Brain aging in a sample of normal Egyptians cognition, education, addiction and smoking

The impact of duration of education, cannabis addiction and smoking on cognition and brain aging is studied in 211 normal Egyptian volunteers with mean age 46.4+/-3.6 years (range: 20-76 years). Subjects were classified into two groups: Gr I(non-addicts) with 174 subjects, mean age 49.9+/-3.8 years (range 20-76 years), smokers and non-smokers, educated and non-educated and Gr II (cannabis addicts) with 37 subjects, mean age 43.6+/-2.6 years (range 20-72 years) all smokers, educated and non-educated. Outcome measures included the Paced Auditory Serial Addition test (PASAT) for testing attention and the Trailmaking test A, and B (TMa and TMb) for testing psychomotor performance. Age correlated positively with score of Trailmaking test (TMb) in the non-addict group and in the addict group (TMa and TMb). Years of education correlated negatively with scores of Trialmaking test (TMb) in the non-addict group (Gr I) but not the addict group (Or II). However, in both groups mean scores of the Trailmaking test (TMa) were significantly lower in subjects with a primary level of education than those with higher levels of education. No significant difference was detected between male smokers and nonsmokers of Gr I (non-addicts) regarding any of the neuropsychological tests. Yet, smokers and the non-educated group had poorer attention compared to non-smokers of the same group. Cannabis addicts (Gr II) had significantly poorer attention than non-addict normal volunteers (Or I). It is concluded that impairment of psychomotor performance is age related whether in normal non-addicts or in cannabis addicts. A decline in attention was detected in cannabis addicts and has been considered a feature of pathological aging. Education in early life as well as the duration of education are neuroprotectors for brain aging more so in the non-addict than addict group. Though cigarette smoking per se has no effect on cognitive abilities in normal aging, it becomes evident that its association with lack of education impairs attention. (C) 1997 Elsevier Science B.V.