ali dadgari department of geriatric nursing, school of nursing & midwifery, shahroud university of medical sciences, shahroud, iran and national institute of gerontology, university putra malaysia, kula lumpur, malaysia tengku aizan hamid national institute of gerontology, university putra malaysia, kula lumpur, malaysia mohammad nazrul hakim department of medicine, school of medicine and health sciences, university putra malaysia, kula lumpur, malaysia reza chaman department of community medicine, school of medicine, yasuj university of medical sciences, yasuj, iran seyed abbas mousavi center for health-related social and behavioral sciences research, shahroud university of medical sciences, shahroud, iran lim poh hin department of medicine, school of medicine and health sciences, university putra malaysia, kula lumpur, malaysia