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| Journal of the New Zealand Medical Association,
03-June-2005, Vol 118 No 1216
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Smoking cessation using mobile phone text messaging is as
effective in Maori as non-Maori
Dale Bramley, Tania Riddell, Robyn Whittaker, Tim Corbett,
Ruey-Bin Lin, Mary Wills, Mark Jones, Anthony Rodgers
Tobacco is the leading single modifiable cause of death for
both Maori and non-Maori in New Zealand.1 In
New Zealand, there has been a decline in the prevalence of cigarette smoking
since the early 1980s, however no such trend is evident for Maori. Indeed, in
2002, about one in two Maori (49.4%) and one in five non-Maori (21.2%) were
smokers.2
Significant inequalities exist in that Maori suffer
disproportionately (compared to non-Maori) the ill effects associated with
tobacco smoking. It is estimated that 29% of the total health loss sustained by
Maori males, and 22% by Maori females, would be regained if tobacco consumption
were eliminated.3
Of particular concern is the fact that although youth
smoking prevalence has declined over recent years for non-Maori, this is not so
for Maori woman. Young Maori women had particularly high smoking rates in 2002,
with 42% of surveyed 14–15 year-olds smoking at least weekly and 34%
smoking daily.2
Health inequalities are therefore likely to further increase
in the future unless effective cessation programmes can be designed that
specifically target Maori. To date in New Zealand there has been a relative
shortage of age-appropriate cessation programmes aimed at young adults, and the
services that are currently available to all are under-utilised by this
group.4 There is also limited direct evidence
of smoking cessation interventions demonstrating efficacy in young
people5 or for Maori.
New smoking cessation interventions for young Maori adults
are clearly needed, and mobile phones could provide an important new delivery
medium. More than 85% of young New Zealand adults now have a mobile phone
(statistics by ethnicity are not available), and text messaging among this age
group has rapidly developed into a new communications medium.
Over a million text messages (where up to160 characters of
text are sent directly from one mobile phone to another) are sent every day in
New Zealand. This could represent a new channel for the delivery of smoking
cessation services inexpensively to a large section of the population wherever
they are located.
MethodsA large, simple randomised
trial of a new smoking cessation service using mobile phone text messaging was
performed (STOp smoking by Mobile Phone – STOMP); the overall methodology
and results of which are reported in another
paper.6
This trial was specifically designed to maximise
participation by Maori, and to allow for analyses to be performed that had
adequate power to report results for Maori and non-Maori.
People were eligible for inclusion provided they met
the following criteria: aged 16 years or more, currently smoking cigarettes
daily, interested in quitting, able to send and receive text messages, current
owner of a Vodafone mobile phone (at the time the trial started Vodafone was the
only telephone network where all users could send and receive text messages),
English speaking, and able to provide informed consent.
Recruitment was targeted to Maori participants in a
variety of ways, with recruitment information being disseminated via: Maori
radio station advertising, mailing lists of Maori students attending tertiary
institutions, advertisements in a Maori student magazine, hospital staff email
lists, faxes to Maori health providers, and via Maori smokefree networks and
providers. Non-targeted advertising for the trial (newspapers, websites,
magazines, Quitline [http://www.quit.org.nz/]) also mentioned that
the researchers were particularly interested in recruiting Maori.
After enrolment participants were randomised to either
a control group or to a group that received a support programme. The
intervention group received regular, personalised text messages providing
smoking cessation advice, support, and distraction. An algorithm was developed
to match participant characteristics with a database of over one thousand text
messages so that an individualised programme was provided.
Participants self-identifying as Maori also received
Maori–specific text messages. A list of approximately 140 texts were
developed by the Maori researchers (DB, TR) and students. These related to Maori
language (Lets learn te reo, words such
as change, courage, challenge, action, goal,
strength), general support messages (in Maori and English), and
information on Maori customs and traditions.
A Quit day was negotiated with each participant, and
five messages were sent per day for the week leading up to the Quit day, and
during the following 4 weeks. On the Quit day, free outgoing text messaging also
began, with participants encouraged to tell all their friends and family they
were quitting on that day, as a means of distraction and communicating the need
for support. Six weeks after randomisation and coinciding approximately with the
end of the free text month, the intervention became less intensive, with the
number of sent text messages reducing from five a day to three per week until
the end of the 26-week follow-up.
Participants allocated to the control group received no
smoking-related information. They received one text message a fortnight
reminding them that completed follow-up would be rewarded with a free month of
text messaging, and giving the study centre contact details. There were no
restrictions on the use of other smoking cessation strategies by trial
participants— i.e. this trial tested the addition of mobile phone-based
services to existing practice.
The main outcome of the trial was the prevalence of
current non-smoking (i.e. not smoking in the past week) 6 weeks after
randomisation. Secondary outcomes included self-reported non-smoking at 12 and
26 weeks. All baseline and follow-up data were collected by mobile phone or text
messaging, and confirmation of informed consent was by text messaging.
Participants were informed at the outset of the study that baseline levels of
smoking and reports of quitting may be verified, in an attempt to improve the
veracity of self-reported data.7 A random
sample of 100 participants who reported quitting at 6 weeks were selected for
personal visits to verify quitting with salivary cotinine levels.
Central telephone randomisation was used—with
age, sex, number of cigarettes, and stage of change as stratification factors in
the minimisation algorithm. Participants were aware of which group they were
allocated to, but follow-up methods were identical for all participants, with
any follow-up phone calls made by staff who were unaware of the treatment
allocation (i.e. single blind).
Data were analysed following a pre-specified analysis
plan. Simple chi-squared analyses compared the proportion quit by treatment
group, with estimation of relative risks (RRs), 95% confidence intervals (CIs),
and two-sided p values. The number of cigarettes smoked and Fagerstrom score (a
measure of nicotine dependence8) during
follow-up were compared with analysis of covariance.
The role of possible baseline effect modifiers and
confounders was assessed with standard logistic regression analyses and was to
be reported if the estimate of treatment effect on the primary outcome changed
by greater than 10%. Participants without follow-up data were assumed to be
still smoking in the primary analysis. Secondary analyses were performed
assuming that participants with no follow-up data either: had the same smoking
status as at last follow-up or, were all non-smoking.
Additional sensitivity analyses assumed that the rate
of non-confirmed quitters for the whole trial was the same as for the sample
assessed for salivary cotinine. Pre-specified subgroup analyses were planned
providing there was a treatment effect of at least three standard deviations in
the primary outcome.
ResultsThe overall results of the STOMP
study are presented in a separate paper.6 We
report here for the first time the results of the Maori and non-Maori analyses.
Overall, 1705 participants were eligible and were randomised to control or
treatment, including 355 (21%) Maori and 1350 (79%) non-Maori participants
(Figure 1).
Twenty-seven Maori participants were lost to 6-week
follow-up (8%), compared to 4% of non-Maori (missing data were assumed smoking).
Follow-up rates at 6 months were lower than at 6 weeks, particularly in the
intervention group. Follow-up in Maori participants at 6 months was 55% in the
intervention group compared to 69% in the control group (p=0.006); and in
non-Maori, 73% compared to 82% in the control group (p=0.0002). Maori in the
control and intervention groups were similar with respect to age, gender, income
level, and smoking dependence/history (Table 1).
In comparison with non-Maori participants, there were a
higher proportion of Maori women and the median age of Maori participants was
older. Maori participants were also less likely to have used a nicotine
replacement product of any type in the past, although were more likely to have
contacted Quitline when compared to non-Maori.
Maori participants in the treatment group were more likely
to report having stopped smoking at 6 weeks than those in the control group,
with 26.1% quit compared to 11.2% (RR: 2.34, 95% CI: 1.44–3.79) (Table 2).
There was no significant difference between the RR for Maori and that for
non-Maori (RR: 2.16, 95% CI: 1.72–2.71), that is the intervention was as
effective for Maori as for non-Maori.
Sensitivity analyses were performed to assess the potential
impact of missing data from those lost to follow-up, with the pattern of missing
data for Maori similar to the overall pattern in the
study.6 Salivary cotinine testing showed no
clear evidence of different degrees of over-reporting of quit rates between the
overall intervention and control groups, with 18% of those invited (47% of those
who undertook the test) congruent with not
smoking.6 The relative risk estimates for the
primary outcome were not substantially altered in sensitivity analyses adjusting
for missing data (Figure 2) and salivary cotinine verification tests.
Secondary outcomes at 12 and 26 weeks are shown in Table 2.
Reported smoking cessation rates remained high at 26 weeks in the intervention
group (21.6%) but increased in the control group (18.4%). For all assessments at
all follow-up times there was no clear difference in proportional effects for
Maori versus non-Maori (p homogeneity ≥0.2 for all comparisons).
DiscussionThis is the first randomised
controlled trial of smoking cessation where Maori smoking cessation rates are
compared to non-Maori. This trial was specifically designed and executed to
ensure high Maori participation in the trial and to ensure that the results
presented would have adequate meaning for Maori.
Such a methodology is essential to ensure that matters
related to indigenous inequalities are addressed in the design and
implementation of clinical trials in New Zealand, and furthermore to ensure that
new and innovative interventions do reach those in highest need and in
particular Maori. If steps are not taken in the design and implementation of
clinical trials to ensure responsiveness to Maori there is a risk that such
research could in fact increase inequalities, in that interventions may be
preferentially taken up by population groups with less need. Such as is seen
with the lower proportion of Maori taking up free diabetes checks (35% compared
to 51% overall), despite higher prevalence
rates.9
This manuscript has been written using a kaupapa Maori
framework whereby the study analysis was undertaken from a Maori
perspective.10 This is distinct from other
methodologies that may ‘minoritise’ Maori with insufficient data
quantity or quality to undertake analyses necessary to inform Maori health
development. Where appropriate, kaupapa Maori methodology enables disparities to
be identified and their elimination prioritised. This is consistent with the
Treaty of Waitangi.
Several lessons can be learned from this study. Clinical
trials can be designed in such a way as to be successful in reaching both Maori
and non-Maori participants. Efforts were made to reach young Maori by targeted
recruitment methods in this trial, resulting in 21% of participants at baseline
(compared to 14.7% of the general
population).11 Also according to the 2001 New
Zealand Census, participants (aged 15–30 years) had a very similar
personal income distribution to that for the same age group in the general
population.11
This trial shows how a modern communications medium, which
has been rapidly adopted by young adults, can be used as a means of delivering
important health services to young people where current delivery systems are not
working. Mobile phones and text messaging are used by a wide range of young
people, and have the benefit of being with the person most of the day.
‘
The high Maori participation reflects the acceptability of
this intervention for young Maori adults, including its use of Maori
(te reo) health-related text messages.
These messages may be able to be used for future interventions. Indeed, there is
potential for other services to use this method of delivering health messages
with the advantages of being affordable, personalised, age-appropriate, and not
location-dependent. Any such services must continue to adapt as communications
technology changes.
The finding that this intervention was as effective for
Maori as for non-Maori is important due to higher smoking rates and the ensuing
higher rates of smoking related disease in Maori compared to
non-Maori. 3 A smoking cessation service that
can target and enrol young Maori in this way has the potential to deliver an
equal benefit to Maori, or perhaps even to positively impact on inequalities in
health status.
Methodological
considerations—Limitations of this study include a differential
loss to follow-up (overall follow-up rates of 67% in the intervention group and
78% in the control group). This reflects a differential incentive to
participate, with the control group receiving their month of free text messaging
after the 26-week follow-up. Due to limited resources, the intervention group
were not offered this incentive. Also the reported quit rates increased over
time in the control group, suggesting that some participants thought their free
text month might depend on reporting quitting. Over-reporting of quitting is
thought to be more likely in young people7 and
was seen here with salivary cotinine validation in a sample of participants
(described in Rodgers et al6).
The greater loss to follow-up at 26 weeks in the
intervention group also means that the treatment of missing data makes a
considerable difference to the result. If all missing data are regarded as
smoking (the primary analysis), then disproportionate numbers in the
intervention group are classified as smokers and this gives a very conservative
estimate of the effect of the intervention (RR close to null). The true effect
of this intervention is in fact more likely to be reflected in the greater RR
estimate found with assuming the continuation of previous smoking status. As
such, analysis with last smoking status value carried forward, or with assuming
not smoking, shows significant improvements for Maori and non-Maori remaining at
26 weeks (Figure 2).
These results need to be validated in a larger study with
adequate power for Maori and non-Maori and with an adequate follow-up period.
Conclusion—This
trial shows that it is possible to reach and recruit young Maori to participate
in an innovative smoking cessation intervention. It also shows that a mobile
phone-based cessation programme was as successful at increasing self-reported
short-term quit rates in Maori as in non-Maori. Smoking prevalence amongst Maori
has changed little in recent years, and new methods of cessation for young Maori
are clearly needed. Any reductions in smoking prevalence in young Maori would
have significant public health benefits, as the earlier a smoker quits smoking
the greater the health gain.12 This
intervention clearly has potential as a public health initiative and the results
shown here form a good basis for further trials.
Author information:
Dale Bramley, Senior Lecturer, Section of Epidemiology and Biostatistics, School
of Population Health; Tania Riddell, Public Health Specialist, Tomaiora Maori
Health Research Centre, Auckland Medical School; Robyn Whittaker, Research
Fellow, Clinical Trials Research Unit; Tim Corbett, Research Fellow, Social and
Community Health; Ruey-Bin Lin, Biostatistician, Clinical Trials Research Unit;
Mary Wills, Study Manager, Clinical Trials Research Unit; Mark Jones,
Biostatistician, Clinical Trials Research Unit; Anthony Rodgers, Director,
Clinical Trials Research Unit, University of Auckland, Auckland
Correspondence: Dr
Dale Bramley, Section of Epidemiology and Biostatistics, School of Population
Health, University of Auckland, Auckland. Fax: (09) 441 8957; email: dale.bramley@waitematadhb.govt.nz
Acknowledgements:
The trial was funded by the National Heart Foundation of New Zealand, the Cancer
Society of New Zealand, Vodafone NZ, and Alcatel. Anthony Rodgers held a Senior
Fellowship from the National Heart Foundation. Jaco van Rooyen, Amanda
Milne, Michael Ng, and Francois Duchaussoy completed programming. Assistance
with text messages was provided by Kristy Carter, Christel Dunshea-Mooij, Marewa
Glover, and Marek Rodgers. The Toxicology Unit, Department of Clinical
Chemistry, LabPlus, Auckland City Hospital conducted salivary cotinine
assessments.
Comments on a draft version of this paper were kindly
provided by Marewa Glover and the CTRU research fellows and biostatistics teams.
Assistance was also provided by Sonya Aitken; Aisha Daji Punga; Deanne Douglas;
Daphne Fairfoot; Todd Goggin; Phil Gouge; Ed Hayes; John Kershaw; Adam
McElroy; Jane Mills; Bree Nicholls; Katrina Sharples; Harry Rae; Marissa Te
Whiu; Esther Vao; Karen White; and Kirsty Wilkinson. Sounds Records Ltd
assisted with follow-up.
(None of the investigators have a personal financial
interest in the software developed as part of this trial. STOMP has been set up
as a not-for-profit entity wholly owned by Auckland University which owns the
software and intellectual property developed for the trial.)
References:
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