The wellness industry has been taking some hits as of late. Employer-sponsored wellness programs have been criticized for demoralizing workers and violating their privacy. And, perhaps most worrisome to corporate boards, a number of prominent critics have argued that wellness programs don’t actually save companies money.

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Some wellness proponents, including human resources officials at Bank of America and Southwest Airlines, have countered that the main goal of wellness programs is to develop happier, healthier and more productive employees, rather than to save money.

But a group of researchers now claim to have conducted the first comprehensive study proving that wellness programs can produce a financial return on investment for employers.

The study, published in the Journal of Occupational and Environmental Medicine, found that a wellness program put in place by Aetna (NYSE:AET) for its employees saved the company an average of $122 each month for every participant, or $1,464 a year.

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Employees aren’t engaging with wellness programs, a study shows.

But unlike many conventional wellness programs, the Aetna initiative focused only on employees most likely to incur big medical costs. Specifically, it targeted employees at risk of metabolic syndrome, which is how doctors refer to those with at least three of the following medical conditions: obesity, high blood pressure, high glucose, high triglycerides and low levels of high-density cholesterol.

The employees recruited for the study had all exhibited at least two risk factors linked to the condition. Over a year, two large groups of participating employees were compared to a large control group of employees with nearly precisely the same rate of risk factors.

Each participant was put in touch with a personal coach and a “client care manager.”

The study authors do not say how much the program cost.

Many participants who had signed up did not remain fully engaged in the program, but the participants still lost an average of ten pounds over the course of the year. The report authors suggested that the immediate benefits realized in the first year were impressive and that the benefits could become even greater in the long-term.

The authors also suggested that future studies should focus on the effect of wellness programs on employee productivity, in addition to medical costs.

“This is an important area for future investigation,” they wrote.