In the US, 27% of those aged 65 or
older have diabetes. Based on fasting blood glucose levels or glycated
haemoglobin levels, the estimate of the prevalence of pre-diabetes is 79
million cases. The economic cost has been estimated at around $2,000 per person
per annum. The maths aren’t complicated working out at about $22 billion per
annum. Most cases of type 2 diabetes are treated
initially by lifestyle changes and then by drugs to manage blood glucose. In
2009, the American Diabetes Association defined partial remission from diabetes
when fasting blood glucose levels were lowered to below the diagnostic norm and
complete remission when fasting blood glucose levels returned to normal, in
both cases in the absence of drug therapy. Relatively little is really known of
the extent to which such partial or complete remission can be achieved with
lifestyle interventions. In 2001, a large multicenter study was established in
the US known as “Look Ahead”, (Actions for Health in Diabetes)[1].
The trial, funded by the National Institute of Health, involved 2,262 type 2
diabetics given a basic diabetes lifestyle intervention and a group of 2,241
type 2 diabetics given an intensive lifestyle intervention. The former were
given 3 group sessions per year while the latter participated in weekly group
and one-on-one counseling for the first 6 months followed by 3 sessions per
month for the next 6 months and twice monthly sessions thereafter. For this
group, a target caloric intake was set between 1,200 and 1,800 calories per day
with an exercise goal of 175 minutes of moderately intensive exercise per week
(25 minutes per day). The Look Ahead
trial laid out its hypothesis quite clearly: that there would be a significant
reduction in heart disease and stroke in the intensively counseled group
compared to the group receiving standard advice on lifestyle. The trial has
produced over 80 peer reviewed papers and has shown that intensive lifestyle
intervention can significantly improve body-weight, blood pressure, blood
glucose control and blood lipid levels.
On October 19th this year, when the
trial was well into its 11th year, the NIH announced the end of the trial on
foot of recommendations from the trial’s data and safety monitoring board. This
independent body of experts noted that despite the above improvements on risk
factors for cardiovascular disease, there was no statistically significant
difference in cardiovascular events between the two groups which was the
central hypothesis. Recently, the trial study group published a paper in the
Journal of the American Medical Association showing that intensive lifestyle
intervention did indeed lead to a greater rate of remission of type 3 diabetes
compared to the standard intervention[2].
The big disappointment was, however, that the impact of intensive lifestyle was
very small. The rate of partial or complete remission in year 1 was 11. 5% in
the intensively tutored group, falling to 7.3% at year 4. In contrast, the
group receiving standard counseling showed a 2% reduction at both time points.
Very clearly, type 2 diabetes is not a reversible condition for the vast
majority of subjects. And just as clearly, this low response rate in correcting
diabetes pathologies explains why no differences in heart disease were observed
between the two treatment groups.
In the same issue of this journal,
an editorial looks at the overall evidence for lifestyle and surgical
interventions in obesity[3].
The latter are usually confined to subjects with very severe cases of obesity.
The latter leads to type 2 diabetes remission rates, which are 12 to 24 fold
greater than intensive lifestyle interventions. The Swedish Obesity Study, also
published in this year’s JAMA, reported on the long-term effects of the
surgical treatment of obesity. Subjects were morbidly obese at baseline (1987
was the start date) and the average duration of follow up was 14.7 years[4].
Compared to conventional medical and lifestyle treatment, the surgical
intervention reduced fatal heart attacks by 47%, all heart attacks by 52% and
stroke by 34%. Surgery is expensive but so too is intensive lifestyle
interventions and thus some cost comparisons between the two would be
interesting.
Clearly, we are in a mess and we
must now live with the mess. But how can we prevent the mess for future
generations?. Whilst 79 million Americans have prediabetes and are at risk of
developing diabetes, the remaining 233 million don’t. Of those aged over 65
years, 11.2 million have type 2 diabetes while the remaining 30 million over
65s do not. They all live in the same obesogenic US environment. One day, not
far from now, we will be able to predict who is likely to to draw the short
straw and develop obesity-related type 2 diabetes. Moreover, this genetic
information will soon be able to zone in on that aspect of diet and lifestyle,
which is most responsible for the development of diabetes. For some, it may be
a metabolically based genetic factor. For others, it may be a food choice
factor that is the driver and for others it may be a defective satiety system.
Understanding personal risk and understanding personalised solutions is the
future for nutrition and health. In the meantime, we have a mess.
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