The longer hours, faster pace and insecurity typical of many new jobs is taking a toll on workers' hearts, according to a growing body of occupational health research.
Studies in Europe, Japan and the United States have linked increases in cardiovascular risks and disease to a global push for greater productivity. Researchers say the damage is cumulative and will become more apparent and costly over time.
"I think we're dramatically underestimating the impacts of these changes," said Peter Schnall, an epidemiologist who directs the UCLA Center for Occupational and Environmental Health. "There are enormous health effects, but they don't make it into the calculations."
The latest research in the field, presented this month at an international forum in Newport Beach, hints at the potential scale of the problem.
U.S. and Japanese workers who put in more than 50 hours a week had markedly higher rates of hypertension, a precursor to heart disease. In Belgium, stressful jobs -- defined as highly demanding with little decision-making authority -- appeared to elevate the blood pressure of workers even as they slept.
China's embrace of rapid economic change has been accompanied by surges in cardiovascular disease that have overwhelmed urban hospitals. And in one small Norwegian town two years ago, the mere rumor of a plant closure was enough to raise overall blood pressure for months.
"Just think about globalization, what that can mean to millions of people around the world. These rumors are everywhere," said Tage Kristensen, who directs Denmark's occupational health program and is considered a pioneer in the burgeoning area of research.
The link being made between shifting corporate employment practices and heart disease reflects a larger interest in the health effects of stress, which began showing up in occupational health journals in the early 1990s. In 1996, the National Institute for Occupational Safety and Health -- part of the Centers for Disease Control and Prevention -- named the changing nature of work a priority for study, seeking to catch up with European counterparts.
But nearly a decade later, after continuing painful shifts in global work arrangements, the answers remain frustratingly vague. "Clearly something is going on," said Steven Souter, who coordinates research on work stress for NIOSH and who spoke at the forum in Newport Beach. "In the United States, we don't have the firm data we need to understand it."
Organized by the decade-old International Commission on Occupational Health, the forum was dominated by talk about the need for bigger, more imaginative research projects and for hard data on the long-term economic benefits of stress reduction. "You need numbers to show that your field is important," Kristensen said.
In this work, however, there is one recurring problem: Stress is a subjective term that doesn't lend itself to hard numbers, especially when comparing across cultures and social classes.
For years, occupational health researchers have struggled to come up with formulas for measuring job stress and determining its effect on health. One model balances high work demands with decision-making latitude, which softens the stress. In another, job pressures are mitigated by a sense of fairness and social support on the job.
At the occupational health forum, the first steps were taken toward crafting a model that reflects changes such as the shift toward temporary and contract work arrangements.
Even updated, however, the measures are likely to draw skepticism. The trends they seek to measure are so broad that many other factors could influence the health outcomes. Is the problem stress or an aging workforce? Are there other societal changes that play a role?
"Some things are un-settle-able," said Ben Ansell, a UCLA internist who co-directs the UCLA Cholesterol, Hypertension and Atherosclerosis Management Program. "In the Western world we're very quantitative, and this is a non-quantitative area."
Ansell, who was not part of the forum, said research and treatment has tended to focus on diet, exercise and smoking for good reason: They lend themselves to controlled studies and measurable interventions.
That's not to say he disputes the link between stress and disease. Ansell said he's seen the evidence himself in executives he monitors through the UCLA program.
About half of them show dangerously high blood sugar levels. "I believe this is a real issue," he said. "But cholesterol is a bad thing too, and that's much easier to explain to people."
The emphasis might change if employer costs continue to rise for heart disease and other stress-related ailments. Already, several major U.S. employers have created stress-reduction programs that go beyond lunchtime yoga, and disability insurers are starting to show interest in the topic.
ORC Worldwide, a Washington-based consulting firm that provides human relations services to major multinational corporations, has urged its clients for years to take stress seriously, pointing out that the problem cuts into productivity and profits, said counselor Joanne Linhard.
According to its website, ORC also has lobbied the U.S. government to be more aggressive in setting a public policy and research agenda on work stress, rather than allowing it to be defined by European governments and labor groups.
John Howard, the director of NIOSH, said work stress is "one of our most fertile areas of research" but added that it hasn't gotten the attention it deserves. "Sometimes employers don't understand that workers are their real asset, especially in a service economy," he said. "If we're going to keep improving productivity, we have to make sure that we keep workers healthy."