A few days ago, I blogged about the important clinical improvement with weight loss in the ongoing Look AHEAD trial seen in patients with type 2 diabetes and knee pain.

A new paper from the same study, by Redmon and colleagues on behalf of the Look AHEAD investigators, published in this month’s edition of Diabetes Care, shows that intensive weight management can significantly improve diabetes control and decrease medication costs in patients with type 1 diabetes.

As regular readers may be well aware, Look AHEAD is a multicenter randomized controlled trial of 5,145 overweight or obese individuals with type 2 diabetes, aged 45-76 years.

The study compares the effects of an intensive lifestyle intervention involving group and individual meetings as well as meal replacements and in some cases pharmacotherapy to achieve and maintain weight loss through decreased caloric intake and increased physical activity vs. a diabetes support and education program.

At one year, participants randomised to the intensive lifestyle intervention had a significant reduction in their use of medications for diabetes, hypertension, and hyperlipidemia (average 3.1 drugs vs. 3.6 in the control group)

This resulted in approximately $30 monthly savings in the weight loss group.

The researchers conclude that weight management in patient with type 2 diabetes not only decreases cardiovascular risk factors but also leads to a reduction in medication use that translates into substantial savings.

It should, however, be noted that weight management does not come free and that there are costs to the lifestyle interventions for weigh loss. Nevertheless, given the multiple benefits of addressing excess weight, readers should have no doubt as to the cost-effectiveness of weight management in patients with type 2 diabetes.

AMS
Toronto, Ontario

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Redmon JB, Bertoni AG, Connelly S, Feeney PA, Glasser SP, Glick H, Greenway F, Hesson LA, Lawlor MS, Montez M, Montgomery B, & Look AHEAD Research Group (2010). Effect of the look AHEAD study intervention on medication use and related cost to treat cardiovascular disease risk factors in individuals with type 2 diabetes. Diabetes care, 33 (6), 1153-8 PMID: 20332353

Yesterday, I blogged about the finding that increased body fat appears to precede lower activity levels and not the other way round (which is probably why attempts to increase physical activity in kids has so far not done much in terms of obesity prevention).

Almost on cue, the latest issue of the Canadian Medical Association Journal (CMAJ) publishes a study by McMaster University’s John Cairney and colleagues, suggesting that kids with developmental coordination problem (perhaps unfairly described as “clumsiness”) may be particularly prone to weight gain.

The study builds on previous reports that kids with developmental coordination disorder were found to be less likely to participate in physical activities.

The researchers studied 2278 (95.8%) of 2378 fourth grade kids (ages 9 to 10) from 75 schools in southwestern Ontario, Canada. Children were followed up over two years, from the spring of 2005 to the spring of 2007.

Not only did the 111 children (46 boys and 65 girls) who had possible developmental coordination disorder have a higher mean BMI and waist circumference at baseline than the other kids, but these differences persisted or increased slightly over time.

In fact, kids with with possible developmental coordination disorder were four times more likely to become obese over the course of the study.

While this study is of course strongly suggestive of less physical activity being a risk factor for childhood obesity, it should be noted that the researchers did not directly measure activity levels. There was also no report of their energy intake or their mental health status (e.g. cognitive ability, depression, attention deficit disorder, etc.), which may significantly affect ingestive behaviours.

There was also no mention of low birth weight, which may be associated both with developmental coordination disorder and excess post-partum weight gain.

Finally, as the authors themselves are careful to note, obese kids have been noted to be less coordinated - so again, it is not clear if the sequence here is “clumsiness -> inactivity -> obesity” or “obesity -> inactivity -> clumsiness” or even “obesity -> clumsiness -> inactivity”.

As always, solving ‘chicken or egg’ questions from cross-sectional or even longitudinal data remains challenging. This is exactly why we need more intervention studies.

AMS
Edmonton, Alberta

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The current dogma is that our kids are getting bigger because of sedentariness and inactivity. Based on this dogma, attempts at reversing the childhood obesity epidemic focus largely on increasing physical activity -so far with little to show for.

Now, a study by Brad Metcalf and colleagues from Plymouth, UK, published online in the Archives of Disease in Childhood, suggests that it may be fatness leading to inactivity rather than the other way round.

For this study, the researchers analyse data from a prospective cohort study examining children annually from 7 to 10 years. Participants were 202 children (53% boys, 25% overweight/obese) recruited from 40 Plymouth primary schools as part of the EarlyBird study.

Importantly, the researchers used accelerometers worn by the children for 7 consecutive days at each annual time point to measure actual levels of physical activity.

In addition, actual body fat per cent was measured annually by dual energy x ray absorptiometry.

While body fat percentage was predictive of changes in physical activity over the following 3 years, physical activity levels were not predictive of subsequent changes in body fat.

Thus, while a 10% higher body fat at age 7 years predicted a relative (albeit modest) decrease in daily moderate and vigorous intensities of 4 min from age 7 to 10 years, greater physical activity at 7 years did not predict a relative decrease in body fat between 7 and 10 years.

The authors conclude that the often found association between lower activity levels and higher body fat may be the result of fatness driving inactivity rather than inactivity driving body fat. Thus, physical inactivity appears to be the result of fatness rather than its cause.

Not surprisingly perhaps, they also note that this “reverse causality” may nicely explain why attempts to tackle childhood obesity by promoting physical activity have been largely unsuccessful.

Given, as blogged previously, that the key determinant of body fatness may well be determined by what happens in utero - the causal sequence for the childhood obesity epidemic may well be:

in utero epigenetic programing > fatter offspring > less active kids.

Thus, while interventions to increase physical activity in kids may well have an important benefits on fitness, balance, coordination and numerous other aspects of health - anyone expecting more activity in kids to reverse the childhood obesity epidemic may well be barking up the wrong tree.

AMS
Edmonton, Alberta

p.s. You can now also follow me and post your comments on Facebook

Metcalf BS, Hosking J, Jeffery AN, Voss LD, Henley W, & Wilkin TJ (2010). Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children (EarlyBird 45). Archives of disease in childhood PMID: 20573741

As most smokers are well aware, smoking cessation is often accompanied by a variable amount of weight gain, and there is some evidence that some people (particularly young women) primarily smoke to control their appetite and weight.

Indeed, as blogged previously, the progress on fighting tobacco in the US may be eroded by the gains in obesity rates, as over the past 15 years, smoking rates in the US have declined by 20%, whereas obesity rates have increased by 48%..

So do policies that address tobacco consumption increase the prevalence of obesity?

This question was addressed by Anindya Sen and colleagues from the University of Waterloo, Ontrario, in a paper just published online in the journal Health Policy.

In this study, the researchers used the the substantial cross-province differences that exist between Eastern and Western Canada to estimate the effects of higher cigarette taxes on aggregate health region and individual level data from the 2003 and 2005 waves of the Canadian Community Health Surveys (CCHS).

According to their estimates, a 10% higher cigarette tax is correlated with a 4% lower rate of smoking but also a 4-5% higher prevalence of obesity. These findings were robust across several models that took into account various demographic variables and potential confounders.

The researchers conclude that health benefits from higher cigarette taxes and lower smoking rates may be partially offset by a corresponding increase in obesity levels.

However, given the tremendous negative impact of smoking on health, one would need to gain quite a considerable amount of weight to fully negate the many potential benefits (less heart disease, COPD, cancers, amputations) of smoking cessation.

Smoking cessation programs and anti-tobacco policies should probably actively promote measures to prevent excessive weight gain.

As blogged before, this may be easier said than done.

AMS
Edmonton, Alberta

p.s. You can now also follow me and post your comments on Facebook

Sen A, Entezarkheir M, & Wilson A (2010). Obesity, smoking, and cigarette taxes: Evidence from the Canadian Community Health Surveys. Health policy (Amsterdam, Netherlands) PMID: 20570008

The Look AHEAD (Action for Health in Diabetes) Trial is a large ongoing prospective trial on the long-term effect of weight management on outcomes in people with type 2 diabetes.

A paper just released online in the journal OBESITY features an article by Capri Foy and colleagues from the Look AHEAD trialists on the impact of intensive lifestyle intervention on physical function and knee pain.

The paper focuses on the 2,203 participants, who reported knee pain at baseline.

The intensive lifestyle intervention arm of the trial includes behavioural interventions as well as the intermittent use of meal replacements and pharmacotherapy to control weight. The control arm of the trial uses conventional diabetes management strategies.

The participants in the intensive intervention arm experienced and almost 10% mean weight loss compared to virtually no change in the control group.

This reduction in body weight over 12 months was associated with a significant and clinically relevant improvement in pain and function of the participants.

A separate analysis demonstrated that apart from the weight loss itself, part of the improvement in pain and functioning was mediated by increased fitness in the intervention group.

The authors conclude that the intensive lifestyle intervention focussing on weight loss in adults with type 2 diabetes and knee pain, results in significant improvement in physical function.

As reported previously, it should be noted that overall the participants in the intensive intervention group also experienced a remarkable improvement in their diabetes control.

Although findings from clinical trials cannot necessarily be extrapolated to usual practice, these findings certainly highlight that a far greater emphasis on weight management will likely benefit patients with type 2 diabetes - benefits that go well beyond simply improving glycemic control.

AMS
Edmonton, Alberta

p.s. You can now also follow me and post your comments on Facebook

Foy CG, Lewis CE, Hairston KG, Miller GD, Lang W, Jakicic JM, Rejeski WJ, Ribisl PM, Walkup MP, & Wagenknecht LE (2010). Intensive Lifestyle Intervention Improves Physical Function Among Obese Adults With Knee Pain: Findings From the Look AHEAD Trial. Obesity (Silver Spring, Md.) PMID: 20559303