1. From the Departments of Public Health (S.-L.W., S.-P.C.) and Family Medicine (M.-C.L.), Chung Shan Dental and Medical College, and National Institute of Family Planning, Department of Health, Executive Yuan (M.-C.C.), Taichung, Taiwan; and the Division of Epidemiology and Public Health, Institute of Biomedical Sciences, Academia Sinica, and School of Public Health, National Taiwan University (W.-H.P.), Taipei, Taiwan, ROC.