title: Lower obesity rate during residence at high altitude among a military population with frequent migration: a quasi experimental model for investigating spatial causation.
abstract: We sought to evaluate whether residence at high altitude is associated with the development of obesity among those at increased risk of becoming obese. Obesity, a leading global health priority, is often refractory to care. A potentially novel intervention is hypoxia, which has demonstrated positive long-term metabolic effects in rats. Whether or not high altitude residence confers benefit in humans, however, remains unknown. Using a quasi-experimental, retrospective study design, we observed all outpatient medical encounters for overweight active component enlisted service members in the U.S. Army or Air Force from January 2006 to December 2012 who were stationed in the United States. We compared high altitude (>1.96 kilometers above sea level) duty assignment with low altitude (<0.98 kilometers). The outcome of interest was obesity related ICD-9 codes (278.00-01, V85.3x-V85.54) by Cox regression. We found service members had a lower hazard ratio (HR) of incident obesity diagnosis if stationed at high altitude as compared to low altitude (HR 0.59, 95% confidence interval [CI] 0.54-0.65; p<0.001). Using geographic distribution of obesity prevalence among civilians throughout the U.S. as a covariate (as measured by the Centers for Disease Control and Prevention and the REGARDS study) also predicted obesity onset among service members. In conclusion, high altitude residence predicts lower rates of new obesity diagnoses among overweight service members in the U.S. Army and Air Force. Future studies should assign exposure using randomization, clarify the mechanism(s) of this relationship, and assess the net balance of harms and benefits of high altitude on obesity prevention.
authors.affiliation: Epidemiology Consult Division, US Air Force School of Aerospace Medicine, Wright Patterson Air Force Base, Ohio, United States of America; Department of Preventive Medicine, Uniformed Services University, Bethesda, Maryland, United States of America.
authors.forename: Jameson D
authors.initials: JD
authors.lastname: Voss
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America; Nutrition and Obesity Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
authors.forename: David B
authors.initials: DB
authors.lastname: Allison
authors.affiliation: Department of Preventive Medicine, Uniformed Services University, Bethesda, Maryland, United States of America; Trainee Health Surveillance, Joint Base San Antonio - Lackland, Lackland, Texas, United States of America.
authors.forename: Bryant J
authors.initials: BJ
authors.lastname: Webber
authors.affiliation: Armed Forces Health Surveillance Center, Silver Spring, Maryland, United States of America; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, United States of America.
authors.forename: Jean L
authors.initials: JL
authors.lastname: Otto
authors.affiliation: Armed Forces Health Surveillance Center, Silver Spring, Maryland, United States of America; General Dynamics Information Technology, Fairfax, Virginia, United States of America.
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Clark
mesh_terms: D000531:Altitude; D005843:Geography; D006801:Humans; D008889:Military Personnel; D009765:Obesity / Q000453:epidemiology*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States
references.citation: Eur J Pharmacol. 1986 Aug 15;127(3):225-31
references.pmid: 3758181
references.citation: Int J Obes (Lond). 2013 Oct;37(10):1407-12
references.pmid: 23357956
references.citation: J Appl Physiol (1985). 2008 Nov;105(5):1684-5
references.pmid: 18276896
references.citation: Diabetes Care. 2013 Feb;36(2):309-15
references.pmid: 22961568
references.citation: Int J Environ Res Public Health. 2010 Apr;7(4):1670-80
references.pmid: 20617052
references.citation: High Alt Med Biol. 2002 Spring;3(1):49-57
references.pmid: 12006164
references.citation: Eur J Nutr. 2013 Mar;52(2):625-35
references.pmid: 22573211
references.citation: High Alt Med Biol. 2006 Spring;7(1):47-53
references.pmid: 16544966
references.citation: J Addict Med. 2012 Jun;6(2):166-71
references.pmid: 22531819
references.citation: Nutr Neurosci. 2005 Jun;8(3):161-5
references.pmid: 16117183
references.citation: JAMA. 2013 Mar 13;309(10):1014-21
references.pmid: 23483176
references.citation: Eur J Gastroenterol Hepatol. 2006 Jan;18(1):5-10
references.pmid: 16357612
references.citation: Respir Care. 2006 Feb;51(2):126-32
references.pmid: 16441956
references.citation: Obesity (Silver Spring). 2014 Jan;22(1):300-6
references.pmid: 23512879
references.citation: Health Econ. 2012 Nov;21(11):1348-66
references.pmid: 21971919
references.citation: Growth Dev Aging. 2005 Winter;69(2):81-8
references.pmid: 16671587
references.citation: Obesity (Silver Spring). 2010 Apr;18(4):675-81
references.pmid: 20134417
references.citation: Med Hypotheses. 2010 May;74(5):901-7
references.pmid: 19913361
references.citation: N Engl J Med. 2007 Jul 26;357(4):370-9
references.pmid: 17652652
references.citation: Int J Obes (Lond). 2014 Jan;38(1):132-9
references.pmid: 23689359
references.citation: Am J Clin Nutr. 2011 Mar;93(3):608-14
references.pmid: 21248187
references.citation: J Appl Physiol (1985). 2012 Feb;112(4):552-9
references.pmid: 22114179
references.citation: J Clin Invest. 2012 Oct;122(10):3529-40
references.pmid: 22996660
references.citation: J Appl Physiol. 1966 Nov;21(6):1741-6
references.pmid: 5929298
references.citation: J Am Soc Nephrol. 2008 Jul;19(7):1389-95
references.pmid: 18385423
references.citation: Nat Commun. 2011 Nov 01;2:520
references.pmid: 22044999
references.citation: N Engl J Med. 2008 May 22;358(21):2249-58
references.pmid: 18499567
references.citation: MSMR. 2011 Jun;18(6):2-6
references.pmid: 21793619
references.citation: Int J Obes (Lond). 2012 Feb;36(2):244-53
references.pmid: 21467998
references.citation: Biochim Biophys Acta. 2012 Jul;1822(7):1090-5
references.pmid: 22504298
references.citation: J Nutr. 1971 Jun;101(6):787-96
references.pmid: 5280928
references.citation: Lancet. 1998 Oct 3;352(9134):1119-20
references.pmid: 9798594
references.citation: High Alt Med Biol. 2010 Summer;11(2):111-9
references.pmid: 20586595
references.citation: FEBS Open Bio. 2012 May 24;2:113-8
references.pmid: 23650589
references.citation: Obes Rev. 2013 Jul;14(7):579-92
references.pmid: 23551535
references.citation: High Alt Med Biol. 2013 Mar;14(1):45-52
references.pmid: 23537260
references.citation: J Appl Physiol (1985). 1989 Mar;66(3):1430-5
references.pmid: 2651390
references.citation: Obesity (Silver Spring). 2012 Jul;20(7):1534-8
references.pmid: 22314620
references.citation: Am J Physiol Endocrinol Metab. 2010 Jun;298(6):E1140-9
references.pmid: 20215574
references.citation: Sheng Li Xue Bao. 2010 Dec 25;62(6):541-6
references.pmid: 21170501
references.citation: Korean J Intern Med. 2013 Mar;28(2):123-40
references.pmid: 23525151
references.citation: Anthropol Anz. 2008 Dec;66(4):419-34
references.pmid: 19216182
references.citation: J Appl Physiol (1985). 1999 Jul;87(1):391-9
references.pmid: 10409600
references.citation: Annu Rev Psychol. 2009;60:607-29
references.pmid: 18616391
references.citation: Am J Physiol Endocrinol Metab. 2006 Jun;290(6):E1078-88
references.pmid: 16380390
references.citation: Am J Health Promot. 2007 Nov-Dec;22(2):120-39
references.pmid: 18019889
references.citation: Physiol Genomics. 2010 May;41(3):275-88
references.pmid: 20103700
references.citation: Acta Physiol Pharmacol Latinoam. 1985;35(3):311-8
references.pmid: 2938414
references.citation: Sleep Breath. 2014 Sep;18(3):591-7
references.pmid: 24318688
references.citation: Arch Argent Pediatr. 2013 Dec;111(6):516-22
references.pmid: 24196765
references.citation: Sleep Breath. 2008 May;12(2):129-34
references.pmid: 18057976
references.citation: J Biol Chem. 2002 Nov 8;277(45):42953-7
references.pmid: 12215445
references.citation: PLoS One. 2013;8(2):e55234
references.pmid: 23418436
references.citation: High Alt Med Biol. 2000 Spring;1(1):9-23
references.pmid: 11258590
references.citation: Acta Physiol Pharmacol Ther Latinoam. 1995;45(1):9-14
references.pmid: 8580521
references.citation: Int Arch Occup Environ Health. 1990;62(6):459-66
references.pmid: 2246065
references.citation: High Alt Med Biol. 2011 Spring;12(1):31-5
references.pmid: 21214344
references.citation: Chin J Physiol. 2013 Feb 28;56(1):18-25
references.pmid: 23347012
references.citation: Am J Prev Med. 2011 Jun;40(6):637-44
references.pmid: 21565657
references.citation: Obesity (Silver Spring). 2014 Feb;22(2):311-7
references.pmid: 23625659
references.citation: PLoS One. 2010 Jul 13;5(7):e11565
references.pmid: 20644637
references.citation: Curr Opin Endocrinol Diabetes Obes. 2011 Oct;18(5):328-31
references.pmid: 21543976
references.citation: Ann Intern Med. 2003 Aug 19;139(4):253-7
references.pmid: 12965980