LONDON (Reuters) - British sportswear retailer JD Sports on Wednesday forecast little or no profit growth this year, even before any potential impact from U.S. tariffs, with the trading environment in its key markets expected to be "volatile". Shares in JD have lost over a third of their value so far this year on worries about consumer spending amid a downturn in demand for Nike products, which account for about 45% of JD's sales. With just under 40% of its sales made in the U.S., the group is also exposed to newly imposed U.S. tariffs. JD said the outcome of the tariffs "is uncertain". "We are in regular dialogue with our brand partners but it is too early to comment on the potential sector impact," it said. JD forecast a year to February 1 2025 profit before tax and adjusting items in line with its guidance in January of 915 million to 935 million pounds ($1.17-$1.20 billion). For the 2025/26 year it forecast an outcome in line with analysts' current consensus expectation of 920 million pounds. However, it flagged that its forecast excludes any potential impact from changes to tariffs. ($1 = 0.7803 pounds) (Reporting by James Davey; Editing by Sachin Ravikumar)