Role of bone mineral density in the inverse relationship between body size and aortic calcification: results from the Baltimore Longitudinal Study of Aging.
OBJECTIVE
There is a J-shaped relationship between body mass index (BMI) and cardiovascular outcomes in elderly patients (obesity paradox). Whether low BMI correlates with aortic calcification (AC) and whether this association is accounted for by bone demineralization is uncertain.


METHODS
Presence of AC was evaluated in 687 community-dwelling individuals (49% male, mean age 67 ± 13 years) using CT images of the thoracic, upper and lower abdominal aorta, and scored from 0 to 3 according to number of sites that showed any calcification. Whole-body bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry. Predictors of AC were assessed by logistic regression, and the role of BMD using mediation analysis.


RESULTS
Age and cardiovascular risk factors were positively associated while both BMI (r = -0.11, p < 0.01) and BMD (r = -0.17, p < 0.0001) were negatively associated with AC severity. In multivariate models, lower BMI (OR 0.96, 95%CI 0.92-0.99, p = 0.01), older age, higher systolic blood pressure, use of lipid-lowering drugs and smoking were independent predictors of AC. A nonlinear relationship between BMI and AC was noticed (p = 0.03), with decreased AC severity among overweight participants. After adjusting for BMD, the coefficient relating BMI to AC was reduced by 14% and was no longer significant, whereas BMD remained negatively associated with AC (OR 0.82, 95%CI 0.069-0.96, p = 0.01), with a trend for a stronger relationship in older participants.


CONCLUSIONS
Low BMI is associated with increased AC, possibly through calcium mobilization from bone, resulting in low BMD. Prevention of weight loss and bone demineralization with aging may help reducing AC.
Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD, USA; Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, NIA/NIH, Baltimore, MD, USA; Department of Internal Medicine, University of Genova, Genova, Italy. Electronic address: marco.canepa@unige.it.
Marco
M
Canepa
Department of Internal Medicine, University of Genova, Genova, Italy.
Pietro
P
Ameri
Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD, USA; Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, NIA/NIH, Baltimore, MD, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Majd
M
AlGhatrif
Department of Internal Medicine, University of Genova, Genova, Italy.
Gabriele
G
Pestelli
Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD, USA; Department of Psychiatry, VU University Medical Center/GGZ inGeest, Amsterdam, The Netherlands.
Yuri
Y
Milaneschi
Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, NIA/NIH, Baltimore, MD, USA.
James B
JB
Strait
Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD, USA.
Francesco
F
Giallauria
Department of Internal Medicine, University of Genova, Genova, Italy.
Giorgio
G
Ghigliotti
Department of Internal Medicine, University of Genova, Genova, Italy.
Claudio
C
Brunelli
Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, NIA/NIH, Baltimore, MD, USA.
Edward G
EG
Lakatta
Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD, USA.
Luigi
L
Ferrucci
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001011:Aorta / Q000503:physiopathology*; D015142:Baltimore; D015992:Body Mass Index; D049628:Body Size; D001835:Body Weight; D015519:Bone Density; D002114:Calcinosis / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000097:blood; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed
Aortic calcification; Body mass index; Body size; Bone mineral density; Calcification paradox; Obesity paradox