Table 3.

Threshold effect analysis of dietary niacin intake and suicidal ideation using the two-piecewise linear regression model

dietary niacin intake	Adjusted OR (95% CI)	P value
Fitting by the standard linear model (ln niacin intake increment)	0.86 (0.77 ~ 0.96)	0.008
Fitting by the two-piecewise linear model
Inflection point	26.78
dietary niacin < 26.78(ln niacin intake increment)	0.81 (0.69 ~ 0.95)	0.008
dietary niacin > 26.78(ln niacin intake increment)	1.37 (0.94 ~ 2.01)	0.102
Log likelihood ratio		0.011

Gender, age, race, drinking, BMI, smoking, physical activities, CHD, hyperlipidemia, stroke, PIR, education level, marital status, albumin, creatinine, depression disorder, and cancer were adjusted