Basic concepts in the taxonomy of health-related behaviors, habits and lifestyle.

BACKGROUND: Health-related Habits (HrH) are a major priority in healthcare. However there is little agreement on whether exercise, diet, smoking or dental hygiene are better described as lifestyles, habits or behaviors, and on what is their hierarchical relationship. This research is aimed at representing the basic concepts which are assumed to constitute the conceptual framework enabling us to interpret and organize the field of HrH. METHODS: A group of 29 experts with different backgrounds agreed on the definition and hierarchy of HrH following an iterative process which involved framing analysis and nominal group techniques. RESULTS: Formal definitions of health-related behavior, habit, life-style and life-style profile were produced. In addition a series of basic descriptors were identified: health reserve, capital, risk and load. Six main categories of HrH were chosen based on relevance to longevity: diet/exercise, vitality/stress, sleep, cognition, substance use and other risk. Attributes of HrH are clinical meaningfulness, quantifiability, temporal stability, associated morbidity, and unitarity (non-redundancy). Two qualifiers (polarity and stages of change) have also been described. CONCLUSIONS: The concepts represented here lay the groundwork for the development of clinical and policy tools related to HrH and lifestyle. An adaptation of this system to define targets of health interventions and to develop the classification of person factors in ICF may be needed in the future.

Factors affecting subspecialty referrals by pediatric primary care providers for children with obesity-related comorbidities.

OBJECTIVE: To determine referral patterns from pediatric primary care to subspecialists for overweight/obesity and related comorbidities. METHODS: We used the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey to identify overweight/obesity and 5 related comorbidities in primary care visits between 2005 and 2009 by children 6 to 18 years. The primary outcome was whether the visit ended in referral. We used multivariable analysis to examine factors associated with referral. RESULTS: We identified 34,225 database visits. A total of 17.1% were with overweight (body mass index=85th to 94th percentile) or obese (body mass index≥95th percentile) patients. A total of 7.1% of primary care visits with overweight/obese children ended in referral. Referral was more likely when obesity was the reason for visit (odds ratio=2.83; 95% confidence interval=1.61-4.97) but was not associated with presence of a comorbidity (odds ratio=1.35; 95% confidence interval=0.75-2.44). CONCLUSIONS: Most overweight or obese children are not referred, regardless of comorbidity status. One reason may be low levels of appropriate diagnosis.

Sensitivity and specificity of obesity diagnosis in pediatric ambulatory care in the United States.

OBJECTIVE: We examined the sensitivity and specificity of an obesity diagnosis in a nationally representative sample of pediatric outpatient visits. METHODS: We used the 2005 to 2009 National Ambulatory Medical Care and National Hospital Ambulatory Medical Care surveys. We included visits with children 2 to 18 years, yielding a sample of 48 145 database visits. We determined 3 methods of identifying obesity: documented body mass index (BMI) ≥95th percentile; International Classification of Diseases, Ninth Revision (ICD-9) code; and positive answer to the question, "Does the patient now have obesity?" Using BMI as the gold standard, we calculated the sensitivity and specificity of a clinical obesity diagnosis. RESULTS: Among the 19.5% of children who were obese by BMI, 7.0% had an ICD-9 code and 15.2% had a positive response to questioning. The sensitivity of an obesity diagnosis was 15.4%, and the specificity was 99.2%. CONCLUSIONS: The sensitivity of the obesity diagnosis in pediatric ambulatory visits is low. Efforts are needed to increase identification of obese children.

Effects of diet composition on postprandial energy availability during weight loss maintenance.

BACKGROUND: The major circulating metabolic fuels regulate hunger, and each is affected by dietary composition. An integrated measure of postprandial energy availability from circulating metabolic fuels may help inform dietary recommendations for weight maintenance after weight loss. AIM: We examined the effect of low-fat (LF, 60% of energy from carbohydrate, 20% fat, 20% protein), low-glycemic index (LGI, 40%-40%-20%), and very low-carbohydrate (VLC, 10%-60%-30%) diets on total postprandial metabolic fuel energy availability (EA) during weight loss maintenance. METHODS: Eight obese young adults were fed a standard hypocaloric diet to produce 10-15% weight loss. They were then provided isocaloric LF, LGI, and VLC diets in a randomized crossover design, each for a 4-week period of weight loss maintenance. At the end of each dietary period, a test meal representing the respective diet was provided, and blood samples were obtained every 30 minutes for 5 hours. The primary outcome was EA, defined as the combined energy density (circulating level × relative energy content) of glucose, free fatty acids, and ß-hydroxybutyrate. Secondary outcomes were individual metabolic fuels, metabolic rate, insulin, glucagon, cortisol, epinephrine, and hunger ratings. Respiratory quotient was a process measure. Data were analyzed by repeated-measures analysis of variance, with outcomes compared in the early (30 to 150 min) and late (180 to 300 min) postprandial periods. RESULTS: EA did not differ between the test meals during the early postprandial period (p = 0.99). However, EA in the late postprandial period was significantly lower after the LF test meal than the LGI (p<0.0001) and VLC (p<0.0001) test meals. Metabolic rate also differed in the late postprandial period (p = 0.0074), with higher values on the VLC than LF (p = 0.0064) and LGI (p = 0.0066) diets. CONCLUSION: These findings suggest that an LF diet may adversely affect postprandial EA and risk for weight regain during weight loss maintenance.

Nutrition attitudes and knowledge in medical students after completion of an integrated nutrition curriculum compared to a dedicated nutrition curriculum: a quasi-experimental study.

BACKGROUND: Nutrition education has presented an ongoing challenge to medical educators. In the 2007-2008 academic year, Harvard Medical School replaced its dedicated Preventive Medicine and Nutrition course with an integrated curriculum. The objective of the current study was to assess the effect of the curriculum change on medical student attitudes and knowledge about nutrition. METHODS: A survey was administered in a quasi-experimental design to students in the last class of the dedicated curriculum (n = 131) and the first class of the integrated curriculum (n = 135) two years after each class completed the required nutrition course. Main measures were attitude scores based on modified Nutrition in Patient care Survey and satisfaction ratings, performance on a nutrition knowledge test, and demographic variables. Two-tailed t-tests were performed. RESULTS: Response rates were 50.4% and 42.2%. There were no differences between the groups in attitude scores from the Nutrition in Patient care Survey (p = 0.43) or knowledge scores (p = 0.63). Students with the integrated curriculum were less satisfied with both the quantity (p < 0.0001) and quality (p = 0.008) of their nutrition education, and were more likely to have completed optional online nutrition training modules (p = 0.0089). CONCLUSIONS: Medical student attitudes and knowledge about nutrition were not affected by the model of nutrition education they receive, though students in an integrated curriculum may feel their education is inadequate and seek additional training.

Methodology for the development of a taxonomy and toolkit to evaluate health-related habits and lifestyle (eVITAL).

BACKGROUND: Chronic diseases cause an ever-increasing percentage of morbidity and mortality, but many have modifiable risk factors. Many behaviors that predispose or protect an individual to chronic disease are interrelated, and therefore are best approached using an integrated model of health and the longevity paradigm, using years lived without disability as the endpoint. FINDINGS: This study used a 4-phase mixed qualitative design to create a taxonomy and related online toolkit for the evaluation of health-related habits. Core members of a working group conducted a literature review and created a framing document that defined relevant constructs. This document was revised, first by a working group and then by a series of multidisciplinary expert groups. The working group and expert panels also designed a systematic evaluation of health behaviors and risks, which was computerized and evaluated for feasibility. A demonstration study of the toolkit was performed in 11 healthy volunteers. DISCUSSION: In this protocol, we used forms of the community intelligence approach, including frame analysis, feasibility, and demonstration, to develop a clinical taxonomy and an online toolkit with standardized procedures for screening and evaluation of multiple domains of health, with a focus on longevity and the goal of integrating the toolkit into routine clinical practice. TRIAL REGISTRATION: IMSERSO registry 200700012672.

Proteoglycan interactions with Sonic Hedgehog specify mitogenic responses.

Sonic Hedgehog (Shh) has dual roles in vertebrate development, promoting progenitor cell proliferation and inducing tissue patterning. We found that the mitogenic and patterning functions of Shh can be uncoupled from one another. Using a genetic approach to selectively inhibit Shh-proteoglycan interactions in a mouse model, we found that binding of Shh to proteoglycans was required for proliferation of neural stem/precursor cells, but not for tissue patterning. Shh-proteoglycan interactions regulated both spatial and temporal features of Shh signaling. Proteoglycans localized Shh to specialized mitogenic niches and also acted at the single-cell level to regulate the duration of Shh signaling, thereby promoting a gene expression program that is important for cell division. Because activation of the Shh pathway is a feature of diverse human cancers, selective stimulation of proliferation by Shh-proteoglycan interactions may also figure prominently in neoplastic growth.