Utah was one of 17 states that saw the ranks of uninsured residents swell last year, a new poll has found — the first such increases since before the Affordable Care Act was rolled out more than four years ago.

The Beehive State’s adult uninsured rate climbed 2.1 percent from 2016 to 2017, to a total of 11.8 percent without health insurance coverage, according to the Gallup poll results released Wednesday.

That number had been on the decline since 2013, when 15.6 percent of Utah adults told Gallup they lacked coverage.

Gallup said the increases were likely due in part to rising insurance premiums in many states on marketplaces offered under the Affordable Care Act, or Obamacare, which has caused some people to drop coverage. In addition, it cited political uncertainty surrounding the law under the Trump administration.

Stacy Stanford, a policy analyst with the nonprofit Utah Health Policy Project, urged caution in reading too much into Utah’s part of the Gallup findings. She noted that the state has “consistently seen a decline in the uninsured rate” for several years, due to strong enrollment in the marketplaces as well as positive economic growth.

But for the first time since 2017, according to the Gallup poll, no U.S. state saw a decrease in its share of people without health insurance compared with the prior year. The uninsured rate nationally rose slightly in 2017, pollsters found, to 12.2 percent.

Gallup noted there was a nearly 4 percent decrease nationally in the number of people enrolled in Obamacare plans in 2017, followed by a similar decline in 2018 enrollments, due to a shorter enrollment period and other steps taken by the Trump administration and Republican lawmakers to undermine the law.

But it’s less clear exactly what factors could have driven Utah’s uninsured rate up last year. While the number of Utahns enrolled in Obamacare dipped slightly for 2018, aligning with the national trend, the number of residents who signed up actually grew between 2016 and 2017.

Overall, the largest factor preventing more Utahns from gaining health coverage has been the reluctance of state lawmakers to fully expand Medicaid, which caters to low-income residents, Stanford said.

“There is a marked difference in the uninsured rates of states with and without expansion,” she said.

The average uninsured rate for states that have expanded Medicaid stood at 8.2 percent in 2016 and rose to 9.1 percent last year.

But for states that had refused to expand coverage to low-income residents in the coverage gap, the average uninsured rate was much higher, moving from 14.5 percent up to 15.9.

“States that have expanded Medicaid continue to have greater reductions in their combined uninsured rate since 2013,” the report’s authors wrote, lowering their rate by 42 percent compared with 21 percent for states that have not expanded coverage.

It’s possible Utah can soon turn the trend around, if a recently passed partial Medicaid expansion law — which would cover more than 70,000 Utahns — is approved by the federal government. A Medicaid expansion ballot initiative that would cover as many as 150,000 residents is also slated to go before voters in November.

Several states adjacent to Utah — Colorado, Arizona and New Mexico — also saw the number of people without insurance increase last year.