Archive for May, 2014

Unstoppable Rise in Global Obesity?

May 29th, 2014

The Lancet has published an analysis of the global, regional, and national prevalence of overweight and obesity in children and adults between 1980-2013. The bottom line: overweight and obesity is increasing in children and adults, among men and women in developed and developing countries, albeit at different rates. No national success story in preventing or controlling obesity has been reported in the past 33 years. The abstract reads, in part, “Worldwide, the proportion of adults with a body-mass index (BMI) of 25 kg/m2 or greater increased between 1980 and 2013 from 28·8% (95% UI 28·4—29·3) to 36·9% (36·3—37·4) in men, and from 29·8% (29·3—30·2) to 38·0% (37·5—38·5) in women. Prevalence has increased substantially in children and adolescents in developed countries; 23·8% (22·9—24·7) of boys and 22·6% (21·7—23·6) of girls were overweight or obese in 2013. The prevalence of overweight and obesity has also increased in children and adolescents in developing countries, from 8·1% (7·7—8·6) to 12·9% (12·3—13·5) in 2013 for boys and from 8·4% (8·1—8·8) to 13·4% (13·0—13·9) in girls. In adults, estimated prevalence of obesity exceeded 50% in men in Tonga and in women in Kuwait, Kiribati, Federated States of Micronesia, Libya, Qatar, Tonga, and Samoa. Since 2006, the increase in adult obesity in developed countries has slowed down. Because of the established health risks and substantial increases in prevalence, obesity has become a major global health challenge. Not only is obesity increasing, but no national success stories have been reported in the past 33 years. Urgent global action and leadership is needed to help countries to more effectively intervene.”

 

What Improvement? US Youth Fitness Drops 10 Points

May 29th, 2014

Michelle Obama is launching a passionate defense of improvements to the National School Lunch Program. She is fighting House Republican proposals to provide waivers of the new requirements for some schools. The arguments against such waivers might be stronger had waivers not been so liberally used in the implementation of the Affordable Care Act. Nevertheless, the First Lady is making much of improvements in children’s health since launching her Let’s Move campaign. Unfortunately, the facts are not very supportive. The National Center for Health Statistics has issued a new report on cardiorespiratory fitness among U.S. youth aged 12-15. Short answer: it has gotten worse. The Report states, “The percentage of youth aged 12-15 who had adequate levels of cardiorespiratory fitness decreased from 52.4% in 1999-2000 to 42.2% in 2012.”

What Leveling Off? Part 2

May 28th, 2014

The Healthy People project is a massive undertaking conducted by the Department of Health and Human Services every ten years. An interim report card, published in JAMA,  focuses on selected “Leading Health Indicators”. Twenty-six out of the thousands of goals in Health People are selected as Leading Health Indicators. 14 of the 26 have documented improvement. 4 have met or exceed the goal. The report found that 3 of the 26 showed a worsening situation. Adult obesity has increased from 33.9% in 2005-2008 to 35.3% in 2009-2012. The goal was a reduction to 30.5%. Obesity among adolescents and children (2 to 19 years of age) as increased from 16.1% in 2005-2008 to 16.9% in 2009-2012. The goal was a reduction to 14.5%. The third negative indicator was daily intake of vegetables. This has remained stable at 0.8% in both timeframes. The goal was an increase to 1.1 vegetable servings.

 

Recession Increased Odds of Becoming Obese

May 28th, 2014

The widely-respected OECD reports that obesity continues to increase rates of obesity. The interesting finding is that the economic recession has increased the prevalence of obesity. Their research indicates that people worried about their economic condition reduced their food budget and moved from healthier, more costly foods to cheaper, more calorically dense foods.

 

 

 

What Leveling Off?

May 23rd, 2014

Recently, the word from the Michelle Obama, Robert Wood Johnson Foundation and others, has been that the obesity epidemic is ‘leveling off,” at least among children. Many of us are skeptical because there was no evidence of the cause of any leveling off (much like we have don’t understand the putative causes of obesity) but mainly because the time separation of one survey from another was really too short to demonstrate a trend.

Now comes another piece to the puzzle. The folks at Gallup Healthways Well-Being Index have surveyed adult individuals in the US since 2008, using self-reported heights and weights to calculate Body Mass Index (BMI). The most recent survey shows adult obesity has increased to 27.7% in 2014 from 27.1% in 2013. The share of the population at a normal weight continues to decline from 35.7% in 2013 to 35.3% in 2014.

 

Meta-analysis shows failure of long-term weight loss maintenance

May 22nd, 2014

A new meta-analysis looks at long term maintenance of weight loss with non-surgical interventions. In a article published in the British Medical Journal, Dombrowski et al examined 45 trials involving 7,788 individuals were included. Behavioral interventions focusing on both food intake and physical activity resulted in an average difference of -1.56 kg compared to controls. (1.56kg equals about 3.5 pounds which is about one-half of a BMI unit).  This review followed Cochrane protocols. The primary outcome was weight at 12 months among participants who had lost >5% of body weight. The average BMI  before weight loss was 35.2. 3 studies involved participants in the community. 42 studies initially recruited 9,451 individuals of whom 7,788 were in maintenance. The average dropout rate was 28.4% before maintenance. Most participants received “standard behavioral therapy”.

The review found, “no evidence of effectiveness for the following interventions:  dietary intervention versus control condition,  high carbohydrate and low fat diets versus other types of diets, physical activity interventions versus control conditions, adding aerobic exercise to a dietary intervention versus diet alone, adding physical activity (such as walking and resistance training) to a dietary intervention versus diet alone, adding meal replacements to dietary recommendations versus dietary recommendations alone.” Further, the authors state, “Although energy prescriptions were poorly described in some weight loss maintenance intervention arms, participants seemed to receive advice to follow a regimen that continued to create an energy deficit, which was perhaps an unrealistic expectation for the long term. This obscures the important distinction between weight loss and weight loss maintenance.”

The abstract may fall into the “overly optimistic” category. It states, “Behavioral interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance.”  Really? The paper just reported “no evidence” for the major types of interventions. “Small?”  My weight can move + or – 1.56kg from day to day, morning to night. How can this be considered significant? Participants in this meta-analysis had an average BMI before weight loss of 35.2. A weight loss of half a BMI would lower this to 34.7. Whopee!  But how can serious people regard this as “significant?” Most people will only read the abstract of this meta-analysis and be sorely misled. This study does not specifically address adaptive thermogenesis, but it’s findings do support that hypothesis.

 

Big Problems Undercut Research Findings

May 21st, 2014

Research is the key to understanding obesity and developing accurate and effective treatments, prevention approaches and public policies. However, researchers have found significant problems in observational studies  and the interpretation of research results.

One study has found that statistical results in psychological studies are biased toward researcher’s own expectations and authors often dismiss data inconsistent with their own hypothesis. Bakker and Wicherts found that, of 281 articles examined, around 18% of the statistical results are incorrectly reported and around 15% contained at least one statistical conclusion that proved to be incorrect. Errors were often in line with researchers’ expectations. Errors were higher in journals with low impact factors.

A study published in Radiology by Ochodo and colleagues examined the diagnostic accuracy in studies found errors in journals with high impact factors. Errors included over-interpretation, overly optimistic abstract, discrepancy between study aim and conclusion, conclusions based on selected subgroups, failure to include a sample size calculation, failure to state a test hypothesis as well as failure to report confidence Intervals.

In a study published in Statistics in Medicine in January 2014, Schuemie and colleagues found that a majority of observational studies would declare statistical significance when no effect is present. At least 54% of findings with p <0.05 are not actually statistically significant.

Closer to home, Jayawardene and colleagues found significant discrepancies in self-reported height and weight among adolescents in the National Youth Physical Activity and Nutrition Study, 2010. Underweight students under-reported height and over-reported weight while overweight and obese students over-reported height and under-reported weight. Weight loss behaviors, both healthy and unhealthy were associated with BMI underestimation while fast food consumption and screen time were associated with overestimation. These problems can work their way into more general views of obesity. For example, many people believe that obesity is much higher in the Southeastern United States but Allison and colleagues, using direct measurements, found that the West North Central and East North Central Census division have higher prevalence. Likewise, Hattori and Sturm found that approximately one in six to seven obese individuals were misclassified as non-obese due to underestimation of BMI.

One of the most disturbing research flaws was a paper published in 2013 by Hand, Hebert and Blair which found that across the 39 year history of the NHANES, energy intake data for 67% of women and 59% of men were “not physiologically plausible.” The authors stated, “The confluence of these results and other methodological limitations suggest that the ability to estimate population trends in caloric intake and generate empirically supported public policy relevant to diet-health relationships from US nutritional surveillance is extremely limited.”

The Body Mass Index (BMI) has been problematic for some time, resulting in misreporting and misclassification. (See article)  Another study found that 29% of subjects classified as lean and 80% of individuals classified as overweight according to BMI had a body fat percentage within the obesity range. Cardiometabolic risk factors were higher in lean and overweight by BMI-classified subjects with percent of body fat within the obesity range. A study using bioelectrical impedance analysis to estimate body fat found that BMI-defined obesity was present in 19% of men and 25% of women, while percent body fat-defined obesity was present in 44% of men and 52% of women. Again BMI had a high specificity but low sensitivity. They found a BMI cutoff of > 30 misses more than half of people with excess fat. They speculate that this might explain the unexpected better survival in overweight/mild obese patients.

Klesges and colleagues examined 77 papers in the important area of prevention of childhood obesity from 1980 to 2008. They found all studies lacked full reporting of generalizing elements including the intervention staff, the implementation of the intervention content, costs and program sustainability. Somewhat similar results were found in 27 publications covering community-based interventions for diet, exercise and smoking cessation. Dzewaltowski et al found that while 88% reported participation rates among eligible members of the target audience, only 11% reported the “adoption” rate among eligible community-based organizations or settings. They also found few studies reported on the representativeness of the participants. Few reported whether individuals maintained the behavior change or whether organizations maintained or institutionalized interventions.

These disturbing results come amid profound doubts arising in several areas, not only psychological science, but  cancer research where several large pharmaceutical have reported that many studies had results which could not be replicated. Concerns go back to a paper by JP Ioannidis, “Why most published research findings are false.”  Ioannidis was an author of another paper which found that many observational studies published in the New England Journal of Medicine, JAMA and the Annals of Internal Medicine made clinical practice recommendations without stating the need for a randomized clinical trial.

In 2010, Graham Colditz noted that, “Prevention trials recruit large numbers of healthy participants, offer them a therapy and then follow them over many years because the chronic diseases being prevented are relatively rare. With substantial noncompliance (often in the range of 20% to 40% over the duration of the trial), an intention-to-treat analysis is no longer unbiased, but rather gives a biased estimate of the effect, typically underestimating the magnitude of the association that is seen in observational studies in which those participants who have had exposure to a particular lifestyle component are compared with those without such an exposure. “

Tajeu et al reported that, in the peer-reviewed obesity literature, of 855 articles examined, 7.3% presented odds ratios. Of these, 23% were presented incorrectly. Overall, almost one-quarter of the studies presenting odds rations misinterpreted them. Menachemi et al reviewed 937 papers in the nutrition and obesity literature found that nearly 10% had overreaching conclusions.

These problems are only amplified when the university or journal press office writes up a press release and then, in many cases, the media boil down the findings to a 10-second sound bite. Funding agencies, journals and professional societies need to more diligent in making sure that obesity research is conducted at the highest level of scientific accuracy for many lives and millions of dollars may be affected.

 

Discrimination, Weight, Old Age

May 19th, 2014

Avid readers of the Downey Obesity Report may recall interesting research by Angelina Sutin and colleagues on personality aspects and obesity. Now, she has published a new study looking at multiple personal characteristics and their association with physical,emotional and cognitive health in older adults. Participants rated their everyday experiences with discrimination and attributed these experiences to eight personal characteristics (race, ancestry, sex, age, weight, physical disability, appearance, and sexual orientation) at two points in time. The results indicate that discrimination based on age, weight, physical disability and appearance were associated with poor subjective health, greater disease burden, lower life satisfaction and greater loneliness at both time points. Discrimination was generally unrelated to cognitive health. They concluded that the adverse effects of discrimination on physical and emotional health are not limited to young adulthood but continue into old age and are primarily driven but changeable characteristics (age and weight) versus fixed characteristics (race and sex). (One interesting finding was that the most consistent effect for race discrimination was found for cognitive health: White participants who perceived discrimination based on their race scored lower on mental status, while African Americans who perceived race discrimination scored higher.)