By Andrew M. Seaman

A girl helps herself to a buffet at a fast food restaurant in Harlem in New York December 16, 2009. REUTERS/Finbarr O'Reilly

(Reuters Health) - - People were less likely to go to the hospital with heart attacks or strokes after several counties in New York State restricted the use of trans fats, according to a new study.

Trans fats raise bad cholesterol, lower good cholesterol and ultimately increase the risk of heart attacks and strokes. They're found naturally in some foods but are often manufactured and added to processed foods to improve taste and texture.

"New York City was progressive and they enacted restrictions on trans fats, but no one looked to see if this made measurable changes to outcomes," said study lead author Dr. Eric Brandt, of Yale University in New Haven, Connecticut.

New York City limited the use of trans fats starting in July 2007. The restrictions applied to food purchased outside of stores, such as at restaurants, street vendors and bakeries, in the city's five counties. Other New York counties took similar actions after New York City's measure was enacted.

Previous research found that death from cardiovascular disease declined 4.5 percent within a year after counties enacted trans fat restrictions, the researchers write in JAMA Cardiology. No study looked at non-fatal cardiovascular issues like hospitalizations due to heart attacks and strokes, however.

For the new study, the researchers compared data on people hospitalized between 2002 and 2013 for heart attacks or strokes in counties that did or didn't restrict trans fats.

Altogether they had data on 3.3 million people in 25 counties without trans fat restrictions and 8.4 million people in 11 counties with restrictions.

In 2006, there were 753 hospital admissions for heart attack or stroke per 100,000 people in counties that never enacted restrictions compared to 726 per 100,000 people in counties that put restrictions in place.

While admissions for heart attacks and strokes fell after 2002 in all the counties, the drop was more substantial in those that enacted trans fat restrictions, the authors found.

After three years or more, the combined rate of hospitalizations for heart attacks or strokes was about 6 percent lower in the counties with trans fat regulations.

Admissions for heart attacks were nearly 8 percent lower in counties with restrictions. Similarly, admissions for strokes were about 4 percent lower in counties with restrictions, but that finding could be due to chance.

Brandt told Reuters Health that New York City was also pushing other public health initiatives around the same time. Those included clean air initiatives and showing calorie counts on restaurant menus.

When they removed New York City data to make sure those other factors weren't driving the findings, the pattern didn't change.

"We still found the same thing," Brandt said.

Still, the study can't say the trans fat restrictions caused fewer admissions in those counties.

Brandt and colleagues write that in 2015, the U.S. Food and Drug Administration (FDA) removed manufactured trans fats from its list of safe food additives. By 2018, those fats will be nearly eliminated from American diets, they add.

"There has been a lot of looking into whether trans fats are harmful," said Brandt. "Here we find on a population level when we restrict them, it benefits society by reducing heart attacks and strokes."

The findings suggest the FDA's action will lead to health benefits across the country, he added.

SOURCE: bit.ly/2otJ6gK JAMA Cardiology, online April 12, 2017.