<qa>  What is the average weekly intake of alcohol within 6 months of the study?- History of regular alcohol consumption within 6 months of the study defined as: An average weekly intake of 21 units for males or 14 units for females. One unit is equivalent to 8 gram g of alcohol: a half-pint approximately 240 milliliter ml of beer, 1 glass 125 ml of wine or 1 25 ml measure of spirits. 