Genetic and environmental contributions to carotid intima-media thickness and obesity phenotypes in the Northern Manhattan Family Study.
OBJECTIVE
Both carotid intima-media thickness (IMT) and obesity are independent determinants of stroke and cardiovascular disease. The prevalence of obesity is higher in Hispanics. The genetic basis of IMT and obesity has not been well-characterized in Caribbean Hispanics. The purpose of this study was to examine the genetic and environmental contributions to IMT and obesity in this population.


METHODS
The data included 440 subjects from 77 Caribbean Hispanic families. Mean IMT and maximum IMT were measured in the internal carotid artery, common carotid artery, and carotid bifurcation. The total IMT was calculated as the mean value of IMT at all segments. Obesity phenotypes included body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), and skin-fold thickness. Variance component methods were used to estimate age-adjusted and sex-adjusted heritability. Bivariate analyses were conducted to test for genetic and environmental correlations between IMT and obesity.


RESULTS
Heritabilities for IMT ranged from 9% to 40%, with the highest for total maximum IMT and lowest for internal carotid artery maximum IMT. Heritabilities for BMI, waist circumference, WHR, and skin-fold thickness were 44%, 47%, 5%, and 36%, respectively. There were significant genetic, but not environmental, correlations between IMT and BMI, waist circumference, and skin-fold thickness. There were no genetic or environmental correlations between IMT and WHR.


CONCLUSIONS
We found a substantial genetic contribution to IMT, BMI, waist circumference, and skin-fold thickness. Obesity and IMT may share common genetic factors. Future gene mapping studies are warranted to identify genes predisposing to IMT and obesity in this population.
Columbia University Genome Center, Mailman School of Public Health, Columbia University, New York, NY 10032, USA. shj34@columbia.edu
Suh-Hang Hank
SH
Juo
Hsiu-Fen
HF
Lin
Tanja
T
Rundek
Edison A
EA
Sabala
Bernadette
B
Boden-Albala
Naeun
N
Park
Min-Yu
MY
Lan
Ralph L
RL
Sacco
D000328:Adult; D000886:Anthropometry; D017691:Caribbean Region / Q000208:ethnology; D002339:Carotid Arteries / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology* / Q000235:genetics*; D010641:Phenotype; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology; D017539:Tunica Intima / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014463:Ultrasonography