Access to this full-text is provided by MDPI.
Content available from International Journal of Environmental Research and Public Health (IJERPH)
This content is subject to copyright.
International Journal of
Environmental Research
and Public Health
Article
Where Do Vapers Buy Their Vaping Supplies?
Findings from the International Tobacco Control
(ITC) 4 Country Smoking and Vaping Survey
David C. Braak 1, K. Michael Cummings 2, 3,* , Georges J. Nahhas 2,3, Bryan W. Heckman 2,3,
Ron Borland 4,5, Geoffrey T. Fong 6,7,8, David Hammond 9, Christian Boudreau 10,
Ann McNeill 11 , David T. Levy 12 and Ce Shang 13
1Colleges of Graduate Studies and Medicine, Medical University of South Carolina, Charleston, SC 29425,
USA; braak@musc.edu
2Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, Charleston,
SC 29425, USA; elnahas@musc.edu (G.J.N.); heckmanb@musc.edu (B.W.H.)
3Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
4Nigel Gray Fellowship Group, Cancer Council Victoria, Melbourne 3004, Australia;
Ron.Borland@cancervic.org.au
5School of Psychology, Deakin University, Burwood, Melbourne 3220, Australia
6Department of Psychology and School of Public Health and Health Systems, University of Waterloo,
Waterloo, ON N2L 3G1, Canada; gfong@uwaterloo.ca
7Department of Psychology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
8Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
9School of Public Health and Health Systems, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
david.hammond@uwaterloo.ca
10 Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
cboudreau@uwaterloo.ca
11 Department of Addictions, Institute of Psychiatry, Psychology, and Neuroscience, King’s College London,
London WC2R 2LS, UK; ann.mcneill@kcl.ac.uk
12 Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington,
DC 20057, USA; dl777@georgetown.edu
13 Oklahoma Tobacco Research Center, Stephenson Cancer Center, University of Oklahoma Health Sciences
Center, Oklahoma City, OK 73104, USA; ce-shang@ouhsc.edu
*Correspondence: cummingk@musc.edu
Received: 19 December 2018; Accepted: 19 January 2019; Published: 26 January 2019
Abstract:
Aim: This study examines where vapers purchase their vaping refills in countries
having different regulations over such devices, Canada (CA), the United States (US), England (EN),
and Australia (AU). Methods: Data were available from 1899 current adult daily and weekly vapers
who participated in the 2016 (Wave 1) International Tobacco Control Four Country Smoking and
Vaping. The outcome was purchase location of vaping supplies (online, vape shop, other). Adjusted
odds ratios and 95% confidence intervals were reported for between country comparisons. Results:
Overall, 41.4% of current vapers bought their vaping products from vape shops, 27.5% bought
them online, and 31.1% from other retail locations. The vast majority of vapers (91.1%) reported
using nicotine-containing e-liquids. In AU, vapers were more likely to buy online vs other locations
compared to CA (OR = 6.4, 2.3–17.9), the US (OR = 4.1, 1.54–10.7), and EN (OR = 7.9, 2.9–21.8). In the
US, they were more likely to buy from vape shops (OR = 3.3, 1.8–6.2) or online (OR = 1.9, 1.0–3.8) vs
other retail locations when compared to those in EN. In CA, vapers were more likely to purchase at
vape shops than at other retail locations when compared to vapers in EN (5.9, 3.2–10.9) and the US
(1.87, 1.0–3.1). Conclusions: The regulatory environment and enforcement of such regulations appear
to influence the location where vapers buy their vaping products. In AU, banning the retail sale of
nicotine vaping products has led vapers to rely mainly on online purchasing sources, whereas the
lack of enforcement of the same regulation in CA has allowed specialty vape shops to flourish.
Int. J. Environ. Res. Public Health 2019,16, 338; doi:10.3390/ijerph16030338 www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2019,16, 338 2 of 13
Keywords: electronic cigarettes; vaping; vaping policies
1. Introduction
Sales of nicotine vaping products (NVPs), also referred to as electronic cigarettes, have increased
over the past decade, and in some countries they have become the most popular quitting aid used
by smokers [
1
–
4
]. As vaping prevalence has increased over time, so has the diversity of products
available to consumers [
5
]. NVPs broadly include three types of products: (1) closed systems that are
intended to be thrown out when emptied (closed disposable system), (2) rechargeable devices which
use pre-filled e-liquid cartridges (closed cartridge system); and (3) and rechargeable open system
devices that allow users to refill the e-liquid used (open tank system). Different NVPs differ in how
they deliver nicotine, which influences quitting cigarette-smoking [
6
–
9
], though individual factors
may contribute as well [
10
]. Some types of products (ex. tank systems) require more accessory parts
than others (ex. disposable), it is possible that some retail locations will be more or less likely to sell
certain products. Users of various products may, therefore, be more or less likely to purchase at certain
locations as well.
A 2014 survey of online sites selling NVPs identified at least 466 brands available in 7764 assorted
flavors, with two types of propellants, offering an average of four to five nicotine strengths [
11
].
Recent evidence reviews suggest that NVPs are likely to have a substantially lower health impact
compared to cigarettes, although these evidence reviews also suggest that nicotine vaping is not done
without some potential health risks and the health risks are likely to be different for smokers who vape
exclusively compared to those who smoke and vape concurrently [
12
,
13
]. Because of their novelty
and the lack of conclusive evidence on their health effects, safety, and cessation efficacy, it has been
unclear whether NVPs should be regulated as tobacco products, therapeutic goods, medical devices,
or consumer lifestyle products [12,13].
Countries have taken different approaches to regulating NVPs, with some banning their sale
at retail without pre-market government authorization, and others allowing their sales with specific
restrictions, primarily age restrictions. Regulation in Australia (AU), and until recently in Canada,
(CA) prohibited the retail sale of NVPs unless government authorization had been obtained prior to
marketing. Non-nicotine vaping products were allowed for sale in all four countries. In CA, the law
restricting the sale of NVPs in retail locations changed in May 2018. However, at the time of this study
in 2016, health authorities in Canada did not enforce the NVP sales ban in retail establishments [
14
].
NVPs could be legally sold to adults at retail locations in England (EN) and the United States (US).
Studies found that government regulations restricting the sale and marketing of NVPs can influence
consumer awareness and use of NVPs [4].
While countries regulated the source of purchase differently, information on where individuals
buy their NVPs is limited. One cross sectional study on California high school students, found that
the most likely purchase location for NVPs was “smoke shops” for those older and younger than 18.
This study did not include “vape shop” in its answer choices, was mainly concerned with tobacco
products in general, and the majority of students surveyed obtained their products from a friend [
15
].
In this study, we reported on where current (daily and/or weekly) vapers purchase their vaping
products and refills, behavioral characteristics of users, and product features by purchase location.
We also compare purchase location by country of residence.
Int. J. Environ. Res. Public Health 2019,16, 338 3 of 13
2. Methods
2.1. Study Participants
Data were available from a sub-sample of the 2016 (Wave 1) International Tobacco Control Four
Country Smoking and Vaping (ITC 4CV1) participants who reported currently vaping daily or weekly.
Details about this survey can be found elsewhere [
16
]. Briefly, the ITC four country survey is an
online panel-based survey which included respondents 18 years or older who had smoked at least 100
cigarettes in their lifetime, who was currently smoking, or who had quit smoking within the last two
years. Recruitment was conducted entirely from web panels. Analyses presented in this paper were
restricted to those who reported purchasing their own vaping device or e-liquid. Those who did not
remember any details of their last purchase and those who did not answer the purchasing question
were excluded. There was a total of 1899 current daily or weekly vapers who reported purchasing
their products within the last 30 days, 456 in CA, 701 in the US, 667 in EN, and 75 in AU. Analyses
presented in this paper were restricted to those who reported purchasing their own vaping device or
e-liquid. Those who did not remember any details of their last purchase and those who did not answer
the purchasing question were excluded. There was a total of 1899 current daily or weekly vapers who
reported purchasing their products within the last 30 days, 456 in CA, 701 in the US, 667 in EN, and 75
in AU.
2.2. Measures
The outcome measure was where vapers reported purchasing their vaping products (online,
vape shop, other location). Participants were asked “Now thinking about the LAST TIME you
purchased disposable e-cigarettes, cartridges, or e-liquid, where did you make this last purchase?”
Responses were grouped into online, vape shop, or other (i.e., “tobacco specialty shop/tobacconist”,
“newsagent/off-license/corner shop/convenience shop”, “convenience store including petrol station”,
“gas/petrol station”, “supermarket”, “pharmacy”, “chemist”, “pub or bar”, “temporary mobile
sales location”, “some other kind of Shop”, “from outside the country”, or “from somewhere else”).
The independent variable was country of purchase (CA, the US, EN, and AU).
User characteristics included, smoking frequency (i.e., daily, non-daily, not at all), vaping
frequency (i.e., daily or weekly), vaping duration (i.e., <1 month, 1–3 months, >3 months). We also
examined how demographic characteristics, and vaping product features varied by purchase location
in each of the four countries.
Participant demographic characteristics included age (i.e., 18–24 years, 25–39 years, 40–54 years,
55+ years), gender (i.e., male vs female), race (i.e., white or non-white), and educational level (i.e.,
low = high school or less, moderate = technical degree or some university, high = completed university).
In addition, participants in each country were asked, “which of the following categories best describes
your annual household income, that is the total income before taxes, or gross income, of all persons
in your household combined, for one year?” Because currencies and standards for defining income
status varied between countries we categorized respondents as either low, moderate, or high income
as follows: US: low = less than 30,000 USD, moderate = 30,000–59,999 USD, and high = 60,000 USD,
and AU: low = less than 30,000 AUD, moderate = 30,000–59,999 AUD, and high = 60,000 CAD. For EN,
low = less than 30,000 GBP, moderate = 30,000–45,999 GBP, and high = 45,000 GBP or more.
Vaping product characteristics included self-reported e-liquid nicotine strength which was
collapsed into three groups: (1) no nicotine, (2) contains nicotine; and (3) don’t know, e-liquid
flavor (i.e., tobacco, menthol or mint, fruit, candy/deserts/sweets, and other), product type (i.e.,
disposable, cartridge, and tank systems), and product modifiability (i.e., power not modifiable, power
adjustment possible—but not used, power adjustment possible—and used, and don’t know), following
the approach suggested by O’Connor et al [5].
Int. J. Environ. Res. Public Health 2019,16, 338 4 of 13
2.3. Data Analysis
Weighted generalized logistic regression for survey data (i.e., proc surveylogistic) was performed
using SAS 9.4 (SAS Institute, Cary, NC, USA), accounting for missing data being missing not at
random (i.e., nomcar option) with purchasing location as the dependent variable and country as
the independent variable. The model was adjusted for smoking and vaping frequency, age, gender,
ethnicity, household income, educational level, e-liquid flavor, and type of vaping device. Those who
refused or did not report ethnicity, household income, and educational level were excluded along with
those who reported buying nicotine-free e-liquid. Frequencies and percentages were reported as well
as odds ratios with 95% confidence intervals for pair-wise comparisons between countries (i.e. country
vs country by location vs location).
2.4. Ethics Approval
The survey protocols and all materials, including the survey questionnaires, were cleared for
ethics by Institutional Review Board, Medical University of South Carolina (ORE #: 20803); Research
Ethics Office, King’s College London, UK (ORE #: 20803 and RESCM-17/18-2240); Office of Research
Ethics, University of Waterloo, Canada (ORE #: 20803 and ORE #: 21609); and Human Research Ethics,
Cancer Council Victoria, Australia (ORE #: 21609 and HREC 1603).
3. Results
Overall, in all four countries the majority of current vapers were white, and male. The ages of
the participants were fairly evenly distributed, though in the US and AU the largest age category was
25–39 (US: 33.4%, AU: 40.8%). In England and in Canada the ages of the participants skewed a little
older with the largest category in England being 55+ (38.3%) and the largest category in Canada being
40–45 (38.6%). In all four countries, most current vapers were categorized as daily vapers; in EN and
AU greater than 50% of current vapers did not smoke at all, whereas in Canada the largest category of
smoking frequency was daily smoking (45.2% of current vapers). Current vapers in all four countries
reported having a high household income the most often, and a moderate education level (except
in the US where the largest category of education level was “low”). In total 41.4% of current vapers
bought their vaping products from vape shops, 27.5% bought them online, and 31.1% from other retail
locations. The vast majority of vapers (91.1%) reported using nicotine-containing e-liquids; 90.3% in
CA, 90.2% in the US, 94.6% in EN, and 88.5% in.
In CA and the US, the majority of vapers bought their vaping products from vape shops, 65.3%
and 43.3%, respectively. In EN, most vapers bought their products from other retail locations (37.7%),
and in AU, mostly from online sources (65.2%). In all four countries, the majority of NVP users who
were purchasing their own products reported using tank system NVPs (67.6% in CA, 59.4% in US,
75.1% in EN, and 82.4% in AU), followed by cartridge systems (19.1% in CA, 29.6% in US, 20.7% in EN,
and 10.1% in AU), and disposables (13.2% in CA, 11% in US, 4.2% in EN, and 7.6% in AU). With the
exception of NVP users in EN (42.5%), the majority of survey participants reported using NVP that
allowed for adjustable power (61.7% in CA, 59.1% in the US, and 57.9% in AU), though this question
did not assess the 259 participants who reported using disposable systems.
Table 1a–d display the bi-variate descriptive characteristics of NVP users by purchase location
separately within each of the four countries. Overall, user characteristics and product characteristics
were fairly similar across the four countries.
Int. J. Environ. Res. Public Health 2019,16, 338 5 of 13
Table 1.
Sample characteristics by e-cigarette purchase location in (
a
) Canada (n= 456); (
b
) the United
States (n= 701); (c) England (n= 667); (d) Australia (n= 75).
(a)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Smoking frequency
Daily 49 (13.8) 139 (53.6) 87 (32.6) 275 (45.2)
Nondaily 14 (10.6) 79 (67.2) 23 (22.2) 116 (16.9)
Not at all 6 (11.4) 54 (78.5) 5 (10.2) 65 (37.9)
Vaping frequency
Daily 37 (10.9) 152 (72.8) 51 (16.3) 240 (59.4)
Nondaily 32 (14.4) 120 (54.4) 64 (31.2) 216 (40.6)
Been vaping for
Less than 1 month 3 (9.2) 16 (75.9) 6 (15) 25 (5.5)
1–3 months 9 (9.3) 39 (65.9) 17 (24.8) 65 (11.5)
>3 months 55 (12.6) 217 (64.8) 92 (22.6) 364 (82.7)
No answer 2 (100) 0 (0) 0 (0) 2 (0.3)
Age
18–24 18 (14.6) 58 (61.5) 27 (23.9) 103 (15.4)
25–39 29 (19.9) 100 (58.8) 36 (21.3) 165 (30.3)
40–45 19 (9.0) 84 (69.1) 38 (21.9) 141 (38.6)
55+ 3 (3.8) 30 (72.3) 14 (23.9) 47 (15.7)
Sex
Female 29 (11.1) 131 (71.2) 47 (17.7) 207 (46.5)
Male 40 (13.4) 141 (60.2) 68 (26.4) 249 (53.5)
Race
White 43 (10.1) 227 (67.4) 89 (22.5) 359 (86)
Nonwhite 26 (26.4) 43 (51.7) 26 (21.8) 95 (13.8)
Refused 0 (0) 2 (100) 0 (0) 2 (0.2)
Don’t know 0 (0) 0 (0) 0 (0) 0 (0) (0)
Household Income
Low 13 (15.6) 53 (61.7) 25 (22.6) 91 (18.7)
Moderate 20 (8.2) 81 (67.5) 34 (24.3) 135 (29.3)
High 36 (15.4) 116 (62.9) 50 (21.7) 202 (45.5)
No answer 0 (0) 22 (82.6) 6 (17.4) 28 (6.5)
Educational level
Low 10 (4.9) 81 (69.2) 31 (26) 122 (30)
Moderate 27 (10.2) 120 (71) 42 (18.7) 189 (45.2)
High 32 (25.4) 69 (49.7) 42 (24.8) 143 (24.5)
No answer 0 (0) 2 (100) 0 (0) 2 (0.3)
E-liquid flavor
Tobacco flavor 16 (10.7) 59 (64.2) 33 (25) 108 (22.3)
Menthol or mint 6 (4.9) 38 (53.9) 18 (41.3) 62 (15.2)
Fruit flavor 22 (17.2) 89 (68.3) 27 (14.5) 138 (31)
Candy, desserts, sweets 5 (4.6) 45 (82.2) 9 (13.2) 59 (12.2)
Other 20 (17) 41 (60.2) 28 (22.7) 89 (19.3)
E-liquid containing nicotine
No 2 (2.6) 14 (71.9) 8 (25.4) 24 (7.8)
Yes 65 (12.4) 254 (65.5) 105 (22.2) 424 (90.3)
Refused 0 (0) 1 (100) 0 (0) 1 (0.1)
Don’t know 2 (52.8) 3 (26.5) 2 (20.7) 7 (1.8)
Product type
Disposable 9 (13.1) 12 (17.4) 40 (69.4) 61 (13.2)
Cartridge 24 (15.2) 61 (61) 32 (23.8) 117 (19.1)
Tank 36 (11.4) 199 (75.9) 43 (12.7) 278 (67.6)
Int. J. Environ. Res. Public Health 2019,16, 338 6 of 13
Table 1. Cont.
(a)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Product power modifiability
Missing 9 (13.1) 12 (17.4) 40 (69.4) 61 (13.2)
Power not adjustable 13 (9.9) 62 (72.6) 21 (17.5) 96 (22)
Power adjustable but I don’t change it 23 (16.2) 78 (65.1) 27 (18.8) 128 (26.6)
Power adjustable and I change it 23 (10.9) 110 (77.1) 26 (12) 159 (35.1)
Don’t know 1 (9.7) 10 (86.2) 1 (4.1) 12 (3.1)
Total 69 (12.3) 272 (65.3) 115 (22.4) 456
(b)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Smoking frequency
Daily 107 (23.4) 168 (36.8) 190 (39.7) 465 (40.1)
Nondaily 33 (28.7) 61 (48.9) 38 (22.4) 132 (13.2)
Not at all 22 (29.2) 52 (47.3) 30 (23.5) 104 (46.7)
Vaping frequency
Daily 111 (27.7) 198 (45.6) 159 (26.8) 468 (78.2)
Nondaily 51 (23.7) 83 (35.3) 99 (40.9) 233 (21.8)
Been vaping for
Less than 1 month 27 (22.2) 30 (53.4) 43 (24.4) 100 (13.2)
1–3 months 14 (10.4) 32 (35.5) 34 (54) 80 (7.1)
>3 months 120 (29.0) 219 (42.5) 178 (28.5) 517 (79.4)
No answer 1 (44.5) 0 (0) 3 (55.5) 4 (0.3)
Age
18–24 33 (27.8) 71 (48.2) 65 (24) 169 (16)
25–39 78 (24.4) 120 (43.9) 120 (31.7) 318 (33.4)
40–45 28 (29) 36 (40.8) 30 (30.2) 94 (27)
55+ 23 (27) 54 (42.2) 43 (30.8) 120 (23.5)
Sex
Female 70 (26.3) 124 (45.8) 94 (27.9) 288 (42.4)
Male 92 (27.2) 157 (41.5) 164 (31.3) 413 (57.6)
Race
White 128 (27.3) 236 (44.5) 203 (28.2) 567 (89.8)
Nonwhite 34 (22.5) 43 (32.8) 55 (44.7) 132 (10.1)
Refused 0 (0) 2 (100) 0 (0) 2 (0.1)
Don’t know 0 (0) 0 (0) 0 (0) 0 (0) (0)
Household Income
Low 31 (31.3) 58 (43.3) 55 (25.5) 144 (32.8)
Moderate 36 (19) 74 (43.7) 54 (37.3) 164 (23.5)
High 95 (28.5) 145 (42.2) 146 (29.2) 386 (42.3)
No answer 0 ((.)) 4 (72.1) 3 (27.9) 7 (1.3)
Educational level
Low 43 (33.8) 72 (41.8) 55 (24.4) 170 (46)
Moderate 43 (24.6) 86 (46.9) 65 (28.6) 194 (26.4)
High 76 (17.3) 123 (42.5) 138 (40.2) 337 (27.6)
No answer 0 (0) 0 (0) 0 (0) 0 (0) (0)
Int. J. Environ. Res. Public Health 2019,16, 338 7 of 13
Table 1. Cont.
(b)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
E-liquid flavor
Tobacco flavor 44 (30.4) 48 (28.5) 82 (41.1) 174 (26.1)
Menthol or mint 24 (18.2) 58 (38.6) 57 (43.3) 139 (14)
Fruit flavor 29 (20.9) 76 (55) 46 (24) 151 (29.3)
Candy, desserts, sweets 15 (37.7) 35 (53.5) 10 (8.8) 60 (13.9)
Other 50 (29.7) 64 (41.5) 63 (28.8) 177 (16.7)
E-liquid containing nicotine
No 5 (47.8) 12 (49.9) 2 (2.3) 19 (3.3)
Yes 156 (27.6) 263 (45.1) 231 (27.3) 650 (90.2)
Refused 0 (0) 0 (0) 1 (100) 1 (0)
Don’t know 1 (5.3) 6 (16.5) 24 (78.2) 31 (6.5)
Product type
Disposable 35 (34.9) 21 (19) 60 (46.2) 116 (11)
Cartridge 55 (24.6) 77 (16.7) 148 (58.7) 280 (29.6)
Tank 72 (26.4) 183 (61.1) 50 (12.5) 305 (59.4)
Product power modifiability
Missing 35 (34.9) 21 (19) 60 (46.2) 116 (11)
Power not adjustable 26 (23.8) 45 (29.8) 67 (46.4) 138 (29.1)
Power adjustable but I don’t change it 38 (20.7) 73 (63.4) 46 (15.9) 157 (19.4)
Power adjustable and I change it 61 (29.9) 140 (50.4) 79 (19.7) 280 (39.7)
Don’t know 2 (19.4) 2 (30.6) 6 (50) 10 (0.8)
Total 162 (26.8) 281 (43.3) 258 (29.9) 701
(c)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Smoking frequency
Daily 100 (26.2) 124 (31.3) 130 (42.5) 354 (23.7)
Nondaily 55 (23.3) 61 (40.7) 58 (36) 174 (12.5)
Not at all 52 (36) 40 (27.7) 47 (36.3) 139 (63.8)
Vaping frequency
Daily 157 (33.6) 160 (29.9) 160 (36.6) 477 (86)
Nondaily 50 (23) 65 (32.1) 75 (45) 190 (14)
Been vaping for
Less than 1 month 13 (39.2) 11 (37.6) 11 (23.3) 35 (3.3)
1–3 months 23 (43) 30 (17.5) 30 (39.5) 83 (10.7)
>3 months 171 (30.6) 183 (31.2) 194 (38.2) 548 (85.8)
No answer 0 (0) 1 (100) 0 (0) 1 (0.3)
Age
18–24 61 (22) 80 (56.2) 54 (21.8) 195 (7.1)
25–39 49 (26.1) 61 (32.7) 73 (41.2) 183 (25.6)
40–45 37 (34.5) 37 (26.1) 47 (39.3) 121 (29)
55+ 60 (36.2) 47 (26.7) 61 (37.1) 168 (38.3)
Sex
Female 77 (30.8) 79 (33.7) 80 (35.5) 236 (48)
Male 130 (33.3) 146 (26.9) 155 (39.8) 431 (52)
Int. J. Environ. Res. Public Health 2019,16, 338 8 of 13
Table 1. Cont.
(c)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Race
White 176 (31) 198 (30.2) 213 (38.9) 587 (92.1)
Nonwhite 24 (49.4) 21 (18.2) 18 (32.3) 63 (5.2)
Refused 1 (17.3) 2 (68) 2 (14.7) 5 (1.2)
Don’t know 6 (54.9) 4 (41.7) 2 (3.4) 12 (1.5)
Household Income
Low 26 (18.6) 39 (32.3) 62 (49) 127 (17.3)
Moderate 59 (30.7) 62 (32.1) 66 (37.2) 187 (31.7)
High 107 (37) 106 (26.4) 97 (36.7) 310 (42.9)
No answer 15 (40.7) 18 (37.9) 10 (21.3) 43 (8.1)
Educational level
Low 41 (29.8) 54 (35.3) 48 (34.9) 143 (19.9)
Moderate 83 (29.7) 87 (29.2) 102 (41.1) 272 (60.2)
High 79 (48.2) 81 (23.9) 82 (27.9) 242 (15.7)
No answer 4 (18.1) 3 (42.8) 3 (39.1) 10 (4.3)
E-liquid flavor
Tobacco flavor 69 (35.2) 56 (23.2) 82 (41.6) 207 (33.8)
Menthol or mint 38 (29.8) 41 (20.5) 53 (49.7) 132 (26.7)
Fruit flavor 58 (28.5) 87 (50.6) 51 (21) 196 (26.1)
Candy, desserts, sweets 9 (16.8) 16 (29.8) 13 (53.4) 38 (3.9)
Other 33 (43.9) 25 (26.3) 36 (29.9) 94 (9.5)
E-liquid containing nicotine
No 7 (70) 4 (18.5) 3 (11.5) 14 (3.2)
Yes 193 (31.0) 219 (31.0) 217 (38.0) 629 (94.6)
Refused 2 (21.4) 0 (0) 2 (78.6) 4 (0.4)
Don’t know 5 (24.4) 2 (14.2) 13 (61.4) 20 (1.8)
Product type
Disposable 19 (18.2) 17 (21) 34 (60.9) 70 (4.2)
Cartridge 67 (36.6) 44 (12.2) 83 (51.2) 194 (20.7)
Tank 121 (31.7) 164 (35.6) 118 (32.7) 403 (75.1)
Product power modifiability
Missing 19 (18.2) 17 (21) 34 (60.9) 70 (4.2)
Power not adjustable 82 (33.5) 66 (24.3) 95 (42.1) 243 (51.7)
Power adjustable but I don’t change it 43 (32.3) 55 (28.9) 41 (38.8) 139 (14.9)
Power adjustable and I change it 57 (31) 84 (43.1) 59 (25.9) 200 (27.6)
Don’t know 6 (40.4) 3 (31.3) 6 (28.3) 15 (1.6)
Total 207 (32.1) 225 (30.2) 235 (37.7) 667
(d)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Smoking frequency
Daily 15 (44.3) 6 (8.5) 21 (47.2) 42 (32.6)
Nondaily 8 (73.8) 0 (0) 4 (26.2) 12 (10.5)
Not at all 15 (75.5) 6 (24.5) 0 (0) 21 (57)
Vaping frequency
Daily 32 (67.9) 12 (20.1) 16 (12) 60 (83)
Nondaily 6 (52.1) 0 (0) 9 (47.9) 15 (17)
Int. J. Environ. Res. Public Health 2019,16, 338 9 of 13
Table 1. Cont.
(d)
Online Vape Shop Other Retail Total
N(row %) N(row %) N(row %) N(col %)
Been vaping for
Less than 1 month 3 (63.6) 1 (5.3) 4 (31.1) 8 (6.4)
1–3 months 3 (33.3) 1 (7.5) 7 (59.2) 11 (12.6)
>3 months 32 (86.6) 10 (19.0) 14 (10.7) 56 (80.9)
No answer 0 (0) 0 (0) 0 (0) 0 (0)
Age
18–24 1 (21.1) 2 (71.3) 1 (7.7) 4 (10.6)
25–39 12 (66.1) 3 (14.2) 7 (19.6) 22 (40.8)
40–45 17 (64.3) 5 (9.2) 13 (26.4) 35 (27.5)
55+ 8 (86.6) 2 (3.8) 4 (9.6) 14 (21.1)
Sex
Female 7 (55.8) 8 (30.7) 11 (13.5) 26 (42.2)
Male 31 (72) 4 (6.5) 14 (21.5) 49 (57.8)
Race
White 35 (70.8) 8 (17.3) 18 (11.9) 61 (88.2)
Nonwhite 3 (22.9) 4 (12.5) 7 (64.6) 14 (11.8)
Refused 0 (0) 0 (0) 0 (0) 0 (0) (0)
Don’t know 0 (0) 0 (0) 0 (0) 0 (0) (0)
Household Income
Low 5 (80.1) 0 (0) 4 (19.9) 9 (8.1)
Moderate 7 (72.8) 2 (11.2) 6 (16) 15 (28.9)
High 26 (63.4) 9 (21.9) 14 (14.7) 49 (59.5)
No answer 0 (0) 1 (13) 1 (87) 2 (3.6)
Educational level
Low 11 (66.1) 3 (27) 3 (6.9) 17 (32.6)
Moderate 12 (65.9) 4 (11.5) 10 (22.6) 26 (43.8)
High 15 (62.5) 5 (12.1) 12 (25.3) 32 (23.6)
No answer 0 (0) 0 (0) 0 (0) 0 (0) (0)
E-liquid flavor
Tobacco flavor 14 (72.8) 1 (2.1) 7 (25.1) 22 (16.3)
Menthol or mint 1 (36.1) 2 (13) 5 (51) 8 (7.2)
Fruit flavor 6 (40.2) 3 (36.1) 5 (23.7) 14 (20)
Candy, desserts, sweets 5 (66.3) 2 (33.7) 0 (0) 7 (18.2)
Other 12 (80) 4 (5.4) 8 (14.6) 24 (38.3)
E-liquid containing nicotine
No 1 (8.1) 1 (10.6) 6 (81.3) 8 (6.5)
Yes 34 (68.6) 11 (18.1) 17 (13.3) 62 (88.5)
Refused 0 (0) 0 (0) 0 (0) 0 (0) (0)
Don’t know 3 (78.5) 0 (0) 2 (21.5) 5 (5)
Product type
Disposable 2 (10.3) 0 (0) 10 (89.7) 12 (7.6)
Cartridge 6 (40.2) 4 (14.6) 8 (45.2) 18 (10.1)
Tank 30 (73.2) 8 (18.5) 7 (8.3) 45 (82.4)
Product power modifiability
Missing 2 (10.3) 0 (0) 10 (89.7) 12 (7.6)
Power not adjustable 11 (75.2) 2 (3.1) 9 (21.8) 22 (33.7)
Power adjustable but I don’t change it 8 (88) 2 (9.6) 1 (2.5) 11 (10.2)
Power adjustable and I change it 16 (61.3) 8 (30.8) 5 (7.9) 29 (47.7)
Don’t know 1 (100) 0 (0) 0 (0) 1 (0.9)
Total 38 (65.2) 12 (16.7) 25 (18.1) 75
Int. J. Environ. Res. Public Health 2019,16, 338 10 of 13
Table 2compares the likelihood of purchasing locations of NVPs between all countries. In AU,
vapers were 6.4 times more likely to buy online vs other locations compared to vapers in CA (95%
CI: 2.3–17.1), 4.1 times more likely than in the US (95% CI: 1.5–10.7), and 7.9 times more likely than
respondents in EN (95% CI: 2.9–21.8). In the US, they were 3.3 times more likely to buy from vape
shops (95% CI: 1.8–6.2) and 1.9 times more likely to buy online (95% CI: 1.0–3.7) vs other retail locations
when compared to those in EN. Additionally, in CA, vapers were 5.1 times more likely to purchase at
vape shops than at other retail locations when compared to vapers in EN (95%CI: 3.2–10.9) and 1.8
times more likely than in the US (95% CI: 1.0–3.1).
Table 2. Adjusted analyses of purchase location (n= 1508).
Online vs Other Vape Shop vs Other Vape Shop vs Online
AOR (95% CI) AOR (95% CI) AOR (95% CI)
Australia vs Canada 6.4 (2.3–17.9) * 0.3 (0.1–1.1) 0.1 (0.01–0.2) *
Australia vs England 7.9 (2.9–21.8) * 2.0 (0.6–6.6) 0.2 (0.1–0.9) *
Australia vs United States 4.1 (1.5–10.7) * 0.6 (0.2–2.1) 0.1 (0.1–0.6) *
Canada vs England 1.2 (0.6–2.6) 5.9 (3.2–10.9) * 4.8 (2.4–9.3) *
Canada vs United States 0.6 (0.3–1.3) 1.8 (1.0–3.1) 2.8 (1.5–5.3) *
England vs United States 0.5 (0.3–1.0) 0.3 (0.2–0.6) * 0.6 (0.3–1.1)
Adjusted for smoking status, vaping status, age, sex, ethnicity, education, income, e-liquid flavor, and device type;
excludes race (refused, don’t know), educational level (no answer), household income (no answer), and nicotine
concentration (0, refused, don’t know). * indicates 95% CI does not include 1.0.
4. Discussion
Differences in how governments regulate and enforce laws regulating the legal points-of-sale
of NVPs appeared to influence where vapers obtained their vaping products and supplies. In CA,
Vape shops were the most preferred location for products purchase. In the US and EN the purchase
locations were fairly evenly distributed among vape shops, online, and other. In AU, most participants
reported purchasing their products online.
In this survey the vaping products that were assessed, aside from the vaping device themselves
were refills (i.e. pods, cartridges, e-liquid). In AU, the ban of sale of NVPs appears to have led to current
vapers relying mainly on online purchasing sources, unless they are buying non-nicotine containing
e-liquid, in which case, other retail outlets were the primary purchase location. The frequent purchase
from vape shops in CA was a surprise since technically the sale of NVPs was prohibited in retail
outlets without prior government approval. Up to 2016, no NVPs had received approval. It was widely
reported that Canadian authorities were not aggressively enforcing the rules preventing the sale of
NVPs in retail establishments, which may explain the reporting of vape shops as the primary source of
NVPs [
14
]. The law prohibiting the sale of NVPs in CA appears to have discouraged the marketing of
NVPs manufactured by cigarette companies and other vaping manufacturers who primarily market
their products in traditional cigarette selling outlets [
17
]. However, the lax enforcement of the law
may have allowed independently owned vape shops to flourish. As of May 2018, NVPs can be legally
sold in retail outlets in Canada that is likely to change where Canadian vapers will report buying their
NVPs in the future [18]. NVP users in the US and EN reported a wider variety of purchasing sources
for their NVPs, although vape shops were a popular location especially for exclusive NVP users using
tank systems.
While it appears that the regulatory environment in different countries can influence vaping
prevalence, even in restricted environments, such as AU, vaping is still happening with consumers
relying on online sources to purchase their nicotine vaping devices and supplies [
4
]. What is less clear
is how the diversity of NVP points of sale influences vaping and/or smoking behaviors. One might
expect that having a greater diversity of purchasing sources would provide more product options
for consumers at lower prices, thereby increasing vaping prevalence and perhaps contributing to an
accelerated decline in cigarette use. On the other hand, it is possible that by having a greater diversity
Int. J. Environ. Res. Public Health 2019,16, 338 11 of 13
of NVP selling outlets would have the unfortunate effect of encouraging the uptake of vaping by
nonsmokers, including teenagers. The apparent growing popularity of JUUL and other pod type
vaping products in the US and more recently in Canada has raised concerns about how NVPs are
marketed and to whom they are sold [19–23].
Vape shops permit the purchase of NVPs in an environment where cigarettes are typically
not available. Two previous studies have suggested that smokers getting their NVPs from vape
shops were more likely to stop smoking cigarettes completely [
24
,
25
]. Although, it remains unclear
if the devices and information received in vape shops account for the higher quit rates or if it is
something about those who purchase vaping products from vape shops which make them more
likely to discontinue smoking. It is well established in the smoking cessation treatment literature that
combining pharmacotherapy with behavioral counseling increases the odds of smoking cessation over
pharmacotherapy or counseling alone [
26
]. In theory, one might expect that smokers purchasing their
NVPs from a vape shop would get better instruction on how to vape to maximize nicotine delivery
compared to those purchasing their NVPs online or in a cigarette selling retail store. Additionally,
since vape shops are typically not in the business of selling cigarettes or other tobacco products, there
would be an incentive for the vape shop owners to encourage consumers to completely switch away
from cigarettes [
27
]. On the other hand, vape shops remain unregulated, so it is unclear if consumers
would get accurate information about the NVPs they are purchasing [
28
]. While vape shops will likely
need to be regulated to some extent, the form and extent of regulatory oversight have not yet been
defined in the US [29].
This study has important limitations to consider. First, this is a descriptive study based on the
first wave of data collection making it impossible to draw firm conclusions about the temporality
of the associations. Second, this study only reports on the purchasing behaviors of current daily or
weekly vapers, whose purchasing patterns may be different for those who vape less frequently or
those who did not purchase their products. Third, the vaping product marketplace is rapidly changing
so that product features common to those NVP users in 2016 may not hold for those vaping today or
in the future. Finally, the small number of participants reporting the use of non-nicotine-containing
e-liquid limited the ability to compare them to those who use nicotine-containing liquid, furthermore
the “other” location in our analysis was a very heterogeneous group of purchase locations due to low
participant counts.
In summary, the findings from this study show that government regulations restricting where
NVPs can be legally sold, and how the regulations are enforced, influence both the location where
current NVP users report purchasing their NVPs and the types of product the report purchasing.
The AU retail sales ban of NVPs appears to have led vapers to rely on online purchasing sources.
In contrast, in CA, the lack of enforcement of this law has allowed vape shops to flourish limiting
access to NVPs sold alongside cigarettes. In the US and EN, NVP users reported a greater diversity of
purchase locations. Future studies should consider longitudinal data in order to elucidate the effects
of policy changes over time. For example, as the US considers limiting the sale of product categories
in certain locations, proceeding waves of the ITC project will be well positioned to capture an effect
on behavior.
Author Contributions:
The authors of this paper attest to their contributions to the paper in the following areas:
conceptualization: D.C.B., K.M.C., G.J.N., B.W.H., R.B., G.T.F., D.H., C.B., A.M., D.T.L. and C.S.; survey design and
execution: K.M.C., R.B., G.T.F., A.M. and C.B.; data analysis: D.C.B., K.M.C., G.J.N., B.W.H. and C.B.; data curation:
G.T.F., and C.B.; writing—original draft preparation: D.C.B., K.M.C., G.J.N., B.W.H. and C.B.; writing—review
and editing: D.C.B., K.M.C., G.J.N., B.W.H., R.B., G.T.F., D.H., C.B., A.M., D.T.L., and C.S.; project administration,
K.M.C., R.B., G.T.F., and A.M.; and funding acquisition: K.M.C., R.B., and G.T.F.
Funding:
This study was supported by grants from the National Cancer Institute of the US P01CA200512,
the Canadian Institutes of Health Research (FDN 148477), and by the National Health and Medical Research
Council of Australia APP1106451. Core support was provided in part through the biostatistics shared resource at
the Hollings Cancer Center, Medical University of South Carolina (P30 CA138313). GTF was supported in part
from a Senior Investigator Award from the Ontario Institute for Cancer Research. BWH was supported by NIDA
(K23 DA041616). DCB supported by NIH/NIDA GM-T32008716.
Int. J. Environ. Res. Public Health 2019,16, 338 12 of 13
Conflicts of Interest:
KMC has received payment as a consultant to Pfizer, Inc., for service on an external advisory
panel to assess ways to improve smoking cessation delivery in health care settings. KMC also has served as paid
expert witness in litigation filed against the tobacco industry.
References
1.
Caraballo, R.S.; Shafer, P.R.; Patel, D.; Davis, K.C.; McAfee, T.A. Quit Methods Used by US Adult Cigarette
Smokers, 2014–2016. Prev. Chron. Dis. 2017,14. [CrossRef] [PubMed]
2.
Beard, E.; West, R.; Michie, S.; Brown, J. Association between electronic cigarette use and changes in quit
attempts, success of quit attempts, use of smoking cessation pharmacotherapy, and use of stop smoking
services in England: Time series analysis of population trends. BMJ. 2016,354, i4645. [CrossRef] [PubMed]
3.
McMillen, R.C.; Gottlieb, M.A.; Shaefer, R.M.W.; Winickoff, J.P.; Klein, J.D. Trends in Electronic Cigarette
Use Among, U.S. Adults: Use is Increasing in Both Smokers and Nonsmokers. Nicotine Tob. Res.
2015
,
17, 1195–1202. [CrossRef] [PubMed]
4.
Gravely, S.; Fong, G.T.; Cummings, K.M.; Yan, M.; Quah, A.C.; Borland, R.; Yong, H.H.; Hitchman, S.C.;
McNeill, A.; Hammond, D.; et al. Awareness, trial, and current use of electronic cigarettes in 10 countries:
Findings from the ITC project. Int. J. Environ. Res. Public Health
2014
,11, 11691–11704. [CrossRef] [PubMed]
5.
O’Connor, R.J.; Fix, B.V.; McNeill, A.; Goniewicz, M.L.; Bansal-Travers, M.; Heckman, B.W.; Cummings, K.M.;
Hitchman, S.; Borland, R.; Hammond, D.; et al. Characteristics of vaporized nicotine products used by
participants in the ITC Four Country Tobacco and E-Cigarette Project, Wave 1. Addiction
2019
. under review.
6.
Carpenter, M.J.; Heckman, B.W.; Wahlquist, A.E.; Wagener, T.L.; Goniewicz, M.L.; Gray, K.M.; Froeliger, B.;
Cummings, K.M. A Naturalistic, Randomized Pilot Trial of E Cigarettes: Uptake, Exposure, and Behavioral
Effects. Cancer Epidemiol. Biomark. Prev. 2017,26, 1795–1803. [CrossRef] [PubMed]
7.
St Helen, G.; Dempsey, D.A.; Havel, C.M.; Jacob, P.; Benowitz, N.L. Impact of e-liquid flavors on nicotine
intake and pharmacology of e-cigarettes. Drug Alcohol. Depend. 2017,178, 391–398. [CrossRef]
8.
Hajek, P.; Przulj, D.; Phillips, A.; Anderson, R.; McRobbie, H. Nicotine delivery to users from cigarettes and
from different types of e-cigarettes. Psychopharmacology 2017,234, 773–779. [CrossRef]
9.
Hitchman, S.C.; Brose, L.S.; Brown, J.; Robson, D.; McNeill, A. Associations Between E-Cigarette Type,
Frequency of Use, and Quitting Smoking: Findings from a Longitudinal Online Panel Survey in Great Britain.
Nicotine Tob. Res. 2015,17, 1187–1194. [CrossRef]
10. Etter, J.-F. Levels of saliva cotinine in electronic cigarette users. Addiction 2014,109, 825–829. [CrossRef]
11.
Zhu, S.H.; Sun, J.Y.; Bonnevie, E.; Cummins, S.E.; Gamst, A.; Yin, L.; Lee, M. Four hundred and sixty brands
of e-cigarettes and counting: Implications for product regulation. Tobacco Control.
2014
,23 (Suppl. 3), iii3–iii9.
[CrossRef] [PubMed]
12.
McNeill, A.; Brose, L.S.; Calder, R.; Bauld, L.; Robson, D. Evidence review of e-cigarettes and heated
tobacco products 2018. In A Report Commissioned by Public Health England; Public Health England: London,
UK. Available online: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/
attachment_data/file/684963/Evidence_review_of_e-cigarettes_and_heated_tobacco_products_2018.pdf
(accessed on 16 January 2018).
13.
National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division, Board on
Population Health and Public Health Practice, Committee on the Review of the Health Effects of Electronic
Nicotine Delivery Systems. Public Health Consequences of E-Cigarettes; Eaton, D.L., Kwan, L.Y., Stratton, K.,
Eds.; National Academies Press (US): Washington, DC, USA, 2018. Available online: http://www.ncbi.nlm.
nih.gov/books/NBK507171/ (accessed on 6 September 2018).
14.
Canadian Public Health Association. A Public Health Approach to Nicotine Containing Vaping Devices.
[Position Statement]. 2018. Available online: https://www.cpha.ca/sites/default/files/uploads/policy/
positionstatements/vaping-devicesposition-statement_e.pdf (accessed on 21 January 2019).
15.
Meyers, M.J.; Delucchi, K.; Halpern-Felsher, B. Access to Tobacco Among California High School Students:
The Role of Family Members, Peers, and Retail Venues. J Adolesc Health.
2017
,61, 385–388. [CrossRef]
[PubMed]
16.
Thompson, M.E.; Fong, G.T.; Boudreau, C.; Driezen, P.; Li, G.; Gravely, S.; Cummings, K.M.; Heckman, B.W.;
O’Connor, R.; Thrasher, J.F.; et al. Methods of the ITC Four Country Smoking and Vaping Survey, Wave 1
(2016). Addiction 2018. [CrossRef] [PubMed]
Int. J. Environ. Res. Public Health 2019,16, 338 13 of 13
17.
Hammond, D.; White, C.M.; Czoli, C.D.; Martin, C.L.; Magennis, P.; Shiplo, S. Retail availability and
marketing of electronic cigarettes in Canada. Can. J. Public Health 2015,106, 408–412. [CrossRef] [PubMed]
18.
Health Canada. Vaping Products. May 2018. Available online: https://www.canada.ca/en/healthcanada/
news/2018/05/backgrounder-vaping-products.html (accessed on 17 August 2018).
19.
Huang, J.; Duan, Z.; Kwok, J.; Binns, S.; Vera, L.E.; Kim, Y.; Szczypka, G.; Emery, S.L. Vaping versus
JUULing: How the extraordinary growth and marketing of JUUL transformed the US retail e-cigarette
market. Tob. Control 2018. [CrossRef] [PubMed]
20.
Marynak, K.; Gentzke, A.; Wang, T.W.; Neff, L.; King, B.A. Exposure to Electronic Cigarette Advertising
Among Middle and High School Students—United States, 2014–2016. MMWR Morb. Mortal. Wkly. Rep.
2018
,
67, 294–299. [CrossRef] [PubMed]
21.
Vallone, D.M.; Bennett, M.; Xiao, H.; Pitzer, L.; Hair, E.C. Prevalence and correlates of JUUL use among a
national sample of youth and young adults. Tob. Control 2018. [CrossRef]
22.
Hammond, D.; Wackowski, O.A.; Reid, J.L.; O’Connor, R.J. Use of JUUL e-cigarettes among youth in the
United States. Nicotine Tob. Res. 2018. [CrossRef]
23.
Hammond, D.; Reid, J.L.; Rynard, V.L.; Fong, G.T.; Cummings, K.M.; McNeill, A.; Hitchman, S.;
Goniewicz, M.L.; O’Connor, R.J.; Levy, D.; et al. Changes in the prevalence of vaping and smoking among
youth in Canada, England and the United States. BMJ 2019. under review.
24.
Polosa, R.; Caponnetto, P.; Cibella, F.; Le-Houezec, J. Quit and Smoking Reduction Rates in Vape Shop
Consumers: A Prospective 12-Month Survey. Int. J. Environ. Res. Public Health
2015
,12, 3428–3438. [CrossRef]
25.
Wagener, T.L.; Shaikh, R.A.; Meier, E.; Tackett, A.; Tahirkheli, N.; Leavens, E.; Driskill, L. Examining the
Smoking and Vaping Behaviors and Preferences of Vape Shop Customers. Tob. Prev. Cessation.
2016
,2.
[CrossRef]
26.
Clinical Guidelines for Prescribing Pharmacotherapy for Smoking Cessation. Content Last Reviewed December
2012; Agency for Healthcare Research and Quality: Rockville, MD, USA. Available online: https://www.ahrq.
gov/professionals/clinicians-providers/guidelines-recommendations/tobacco/prescrib.html (accessed on
21 January 2019).
27.
Yang, J.S.; Lee, E. A qualitative assessment of business perspectives and tactics of tobacco and vape shop
retailers in three communities in Orange County, CA, 2015–2016. Arch. Public Health
2018
,76, 57. [CrossRef]
[PubMed]
28.
Tsai, J.Y.; Bluthenthal, R.; Allem, J.-P.; Garcia, R.; Garcia, J.; Unger, J.; Baezconde-Garbanati, L.;
Sussman, S.Y. Vape shop retailers’ perceptions of their customers, products and services: A content analysis.
Tob. Prev. Cessat. 2016,2. [CrossRef] [PubMed]
29.
U.S. Food and Drug Administration. Interpretation of and Compliance Policy for Certain Label
Requirement; Applicability of Certain Federal Food, Drug, and Cosmetic Act Requirements
to Vape Shops; Draft Guidance for Industry; Availability. 82 FR 4893. Available online:
https://www.federalregister.gov/documents/2017/01/17/2017-00773/interpretation-of-andcompliance-
policy-for-certain-label-requirement-applicability-of-certain (accessed on 7 December 2018).
©
2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Available via license: CC BY 4.0
Content may be subject to copyright.