Associations of Plasma Phospholipid and Dietary Alpha Linolenic Acid With Incident Atrial Fibrillation in Older Adults: The Cardiovascular Health Study
Associations of Plasma Phospholipid and Dietary Alpha Linolenic Acid With Incident Atrial Fibrillation in Older Adults: The Cardiovascular Health Study
Year: 2013
Authors: Fretts, A.M. Mozaffarian, D. Siscovick, D.S. Heckbert, S.R. McKnight, B. King, I.B. Rimm, E.B. Psaty, B.M. et al
Publication Name: J Am Heart Assoc.
Publication Details: doi: 10.1161/JAHA 112.003814
Abstract:
Few studies have examined the relationship of alpha linolenic acid (ALA 18 3n3), an intermediate chain essential n 3 polyunsaturated fatty acid derived from plants and vegetable oils, with incident atrial fibrillation (AF). Methods and Results The study population included participants from the Cardiovascular Health Study, a community based longitudinal cohort of adults aged 65 or older, free of prevalent coronary heart disease and atrial fibrillation. We assessed the associations of plasma phospholipid and dietary ALA with incident AF using Cox regression. The biomarker analysis comprised a total of 2899 participants, and the dietary analysis comprised 4337 participants. We found no association of plasma phospholipid ALA and incident AF. Comparing each of the second, third, and fourth quartiles to the lowest quartile, the hazard ratios for AF were 1.11 (95 per cent CI, 0.90 to 1.37), 1.09 (95 per cent CI, 0.88 to 1.35), and 0.92 (95 per cent CI, 0.74 to 1.15), after adjustment for age, sex, race, clinic, education, smoking, alcohol, body mass index, waist circumference, diabetes, heart failure, stroke, treated hypertension, and physical activity. When dietary ALA was considered the exposure of interest, results were similar. Conclusions Results from this prospective cohort study of older adults indicate no association of plasma phospholipid or dietary ALA and incident AF. (Authors abstract)
Atrial fibrillation (AF) is the most common chronic arrhythmia in the United States. According to results from the Framingham Heart Study, the lifetime risk of developing AF is 26 per cent in men and 23 per cent in women. Risk of AF increases with age, and the burden of disease is particularly high among individuals 65 years of age or older. Because AF is associated with significant morbidity, including stroke, heart failure, and mortality, and there are limited treatment options for AF, primary prevention of AF is essential. Estimation of dietary ALA is challenging because it is present in many foods and depends on food oil composition. Plasma phospholipid ALA, an objective biomarker of dietary ALA that reflects both diet and metabolism, is a measure of circulating ALA over the past 4 to 8 weeks. The purpose of this study was to examine the association of plasma phospholipid and dietary ALA with incident AF in the Cardiovascular Health Study (CHS), a community-based longitudinal cohort of adults aged 65 or older. It was hypothesized that higher levels of plasma phospholipid and dietary intake of ALA are associated with a lower risk of AF among older adults. Results from this prospective cohort study of older adults indicate no association of plasma phospholipid or dietary ALA and incident AF. To date, only 1 other study has examined the association of circulating levels of ALA and incident AF in humans. In that study of Finnish men (mean age at baseline, 53 years), serum ALA was not associated with hospital diagnosed AF during 18 years of follow up. In addition, the study found no evidence of effect modification by fish intake (high intake versus low intake). In this analysis, plasma phospholipid ALA was only modestly correlated with dietary ALA measured from the FFQs . This is not surprising, as measurement of dietary intake of ALA is prone to error because ALA is present in varying amounts in many foods and oils. In addition, it is unknown if plasma phospholipid ALA is a good marker of dietary ALA intake. Because dietary ALA has been shown to be metabolized shortly after consumption or elongated and desaturated to form EPA and DHA in limited amounts, ALA that accumulates in serum may not be a good marker of dietary ALA intake. This analysis has limitations. Plasma phospholipid ALA was only measured at 1 exam (1992 to 1993), and the authors were unable to account for potential changes in circulating levels of ALA from fluctuations in diet and metabolism that occurred during the 16 years of follow up. Intake of dietary ALA was based on responses to an FFQ, and some participants might not have accurately recalled dietary information such as specific foods consumed, frequency, or portion sizes, thereby limiting ability to accurately measure dietary ALA. Additional studies are needed to investigate the association of ALA on AF in populations with higher ALA intake and different background diets, including diets low in LA, diets with no fish intake and vegetarian diets. (Editors comments)
Atrial fibrillation (AF) is the most common chronic arrhythmia in the United States. According to results from the Framingham Heart Study, the lifetime risk of developing AF is 26 per cent in men and 23 per cent in women. Risk of AF increases with age, and the burden of disease is particularly high among individuals 65 years of age or older. Because AF is associated with significant morbidity, including stroke, heart failure, and mortality, and there are limited treatment options for AF, primary prevention of AF is essential. Estimation of dietary ALA is challenging because it is present in many foods and depends on food oil composition. Plasma phospholipid ALA, an objective biomarker of dietary ALA that reflects both diet and metabolism, is a measure of circulating ALA over the past 4 to 8 weeks. The purpose of this study was to examine the association of plasma phospholipid and dietary ALA with incident AF in the Cardiovascular Health Study (CHS), a community-based longitudinal cohort of adults aged 65 or older. It was hypothesized that higher levels of plasma phospholipid and dietary intake of ALA are associated with a lower risk of AF among older adults. Results from this prospective cohort study of older adults indicate no association of plasma phospholipid or dietary ALA and incident AF. To date, only 1 other study has examined the association of circulating levels of ALA and incident AF in humans. In that study of Finnish men (mean age at baseline, 53 years), serum ALA was not associated with hospital diagnosed AF during 18 years of follow up. In addition, the study found no evidence of effect modification by fish intake (high intake versus low intake). In this analysis, plasma phospholipid ALA was only modestly correlated with dietary ALA measured from the FFQs . This is not surprising, as measurement of dietary intake of ALA is prone to error because ALA is present in varying amounts in many foods and oils. In addition, it is unknown if plasma phospholipid ALA is a good marker of dietary ALA intake. Because dietary ALA has been shown to be metabolized shortly after consumption or elongated and desaturated to form EPA and DHA in limited amounts, ALA that accumulates in serum may not be a good marker of dietary ALA intake. This analysis has limitations. Plasma phospholipid ALA was only measured at 1 exam (1992 to 1993), and the authors were unable to account for potential changes in circulating levels of ALA from fluctuations in diet and metabolism that occurred during the 16 years of follow up. Intake of dietary ALA was based on responses to an FFQ, and some participants might not have accurately recalled dietary information such as specific foods consumed, frequency, or portion sizes, thereby limiting ability to accurately measure dietary ALA. Additional studies are needed to investigate the association of ALA on AF in populations with higher ALA intake and different background diets, including diets low in LA, diets with no fish intake and vegetarian diets. (Editors comments)
