Fig. 1From: The association of cigarette smoking and alcohol drinking with body mass index: a cross-sectional, population-based study among Chinese adult male twinsGene-environment interaction model. M: environment moderator; BMI1 and BMI2: BMI in twin 1 and 2 within a twin pair, respectively; A1 and A2: additive genetic effects for twins 1 and 2 within a twin pair, respectively; C1 and C2: common environmental effects for twins 1 and 2 within a twin pair, respectively; E1 and E2: unique environmental effects for twins 1 and 2 within a twin pair, respectively; βm: mean moderator effect; βa: additive genetic moderator effect; βc: common environment moderator effect; βe: unique environment moderator effectBack to article page