Lifestyle Patterns Among Obese Adults – Chicken or Egg?
Weight gain is the result of positive energy balance and the only way you can get into positive balance is if energy input exceeds output. As all calories enter the body as food or drink, ingestive behaviour is obviously an important determinant of energy balance. Although physical activity accounts for only around one-third of total energy expenditure (two-thirds of energy is burnt just to keep your body alive), it is still an important component of energy balance. It is therefore not surprising when studies find that “eating too much” or “not moving enough” is often (but not always!) associated with weight gain. This is in fact exactly what was found in a new study by Robert Kushner and SW Choi from the Northwestern University, Chicago, IL, just published in OBESITY. This study looked at responses to a 53-item lifestyle pattern questionnaire posted on a commercial weight loss program Web site (2004- 2008) in 446,608 adults with an average BMI of 30.5. Categorically, 25.5% were healthy weight, 29.0% were overweight, 33.7% were class I-II obesity, and 11.8% class III obesity. A stratified random sample was used to estimate the prevalence of 21 lifestyle patterns (7 eating, 7 exercise, and 7 coping: figure) and the odds ratio of the pattern prevalence for each BMI category. “Unhealthy” lifestyle patterns in diet, exercise, and coping were highly prevalent among the entire population, whereby, the prevalence of these patterns rose with increasing BMI and advancing age. Gender differences were seen with many of the patterns, most noticeably among the coping patterns. Thus, prevalence of five coping patterns was noticeably higher among women compared to men: emotional eater (41% vs. 29%), self-scrutinizer (negative self-talk) (52% vs. 27%), persistent procrastinator (73% vs. 61%), people pleaser (low self-care) (54% vs. 40%), and doubtful dieter (pessimistic thinking) (41% vs. 29%). Overall, the lifestyle patterns and terminology used in this study is reminiscent of the “personality types” that Dr. Kushner has described before (see previous blog entry on this). Based on the current study, the authors conclude that “unhealthy” behavioural patterns are associated with obesity and that behavioural pattern recognition could help identify patients at risk. For me the paper raises more questions than it answers: Firstly, I was surprised that despite the significant associations, the effect sizes of individual patterns was actually quite low: this means that a lot of people in the “healthy weight” range apparently also engage… Read More »
Diabetes Prevention Works
Yesterday, The Lancet released the 10-year follow-up of the landmark Diabetes Prevention Program (DPP) Outcomes Study. Readers may recall that the original publication showed that in the 2.8 years of intervention, high-risk adults randomised to intensive lifestyle intervention had a risk reduction of 58% in the incidence for type 2 diabetes and a 31% risk reduction with metformin, compared with placebo. This report now examines whether these effects persist in the long term in 2766 of 3150 (88%) original patients enrolled for a median additional follow-up of 5·7 years. 910 participants were from the lifestyle, 924 from the metformin, and 932 were from the original placebo groups. While all three groups were offered group-implemented lifestyle intervention, metformin treatment was continued in the original metformin group (850 mg twice daily as tolerated) and the original lifestyle intervention group was offered additional lifestyle support. During the 10-year follow-up since randomisation to DPP, the original lifestyle group lost, then partly regained weight. In contrast, the metformin group maintained most of the modest weight loss achieved in the first years of the trial. In contrast to the marked differences in diabetes incidence between groups in the initial study, the incidence of diabetes in this follow-up study were similar between treatment groups: 5·9 per 100 person-years for lifestyle, 4·9 for metformin, and 5·6 for placebo. Interestingly, this finding was not attributable to a rebound effect in the lifestyle group but to a fall in incidence in the placebo and metformin groups that resulted in similar rates as achieved by lifestyle intervention, which changed little throughout follow-up. Nevertheless, when compared over the 10 years since enrollment in DPP, diabetes incidence was still 34% lower in the lifestyle group and 18% lower in the metformin group than with placebo. Thus, although the incidence rates of diabetes between the groups began to converge over the 10 year period, the cumulative incidence of diabetes remained lowest in the lifestyle group. The study therefore supports the notion that an intensive lifestyle intervention and metformin can both prevent or delay the incidence of diabetes and that this effect can persist for as long as 10 years. In an accompanying editorial, my Indian friend and colleague Anoop Misra, about whom I have blogged previously, comments: “Prevention of diabetes is a long and winding road. There seems to be no short cut, and a persistent and prolonged intensive lifestyle intervention seems to be… Read More »
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