Study reveals the work and health insurance roller coaster millions of Americans ride

In the 46 years since Dolly Parton wrote the workers’ anthem “9 to 5,” American jobs, and access to employment-based health insurance, have changed a lot. 

Millions more people work as contractors, freelancers and gig or temporary workers, or are self-employed, run small businesses or have multiple part-time jobs.

Now, a new study reveals details about how the variable hours and incomes that come with this kind of work are linked to different types of health insurance coverage for low- and middle-income Americans. 

Workers with highly variable weekly work hours, fluctuating annual incomes or employment disruptions have far lower odds of having the option of getting health insurance coverage through an employer. 

They’re more likely to be young, female and to have low incomes than those with stable hours and incomes. 

And they are much more likely to rely on Medicaid or health plans bought on the Affordable Care Act marketplaces, compared with workers in the same income range who had more stable hours and incomes; those workers were more likely to be covered by an employer-sponsored plan. 

The study is published in JAMA Network Open by a team from Mount Sinai Hospital and the University of Michigan Medical School, who note that volatile or unstable work arrangements are common among low- and middle-income working Americans.

Implications for 2027 Medicaid and ACA Marketplace coverage

The new results are being published just as 44 states prepare to require millions of Medicaid enrollees to document that they are working at least at least 80 hours per month or meeting other requirements, starting in 2027.

If they can’t, they will lose their coverage. 

The study suggests that workers with volatile work situations will be particularly susceptible to Medicaid disenrollment due to fluctuating hours and employment, even though they worked 33 to 35 hours per week, on average. (That total was typical of all low- and middle-income workers in the study.)

In all, 70% of those with volatile hours had work schedules that fluctuated below 20 hours per week at some points during the year. 

The study also comes at a time when the ACA Marketplace will have changes to eligibility, including those based on immigration status, and increases in costs.

These changes follow on the heels of the expiration of enhanced premium subsidies for 2026 plans. Marketplace enrollment for 2027 begins November 1 via healthcare.gov.

“Low- and middle-income workers rely on those other forms of coverage because they can’t rely on access to employer coverage as companies outsource certain functions to contractors or hire more employees in roles that aren’t eligible for benefits,” said Sumit Agarwal, M.D., M.P.H., Ph.D., the study’s senior author and an Assistant Professor at the U-M Medical School and School of Public Health. 

“They are the ones who will be hurt the most from changes in health policy that reduce access to the programs, such as Medicaid expansion and the ACA Marketplace, that were intended to fill in the gaps in the employer-first insurance system,” he said. “Millions of people are in those gaps.”

The researchers focused on people with incomes up to the level that qualifies for enrollment in Medicaid, particularly in states that expanded Medicaid to cover adults under 65 with incomes up to 138% of poverty level.

They also focused on people with incomes up to 400% of poverty level, the limit for some money-saving options on the ACA Marketplace. 

During the 2022-2023 span examined in the study, the highest income in the study (400% of poverty) would have been about $58,300 for a single person and $120,000 for a family of four. 

In 2026, the income cutoff for Medicaid enrollment in most states (138% of poverty) is just over $22,000 for a single person and $45,500 for a family of four, while an income that’s 400% of poverty level is $63,840 for a single person and $132,000 for a family of four. Alaska and Hawaii have different poverty levels.

Current patients already concerned

Agarwal is both a general internal medicine physician at U-M Health and a health economist. 

He said he has patients covered by Michigan’s Medicaid expansion program, the Healthy Michigan Plan, who are already very worried that their irregular work patterns will make it hard for them to meet the work requirements when they go into effect next year. 

“Some of my patients are already anticipating that they will lose their coverage,” he said.

“These are people who are working.” 

The specific requirements, and how states will implement systems for reporting or automatically tracking work or other activities, or granting exemptions based on health or other factors, will vary by state.

A tracker is available from the Kaiser Family Foundation. 

U-M Health is preparing to help patients understand how to navigate the requirements of the system once they are known.

For now, anyone covered by a Michigan Medicaid plan can check the state website for current information. 

Millions potentially affected

Agarwal and his colleagues, including lead author Vineeth Amba, M.D., M.P.H., a resident at Mount Sinai Hospital in New York, performed the study using data from the Medical Expenditure Panel Survey, a nationally representative survey run by the Agency for Healthcare Research and Quality.

“A major advantage of the MEPS is that they interview people multiple times over two years, so we could identify which workers were in volatile versus stable work arrangements,” said Amba.

“Workers in unstable jobs are a growing share of the low- and middle-income working population.”

The researchers looked at how health insurance coverage and type were associated with measures such as income that varied more than 25% from 2022 to 2023, work hour volatility by week and transitions from unemployed to employed.

The study sample was 1,621 people.Extended to the whole U.S. population, 14.6 million had volatile incomes, compared with 10.6 million with stable incomes, and 11.4 million had volatile hours, compared with 13.5 million with stable hours, and 2.9 million experienced an employment disruption, compared with 22.4 million having stable employment. 

The changes taking effect for Medicaid and the ACA Marketplace for 2027 stem from the federal budget bill signed into law in July 2025.

The changes will disproportionately affect workers in volatile or unstable jobs, Agarwal says.

At the time of the bill signing, Agarwal wrote about the changes in employment-based health insurance, and the experiences of Michigan and Arkansas that attempted to implement Medicaid work requirements, in a commentary for the nonprofit academic website The Conversation. 

In addition to Agarwal and Amba, the new study’s authors are Renuka Tipirneni, M.D., M.Sc., and John Z. Ayanian, M.D., M.P.P., who, like Agarwal, are members of the faculty in the Division of General Medicine in the U-M Medical School Department of Internal Medicine. Ayanian directs, and Agarwal and Tipirneni are members of, the U-M Institute for Healthcare Policy and Innovation. 

Paper cited: "Volatile Employment and Health Insurance Gaps Among Low- and Middle-Income Workers," JAMA Network Open. DOI: 10.1001/jamanetworkopen.2026.33883