The relation of sex, age, smoking status, birth rank and parental ages to pseudocholinesterase activity and phenotypes in a sample of Australian Caucasian adults.

The frequencies of the pseudocholinesterase alleles E1u, E1a and E1f have been determined in a random sample of Australian residents. The frequency of E1a is the highest yet reported in a large caucasian sample. The considerable variation in E1f frequencies in previously reported samples is discussed in terms of possible sources of error in fluoride number determinations. Enzyme activity was found to increase with age in adulthood and was higher in males than in females. It was also positively correlated with dibucaine number in type U subjects. These observations are in conflict with those reported in previous investigations.