The Impact of Cell Phone Inclusion on Binge Drinking Estimates in New Mexico, 2006-2011

BACKGROUND: Binge drinking (≥ 4 drinks for women; ≥ 5 drinks for men, per occasion) is responsible for more than half of the estimated 80,000 U.S. alcohol-attributable deaths (AAD) annually and three-quarters of the $223.5 billion in costs in 2006.  The prevalence of binge drinking among New Mexico adults, as measured by the New Mexico Behavioral Risk Factor Surveillance System (NMBRFSS), has historically been close to the national median; and has been declining in recent years, while New Mexico’s AAD rate has remained among the highest in the United States.  Concern has increased that the BRFSS, traditionally a landline telephone survey, might be missing the younger population that has increasingly adopted cell phones; and that this might impact prevalence estimates for behaviors like binge drinking that are more prevalent in the younger population.  In 2011, the NMBRFSS survey addressed this concern by including a substantial cell phone sample.  This paper will compare NMBRFSS binge drinking estimates from before and after the inclusion of cell phones.   

METHODS: Data were analyzed from 42,838 adult respondents to the 2006-2011 NMBRFSS surveys. Weighted estimates of binge drinking prevalence, frequency, and intensity (measured using maximum drinks) for the 5-year period prior to the inclusion of cell phones (2006-2010) were compared to estimates for the first full year of cell phone inclusion (2011).  Estimates were compared by age, sex, race/ethnicity, education, marital status, income, and region.  

RESULTS: The prevalence of binge drinking increased significantly between 2006-2010 and 2011, from 12.4% to 17.1% (38%, p < 0.0001).  Increases in estimated binge drinking prevalence were particularly substantial among young adults aged 25-34 (62.0%), females (41.8%), Hispanics and American Indians (42.4%), persons with less than a high school education (50.6%), and in New Mexico’s most metropolitan region (52.2%).  There were no significant changes in either binge drinking frequency or binge drinking intensity associated with the inclusion of cell phone respondents, either overall or by demographic subgroup.  The only substantial change in binge intensity, 23% among 18-24 year olds (from 8.1 to 10.0 drinks), was not statistically significant. 

CONCLUSIONS: The inclusion of cell phone respondents in the NMBRFSS survey resulted in a substantial and significant 38% increase in binge drinking prevalence, driven by a 62% increase in reported prevalence among young adults aged 25-34.  The expanded sample of binge drinkers engaged by the inclusion of cell phones did not differ from previous samples in either the frequency or intensity of their binge drinking behavior.