Download Mozaffarian D, Lemaitre RN, King IB, et al. Circulating long

Mozaffarian D, Lemaitre RN, King IB, et al. Circulating long-chain omega-3 fatty acids and incidence of
congestive heart failure in older adults: The Cardiovascular Health Study. Ann Intern Med. 2011;155(3):160170.
Extensive research suggests that dietary factors such as omega-3-polyunsaturated fatty acids (O-3FA’s) may reduce coronary heart disease (CHD) risk, especially coronary death. However, the effects of O-3FA’s on congestive heart failure (CHF) are less known. The incidence and healthcare costs of CHF are
steadily on the rise. Although it is possible for patients to have both CHD and CHF, many patients with CHD
do not develop CHF, and many older patients with CHF do not have a significant coronary heart disease.
Congestive Heart Failure has serious health consequences including morbidity, mortality, and high health
care costs. Identifying potential targets for preventing CHF is a priority particularly among older adults.
Within American adults aged 65 or over, CHF is the leading cause of all hospitalizations. Omega-3 fatty acids
have demonstrated to effectively reduce the risk of CHF, including effects on ventricular function,
myocardial efficiency, blood pressure, heart rate (HR), arteriolar resistance, endothelial function, blood
lipids, inflammation, and autonomic function. Studies evaluating O-3-FA consumption using dietary
questionnaires to measure CHF incidence have yielded conflicting results. However, circulating O-3-FA
amounts provide impartial biomarkers that show dietary consumption, absorption, incorporation, and
metabolism. Biomarker levels also allow evaluating specific individual fatty acids with different effects, such
as eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA).
In this prospective cohort study in older adults, researchers hypothesized that both total and
individual long-chain fatty acids may reduce the onset of CHF. This was done by evaluating the associations
of EPA, DPA, and DHA as circulating biomarkers, with incident CHF in the Cardiovascular Health Study (CHS).
The CHS (1992-2006) involved 2,735 U.S. adults from 4 major U.S. cities. After 12-hours fasting, blood was
drawn, stored (−70°C), and shipped on dry ice for long-term storage (−80°C). Fatty acids were measured in
2,735 participants from stored blood samples taken at baseline (1992–93). This included randomly selected
blood samples in addition to previously measured fatty acid samples as part of a case-control study of
incident myocardial infarction in CHS.
Phospholipid fatty acids were measured, providing 45 FA measurements as percentage of total FAs.
Standard methods were used to assess other risk factors such as: body mass index, waist circumference,
heart rate, blood pressure, fasting blood lipids, glucose, insulin, fibrinogen and C-reactive protein.
Participants were followed via annual study-clinic examinations including phone contacts. For each
suspected case of incident CHF, pertinent patient information were obtained and reviewed by a CHS
committee who were unaware of participants’ FA status. Confirmation of definite CHF required each of 3
criteria: (1) CHF diagnosis by a physician; (2) either CHF signs and symptoms or clinical findings; and (3)
medical therapy for CHF. Relationships with incident CHF were assessed using Cox proportional-hazards.
After multivariable-adjustment, EPA levels were most strongly associated with lower CHF incidence, with
50% lower risk among individuals in the highest statistical group [hazard ratio (95%CI)=0.52 (0.38–0.72), Ptrend=0.001]. Other trends toward lower risk were seen for DPA [0.76 (0.56–1.04), P-trend=0.057] and total
long-chain fatty acids [0.70 (0.49–0.99); P-trend= 0.062], but not DHA [0.84 (0.58–1.21); P-trend=0.38].
Supportive evidence is reflected in a randomized trial (Yokoyama M et al, 2007), where EPA
supplementation reduced risk of nonfatal coronary events, especially unstable angina. In a recent casecontrol study (Sun Q et al, 2008), EPA and DPA levels had stronger inverse relationships with risk of nonfatal
myocardial infarction than did DHA. These findings combined with current results and those of prior studies
suggest the possibility that EPA and DPA, receiving little attention, may be relevant for protection against
non-arrhythmia-related cardiovascular events due to improvements in risk factors. Several other studies
confirmed FA consumption to improve left ventricular diastolic filling, cardiac efficiency, reduced
myocardial oxygen consumption, and increased stroke volume.
I came across this article and thought it was interesting because of the curiosity that everyday
consumers have in relation to which particular fish oils to buy or even whether fatty acid supplementation
is beneficial to our cardiovascular health. I believe this paper provides a more objective measurement of
dietary n-3 consumption using biomarkers as opposed to self-reported estimates of fish consumption. I like
the fact that researchers evaluated specific individual fatty acids, and accounted for potential metabolic
actions such as EPA conversion to DPA that may also reduce CHF risk. Too many studies cite general O-3-FA
consumption. Looking at CVD risk factors, this investigation does suggest that EPA, DPA and DHA may have
distinct and complementary physiologic benefits to improve cardiac health.
One big weakness of the study is the prolonged storage of blood samples, which may change fatty
acid levels over time and possibly underestimate associations. One way to improve study is to shorten the
sample storage duration from 3 years. Specific fatty acid amounts were based on self-reported dietary
habits (fish consumption) which are not always accurate. Also, the possibility of improperly measuring
these fatty acids may lead to less than accurate results; however it is often difficult to overcome these
study measurement errors. I agree with this paper providing supportive argument that fatty acid
consumption significantly lowers overall cardiovascular risks.
 According to the American Heart Association, O-3-FAs benefit the heart of healthy people as well as
those at high risk of cardiovascular disease. Research has shown that O-3-FAs decrease risk of
arrhythmias (abnormal heartbeats), which can lead to sudden death. O-3-FAs also decrease
triglyceride levels, slow artery plaque build-up, and lower blood pressure.
 Based on the information above, I agree with The American Heart Association’s current
recommendation of healthy individuals eating fish (fatty fish like salmon, mackerel, herring, lake
trout, sardines and albacore tuna) at least two times (two 3.5 ounce servings) a week.
 Patients with CAD or with high triglycerides may not get enough omega-3 by diet alone and may
want to talk to their doctor about supplements (1 g of EPA+DHA per day or 2-4 grams of EPA+DHA
per day respectively)
 Patients taking more than 3 grams of omega-3 fatty acids from capsules should do so only under a
physician’s care as high intakes could cause excessive bleeding in some people.