U.S. consumer sentiment improved across the board in January, though concerns about high prices and the labor market lingered, a survey showed on Friday. The University of Michigan's Surveys of Consumers said its Consumer Sentiment Index increased to a final reading of 56.4 this month, from an earlier estimate of 54.0. The index was at 52.9 in December. Economists polled by Reuters had forecast the index would be unrevised from the preliminary estimate.