London -- Reed Elsevier, the parent company of Newton, Mass.-based Cahners Business Information, Thursday released its preliminary year-end results for 1998. The company saw operating profits decline 6% between 1997 and 1998. It blamed the slide on, among other factors, softness in its travel industry publications. Cahners Business Information, however, was a particularly strong Reed Elsevier unit. It saw revenue increase 16% between 1997 and 1998, thanks in large part to its acquisition of the Chilton Business Group. Operating profit for Cahners Business Information climbed 10% in the same period.