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(A) <45 year: χ2 = 2.097, P = 0.553; (B) 45–60 year: χ2 = 46.729, P < 0.001; (C) 61–75 year: χ2 = 14.877, P = 0.002; (D) >75 year: χ2 = 5.327, P = 0.149.
