Diurnal Evening Type is Associated with Current Smoking, Nicotine Dependence and Nicotine Intake in the Population Based National FINRISK 2007 Study.

AIMS: To examine whether smoking habits, nicotine dependence (ND) and plasma cotinine levels differ by diurnal type. DESIGN: Data originated from the national FINRISK 2007 survey. Regression analyses were calculated to examine the association between diurnal type and smoking status, ND, and nicotine intake. PARTICIPANTS: 7091 FINRISK participants with smoking and diurnal type information and a subset of 1746 ever smokers with detailed smoking, and ND assessments. MEASUREMENTS: Diurnal type assessed with a six-item sum scale was categorized as morning, intermediate and evening type. Smoking status was determined as current (daily or occasional), former, and never smokers. ND was measured with the Fagerström Test for Nicotine Dependence (FTND), the Hooked on Nicotine Checklist (HONC), and the Nicotine Dependence Syndrome Scale (NDSS). For current smokers, plasma cotinine was analyzed as biochemical measurement of nicotine intake. FINDINGS: Evening type was associated with current smoking (OR=1.66, 95% CI 1.40, 1.97). A significant association with diurnal type was seen for FTND among men (beta= -0.46, 95% CI -0.72, -0.21), sexes combined for HONC (beta= -0.31, 95% CI -0.52, -0.11) and NDSS (beta= -0.86, 95% CI -1.43, -0.29) and for cotinine among men (beta= -0.73, 95% CI -1.16, -0.29). Adjustment for depressive symptoms attenuated the association of diurnal type with NDSS to be non-significant. CONCLUSIONS: Diurnal type was associated with multiple ND measures and nicotine intake, interestingly more so among men. Evening type persons are at higher risk of dependence, but depressive symptoms attenuates this association clearly.