New York Trans Fat Bans Successfully Lowered Heart Attack, Stroke Rates

New York counties that instituted restrictions on the use of trans fats in foods observed a significant decline in cardiovascular events compared to similar counties that had not enacted such bans.

In 2007, the 5 counties comprising New York City banned the use of trans fats in foods prepared and sold by restaurants, cafes, and other food vendors, and 6 more counties in the state followed suit by the end of 2011. The concern that trans fats, which are most commonly found in partially hydrogenated oils, could increase cholesterol and elevate the risk of stroke, coronary heart disease, and cardiac death was validated in 2015 when the FDA declared these oils were no longer “Generally Recognized As Safe.” The agency decreed that by 2018, all food manufacturers must cease using partially hydrogenated oils, which will substantially reduce the amount of trans fats consumed by the average American.

Given that New York City and the other nearby counties were ahead of the curve on banning trans fats, researchers have looked to cardiac outcomes in the region for evidence of the ban’s effects. In 2016, a study found that in the year after restrictions were put in place, cardiovascular mortality dropped by 4.5% in those counties, saving 13 lives per 100,000 persons. However, researchers decided to investigate nonfatal outcomes in these counties by comparing their hospital admission rates for myocardial infarction (MI) and stroke to those of other counties.

Their study, published this week in JAMA Cardiology, used hospital admissions data to measure the primary outcome, a composite of MI and stroke event rates. The study populations included 17 highly urban counties, 9 with trans fat restrictions and 8 without, and 19 less urban counties, 2 with the restrictions and 17 without.

Before the restrictions were enacted, admissions for MI and stroke were already declining at a similar rate in all counties studies. After 3 years of the laws being in place, however, the counties with the restrictions saw a significant decline of 6.2% in combined MI and stroke admissions compared with the other counties, even beyond the trends that had been occurring previously. The researchers estimated that 43 additional cardiovascular events had been prevented per 100,000 residents in the counties with trans fat laws.

Admissions for MI and stroke as individual outcomes also declined, though only the 7.8% decrease in MI reached statistical significance. The researchers found the results were the same after restricting the sample to only the most urban counties, and after adjusting for lifestyle differences between the counties that enacted trans fat laws and those that had not. Finally, their results were unchanged after they excluded the New York City counties, as they sought to demonstrate the influence of the trans fat restrictions apart from other public health efforts implemented in the city around that time, like the law made effective in 2008 that required food service establishments to post calorie counts on menus.

The study authors also noted that “the effect of the restriction exhibited a dose-response by time, wherein there was typically greater degree of decline and significance of decline in events with the passage of time, which is the biologically expected response to cardiovascular risk factor modification.”

They wrote that their findings provide cause for hope that the FDA’s impending restriction on trans fats in packaged food could lower the rates of MI and stroke across the US.