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<br />Brief rep6rt---
<br />17 089 each year. Student gender and grade distributions were
<br />similar across all years.
<br />Measures
<br />The MWAHS instrument is a classroom -administered anonym-
<br />ous survey that incorporates items from the Center for Disease
<br />Control and Prevention's Youth Risk Behavior Survey.lo We
<br />examined two tobacco outcome measures: (1) current (30 -day)
<br />cigarette smoking (any vs none) using the question "During the
<br />past 30 days, on how many days did you smoke cigarettes", and
<br />(2) current (30 -day) purchase of cigarettes in a store (any vs
<br />none), using the question "During the past 30 days, how did
<br />you usually get your own cigarettes?" with seven response cat-
<br />egories: did not try to get cigarettes/bought them in a store/gave
<br />someone else money to buy them for me/borrowed or bummed
<br />them/a person 18 or older gave them to. me/took them from a
<br />store or family member/got them some other way. This latter
<br />measure of store purchases was restricted to current smokers
<br />under age 18 who gave a response other than that they did not
<br />try to get cigarettes in the past 30 days. We also examined
<br />current (30 -day) alcohol use (any vs none) to determine if
<br />trends for smoking and drinking differed.
<br />Analyses
<br />To compare smoking outcomes in Needham with the 16 com-
<br />parison communities, we conducted pooled cross-sectional ana-
<br />lyses. First, we fit a series of Poisson regression models for each
<br />of the two smoking outcomes (current smoking and current
<br />purchase of cigarettes in a store) using generalised estimating
<br />equations .(SAS Proc GENMOD).11 The models estimated three
<br />parameters: (1) differences in the proportion of youth reporting
<br />each outcome at baseline (2006), comparing Needham to the
<br />16 surrounding communities (Rl); (2) change in these propor-
<br />tions across consecutive survey years (eg, 2006-2008, 2008-
<br />2010, and 2010-2012) across all study communities 02); and
<br />(3) whether the change over time differed between Needham
<br />and the comparison communities, the main parameter of inter-
<br />est (P3). All models adjusted for two measures of school com-
<br />position: per cent of students receiving free/reduced cost school
<br />lunch (an index of socioeconomic status) and per cent of
<br />Caucasian students (an index of racial/ethnic composition), both
<br />mean centred. For example, to compare the prevalence of
<br />current smoking between 2006 and 2008, we used data for
<br />these 2 years only and fit the following model:
<br />Smoking = Ro + (31Needham +(322008 +(332008 x Needham
<br />+ N(%free lunch) + RS(%non - white)
<br />Similar models were fit comparing 2008 with 2010 and 2010
<br />with 2012, with separate models estimated for the prevalence of
<br />current cigarette use, current purchase of cigarettes in a store
<br />and current alcohol use.
<br />Second, we modelled the prevalence of current smoking,
<br />current store purchases of cigarettes and current alcohol use for
<br />years 2006-2010 only, with a linear term for study year
<br />because, as shown below, models including these years produced
<br />a consistent pattern of results. This final model was:
<br />Smoking = Ro + P,Needham + (32Study year + (33Study year
<br />x Needham + N M free lunch) + RS (%non - white)
<br />where again R3 is the coefficient of interest reflecting differences
<br />in change over time for Needham compared with the 16
<br />comparison communities from 2006 to 2010. This model was
<br />fit for current smoking and current alcohol use for various sub-
<br />groups (gender, race/ethnicity, grade) to examine whether the
<br />overall pattern of results was consistent across different student
<br />populations.
<br />RESULTS
<br />Smoking behavior
<br />Thirty -day smoking prevalence is shown in figure 1A, along
<br />with the results of the Poisson regression models that summarise
<br />the findings for consecutive survey years. In 2006, current
<br />smoking did not differ significantly between Needham and the
<br />16 comparison communities. From 2006 to 2008, current
<br />smoking decreased at a greater rate in Needham than in the
<br />comparison communities 03=-0.174, p<0.001), and again
<br />from 2008 to 2010 ((33=-0.278, p<0.001). However, from
<br />2010 to 2012, decreases in current smoking were significantly
<br />greater in the comparison communities than in Needham
<br />(03=0.143, p<0.01).
<br />Results of additional analyses on current smoking restricting
<br />data to the time period 2006-2010 are presented in table 1.
<br />These analyses were restricted to the first three surveys because
<br />that was the period of time during which the decline in youth
<br />smoking was significantly greater in Needham relative to the
<br />comparison communities. In 2006, shortly after the minimum
<br />purchase age was raised in Needham, the estimated prevalence
<br />of 30 -day smoking between Needham and the comparison com-
<br />munities did not differ (01=0.062; ns (non-significant)); the
<br />prevalence for all communities decreased significantly with time
<br />((32=-0.050; p<0.001). Most notably, the overall decline in
<br />Needham's 30 -day smoking prevalence exceeded that of the
<br />comparison communities combined (03=-0.108; p<0.001).
<br />This statistically greater decline in Needham was observed for
<br />all subgroups (females, males, Caucasian, non -Caucasian, and
<br />by student grade), with the exception of ninth grade youth, who
<br />reported low levels of smoking.
<br />Cigarette purchases in stores
<br />From 2006 to 2012, the percentage of youth under age 18 who
<br />purchased cigarettes in stores decreased significantly more in
<br />Needham (from 18.4% to 11.6%) than in the comparison com-
<br />munities (from 19.4% to 19.0%; p<0.001) (see figure 1B). The
<br />findings follow the same general pattern as current smoking: the
<br />rate of decline in purchasing cigarettes in Needham relative to
<br />the comparison communities was greatest for the period from
<br />2006 to 2008 03=-0.667; p<0.001), lessened for the period
<br />from 2008 to 2010 (R3=0.200; p<0.05), and did not show a
<br />significant change from 2010 to 2012 (p3=0.029; ns). Since the
<br />pattern of findings was similar to that of current smoking, we
<br />also examined the overall change from 2006 to 2010; the
<br />decline in store purchases in Needham over this period was
<br />greater than in the comparison communities 03=-0.46S,
<br />P<0.001).
<br />Comparison to alcohol use
<br />Notably, the findings for current alcohol use were distinct from
<br />those for current cigarette smoking: from 2006 to 2012, there
<br />was a general decline in the 30 -day prevalence of drinking, with
<br />no significant differences between Needham and the compari-
<br />son communities over any of the consecutive survey waves (see
<br />figure 1C). Models for the combined years spanning 2006-
<br />2010 also show that there was no significant difference in the
<br />30 -day prevalence of drinking in Needham compared with the
<br />16 comparison communities (I'3=-0.003; ns) (data not shown).
<br />356 Kessel Schneider S, et al. Tob Control 2016;25:355-359. doi:10.1136/tobaccocontrol-2014-052207
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