TABLE 3.

Effect of the Number of Cigarettes Smoked on Change in Cognitive Functions Over a 5-Year Period Among Ever Smokers: Doetinchem Cohort Study, Doetinchem, Netherlands, 1995–2005

	b	P
Memory function (n = 1162)	−0.04	.03
Speed of cognitive processes (n = 1161)	−0.02	.03
Cognitive flexibility (n = 1165)	−0.03	.04
Global cognitive function (n = 1146)	−0.02	.06

Note. The changes in domains of cognitive function are expressed in standardized scores per log-transformed pack-year (pack-years were calculated by dividing the average number of cigarettes smoked daily by 20 and then multiplying that by the number of years the participant had smoked). A negative value means more cognitive decline with more cigarettes smoked. Effects of smoking are adjusted for age (continuous), gender, level of education (5 classes), body mass index, hypertension, serum high-density lipoprotein cholesterol, cardiovascular disease, total energy intake, physical activity, alcohol consumption (5 classes), intake of total fat, beta-carotene and vitamin C (as energy residuals), and the baseline level of cognitive function.