Table 5. Threshold effect analysis of on using piecewise linear regression.

Marital status	Nonwidowed	Widowed
Inflection point (IP) of PSA level (ng/mL)	15.6	45.4
Lower than IP	1.089 (1.064, 1.115); <0.0001	1.056 (1.028, 1.084); <0.0001
Higher than IP	1.013 (1.005, 1.021); 0.0008	0.995 (0.958, 1.034); 0.8037