Table 1 Characteristics of smokers and non-smokers.

From: Effects of smoking on cognition and BDNF levels in a male Chinese population: relationship with BDNF Val66Met polymorphism

 

Smokers (N = 322)

Nonsmokers (N = 306)

F

P

Age (years)

46.6 ± 11.8

45.8 ± 13.3

0.46

>0.05

Education (years)

9.1 ± 3.5

9.2 ± 3.6

0.21

>0.05

BMI (Kg/m2)

25.4 ± 6.1

24.9 ± 5.8

0.89

>0.05

BDNF (ng/ml)a

11.6 ± 2.3

11.5 ± 3.0

0.23

>0.05

Allele frequency (%)

  Val

339 (52.6%)

304 (49.7%)

1.11

>0.05

  Met

305 (47.4%)

308 (50.3%)

  

Genotype frequency (%)

 

2.26

>0.05

  Val/Val

81 (25.1%)

74 (24.2%)

  

  Met/Val

177 (55.0%)

156 (51.0%)

  

  Met/Met

64 (19.9%)

76 (24.8%)

  
  1. Note: BMI = body mass index; BDNF = brain-derived neurotrophic factor.
  2. aBDNF serum level data were available from 103 smokers and 89 nonsmokers.