More than 100 million people in this country have a pre-existing medical condition that could make finding health coverage difficult, if not impossible, should current protections be lifted, a national study released has found.

That means more than half of Americans with insurance outside major public programs, such as Medicaid or Medicare, could potentially feel the brunt of a lawsuit seeking to declare the Affordable Care Act unconstitutional and dismantle the law's consumer protections, according to Avalere, a national health care research and consulting firm.

In February, Texas Attorney General Ken Paxton, joined by 19 other state attorneys general across the country, filed a legal challenge to the law known as Obamacare in federal court in Fort Worth. The case argues that when Congress last year removed the penalty for not having health insurance it rendered the entire law invalid.

The Trump administration later gave credence to the challenge by refusing to defend the health care law. The lawsuit is still pending with a decision expected this year but many believe it will ultimately be decided in the U.S. Supreme Court.

Paxton's office declined to comment on the lawsuit because it is still pending, a spokesman said.

RELATED: Texas leads new lawsuit to effectively repeal Obamacare

Prior to the passage of the ACA in 2010, people with chronic health problems or pre-existing conditions, even many years prior, could be charged significantly more by insurers or denied outright under a practice known as medical underwriting. The current health care law made that illegal.

A separate 2016 study by Kaiser Family Foundation estimated about 27 percent of adult Texans under the age of 65, or roughly 4.5 million, had a health issue that would have led them to be denied health coverage in the pre-Obamacare era.

"Virtually every American has someone with an existing health condition in their family at any given time," said Dan Mendelson, founder of Avalere, in a statement on Tuesday.

Pre-existing condition protections have become a rallying cry in the mid-term elections, especially among Democrats who point to repeated Republican efforts to repeal, undercut or replace Obamacare.

RELATED: Voters worried about pre-existing condition protection

Last week, President Donald Trump returned to his presidential campaign promise to preserve the protections, despite his more recent support of the lawsuit and other measures that would eliminate them. On Oct. 18, he tweeted: "All Republicans support people with pre-existing conditions and if they don't they will after I speak to them."

Even as Senate Majority Leader Mitch McConnell, R-Ky., has pledged to try again to repeal the federal health care law that extended protections for pre-existing conditions should Republicans maintain their control of Congress, Trump doubled down Wednesday to make the GOP the champions of patients with health conditions with this tweet: Republicans will totally protect people with Pre-Existing Conditions, Democrats will not! Vote Republican.

The Avalere report found overall that 102,400,000 people, without Medicare or Medicaid, had some sort of pre-existing condition. Their research was based on the 2015 Medical Expenditures Panel Survey which looks at health conditions, coverage sources and health costs for a representative sample of the U.S, population.

About 50 percent of those with pre-existing conditions had cardiovascular disease and roughly 28 percent had a mental health disorder. Obesity, diabetes and chronic obstructive pulmonary disease, known as COPD, also fell under the heading of pre-exisiting condition. So did cancer and pregnancy, the data showed.

"Protections for pre-existing conditions are the only reason some Americans are able to afford health insurance," said Chris Sloan, director at Avalere. "Many of the most common health conditions in the country could lead to individuals being denied access to health insurance if pre-existing condition protections are eliminated."