GOOD times seem like they should bring good health. More people have jobs and health insurance when an economy is growing. Fewer people skip visits to the doctor to save money or suffer the severe stress that comes with a layoff. So with job growth now stronger than it has been since 2000, the country can look forward to some vigorous years, it might seem.

But that is not quite how the world works, some new research has found. In fact, a strong economy should probably come with a warning label. A one-percentage-point fall in the unemployment rate - which is what has happened since the summer of 2003 - leads to 12,000 deaths a year in the United States that might not otherwise have happened, according to Christopher J. Ruhm, an economist at the University of North Carolina, Greensboro.

When the economy improves, the number of car and workplace accidents rise, as people are on the job and on the road more often. Deaths from heart attacks, flu and pneumonia increase, too. Cancer deaths do not change and suicides fall, but not by nearly enough to overcome the other increase in mortality.

Smoking rises, as does obesity, during a boom. Physical activity falls. The part of the population that drinks remains the same, but some moderate drinkers become heavy drinkers.

Put it all together, and an economic expansion ends up looking like a counterintuitive health risk.

“Things don’t go uniformly in one direction or the other,” said Mr. Ruhm, who in recent years has published a flurry of academic articles with titles like, “Healthy Living in Hard Times.”

“Good life events,” he said, “don’t always lead to good health.”

The pattern is a testament to the sway that economic incentives hold over consumers, even when they do not realize that they are responding to those incentives. Rising incomes tempt our powers of self-control, effectively lowering the cost of a bottle of good Scotch, a buttery steak Bordelaise and other luxuries that are more enjoyable than healthy.