Context Weight loss programs on the Internet appear promising for short-term
weight loss but have not been studied for weight loss in individuals at risk
of type 2 diabetes; thus, the longer-term efficacy is unknown.
Objective To compare the effects of an Internet weight loss program alone vs with
the addition of behavioral counseling via e-mail provided for 1 year to individuals
at risk of type 2 diabetes.
Design, Setting, and Participants A single-center randomized controlled trial conducted from September
2001 to September 2002 in Providence, RI, of 92 overweight adults whose mean
(SD) age was 48.5 (9.4) years and body mass index, 33.1 (3.8).
Interventions Participants were randomized to a basic Internet (n = 46) or to an Internet
plus behavioral e-counseling program (n = 46). Both groups received 1 face-to-face
counseling session and the same core Internet programs and were instructed
to submit weekly weights. Participants in e-counseling submitted calorie and
exercise information and received weekly e-mail behavioral counseling and
feedback from a counselor.
Main Outcome Measures Measured weight and waist circumference at 0 and 12 months.
Results Intent-to-treat analyses showed the behavioral e-counseling group lost
more mean (SD) weight at 12 months than the basic Internet group (−4.4
[6.2] vs −2.0 [5.7] kg; P = .04), and had greater
decreases in percentage of initial body weight (4.8% vs 2.2%; P = .03), body mass index (−1.6 [2.2] vs −0.8 [2.1]; P = .03), and waist circumference (−7.2 [7.5] vs
−4.4 [5.7] cm; P = .05).
Conclusion Adding e-mail counseling to a basic Internet weight loss intervention
program significantly improved weight loss in adults at risk of diabetes.
Behavioral weight loss interventions markedly reduce the risk of developing
diabetes, and recent studies suggest that new approaches to prevention are
needed.1-3 In the
Diabetes Prevention Program (DPP), a behavioral weight loss program produced
a 58% reduction in diabetes incidence after 2.8 years. The DPP involved substantial
individual face-to-face counseling; such an intensive intervention may be
impractical to treat the large number of at-risk individuals.4 Consumers
also desire alternatives to face-to-face treatment,5 creating
a need for effective behavioral interventions requiring less face-to-face
contact.
The Internet offers opportunities to develop behavioral change interventions
minimizing face-to-face interaction. It has been used for diabetes education
and self-management,6,7 and we
have used the Internet to deliver a behavioral weight loss program with favorable
short-term results.8 However, the efficacy
of Internet-based weight loss programs and specifically e-mail counseling
has not been used in a population at risk of diabetes nor evaluated for a
year-long weight loss intervention.
The 92 participants in our study were recruited through newspaper advertisements
and were drawn from a waiting list at our research center (Figure 1). Eligibility criteria included access to a computer, being
overweight or obese (body mass index [BMI], 27-40), and 1 or more other risk
factors for type 2 diabetes.4 (BMI is calculated
as weight in kilograms divided by the square of height in meters).
Participants with major health or psychiatric diseases, pregnancy, or
recent weight loss of 4.5 kg or more were excluded. Physician consent was
required from individuals endorsing any items on the Physical Activity Readiness
Questionnaire (PAR-Q)9 or taking medications
that might be affected by weight loss (n = 44). Participants attended a face-to-face
orientation and completed baseline measurements including fasting plasma glucose
to screen for diabetes. One participant had fasting plasma glucose greater
than 126 mg/dL (>6.9 mmol/L), confirmed on retest, and was ineligible.
The protocol was approved by the institutional review board at Miriam
Hospital, RI, and written informed consent was obtained from all participants.
Following completion of baseline measurements, participants were randomly
assigned following simple randomization procedures (computerized random numbers)
to 1 of 2 treatment groups: 46 to the basic Internet weight loss program (basic
Internet) and 46 to the Internet weight loss program plus behavioral e-counseling
(behavioral e-counseling). Participants were seen at baseline and at months
3, 6, and 12 months for measurement of weight, waist circumference, and fasting
blood glucose and were paid $10 to $25 for attending the respective assessments.
All participants attended a 1-hour introductory group weight loss session.
Internet navigation and login procedures were demonstrated on a computer and
participants were provided with a written guide. To protect confidentiality,
the study Web site was password protected, participants were given a login
identification code, and weight data were transmitted via a Web-based form
and stored on a secure server without participant names. Participants were
advised of potential breaches in confidentiality during data transmission
and e-mail communications and limits to confidentiality were disclosed in
the consent form.
During the introductory session, participants received standard behavioral
weight-control instruction on diet, exercise, and behavior change.10 Recommendations included a calorie restricted diet
of between 1200 and 1500 kcal/d, fat intake of 20% or fewer calories, and
a minimum of 1000 kcal/wk of physical activity (equivalent to walking 10 miles/wk).
All participants were encouraged to self-monitor their daily diet and exercise
using diaries and calorie books provided.
The study Web site provided a tutorial on weight loss, a new tip and
link each week, and a directory of selected Internet weight loss resources.
Each group had a separate message board to prevent contamination. Each week,
all participants received an e-mail reminder to submit his/her weight and
received weight loss information.
Internet Behavioral e-Counseling
Participants in behavioral e-counseling underwent the same procedures
as the basic Internet group plus they communicated via e-mail with their assigned
weight loss counselor. Counselors had master's or doctoral degrees in health
education, nutrition, or psychology and did not know participants prior to
the study. Participants were instructed to report calorie and fat intake,
exercise energy expenditure, and any comments or questions for the therapist
via a Web-based diary. Participants were instructed to submit daily diaries
for the first month and were given the option of submitting daily or weekly
thereafter. During the first month, the therapist e-mailed participants 5
times each week. Therapists sent weekly e-mails for the remaining 11 months.
Counselor e-mails provided feedback on the self-monitoring record, reinforcement,
recommendations for change, answers to questions, and general support. Participants
who did not report were sent a personal follow-up e-mail.
The primary dependent measure was change in body weight from baseline
to 12 months. Weight was measured in the clinic at baseline and at months
3, 6, and 12 in a hospital gown, without shoes, on a calibrated scale. Height
was measured using a wall-mounted stadiometer. Waist circumference was measured
at the umbilicus.11 Venous blood glucose was
measured after an overnight fast and analyzed by an independent laboratory.
Patients also completed the Paffenbarger activity questionnaire,12 the
Block Food Frequency questionnaire (version 1998),13 and
the Centers for Epidemiological Studies Depression Scale.14 An
index of prior Internet or e-mail experience was created by summing months
of e-mail and Internet use.
Unless noted, all analyses followed an intent-to-treat principle using
all randomized participants and assuming no change from baseline for those
with missing data. Changes in weight, waist circumference, dietary intake,
and energy expenditure were examined separately using repeated measures analysis
of variance (ANOVA) when assumptions of the ANOVA were met and nonparametric
tests when key assumptions were violated. All analyses were performed using
the Statistical Package for Windows version 11 for the Social Sciences (SPSS,
Chicago, Ill).
The 2 study groups did not differ on key baseline measures (Table 1). The 82 women and 10 men were
a mean (SD) age of 48.5 (9.4) years and had a BMI of 33.1 (3.8). Numbers of
those with the included risk factors are age 45 years or older, 66 (72%);
family history of diabetes, 42 (46%); high cholesterol levels or blood pressure,
29 (32%); impaired glucose tolerance, 6 (7%); history of gestational diabetes,
8 (9%); being delivered of a neonate weighing 4 kg or more, 20 (22%); or belonging
to a minority group, 10 (11%). Sixty-three participants (69%) reported 3 or
more risk factors for type 2 diabetes. Eighty-four percent (n = 77) of randomized
participants attended the 12-month assessment; attendance did not vary by
treatment group (χ2 = 0.08; P = .78; Figure 1). Participants who did not attend
the 12-month follow-up reported expending significantly fewer calories in
physical activity at baseline (t = –2.97, P = .005) but did not differ otherwise from attendees at
baseline.
The intent-to-treat analysis at 12 months showed that behavioral e-counseling
group had greater reductions in weight (−4.4 [6.2] vs −2.0 [5.7]
kg; 95% confidence interval for difference [CI], −0.1 to 4.9; χ2 = 4.4, P = .04), percentage of initial body
weight (4.8% vs 2.2%, χ2 = 4.8; P =
.03), body mass index (−1.6 [2.2] vs −0.8 [2.1]; 95% CI for difference,
−0.04 to 1.8; χ2 = 4.7, P =
.03), and waist circumference (−7.2 [7.5] vs −4.4 [5.7] cm; F
= 4.0; 95% CI for difference, 0.02 to 5.6; P = .05)
compared with the basic Internet group.
The pattern of weight change is shown in Figure 2. Weight change for the 77 participants who completed the
12-month follow-up followed a similar pattern with larger mean (SD) weight
losses in the behavioral e-counseling group at 3 months (−4.1 [3.7]
vs −2.7 [3.3] kg; P = .04), 6 months (−5.2
[5.4] vs −2.5 [4.7] kg; P = .007), and 12 months
(−5.3 [6.5] vs −2.3 [6.1] kg; P = .03).
The analysis of fasting plasma glucose showed no differences between groups
at 12 months (P = .93); however, reduction in glucose
was significantly greater in behavioral e-counseling after 3 months (−4.6
[7.9] vs −0.3 [8.4] mg/dL [−0.26 {0.44} vs −0.02 {0.47}
mmol/L]; t = 2.5; P = .01)
corresponding to the initial weight loss period.
Both groups reported significant reductions in caloric intake between
0 and 12 months (F = 21.734, P<.001). The behavioral
e-counseling group reduced percentage of calories consumed from fat by 4%
compared with 1% reduction in the basic Internet group from 0 to 12 months
(F = 3.6; P = .06). The respective mean (SD) increase
in exercise energy expenditure of the groups did not differ from 0 through
12 months (342 [945] vs 63 [1211] kcal; P = .26).
Changes in exercise followed the same pattern as blood glucose with between-group
differences on increases in energy expenditure at 3 months only (446 [789]
vs 38 [674] kcal, respectively; P = .02).
Logins to the Web site were significantly greater in the behavioral
e-counseling group at all times (Figure 3; P<.05). Logins were significantly
correlated with weight change between 0 and 12 months in both groups (behavioral
e-counseling, r = −0.47; P = .003; basic Internet, r = −0.61, P<.001). Logins during the first 3 months of the program
were significantly lower in those participants who did not attend the 12 month
follow-up compared with those who completed the program (t = 5.0, P<.001).
The impact of the DPP lifestyle intervention on preventing diabetes
has made dissemination of behavioral interventions a priority. This study
showed that for individuals at risk of type 2 diabetes, an Internet weight
loss program with behavioral e-counseling produced significantly more weight
loss and greater reductions in waist circumference at 1 year than the same
basic program without behavioral e-counseling. The addition of e-counseling
doubled the percentage of initial body weight lost. The weight loss observed
in the behavioral e-counseling group at 12 months is encouraging because weight
losses of similar magnitude (4.1 kg in DPS and 6.4 kg in DPP)2,3 are
known to reduce risk for diabetes. Outcomes achieved in our study with only
1 in-person meeting are comparable to prior results,2,3,15 suggesting
that Internet behavioral programs may offer an alternative to more burdensome
clinic programs.
We previously reported that an Internet behavior therapy program produced
greater weight loss at 6 months than an Internet educational program8 but were unable to determine if therapist contact
was a key component of the overall program. This is critical information for
evaluating the public health application of the Internet given the expense
of the counselors. Results from our study suggest that therapist contact improves
1-year efficacy.
Future research should explore the optimal use of Internet communications
for promoting weight loss and maintenance. From a public health perspective,
it is important to determine whether an expert system providing automated
feedback contingent on predetermined criteria produces weight loss. Future
studies are also needed to improve long-term efficacy of Internet programs
that produce less weight loss than group face-to-face treatment and to determine
the optimal combination of Internet and face-to-face modalities.16
The major strength of this study is that it was a randomized trial with
objective measurements after 12 months of Internet treatment in an at-risk
population. This study used an easy way to identify a high-risk population
appropriate for weight-loss intervention by selecting overweight individuals
with an additional diabetes risk factor rather than screening for impaired
glucose tolerance. In addition, this study demonstrates that Internet interventions
can be used for longer periods; a necessary model for treatment of chronic
diseases.
The limitations of our study include relatively small sample size, no
follow-up beyond 1 year, and no data on whether weight losses achieved in
this study reduce diabetes incidence. In addition, participants were predominantly
white, were college educated, and were required to have computer access, which
are characteristics that may reflect the fact that computer access is more
available to those with higher income. It is also likely that adults interested
in computer communications self-selected into our program. This study confirmed
that older adults and novice computer users can benefit from interactive technology
interventions.17,18 Neither prior
Internet experience nor average hours of Internet use at baseline were related
to outcome. Although participants were advised during the consent process
of the risks to confidentiality in receiving e-mail counseling, future studies
may need to provide additional safeguards such as encrypted e-mail, an e-mail
anonymizer, or password restricted access to a database in which messages
are stored without identifying information.
In summary, the results of this study showed that an Internet weight
loss program with weekly e-mail counseling produced an average weight loss
of 4.4 kg after 1 year among adults at risk of type 2 diabetes. The addition
of e-mail behavioral counseling doubled the percentage of initial body weight
lost compared with an Internet intervention without individualized therapist
guidance. Thus, Internet interventions involving weekly behavioral e-counseling
have the potential for producing behavioral changes and weight loss, which
may help reduce risk for type 2 diabetes.
1.Glasgow RE, Wagner EH, Kaplan RM, Vinicor F, Smith L, Norman J. If diabetes is a public health problem, why not treat it as one? a
population-based approach to chronic illness.
Ann Behav Med.1999;21:159-170.Google Scholar 2.Group DPPR. Reduction in the incidence of type 2 diabetes with lifestyle intervention
or Metformin.
N Engl J Med.2002;346:393-403.Google Scholar 3.Tuomilehto J, Lindstrom J, Eriksson J.
et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among
subjects with impaired glucose tolerance.
N Engl J Med.2001;344:1343-1350.Google Scholar 4. The prevention or delay of type 2 diabetes.
Diabetes Care.2002;25:742-749.Google Scholar 5.Sherwood NE, Morton N, Jeffery RW, French SA, Neumark-Sztainer D, Falkner NH. Consumer preferences in format and type of community-based weight control
programs.
Am J Health Promot.1998;13:12-18.Google Scholar 6.McKay HG, Feil EG, Glasgow RE, Brown JE. Feasibility and use of an Internet support service for diabetes self-management.
Diabetes Educ.1998;24:174-179.Google Scholar 7.Glasgow RE, Bull SS. Making a difference with interactive technology: considerations in
using and evaluating computerized aids for diabetes self-management education.
Diabetes Spectrum.2001;14:99-106.Google Scholar 8.Tate DF, Wing RR, Winett RA. Using Internet technology to deliver a behavioral weight loss program.
JAMA.2001;285:1172-1177.Google Scholar 9.Thomas S, Reading J, Shephard R. Revision of the Physical Activity Readiness Questionnaire (PAR-Q).
Can J Sports Sci.1992;17:338-345.Google Scholar 10.Wing RR. Behavioral approaches to the treatment of obesity. In: Bray G, Bouchard C, James P, eds. Handbook
of Obesity. New York, NY: Marcel Dekker Inc; 1998:855-873.
11. Anthropometric Standardization Reference Manual. Champaign, Ill: Human Kinetics; 1988.
12.Paffenbarger RS, Wing AL, Hyde RT. Physical activity as an index of heart attack risk in college alumni.
Am J Epidemiol.1978;108:161-175.Google Scholar 13.Block G, Hartman AM, Dresser CM, Carroll MD, Gannon J, Gardner L. A data-based approach to diet questionnaire design and testing.
Am J Epidemiol.1986;124:453-469.Google Scholar 14.Radloff LS. The CES-D scale: a self-report depression scale for research in the
general population.
Appl Psychol Measur.1977;1:385-401.Google Scholar 15.Jeffery RW, Wing RR, Thorson C, Burton LC. Use of personal trainers and financial incentives to increase exercise
in a behavioral weight-loss program.
J Consult Clin Psychol.1998;66:777-783.Google Scholar 16.Harvey-Berino J, Pintauro S, Bulzzell P.
et al. Does using the Internet facilitate the maintenance of weight loss?
Int J Obes Relat Metab Disord.2002;26:1254-1260.Google Scholar 17.Glasgow RE, Toobert DJ. Brief, computer-assisted diabetes dietary self-management counseling:
effects on behavior, physiologic outcomes, and quality of life.
Med Care.2000;38:1062-1073.Google Scholar 18.Feil EG, Glasgow RE, Boles SM, McKay HG. Who participates in Internet-based self-management programs? a study
among novice computer users in a primary care setting.
Diabetes Educ.2000;26:806-811.Google Scholar