title: Seasonality in sales of nicotine replacement therapies: patterns and implications for tobacco control.
abstract: BACKGROUND
  Over the counter, nicotine replacement therapies (NRTs) are the most widely used smoking cessation treatment. This study sheds light on the seasonality of sales of NRT.
  
  
  METHODS
  A seasonal adjustment algorithm was applied to data on the sales of NRT products for 50 metro markets in the United States to test for and characterize seasonality in NRT sales. Granger's test was applied to the data to test whether changes in NRT sales systematically predicted changes in cigarette sales 1 month later.
  
  
  RESULTS
  The results show (a) that sales of NRT products are seasonal, (b) that the seasonality pattern is the opposite of the seasonality pattern for cigarette sales, (c) that seasonally higher NRT sales in a given month tend to be followed by seasonally lower cigarette sales in the following month, and (d) that seasonally high months for NRT sales (January to March) correspond to seasonally low months for cigarette sales.
  
  
  CONCLUSIONS
  NRT sales show a strong seasonality pattern that is the opposite of the seasonality pattern for cigarette sales. These patterns are indicative of seasonal variations in quitting behavior.
authors.affiliation: Asian Studies Center, Michigan State University, 301 International Center, East Lansing, MI 48824, USA. chandr45@msu.edu
authors.forename: Siddharth
authors.initials: S
authors.lastname: Chandra
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Gitchell
authors.forename: Saul
authors.initials: S
authors.lastname: Shiffman
mesh_terms: D000465:Algorithms; D003132:Commerce / Q000706:statistics & numerical data*; D006801:Humans; D012621:Seasons; D012907:Smoking / Q000523:psychology; D016540:Smoking Cessation / Q000523:psychology* / Q000706:statistics & numerical data*; D000074606:Smoking Prevention; D014481:United States