Fish Consumption May Lower CV Risk in Patients with Vascular Disease

Fish with higher amounts of ω-3 fatty acids was strongly associated with lower risk of poor cardiovascular outcomes in those with vascular disease.

A new study has indicated that fish consumption may lower major cardiovascular disease (CVD) and mortality risks in those with a history of vascular disease.

However, the association between consumption of fish and decreased cardiovascular risk was shown to be minimal to negligent among the general population.

A pooled analysis of 4 cohort studies was led by Deepa Mohan, PhD, Madras Diabetes Research Foundation and Dr. Mohan’s Diabetes Specialities Centre, Chennai, India.

“To date, most cohort studies evaluating fish consumption and CVD events have been conducted in Europe, North America, Japan, and China, with little information from other world regions, where varying amounts and types of fish are consumed,” wrote the investigative team.

“Furthermore,” they continued, “whether the associations of fish consumption with CVD events vary between those with and those without vascular disease is unclear.”

Fish Consumption and CVD risk

The present study represented 191,558 individuals from 58 countries across 6 continents.

The cohort studies included in the analysis were the ongoing Prospective Urban Rural Epidemiology (PURE) study, ongoing Telmisartan Alone and in Combination With Ramipril Global End Point Trial (ONTARGET), Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease (TRANSCEND), and Outcome Reduction With Initial Glargine Intervention (ORIGIN) trial.

“Adjusted hazard ratios (HRs) were calculated by multilevel Cox regression separately within each study and then pooled using random-effects meta-analysis,” Mohan and team wrote.

Analysis was conducted from January-June 2020.

Thus, among the entire pooled population, 51,731 presented with cardiovascular disease and 139,827 were considered generally healthy.

The mean age of the population 54.1 years, with the majority (52.1%) being female.

The median duration of follow-up was 7.5 years (interquartile range [IQR], 4.9-9.4 years). Furthermore, 96% of participants completed follow-up.

“During 9.1 years of follow-up in PURE, compared with little or no fish intake (≤50 g/mo), an intake of 350 g/wk or more was not associated with risk of major CVD (HR, 0.95; 95% CI, 0.86-1.04) or total mortality (HR, 0.96; 0.88-1.05),” the investigators reported.

However, among the other 3 cohorts—which only evaluated those with vascular disease—the hazard ratio for risk of major cardiovascular disease (HR, 0.84; 95% CI, 0.73-0.96) and total mortality (HR, 0.82; 95% CI, 0.74-0.91) was lowest with intakes of 175 g/wk, as compared with 50 g/mo or lower.

Further, risk did not appear to decrease with consumption of 350 g/wk or higher.

The team also noted that fish with higher amounts of ω-3 fatty acids had strong associations with lower risk of CVD (HR, 0.94; 95% CI, 0.92-0.97 per 5-g increment of intake). Other fish were considered neutral.

“A similar pattern of results was found for sudden cardiac death, with significant protective associations observed among patients with vascular disease, but neutral in general populations without vascular disease,” the investigators wrote.

Limitations of the analysis included self-reported diets, the inability to study cooking methods and means of consumption, and potential confounders such as socioeconomic status and geographic location.

They noted that further studies and randomized clinical trials that evaluate and confirm the effects of increased ingestion of fish, most especially oily fish, on clinical outcomes in people with vascular disease are warranted.

“Given that there are associations with CVD risk markers, some of which may be protective and others harmful, and that some fish may contain contaminants, studying the association of fish intake with outcome events is essential to inform recommendations for populations,” the investigators indicated.

The study, “Associations of Fish Consumption With Risk of Cardiovascular Disease and Mortality Among Individuals With or Without Vascular Disease From 58 Countries,” was published online in JAMA Internal Medicine.