When I took a few sick days earlier this year due to a nasty case of strep throat, my wife was shocked.

She said something like, "You must be REALLY sick if you're taking time off."

To which I responded, "Well, I'm contagious, and I wouldn't want to infect my co-workers."

This brought a derisive chuckle from her, as she commented that that never stopped me before.

OK, I admit it. I've come to work sick a time or two. Or three. Or four. But it was always just a cold that was keeping me down. And, I reasoned each time, I had tons of work to do!

If you can relate to my situation — yes, I know you're out there — you need to know about a recent study by the Cornell University Institute for Health and Productivity Studies and health-information firm Medstat, supported by the National Pharmaceutical Council.

The study showed that absenteeism isn't the only health-related problem that costs employers money. In fact, it said, "presenteeism" may be even worse.

Economists use presenteeism to describe the loss of productivity from employees who go to work while suffering from a variety of medical complaints. The Cornell study says companies' on-the-job productivity losses from presenteeism are possibly as high as 60 percent of the total cost of worker illness — exceeding the costs of absenteeism and medical and disability benefits.

In fact, the study found that for conditions like allergies and headaches, on-the-job productivity losses could account for more than 80 percent of employers' total illness cost.

"All in all, this means that from about one-fifth to three-fifths of the total dollars attributable to common health conditions faced by employers appear to be the result of on-the-job productivity losses," said Ron Goetzel, director of the institute, in a prepared statement. He said headaches, allergies, arthritis, asthma and mental health-related problems such as depression incur the greatest on-the-job productivity losses.

"In this day and age where employers are hesitant to hire because of skyrocketing medical care costs, it's important to broaden the view of health costs beyond the cost of patient care," Goetzel said. "If a company's health plan is poor, for example, disorders may not be well managed. Workers will come to work and not be as productive.

"Employers need to weigh the costs of good medical care against the potential for on-the-job productivity losses, which we see are substantial in many cases."

Not to mention the fact that a worker who stays home can't set off the equivalent of a productivity "dirty bomb," passing on health problems to everyone within a 10-cubicle radius.