Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies

• Published in: The American journal of clinical nutrition Vol. 112; no. 1; pp. 150 - 167
• Main Authors: Li, Jun, Guasch-Ferré, Marta, Li, Yanping, Hu, Frank B
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2020; Oxford University Press; American Society for Clinical Nutrition, Inc
• Subjects: Adipose tissue; Adult; Aged; Aged, 80 and over; Biomarkers; Blood; Cancer; cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - drug therapy; Cardiovascular Diseases - mortality; Cohort analysis; Compartments; Diet; Dietary intake; dietary polyunsaturated fatty acid; Fatalities; Fatty acids; Fatty Acids, Omega-6 - administration & dosage; Female; Food intake; Health risk assessment; Heart diseases; Heterogeneity; Humans; Linoleic acid; Linoleic Acid - administration & dosage; Male; Meta-analysis; Middle Aged; Mortality; Mortality risk; Neoplasms - drug therapy; Neoplasms - mortality; Original Research Communications; Polls & surveys; Polyunsaturated fatty acids; Prospective Studies; Randomized Controlled Trials as Topic; Regression analysis; Systematic review; Young Adult; AA; CVD; FFQ; cardiovascular disease; dietary polyunsaturated fatty acid; RCT; NOS; LA; biomarkers; CAD; linoleic acid; mortality
• ISSN: 0002-9165; 1938-3207; 1938-3207
• DOI: 10.1093/ajcn/nqz349

Current evidence on associations between intakes of linoleic acid (LA), the predominant n–6 (ω-6) fatty acid, and mortality is inconsistent and has not been summarized by a systematic review and meta-analysis. The aim was to perform a systematic review and meta-analysis of prospective cohort studies to examine associations between LA intake and mortality. We conducted a comprehensive search of MEDLINE and EMBASE databases through 31 July 2019 for prospective cohort studies reporting associations of LA (assessed by dietary surveys and/or LA concentrations in adipose tissue or blood compartments) with mortality from all causes, cardiovascular disease (CVD), and cancer. Multivariable-adjusted RRs were pooled using random-effects meta-analysis. Thirty-eight studies reporting 44 prospective cohorts were identified; these included 811,069 participants with dietary intake assessment (170,076 all-cause, 50,786 CVD, and 59,684 cancer deaths) and 65,411 participants with biomarker measurements (9758 all-cause, 6492 CVD, and 1719 cancer deaths). Pooled RRs comparing extreme categories of dietary LA intake (high vs low) were 0.87 (95% CI: 0.81, 0.94; I2= 67.9%) for total mortality, 0.87 (95% CI: 0.82, 0.92; I2= 3.7%) for CVD mortality, and 0.89 (95% CI: 0.85, 0.93; I2= 0%) for cancer mortality. Pooled RRs for each SD increment in LA concentrations in adipose tissue/blood compartments were 0.91 (95% CI: 0.87, 0.95; I2= 64.1%) for total mortality, 0.89 (95% CI: 0.85, 0.94; I2= 28.9%) for CVD mortality, and 0.91 (95% CI: 0.84, 0.98; I2= 26.3%) for cancer mortality. Meta-regressions suggested baseline age and dietary assessment methods as potential sources of heterogeneity for the association between LA and total mortality. In prospective cohort studies, higher LA intake, assessed by dietary surveys or biomarkers, was associated with a modestly lower risk of mortality from all causes, CVD, and cancer. These data support the potential long-term benefits of PUFA intake in lowering the risk of CVD and premature death.