The impact of obesity on the left ventricle: the Multi-Ethnic Study of Atherosclerosis (MESA).
OBJECTIVE
The purpose of this study was to evaluate the relationship of left ventricular (LV) remodeling assessed by cardiac magnetic resonance to various measures of obesity in a large population-based study.


BACKGROUND
Obesity is a well-known risk factor for cardiovascular disease, yet its relationship with LV size and function is poorly understood.


METHODS
A total of 5,098 participants (age 45 to 84 years; 48% men) in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cardiovascular disease underwent cardiac magnetic resonance to assess LV size and function as well as measures of obesity, including body mass index, waist-to-hip ratio and waist circumference, and cardiovascular risk factors. Fat mass (FM) was estimated based on height-weight models derived from bioelectrical impedance studies. The associations of obesity measures with LV size and function were evaluated using linear spline regression models for body mass index and multivariable regression models for other measures of obesity; they were displayed graphically using generalized additive models.


RESULTS
LV mass and end-diastolic volume were positively associated with measures of obesity in both sexes after adjustment for risk factors (e.g., 5.7-g and 6.9-g increase in LV mass per 10-kg increase in FM in women and men, respectively [p < 0.001]). LV mass-to-volume ratio was positively associated with increased body mass index, waist-to-hip ratio, waist circumference, and estimated FM (e.g., 0.02-g/ml and 0.06-g/ml increase in mass-to-volume ratio per 10-kg increase in FM in women and men, respectively [p < 0.001]). The increased mass-to-volume ratio was due to a greater increase in LV mass relative to LV end-diastolic volume. All associations were stronger for men than for women. Ejection fraction showed no significant association with measures of obesity.


CONCLUSIONS
Obesity was associated with concentric LV remodeling without change in ejection fraction in a large, multiethnic cohort study.
Turkbey
Evrim B
EB
Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, Bethesda, Maryland 20892, USA.
McClelland
Robyn L
RL
Kronmal
Richard A
RA
Burke
Gregory L
GL
Bild
Diane E
DE
Tracy
Russell P
RP
Arai
Andrew E
AE
Lima
João A C
JA
Bluemke
David A
DA
D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000208:ethnology / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D015992:Body Mass Index; D005260:Female; D006331:Heart Diseases / Q000208:ethnology / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000208:ethnology / Q000473:pathology / Q000503:physiopathology; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D014481:United States / Q000453:epidemiology; D020257:Ventricular Remodeling; D055105:Waist Circumference; D049629:Waist-Hip Ratio