Summary

Men with a heart attack risk factor are still at relatively low risk when the HDL-cholesterol level is high and the triglyceride (TG) level low, according to results of a Danish study. Almost 3000 men took part in the 8-year study in which a heart attack occurred in 229 men. The authors conclude that even if a major risk factor for heart attack is present, the risk is still low providing the TG level is low and the HDL-C level is high. The study says measurement of TG and HDL-C levels should always be included in screening tests. Dietary advice (plus the usual advice on smoking and checking for high blood pressure) may be sufficient for those with high cholesterol levels but low TG and high HDL-C levels.
Jeppesen J, et al. Archives of Internal Medicine 161:361-6, 12 Feb 2001

Study details

According to results of a Danish study, when the HDL-C level is high and the triglyceride (TG) level low, men with conventional risk factors for CHD still have a relatively low risk of a CHD event. The Copenhagen Male Study published in 1998 showed that a high triglyceride and low HDL-C level conferred a high risk of a CHD event, and the opposite a low risk. Conventional CHD risk factors tend to coexist with high TG and low HDL-C levels. A study was undertaken to determine CHD risk of men with traditional risk factors but low TG and high HDL-C levels. Participants were males aged a mean of 63 years in 1985-6 without evidence of CHD (n=3387). In total, 2906 were randomised. A high TG level was defined as =1.6 mmol/L and a low HDL-C level was that under 1.18 mmol/L. A low TG level was below 1.09 mmol/L and a high HDL-C was above 1.48 mmol/L. A first CHD event occurred in 229 men during eight years of follow-up. Overall, CHD occurred in 4.5 per cent of those with low TG and high HDL-C versus 12.2 per cent of those with high TG and low HDL-C, a significant difference.

A high TG and low HDL-C was associated with an odds ratio of 1.6 and conferred greater risk than any of the conventional risk factors. A low TG and high HDL-C level was associated with a significant reduction in the odds of a CHD event (OR=0.6). With each of the major CHD risk factors, a clear gradient of risk was apparent, being low with the low TG-high HDL-C group and two- to three-fold higher with the high TG-low HDL-C scenario. Risk of a CHD event was 5 per cent or less in those with conventional risk factors but low TG and high HDL-C. In patients with a high LDL-C level but low TG-high HDL, risk of a CHD event was much lower than in those with low LDL-C but high TG-low HDL-C.

The authors calculated that one-third of the CHD events could have been avoided if all men were part of the low TG-high HDL-C group. It appears that a low TG-high HDL-C level is a stronger CHD risk factor than the major conventional risk factors, and even if a major risk factor is present, risk of a CHD event is still low providing TG level is low and HDL-C level is high. Those with high TG and low HDL-C levels often display aspects of the metabolic syndrome, ie, insulin resistance, glucose intolerance and hypertension. In these people the LDL particle tends to be smaller and more atherogenic, as are the TG-rich lipoproteins. Moreover, high TG and low HDL-C is associated with poor fibrinolysis. Another study from the West of Scotland produced similar findings: middle-aged men with hypercholesterolaemia alone had a 5 per cent 5-year risk of CHD whereas those with the metabolic syndrome had a 14 per cent event rate. "Measurement of TG and HDL-C levels should always be included in screening tests". Be mindful of the metabolic syndrome, and individuals with this disorder should undergo lifestyle modification (weight loss, low fat diet, exercise) and be considered for fibrate and statin therapy.

Dietary advice (plus the usual advice on smoking and checking for hypertension) may be sufficient for those with high cholesterol levels but low TG-high HDL-C.
Jeppesen J, et al. Archives of Internal Medicine 161:361-6, 12 Feb 2001

Originally posted week beginning 13 March 2001

Disclaimer

This is a summary article from MedALERT, a clinical journal review service written by Dr Peter Louisson (MB ChB). Originally selected to inform General Practitioners, knowledgeable New Zealand health consumers may also find this article useful. This information is intended solely for New Zealand residents and is of a general nature only and no person should act in reliance on any statement contained in the information provided and at all times should obtain specific advice from a health professional. All rights reserved. © UBM Medica (NZ) Ltd. This publication is copyright.