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A 50-year-old sedentary male with a BMI of 32 kg/m2,
a family history of type 2 diabetes, and an impaired glucose tolerance
test seeks help to prevent the onset of diabetes. All of the following
strategies are appropriate for the long term except:
1. Weight loss goal of 2 to 3 kg/week
2. Increase duration and intensity of daily physical activity
3. Fiber intake of 15 g/1,000 kcal
4. Total fat intake of 30% of total energy intake
Intensive lifestyle interventions can help prevent diabetes, according
to three-year results of the Finnish Diabetes Prevention Study (DPS)
study published in the December issue of Diabetes Care.
"It is evident that lifestyle intervention can prevent or at least
postpone type 2 diabetes and should therefore be implemented in primary
health care," write Jaana Lindström, MSC, from the National
Public Health Institute in Helsinki, Finland, and colleagues. "However,
the lifestyle interventions used have been either insufficiently described
or not intended as conventional treatment of high-risk individuals."
In the DPS, 522 middle-aged, overweight subjects with impaired glucose
tolerance were randomized to receive either usual care or intensive
lifestyle intervention aimed at reducing body weight and dietary and
saturated fat and increasing physical activity and dietary fiber.
Both groups received general dietary and exercise advice at baseline
and had an annual physical examination. In the intervention group, subjects
also received additional individualized dietary counseling from a nutritionist,
were offered circuit-type resistance training sessions, and were advised
to increase overall physical activity. These interventions were most
intensive during the first year.
The intervention group fared significantly better than the control group
in each intervention goal, including weight reduction after one year
(4.5 kg vs. 1.0 kg), weight reduction after three years (3.5 kg vs.
0.9 kg), and measures of glycemia and lipemia.
Study limitations include possible underreporting of dietary intake
and recollection bias.
"The intensive lifestyle intervention produced long-term beneficial
changes in diet, physical activity, and clinical and biochemical parameters
and reduced diabetes risk," the authors write. "This type
of intervention is a feasible option to prevent type 2 diabetes and
should be implemented in the primary health care system.... In the long
run, a lifestyle-intervention approach to weight control rather than
a weight-reduction diet might be a more cost-efficient way to manage
overweight in individuals at high risk for diabetes."
The Finnish Academy, the Ministry of Education, the Novo Nordisk Foundation,
Yrjö Jahnsson Foundation, Juho Vainio Foundation, and the Finnish
Diabetes Research Foundation supported the DPS study.
Diabetes Care. 2003;26:3230-3236
The DPS has previously shown a reduction in incidence of diabetes by
58% with lifestyle intervention compared with a usual-care group, according
to a study by Tuomilehto and colleagues published in the May 3, 2001,
issue of the New England Journal of Medicine. This finding was replicated
by the Diabetes Prevention Program (DPP), in which a more expensive,
customized model of intensive lifestyle intervention was associated
with a 58% risk reduction in diabetes compared with metformin treatment,
as reported in the Feb. 7, 2002, issue of the New England Journal of
Medicine by the DPP Research Group.
This randomized, longitudinal prospective study conducted at five Finnish
participating centers employed a physician, study nurse, and nutritionist
(with MSc in nutrition) and hired or paid for the services of an exercise
physiologist or physiotherapist for exercise counseling at each center.
Patients were followed for one to three years to assess the efficacy
of maintenance of changes. The authors hypothesized that long-term lifestyle
modification may be more cost-effective for weight management of individuals
at high risk for diabetes than short-term weight-reduction diets.
Study Highlights
522 middle-aged, overweight subjects with impaired glucose tolerance
defined by the World Health Organization criteria were recruited via
local advertising or screening relatives of patients with type 2 diabetes.
265 subjects were randomized to the intervention group and 257 to the
control group between 1993 and 1998. They were stratified by center,
sex, and 2-hour plasma glucose results. Dropout rate was similar between
groups.
The study was prematurely terminated in March 2000 because the incidence
of diabetes was found to be significantly lower in the intervention
group compared with the control group. However, follow-up of participating
subjects continued to year 3.
Lifestyle intervention goals were 5% weight reduction (recommended weight
loss rate, 0.5-1.0 kg/week), moderate-intensity physical activity (PA)
of 30 min/day, dietary fat of 30% or less of total daily energy intake,
saturated fat of 10% or less of daily intake, and fiber intake of 15
g/1,000 kcal or more.
Intervention group subjects received 7 individualized face-to-face,
30-minute sessions with the study nutritionist in year 1, and 4 sessions
per year thereafter. A subgroup of 48 subjects participated in a very-low-calorie
diet for 2 to 5 weeks after 6 months. All subjects regularly measured
and recorded weight and physical activity.
Control group subjects were given the same general goals and information
in a single group session with printed materials, but there was no individualized
counseling.
Annual measurements included oral glucose tolerance testing, medical
history and physical examination, height, weight, waist circumference,
and complete lipid profile.
Patients assessed their dietary intake with a 3-day food record before
every visit using a standardized book, and a dietary analysis program
was used to calculate caloric intake. Subjects were similar in baseline
characteristics of mean age (55 years), sex (50%-55% male), first-degree
relative with diabetes (one third), education level, occupation, mean
weight at entry (86 kg), body mass index (BMI) of 31 kg/m2 (55% had
BMI of 30 kg/m2), waist circumference (101 cm), fasting plasma glucose
(6.1 mmol/L), HbA1C (5.6%), cholesterol profile, total LTPA per week
(mean of 160 min/week with one third of subjects defined as sedentary)
and caloric intake of micro- and macronutrients per day.
PA was significantly higher at years 1 and 3 for the intervention group
(30% and 29%, respectively) compared with the control group (14% and
17%, respectively). Comparisons were significant at year 1 (P < .0001)
and year 3 (P = .0028). Moderate-to-vigorous physical activity increased
in the intervention group compared with the control group.
The intervention group had a significantly better weight loss at year
1 of 4.5 kg compared with 1.0 kg weight loss in the control group. In
addition, 46% attained the 5% weight loss goal compared with 14% in
the control group (P < .0001). At year 3, mean weight reduction was
3.5 kg in the intervention group compared with 0.9 kg in the control
group.
Dietary fat intake goal was reached by 37% vs. 20%, respectively (P
< .0001), saturated fat goal was reached by 21% vs. 9%, respectively
(P < .0001), and fiber intake goal was reached by 37% vs. 23%, respectively
(P < .0006).
Fasting plasma glucose and 2-hour glucose values were improved in the
intervention group compared with the control group in year 1 (-0.2 mmol/L
vs. 0.0 mmol/L; P < .0001), and this difference persisted in year
3 (P = .002). Lipid measures were more improved in the intervention
group compared with the control group.
Pearls for Practice
Intensive lifestyle modification using an individualized approach and
a team of skilled healthcare professionals produces positive outcomes
of weight reduction, increased physical activity, and glucose and lipid
metabolism improvement over three years compared to simple one-time
group counseling.
Lifestyle intervention can prevent or postpone the onset of type 2 diabetes
in susceptible individuals.
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