exposure to tobacco smoke, sun light ,pets and farm animals and multiple sclerosis: a case control study in ahvaz (iran)

background: numerous studies have assessed risk factors for multiple sclerosis (ms), but regarded to paradoxical results & specific ethnical- cultural circumstances in ahvaz, as a city in iran, this case-control study was aimed to assess some factors related to lifestyle (consumption & exposure with cigarette smoking, duration & surface of sun light exposure, exposure to pets and farm animals) for ms. methods: this case–control study, including 155 ms cases and 155 matched controls, was conducted in ahvaz ms society. for data gathering, questionnaire made by researcher including demographics and disease characteristics, and some factors related to life style after approval of validating & reliability (cronbach alpha 0.9) .data analyzed with spss software version 19.  findings: consumption and exposure with cigarette smoking, surface of sun light exposure, & exposure with noose or indoor animal had no significant influence on afflicting to ms disease, but there was significant difference between two groups in duration of sun light exposure & afflicting to ms disease (p=0.04). conclusion: this study showed that some environmental factors such as duration of sun light exposure can play role in afflicting to ms disease.