GSTM1 and Marchiafava-Bignami disease: Regarding linear regression and multinominal analysis in Table 7, age, place of residence, and duration of activity (per year) influence change of CRP, RBC, Hb, monocytes and lymphocytes of MBD in Douala, after adjustment for age, level of education, BMI, smoking, and use of domestic gas, firewood and coal.