Association between dietary omega-3 intake and coronary heart disease among American adults: The NHANES, 1999-2018

Background: Omega-3 has been extensively studied for its cardiovascular disease (CVD) benefits.
However, the results of this evidence are inconsistent. Therefore, in this study, dietary omega-3 intake
was investigated further in relation to coronary heart disease (CHD) risk among U.S. adults.
Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) database
for people ages 20 years and older between 1999 and 2018 to conduct a cross-sectional survey. The
Medical Condition Questionnaire (MCQ) was used to determine CHD status. We measured dietary
omega-3 intake using two 24-hour dietary recall interviews. Multivariate logistic regression and
subgroup analysis were used to explore the correlation between dietary omega-3 intake and CHD. The
dose-response relationship between the two was analyzed with a restricted cubic spline (RCS).
Results: 31,184 study subjects were included, of whom 1,604 (5.14%) were patients with CHD. By
quintile (Q) of dietary omega-3 intake, after adjusting for all confounding factors, compared with Q1,
when total dietary omega-3, alpha-linolenic acid (ALA), docosapentaenoic acid (DPA), eicosatetraenoic
acid (ETA), eicosapentaenoic acid (EPA), and docosahexenoic acid (DHA) intake reached Q5, the odds
ratio (95% confidence interval, CI) of CHD were 0.76 (0.60, 0.96), 0.73 (0.57, 0.94), 0.70 (0.54, 0.92), 0.66
(0.50, 0.85), 0.84 (0.69, 1.02), and 0.83 (0.64, 1.07), respectively, while EPA and DHA were not
significantly associated with the disease (Trend p > 0.05). Intake of omega-3 and CHD were linearly
related (P for nonlinear = 0.603). No significant interactions were found within subgroups except for the
age group (P for interaction = 0.001). Sensitivity analysis and multivariate logistic regression results are
generally in agreement. Conclusions: Total dietary omega-3, ALA, DPA, and ETA intake were negatively
associated with CHD risk. In contrast, EPA and DHA had no significant correlation with CHD.