Table 4

Interaction betweenUCHL1 S18Y polymorphism and smoking status affecting sporadic Parkinson’s disease in a Japanese population
Ever smoked
Yes No
Genotype No. cases/controls Adjusted OR (95 % CI)* No. cases/controls Adjusted OR (95 % CI)*
CC + CA 42/113 1.00 117/166 2.73 (1.62 − 4.61)
AA 20/32 1.72 (0.87 − 3.38) 50/46 4.08 (2.18 − 7.63)
P for multiplicative interaction = 0.74
Measures of additive interaction
 Relative excess risk due to interaction (RERI) = 0.63 (95 % CI: -1.48 − 2.75)
 Attributable proportion due to interaction (AP) = 0.16 (95 % CI: -0.31 − 0.62)
 Synergy index (S) = 1.26 (95 % CI: 0.59 − 2.68)

*Adjusted for sex, age, region of residence, and caffeine intake.

Statistically significant when the 95 % CI of RERI > 0, the 95 % CI of AP > 0, or the 95 % CI of S > 1, indicating additive interaction.

Miyake et al.

Miyake et al. BMC Neurology 2012 12:62   doi:10.1186/1471-2377-12-62

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