Nutrition supplement retailer GNC announced on Monday that it expects to close up to 900 stores by the end of next year.

During a quarterly earnings conference call, GNC chairman and CEO Ken Martindale told investors that the company had seen an increase in the negative trends involving their stores based in shopping malls, and the company is taking a close look at those mall stores.

Sixty-one percent of GNC stores are located in strip shopping centers. Twenty-eight percent are in shopping malls.

Here in the Valley, GNC has stores in both the Eastwood and Southern Park Malls, as well as plaza locations in Austintown, Boardman, Bazetta Townships and New Castle.

GNC has not announced which stores are closing.