Aon Corp , the world's largest insurance broker, said on Friday that first-quarter profit rose 28 percent, as cost savings from a restructuring helped overcome a slippage in revenue caused by currency fluctuations and lower investment income.

Chicago-based Aon, which helps business clients secure insurance coverage, said net income increased to $280 million, or 97 cents per share. Income from continuing operations rose 30 percent to $230 million, or 80 cents per share.

Excluding items, mostly related to restructuring efforts, the company said its earnings improved 9 percent to 76 cents per share, 12 cents shy of analysts' forecasts, according to Reuters Estimates.

Revenue slipped 3 percent to $1.9 billion due to a 10 percent decline from foreign currency translation and a 44 percent drop in investment income.

Fluctuations in the U.S. dollar against other major currencies shaved two cents a share from net earnings, Aon said.

But the company said income from acquisitions, primarily its purchase of reinsurance broker Benfield last year, rose 7 percent.

Reinsurance was the only area where Aon's main business -- risk and insurance brokerage -- saw any growth in the quarter.

Overall revenue for the division fell 1 percent to $1.55 billion, reflecting declines across all regions where Aon operates.

Cost savings from restructuring were $45 million in the quarter, and Aon said it still expects to trim expenses by between $273 million and $306 million this year.

Aon shares fell 3.4 percent in light premarket trade from their Thursday close at $42.20 on the New York Stock Exchange.

The stock has fallen about 10 percent in the last 12 months but has bounced back from a 52-week low of $33.58 last October, Reuters data shows.

(Reporting by Christopher Kaufman and Lilla Zuill; Editing by Lisa Von Ahn and Steve Orlofsky)