Sex No Age Average age(mean + SD) 20-29 30-39 40-49 50- Male 184 46 38 78 22 38.7 + 9.5 Female 152 128 19 5 0 25.6 + 4.9 Total 336 174 57 83 22 32.7 + 10.1

Table 1: Classification of subjects by age and gender. The questionnaires remained anonymous and when completed they were stored in a box to maintain privacy. All protocols were reviewed by the Yamaguchi University Institutional Review Board.