Conventional risk factors tend to coexist with high TG–low HDL-C levels.

In an observational cohort study of 2906 men aged 53 to 74 years free of IHD at baseline, we tested the hypothesis that subjects with conventional risk factors would still have a low risk of IHD if they had low TG–high HDL-C levels.

During 8 years, 229 subjects developed IHD. Stratified by conventional risk factors, such as:

• low-density lipoprotein cholesterol level ( 4.40 mmol/L or >4.40 mmol/L [ 170 mg/dL or >170 mg/dL] [median value]),
• hypertensive status (blood pressure >150/100 mm Hg or taking medication),
• level of physical activity (>4 h/wk or 4 h/wk), and
• smoking status (nonsmokers vs smokers) -

The incidence in men with high TG–low HDL-C levels was:

• 9.8% to 12.2% in the low-risk and
• 12.2% to 16.4% in the high-risk strata.

The corresponding values in men with low TG–high HDL-C concentrations were:

• 4.0% to 5.1% and
• 3.7% to 5.3%, respectively.

Based on an estimate of attributable risk, 35% of IHD might have been prevented if all subjects had had low TG–high HDL-C levels.

Conclusion:
Men with conventional risk factors for IHD have a low risk of IHD if they have low TG–high HDL-C levels.

These Danish researchers studied the interaction between HDL and TG in 2906 men (age range, 53 to 74) without clinical evidence of CAD at baseline. Only 2 percent of participants had diabetes.

Participants were divided into 3 groups:

1) high TG ( 142 mg/dL) plus low HDL ( 46 mg/dL);
2) low TG ( 97 mg/dL) plus high HDL ( 57 mg/dL); and
3) intermediate (fitting into neither group 1 nor group 2).

During 8 years of follow-up, 229 men had a first CAD event; about 25 percent of those events were fatal.

The crude cumulative incidence of CAD events was:

• 5 percent in the low-TG plus high-HDL group,
• 7 percent in the intermediate group, and
• 12 percent in the high-TG plus low-HDL group.

High TG plus low HDL conferred a significantly increased risk for CAD events after adjustment for other risk factors, including LDL level.

These researchers, however, did not tease apart the independent contributions of LDL, HDL, and TG; in addition, the prevalence of type 2 diabetes was surprisingly low (3 percent) in the high-TG plus low-HDL group.>

Although primary prevention studies focused on the high-TG plus low-HDL combination (independent of LDL) have not been done, the findings here suggest that aggressive risk factor modification might be beneficial in this high-risk patient subset.