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body mass index (BMI)

BMI = mass in kg/ height in m2 (weight (mass) in kg divided by square of height in meters) Reference interval: BMI: 22-25 kg/m2 = normal BMI: 27-30 kg/m2 = mild obesity BMI: 30-35 kg/m2 = moderate obesity BMI: 35-40 kg/m2 = severe obesity BMI: >40 kg/m2 = morbid obesity A BMI calculator is available on the internet [3] waist/hip ratio may be a better predictor of cardiovascular risk Indications: - health maintenance assessment - evaluation of obesity - evaluation of malnutrition Pathology: - low & high body mass index associated with increased mortality [4] - including elderly > 65 years of age, i.e. U-shaped mortality vs BMI - for BMI > 25, every 5-unit increase in BMI translates to: a) 30% increased risk for all-cause mortality b) 40% higher risk for death from cardiovascular disease c) 60-120% increase in mortality due to renal disease, liver disease or diabetes mellitus d) 10% increased risk for cancer-related deaths - lower BMI associated with higher mortality after adjustment for adiposity [11] - for BMI < 22, increased mortality is partly due to smoking - overweight in midlife, compared with normal BMI, is associated with greater long-term morbidity, but similar longevity [16] Risk of all-cause mortality by BMI [5] BMI Hazzard Ratio 15.0-18.4.............. 1.5 18.5-19.9.............. 1.1 20.0-22.4.............. 1.0 22.5-24.9.............. 1.0 25.0-29.9.............. 1.1 30.0-34.9.............. 1.4 35.0-39.9.............. 1.9 40.0-49.9.............. 2.5 Different studies reach different conclusions: - BMI 25-30 associated with lower mortality than BMI 18.5-25 kg/m2 (RR 0.76) & BMI 30-34 not associated with increased mortality [6,7] - in the elderly, obesity may be paradoxically associated with a lower, not higher, mortality risk [10] - BMI with lowest all-cause mortality in Danish increased from 23.7 in 1976-1978 to 27.0 in 2003-2013 [12] - Mortality rates lowest for BMIs between 27-29 kg/m2 [15] Genetics: - genetic variation in PPARG may influence body mass index - genetic variations in FFAR4 define the body mass index quantitative trait locus 10 (BMIQ10) [8] Notes: - post-menopausal women with normal BMI may be overweight [14]

Related

body mass index quantitative trait locus (BMIQ) body roundness index ideal body weight (IBW)

General

index

Database Correlations

OMIM correlations

References

  1. Guide to Ambulatory Care, Brian Yee, Bristol Meyers Squibb, 1997
  2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 693-94
  3. BMI calculator http://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm
  4. Prospective Studies Collaboration Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies The Lancet 2009, Vol 373:(9669)1083-1096 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)60318-4/abstract
  5. Berrington de Gonzalez A et al Body-Mass Index and Mortality among 1.46 Million White Adults N Engl J Med. 2010 Dec 2;363(23):2211-9. PMID: 21121834 http://www.nejm.org/doi/full/10.1056/NEJMoa1000367
  6. Beleigoli AM et al Overweight and class I obesity are associated with lower 10-year risk of mortality in brazilian older adults: the bambui cohort study of ageing. PLoS One. 2012;7(12):e52111 PMID: 23251690
  7. Flegal KM et al Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis. JAMA. 2013 Jan 2;309(1):71-82 PMID: 23280227 - Heymsfield SB, Cefalu WT. Does body mass index adequately convey a patient's mortality risk? PMID: 23280230
  8. OMIM :accession 607514
  9. Cereda E, Pedrolli C, Zagami A et al Body mass index and mortality in institutionalized elderly. J Am Med Dir Assoc. 2011 Mar;12(3):174-8. PMID: 21333917
  10. Oreopoulos A, Kalantar-Zadeh K, Sharma AM, Fonarow GC. The obesity paradox in the elderly: potential mechanisms and clinical implications. Clin Geriatr Med. 2009 Nov;25(4):643-59, viii. Review. PMID: 19944265
  11. Padwal R, Leslie WD, Lix LM, Majumdar SR. Relationship among body fat percentage, body mass index, and all-cause mortality: A cohort study. Ann Intern Med 2016 Mar 8; PMID: 26954388
  12. Afzal S, Tybjaerg-Hansen A, Jensen GB, Nordestgaard BG, Change in Body Mass Index Associated With Lowest Mortality in Denmark, 1976-2013 JAMA. 2016;315(18):1989-1996. PMID: 27163987
  13. World Health Organization (WHO) Global Database on Body Mass Index http://apps.who.int/bmi/index.jsp?introPage=intro_3.html
  14. Rubin R Postmenopausal Women With a "Normal" BMI Might Be Overweight or Even Obese. JAMA. Published online March 7, 2018 PMID: 29516084 https://jamanetwork.com/journals/jama/fullarticle/2674709
  15. Talebraza S et al Geriatrics Evaluation & Management Tools American Geriatrics Society. 2021 https://geriatricscareonline.org/ProductAbstract/geriatrics-evaluation-management-tools/B007/
  16. Khan SS, Krefman AE, Zhao L et al Association of Body Mass Index in Midlife With Morbidity Burden in Older Adulthood and Longevity. JAMA Netw Open. 2022;5(3):e222318 PMID: 35289856 PMCID: PMC8924714 Free PMC article https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2790100
  17. Winter JE, MacInnis RJ, Wattanapenpaiboon N, Nowson CA. BMI and all-cause mortality in older adults: a meta-analysis. Am J Clin Nutr 2014;99(4):875-890 PMID: 24452240