The Metabolic Syndrome, Circulating Oxidized LDL, and Risk of Myocardial Infarction in Well-Functioning Elderly People in the Health, Aging, and Body Composition Cohort

Pathophysiology

¹Center for Experimental Surgery and Anesthesiology, Catholic University, Leuven, Belgium
²J. Paul Sticht Center on Aging, Wake Forest University Health Sciences, Winston-Salem, North Carolina
³Department of Pathology, University of Vermont, Burlington, Vermont
⁴Department of Biochemistry, University of Vermont, Burlington, Vermont
⁵Prevention Sciences Group, University of California, San Francisco, California
⁶Vanderbilt University, Nashville, Tennessee
⁷Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
⁸Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, National Institutes of Health, Bethesda, Maryland

Address correspondence and reprint requests to Paul Holvoet, PhD, Center for Experimental Surgery and Anesthesiology, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium. E-mail: paul.holvoet{at}med.kuleuven.ac.be

Article Figures & Tables

TABLE 1

Characteristics of the study cohort

	Total population	Subjects without metabolic syndrome	Subjects with metabolic syndrome	P
n	3,033	1,886	1,147	—
Age (years)	74 ± 2.9	74 ± 2.9	74 ± 2.8	NS
Male (%)	48	52	42	<0.0001
African American (%)	42	42	41	NS
BMI (kg/m²)	27 ± 4.9	27 ± 4.7	29 ± 4.8	<0.0001
Waist circumference (cm)	100 ± 13	98 ± 13	102 ± 12	<0.0001
High blood pressure (%)	39	35	45	<0.0001
Systolic blood pressure (mmHg)	136 ± 21	134 ± 21	139 ± 21	<0.0001
Diastolic blood pressure (mmHg)	71 ± 12	71 ± 12	72 ± 11	NS
Diabetes (%)	19	7	38	<0.0001
Glucose intolerance (%)*	24	9	49	<0.0001
Fasting glucose (mmol/l)	5.83 ± 1.94	5.33 ± 1.28	6.66 ± 2.55	<0.0001
Fasting insulin (units/ml)	8.55 ± 7.52	7.31 ± 5.99	10.90 ± 9.34	<0.0001
HbA_1c (%)	6.37 ± 1.13	6.12 ± 0.83	6.78 ± 1.40	<0.0001
Lipid-lowering drugs (%)	15	13	19	<0.0001
Total cholesterol (mmol/l)	5.25 ± 1.01	5.22 ± 0.096	5.28 ± 1.06	NS
LDL cholesterol (mmol/l)	3.15 ± 0.91	3.15 ± 0.88	3.13 ± 0.93	NS
Low HDL cholesterol (%)	29	10	62	<0.0001
HDL cholesterol (mmol/l)	1.40 ± 0.44	1.53 ± 0.44	1.19 ± 0.36	<0.0001
High triglycerides (%)	30	9.2	66	<0.0001
Triglycerides (mmol/l)	1.56 ± 0.93	1.22 ± 0.48	2.14 ± 1.19	<0.0001
Triglyceride-to-HDL molar ratio	1.31 ± 1.22	0.88 ± 0.50	2.01 ± 1.65	<0.0001
Smoking: former/current (%)	46/10	46/11	46/9.1	NS
Average pack-years among smokers	19 ± 28	19 ± 27	20 ± 21	NS
OxLDL (mg/dl)	1.32 ± 0.74	1.23 ± 0.67	1.45 ± 0.82	<0.0001
OxLDL (% of LDL)	1.09 ± 0.53	1.01 ± 0.46	1.21 ± 0.59	<0.0001

Data are means ± SD. Subjects without and with the metabolic syndrome were compared with the Kruskal-Wallis or χ² test.
*
* Glucose intolerance determined according to American Diabetes Association criteria.

TABLE 2

Logistic regression analysis of the relation between the metabolic syndrome and prevalence of high circulating oxLDL

	Subjects without metabolic syndrome	Subjects with metabolic syndrome
High oxLDL >1.90 mg/dl	1.00 (—)	1.82 (1.49–2.23)
Adjusted for age, sex, ethnicity, and smoking status
Adjusted for age, sex, ethnicity, smoking status, and LDL cholesterol	1.00 (—)	2.01 (1.61–2.52)
High oxLDL >1.58% of LDL, adjusted for age, sex, ethnicity, and smoking status	1.00 (—)	2.56 (2.05–3.20)

Data are OR (95% CI). The ORs for high oxLDL (exceeding the 90th percentile of distribution for subjects without the metabolic syndrome) for those with the metabolic syndrome were determined by logistic regression analysis comparing with subjects without the metabolic syndrome.

TABLE 3

ORs of high oxLDL according to the degree of individual metabolic syndrome components

Metabolic syndrome component	Quintile of metabolic syndrome component
Metabolic syndrome component		1st	2nd	3rd	4th	5th
Waist circumference	1 (—)	1.14 (0.80–1.61)	1.22 (0.86–1.72)	0.99 (0.70–1.41)	1.48 (1.05–2.09)
HDL cholesterol	1 (—)	1.42 (0.96–2.10)	1.88 (1.28–2.78)	2.08 (1.42–3.05)	3.10 (2.06–4.65)
Triglycerides	1 (—)	1.47 (0.95–1.88)	1.34 (0.87–2.07)	1.79 (1.17–2.74)	3.12 (2.06–4.73)
Insulin	1 (—)	0.70 (0.46–1.06)	1.12 (0.75–1.66)	1.75 (1.20–2.56)	1.98 (1.36–2.88)
Glucose	1 (—)	1.11 (0.76–1.62)	1.05 (0.71–1.55)	1.29 (0.90–1.86)	2.03 (1.41–2.92)
Blood pressure	1 (—)	1.03 (0.72–1.49)	1.08 (0.76–1.52)	1.04 (0.73–1.47)	1.27 (0.91–1.78)

Data are OR (95% CI). The ORs and 95% CI for high oxLDL for subjects in the highest quintile (lowest quintile for HDL cholesterol) compared with subjects in the lowest quintile (highest quintile for HDL cholesterol) were obtained by logistic regression analysis and adjusted for age, sex, ethnicity, LDL cholesterol, and smoking status.

TABLE 4

Relative risk of MI according to metabolic syndrome or/and high oxLDL

Data are relative risk ratio (95% CI), determined by logistic regression analysis comparing subjects with to subjects without the metabolic syndrome and/or subjects in higher quintiles to subjects in the lowest quintile of oxLDL.