In an ominous sign for the health industry, Illinois’ largest insurer said its business may not grow for the first time in 25 years. The top executive at Blue Cross and Blue Shield of Illinois said the recession and rising number of unemployed consumers will lead to losses in the number of health plan subscribers.

Illinois Blue Cross, which grew its enrollment 2 percent, to 7.3 million plan members, last year from 2007, did not say how much it expected its membership to decline.

“I would be surprised if we grew,” said Paul Boulis, president of Blue Cross and Blue Shield of Illinois. “I don’t think since the 1984-85 cycle that we have lost business.”

Any reduction of members at the Illinois insurer is a national economic barometer for the health sector.

Illinois Blue Cross provides the bulk of the 12.4 million health plan members of its parent company, Health Care Service Corp.

The Chicago-based company is the nation’s fourth-largest health insurer, with Blue Cross plans also in Oklahoma, Texas and New Mexico.

Though Boulis said Health Care Service plans elsewhere are growing, Illinois Blue Cross is suffering partly because of its national accounts: companies with workers in multiple states, and unionized workers who get health benefits through health and welfare trusts. Such union workers losing their jobs include carpenters, plumbers and pipe fitters.

“We have 1 million members in health and welfare trusts,” Boulis said. “As the housing industry tanked, they were the [workers] immediately affected.”

When large health insurers lose business, it often means more people are joining the ranks of the uninsured. That, Boulis said, will put pressure on policymakers in Washington as they work to address the more than 45 million Americans without health insurance.

“It just makes the challenge for the Obama administration much more Herculean,” Boulis said.