Soda sales plummeted in Philadelphia following the implementation of a tax on them, according to a new study.

A study published in the Journal of the American Medical Association found that the city's new tax caused a "significant and substantial decline" in soda sales.

The results also show that the tax crushed sales of soda in the city of Philadelphia while boosting sales in nearby areas as customers sought to avoid the levy.

Overall, sales fell by 38% even when factoring in the spike in neighboring areas, according to the study.

Philadelphia region shoppers bought almost 1 billion fewer ounces of soda in 2017 than in 2016, according to the study.

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The outcome could influence policymakers weighing similar moves in other jurisdictions.

Supporters say the soda tax effectively discourages unhealthy consumption of sugary beverages, potentially fighting obesity and other conditions. Opponents say it disproportionately hurts lower-income people, damages businesses and represents an inappropriate infringement on consumer rights.

The tax, which took effect at the beginning of 2017, is 1.5 cents per ounce on sugary or artificially sweetened drinks. That translates into 30 cents for a 20-ounce bottle and about a dollar for a 2-liter.

Sales inside the city of Philadelphia fell 51%. Sales in nearby areas increased 43%.

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The study authors are Christina Roberto and Michael LeVasseur of the University of Pennsylvania's Perelman School of Medicine and Hannah Lawman of the Philadelphia Department of Public Health.

They examined 291 stores, including supermarkets, mass merchandise stores and pharmacies. They used the city of Baltimore as a control group to account for other factors not related to the tax.

The American Beverage Association, which has opposed soda taxes, said the study shows that "beverage taxes hurt working families, small local business and their employees."

The interest group said "taxes on common grocery items like beverages have never really improved public health" and said half of all beverages contain no sugar.

“America’s beverage companies believe there is a better way to help people reduce the amount of sugar they get from beverages than unproductive taxes," the group said in a statement. "We’re creating more drinks with less or no sugar and we’re making smaller bottle and can options more widely available and boosting consumer demand for these options through our marketing."

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.