metabolism. 63 (9): 1084–1092. doi:10.1016/j.metabol.2014.06.009. PMID 25038727.
van Vliet-Ostaptchouk, Jana V; Nuotio, Marja-Liisa; Slagter, Sandra N; Doiron, Dany; Fischer, Krista; Foco, Luisa; Gaye, Amadou; Gögele, Martin; Heier, Margit; Hiekkalinna, Tero; Joensuu, Anni; Newby, Christopher; Pang, Chao; Partinen, Eemil; Reischl, Eva; Schwienbacher, Christine; Tammesoo, Mari-Liis; Swertz, Morris A; Burton, Paul; Ferretti, Vincent; Fortier, Isabel; Giepmans, Lisette; Harris, Jennifer R; Hillege, Hans L; Holmen, Jostein; Jula, Antti; Kootstra-Ros, Jenny E; Kvaløy, Kirsti; Holmen, Turid; Männistö, Satu; Metspalu, Andres; Midthjell, Kristian; Murtagh, Madeleine J; Peters, Annette; Pramstaller, Peter P; Saaristo, Timo; Salomaa, Veikko; Stolk, Ronald P; Uusitupa, Matti; van der Harst, Pim; van der Klauw, Melanie M; Waldenberger, Melanie; Perola, Markus; Wolffenbuttel, Bruce HR (2014). "The prevalence of metabolic syndrome and metabolically healthy obesity in Europe: a collaborative analysis of ten large cohort studies". BMC Endocrine Disorders. 14 (1): 9. doi:10.1186/1472-6823-14-9. PMC 3923238. PMID 24484869.
Eckel, Nathalie; Meidtner, Karina; Kalle-Uhlmann, Tamara; Stefan, Norbert; Schulze, Matthias B (2016). "Metabolically healthy obesity and cardiovascular events: A systematic review and meta-analysis". European Journal of Preventive Cardiology. 23 (9): 956–966. doi:10.1177/2047487315623884. PMID 26701871. S2CID 6085134.
Primeau, V; Coderre, L; Karelis, A D; Brochu, M; Lavoie, M-E; Messier, V; Sladek, R; Rabasa-Lhoret, R (26 October 2010). "Characterizing the profile of obese patients who are metabolically healthy". International Journal of Obesity. 35 (7): 971–981. doi:10.1038/ijo.2010.216. PMID 20975726.
Roberson, Lara L; Aneni, Ehimen C; Maziak, Wasim; Agatston, Arthur; Feldman, Theodore; Rouseff, Maribeth; Tran, Thinh; Blaha, Michael J; Santos, Raul D; Sposito, Andrei; Al-Mallah, Mouaz H; Blankstein, Ron; Budoff, Matthew J; Nasir, Khurram (2014). "Beyond BMI: The "Metabolically healthy obese" phenotype & its association with clinical/subclinical cardiovascular disease and all-cause mortality -- a systematic review". BMC Public Health. 14 (1): 14. doi:10.1186/1471-2458-14-14. PMC 3890499. PMID 24400816.
Fan, Jingyao; Song, Yiqing; Chen, Yu; Hui, Rutai; Zhang, Weili (October 2013). "Combined effect of obesity and cardio-metabolic abnormality on the risk of cardiovascular disease: A meta-analysis of prospective cohort studies". International Journal of Cardiology. 168 (5): 4761–4768. doi:10.1016/j.ijcard.2013.07.230. PMID 23972953.
Zheng, R; Zhou, D; Zhu, Y (28 April 2016). "The long-term prognosis of cardiovascular disease and all-cause mortality for metabolically healthy obesity: a systematic review and meta-analysis". Journal of Epidemiology and Community Health. 70 (10): 1024–1031. doi:10.1136/jech-2015-206948. PMID 27126492. S2CID 21145367.