The JELIS Trial

The Japan eicosapentaenoic acid (EPA) Lipid Intervention Study (JELIS) is a clinical trial that all Track Your Plaquers should know about.

This enormous trial followed a simple design:

Japanese men, between 40-75 years, and Japanese postmenopausal women aged <75 years with total cholesterol 250 mg/dl or greater were enrolled. A total of 18,645 subjects (mean age, 61 years; 31% male) participated: 36% had hypertension, 15% had diabetes, and 20% had coronary disease (history of heart attack or heart procedure). Average starting total cholesterol 275 mg/dl; LDL 180 mg/dl. All participants were treated with pravastatin 10 mg/day or simvastatin 5 mg/day; approximately half also received the omega-3, EPA, 1800 mg/day, in addition to one of the statin drugs.

Treatment resulted in an average LDL reduction of 26% in all participants; the group taking EPA experienced an additional 10% reduction in triglycerides. All major cardiovascular events were tracked and tabulated, including sudden cardiac death, fatal or nonfatal myocardial infarction (MI), unstable angina pectoris, coronary artery bypass surgery, and coronary angioplasty.

After nearly five years, 3.5% of statin-only participants experienced an event; 2.8% of statin + EPA experienced an event. The (often misleading and frequently abused value) "relative reduction" was therefore 19%.

There are several features that make the JELIS trial interesting:

--There were an unusually low number of cardiovascular events in the entire group, lower than nearly all American and European trials of similar design. This likely points to the greater burden of atherosclerotic heart disease in the U.S. compared to Japan. Rates in comparable U.S.-based trials usually range from 6-14%, sometimes more.

--Both the participants without identified heart disease at enrollment and those with heart disease at enrollment obtained a similar magnitude of beneficial reduction in cardiovascular events.

--There was an unusual preponderance of women--69%--unlike most other trials of cardiovascular events. We might therefore argue that JELIS most conclusively showed that benefits of EPA are most confidently demonstrated for females.

--A fish oil preparation containing only EPA was used, rather than the usual EPA + DHA. There are discussions from some corners that argue that DHA is more important than EPA, e.g., algae sources. However, JELIS would argue that EPA does play a role. Is EPA with DHA better, worse, or no different? Unfortunately, there are insufficient data--large, randomized data like JELIS--to help us. Recall that GISSI Prevenzione used a combination of EPA and DHA, as have virtually all other trials examining the effects of fish oil. Also, keep in mind that the epidemiologic observations of the cardiovascular benefits of eating fish suggest that the naturally-sourced omega-3s--a combination of EPA and DHA--are associated with benefit.

--It's surprising that any difference at all was demonstrated, given the high intake of fish in the Japanese. In fact, blood levels of EPA in participants before taking EPA was five-fold higher than in western populations.

One potential difficulty: The study was funded by the manufacturer of the EPA preparation used, Mochida Pharmaceutical Company. We all know what that can do to results.

Nonetheless, the JELIS trial is a study that adds to the emerging wisdom in fish oil.