Tokyo, Dec. 30 (Jiji Press)--Sumitomo Life Insurance Co. aims to double membership of its flagship health-promotion insurance program, Vitality, to 5 million over the next five years, banking on a new related asset-building product to drive this growth, President Yukinori Takada said in a recent interview. Takada said the company plans to launch the new Vitality-linked asset-building product...