6Centers for Disease Control and Prevention,Public Health Surveillance and Informatics Program Office.Behavioral risk factor surveillance system:history[EB/OL].2012.(2014-10-15).http://www.cdc. gov/brfss/factsheets/pdf/BRFSS-History.pdf.
7Centers for Disease Control and Prevention.Behavioral risk factor sur- veillance system 2012 summary data quality report[EB/OL].2013. http://www.cdc.gov/brfss/annual _ data/2012/pdf/ SummaryDa- taQualityReport2012_20130712.pdf.
8Centers for Disease Control and Prevention.Behavioral risk factor sur- veillance system OVERVIEW:BRFSS[EB/OL].2012.2012.http:// www.cdc.gov/brfss/annual_data/2012/pdf/0verview_2012.pdf.
9Centers for Disease Control and Prevention.2013 Behavioral risk fac- tor surveillance system questionnaire[EB/OL].2013.(2014-10-15). http://www.cdc.gov/brfss/questionnaires/pdf-ques/2013_ BRFSS. pdf.
10Hu SS,Pierannunzi C,Balluz L.Integrating a multimode design into a national random-digit-dialed telephone survey[J j.Prev Chronic:Dis, 2011,8(6):A145.