Depression and obesity: do shared genes explain the relationship?
BACKGROUND
Studies have found a modest association between depression and obesity, especially in women. Given the substantial genetic contribution to both depression and obesity, we sought to determine whether shared genetic influences are responsible for the association between these two conditions.


METHODS
Data were obtained from 712 monozygotic and 281 dizygotic female twin pairs who are members of the community-based University of Washington Twin Registry. The presence of depression was determined by self-report of doctor-diagnosed depression. Obesity was defined as body mass index of > or =30 kg/m(2), based on self-reported height and weight. Generalized estimating regression models were used to assess the age-adjusted association between depression and obesity. Univariate and bivariate structural equation models estimated the components of variance attributable to genetic and environmental influences.


RESULTS
We found a modest phenotypic association between depression and obesity (odds ratio=1.6, 95% confidence interval=1.2-2.1). Additive genetic effects contributed substantially to depression (57%) and obesity (81%). The best-fitting bivariate model indicated that 12% of the genetic component of depression is shared with obesity.


CONCLUSIONS
The association between depression and obesity in women may be in part due to shared genetic risk for both conditions. Future studies should examine the genetic, environmental, social, and cultural mechanisms underlying the relationship between this association.
Afari
Niloofar
N
Department of Psychiatry, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0738, USA. nafari@ucsd.edu
Noonan
Carolyn
C
Goldberg
Jack
J
Roy-Byrne
Peter
P
Schur
Ellen
E
Golnari
Golnaz
G
Buchwald
Dedra
D
D000328:Adult; D015992:Body Mass Index; D003863:Depression / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D008957:Models, Genetic; D009765:Obesity / Q000235:genetics*; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*; D014861:Washington; D055815:Young Adult
Twin Res Hum Genet. 2006 Dec;9(6):1023-9
17254446
Science. 2007 May 11;316(5826):889-94
17434869
Obesity (Silver Spring). 2008 Feb;16(2):473-5
18239662
Biol Psychiatry. 2003 Aug 1;54(3):330-7
12893108
Diabetes Care. 2001 Jun;24(6):1069-78
11375373
Ciba Found Symp. 1996;201:108-15; discussion 115-7, 188-93
9017277
Am J Med Sci. 2006 Apr;331(4):166-74
16617231
Ann Endocrinol (Paris). 2000 Dec;61 Suppl 6:24-30
11148333
Handb Exp Pharmacol. 2006;(175):485-524
16722247
Clin Genet. 1983 Aug;24(2):103-12
6577993
J Health Psychol. 2008 Nov;13(8):1190-7
18987092
J Psychosom Res. 2006 Mar;60(3):263-71
16516658
Science. 1996 Nov 29;274(5292):1527-31
8929413
Annu Rev Med. 2003;54:453-71
12414915
Am J Public Health. 1983 Feb;73(2):171-8
6600376
PLoS Genet. 2007 Jul;3(7):e115
17658951
JAMA. 2002 Oct 9;288(14):1723-7
12365955
Am J Psychiatry. 2000 Oct;157(10):1552-62
11007705
Psychiatr Genet. 2009 Feb;19(1):32-8
19125106
Int J Obes (Lond). 2008 Jun;32(6):881-91
18414420
Gen Hosp Psychiatry. 2008 Mar-Apr;30(2):127-37
18291294
Pediatrics. 2001 May;107(5):1049-56
11331685
Neuropsychopharmacology. 2006 Mar;31(3):620-7
16192984
Acta Genet Med Gemellol (Roma). 1979;28(3):225-36
297423
Gen Hosp Psychiatry. 2008 Jan-Feb;30(1):32-9
18164938
Int J Obes Relat Metab Disord. 2004 Mar;28(3):442-6
14724656
Am J Psychiatry. 2006 Jan;163(1):109-14
16390897
Nature. 2000 Apr 6;404(6778):644-51
10766251
Am J Med Genet B Neuropsychiatr Genet. 2003 Jan 1;116B(1):103-25
12497624
BMC Med Res Methodol. 2007 Apr 30;7:17
17470289
Arch Intern Med. 2001 Jul 23;161(14):1725-30
11485505
Science. 2003 Jul 18;301(5631):386-9
12869766
Am J Geriatr Psychiatry. 2007 Sep;15(9):815-25
17804833
Eur J Neurol. 2001 Jul;8(4):315-9
11422427
Biol Psychiatry. 2007 Jan 15;61(2):223-30
16806099
Prev Chronic Dis. 2009 Jan;6(1):A10
19080016
J Am Geriatr Soc. 2001 Jun;49(6):732-6
11454111
Nat Genet. 2009 Jan;41(1):25-34
19079261
Biol Psychiatry. 1998 Aug 1;44(3):151-62
9693387
Brain Behav Immun. 2005 Jul;19(4):275-80
15944067
Mol Psychiatry. 2001 Sep;6(5):579-85
11526472
J Psychosom Res. 1996 Jan;40(1):59-66
8730645
Am J Geriatr Psychiatry. 1999 Spring;7(2):124-31
10322239
Soc Sci Med. 2007 Dec;65(12):2458-63
17761378
Biol Psychiatry. 2005 May 1;57(9):999-1003
15860340
Obesity (Silver Spring). 2006 Apr;14(4):529-644
16741264
Arch Gen Psychiatry. 1994 Jan;51(1):8-19
8279933
Obes Res. 2003 Jun;11(6):802-8
12805402
Epidemiol Rev. 2007;29:49-61
17566051
Obes Res. 2002 Jul;10(7):585-9
12105278
Arch Intern Med. 2000 Jun 26;160(12):1761-8
10871968
Ann Epidemiol. 2008 Jun;18(6):458-66
18329894
Arch Pediatr Adolesc Med. 2000 Sep;154(9):931-5
10980798
Mol Psychiatry. 2008 Aug;13(8):772-85
17938638
Curr Opin Lipidol. 2008 Apr;19(2):113-21
18388690
Eat Weight Disord. 1998 Jun;3(2):71-7
10728153
J Psychosom Res. 1980;24(5):233-41
7205712
Mol Psychiatry. 2006 Oct;11(10):892-902
16880826
Am J Public Health. 2000 Feb;90(2):251-7
10667187
J Affect Disord. 1993 Oct-Nov;29(2-3):85-96
8300981
J Psychosom Res. 1981;25(2):75-82
7277275
Obes Res. 1998 Sep;6 Suppl 2:51S-209S
9813653
Ann Behav Med. 2006 Aug;32(1):68-76
16827631
Psychol Bull. 1995 Jan;117(1):3-20
7870862
Int J Obes Relat Metab Disord. 1992 Dec;16(12):999-1003
1335980
Arch Gen Psychiatry. 2006 Jul;63(7):824-30
16818872
Twin Res Hum Genet. 2005 Aug;8(4):362-7
16176721
Br Med J. 1976 Jan 3;1(6000):7-9
1247732
Int J Obes (Lond). 2008 Mar;32(3):558-66
17895885
Nat Genet. 2009 Jan;41(1):18-24
19079260
J Psychol. 1989 Jul;123(4):385-95
2795495
Clin Genet. 1989 Jun;35(6):423-32
2736790
Int J Obes Relat Metab Disord. 2003 Apr;27(4):514-21
12664085
Neurosci Lett. 2007 Mar 6;414(2):155-8
17258395
Am J Epidemiol. 2003 Dec 15;158(12):1139-47
14652298
Gen Hosp Psychiatry. 2007 Mar-Apr;29(2):147-55
17336664
Am J Epidemiol. 2000 Jul 15;152(2):163-70
10909953