"The challenge employers face is the need to balance short-term administrative costs with a desire to impact longer-term healthcare costs, reduce absence and improve productivity," said Michele Becker, a vice president with Aon Consulting.

Senior managers (63 percent) are especially concerned about costs associated with obesity and physical inactivity. Interestingly, a much smaller percentage see stress as a major problem (15 percent). Job stress issues are on the radar screen of executives and regulators in Europe far more than in the U.S.

Nearly three-quarters (72 percent) of companies with formal health/wellness strategies host on-site health screenings for employees.

Fifty-two percent of managers expect a return on investment (ROI) for health promotion/wellness programs, but only 16 percent said positive ROI is expected in the first year of the program. Key non-financial metrics: reduced health risk factors, high program participation, and reduced healthcare utilization — such as fewer emergency room and office visits.

And why won't many employees participate in health management programs? Survey respondents (company HR officials) cite a lack of motivation as the primary reason (41 percent), followed by employees who were too busy to participate (21 percent), those with privacy concerns (15 percent), and those who simply don't place a high priority on getting healthier (12 percent).

Incentives increase participation, said Aon's Becker. "To realize ROI, companies must incorporate incentives… such as reduced contributions, wellness credits, and deposits to flexible spending accounts."