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 dramatically. Millions more Americans now work as contractors, freelancers, gig or temporary workers, are self-employed, run small businesses, or hold multiple part-time jobs.

A new study published in JAMA Network Open examines how the variable hours, incomes and employment disruptions associated with these work arrangements are linked to health insurance coverage among low- and middle-income Americans. Researchers from Mount Sinai Hospital and the University of Michigan found that workers with highly variable hours or incomes, or disruptions in employment, had much lower odds of having access to employer-sponsored health insurance.

These workers were more likely to be young, female and have lower incomes than workers with stable employment. They were also much more likely to rely on Medicaid or health plans purchased through Affordable Care Act (ACA) Marketplaces. By contrast, workers in similar income ranges with stable hours and incomes were more likely to have employer-sponsored coverage.

The findings come as 44 states prepare for new Medicaid requirements beginning in 2027. Millions of enrollees will have to document that they are working at least 80 hours a month — about 20 hours a week on average — or meet other qualifying requirements to maintain coverage. Workers with unstable schedules may be particularly vulnerable: although they averaged 33 to 35 work hours per week, 70% of those with volatile schedules fell below 20 hours in some weeks during the year.

Changes are also coming to ACA Marketplace coverage in 2027, including changes affecting eligibility and costs, following the expiration of enhanced premium subsidies for 2026 plans. Senior author Dr. Sumit Agarwal said low- and middle-income workers often depend on Medicaid and Marketplace coverage because they cannot consistently obtain insurance through their employers.

“Millions of people are in those gaps,” Agarwal said, noting that workers with unstable employment may be particularly affected by policy changes that reduce access to programmes designed to supplement the employer-based insurance system. As a physician at U-M Health, he said some patients covered through Michigan’s Medicaid expansion programme are already concerned that irregular work schedules could make it difficult to satisfy the new requirements.

The researchers analysed data from the nationally representative Medical Expenditure Panel Survey, which follows participants repeatedly over two years. The study included 1,621 people and examined income changes of more than 25% between 2022 and 2023, weekly fluctuations in work hours, and transitions between employment and unemployment.

When projected to the U.S. population, the findings represent millions of workers: an estimated 14.6 million had volatile incomes, 11.4 million had volatile work hours, and 2.9 million experienced an employment disruption. Lead author Dr. Vineeth Amba said unstable jobs represent a growing share of the low- and middle-income workforce. The findings suggest that for many Americans, changes in work hours and income are closely intertwined with changes in how — and whether — they obtain health insurance.

More information: Vineeth Amba et al, Volatile Employment and Health Insurance Gaps Among Low- and Middle-Income Workers, JAMA Network Open. DOI: 10.1001/jamanetworkopen.2026.33883

Journal information: JAMA Network Open Provided by Michigan Medicine – University of Michigan