Paediatric obesity appears to lower the risk of diabetes if selection bias is ignored

BACKGROUND

Frustrated with the onslaught of articles reporting fascination with results that appear paradoxical but are merely due to selection bias, we studied the apparent effect of obesity on diabetes risk in youth who had a test for diabetes. We hypothesised that obese subjects would have lower rates of diabetes than non-obese subjects due to selection bias, and consequently, obesity would appear to lower the risk of diabetes.

METHODS

Retrospective cohort study of children (4-9 years), pre-teens (10-12 years) and teenagers (13-19 years). Participation was restricted to those who had a test of haemoglobin A1C along with measured height and weight. Body mass index percentile via the Centers for Disease Control and Prevention age and sex standards was calculated and categorised. The main outcome was A1C%, subsequently categorised at the level for diagnosis of diabetes mellitus (≥6.5%).

RESULTS

The sample consisted of 134 (2%) underweight, 1718 (30%) healthy weight, 660 (12%) overweight and 3190 (56%) obese individuals. 16% (n=936) had an A1C≥6.5%. Overall, healthy weight children had 8.2 times the risk of A1C≥6.5% (95% CI 5.3 to 12.7) compared with those in the obese category. The relative risk was 13 in pre-teens (95% CI 8.5 to 20.0) and 3.9 in teenagers (95% CI 3.3 to 4.7).

CONCLUSIONS

Healthy weight was associated with a 4-13 times higher relative risk of diabetes mellitus compared with being obese. While apparently shocking, the study's fatal flaw (selection bias) explains the 'paradoxical' finding. Ignoring selection bias can delay advances in medical science.

Effectively engaging patients in everyday health-care decisions

You can improve health outcomes and patient satisfaction--without increasing the length of the patient visit--by employing the tenets of shared decision-making.

Healthy Eating and Activity Across the Lifespan (HEAL): A call to action to integrate research, clinical practice, policy, and community resources to address weight-related health disparities

Despite intense nationwide efforts to improve healthy eating and physical activity across the lifespan, progress has plateaued. Moreover, health inequities remain. Frameworks that integrate research, clinical practice, policy, and community resources to address weight-related behaviors are needed. Implementation and evaluation of integration efforts also remain a challenge. The purpose of this paper is to: (1) Describe the planning and development process of an integrator entity, HEAL (Healthy Eating and Activity across the Lifespan); (2) present outcomes of the HEAL development process including the HEAL vision, mission, and values statements; (3) define the planned integrator functions of HEAL; and (4) describe the ongoing evaluation of the integration process. HEAL team members used a theoretically-driven, evidence-based, systemic, twelve-month planning process to guide the development of HEAL and to lay the foundation for short- and long-term integration initiatives. Key development activities included a review of the literature and case studies, identifying guiding principles and infrastructure needs, conducting stakeholder/key informant interviews, and continuous capacity building among team members. Outcomes/deliverables of the first year of HEAL included a mission, vision, and values statements; definitions of integration and integrator functions and roles; a set of long-range plans; and an integration evaluation plan. Application of the HEAL integration model is currently underway through community solicited initiatives. Overall, HEAL aims to lead real world integrative work that coalesce across research, clinical practice, and policy with community resources to inspire a culture of health equity aimed at improving healthy eating and physical activity across the lifespan.

Statistical testing of baseline differences in sports medicine RCTs: a systematic evaluation

Background/Aim

The CONSORT (Consolidated Standards of Reporting Trials) statement discourages reporting statistical tests of baseline differences between groups in randomised controlled trials (RCTs). However, this practice is still common in many medical fields. Our aim was to determine the prevalence of this practice in leading sports medicine journals.

Methods

We conducted a comprehensive search in Medline through PubMed to identify RCTs published in the years 2005 and 2015 from 10 high-impact sports medicine journals. Two reviewers independently confirmed the trial design and reached consensus on which articles contained statistical tests of baseline differences.

Results

Our search strategy identified a total of 324 RCTs, with 85 from the year 2005 and 239 from the year 2015. Overall, 64.8% of studies (95% CI (59.6, 70.0)) reported statistical tests of baseline differences; broken down by year, this percentage was 67.1% in 2005 (95% CI (57.1, 77.1)) and 64.0% in 2015 (95% CI (57.9, 70.1)).

Conclusions

Although discouraged by the CONSORT statement, statistical testing of baseline differences remains highly prevalent in sports medicine RCTs. Statistical testing of baseline differences can mislead authors; for example, by failing to identify meaningful baseline differences in small studies. Journals that ask authors to follow the CONSORT statement guidelines should recognise that many manuscripts are ignoring the recommendation against statistical testing of baseline differences.

What Definition Is Used to Describe Second Impact Syndrome in Sports? A Systematic and Critical Review

Concern about what has been termed, "second impact syndrome" (SIS) is a major factor determining return-to-play decisions after concussion. However, definitions of SIS vary. We used Scopus to conduct a systematic review and categorize the definitions used to describe SIS. Of the 91 sources identified, 79 (87%) clearly specified that SIS involved either cerebral edema or death after a concussion when a prior concussion had not resolved. Twelve articles (13%) could be interpreted as merely the events of two consecutive concussions. Among the articles that listed mortality rates, nearly all (33/35, 94%) said the rate of death was "high" (e.g., 50% to 100%). Our review found that most articles define SIS as a syndrome requiring catastrophic brain injury after consecutive concussive episodes. Given that it is unclear how common it is to have a second concussion while not fully recovered from a first concussion, the actual mortality rate of SIS is unknown.

Bone strength estimates relative to vertical ground reaction force discriminates women runners with stress fracture history

PURPOSE

To determine differences in bone geometry, estimates of bone strength, muscle size and bone strength relative to load, in women runners with and without a history of stress fracture.

METHODS

We recruited 32 competitive distance runners aged 18-35, with (SFX, n=16) or without (NSFX, n=16) a history of stress fracture for this case-control study. Peripheral quantitative computed tomography (pQCT) was used to assess volumetric bone mineral density (vBMD, mg/mm³), total (ToA) and cortical (CtA) bone areas (mm²), and estimated compressive bone strength (bone strength index; BSI, mg/mm⁴) at the distal tibia. ToA, CtA, cortical vBMD, and estimated strength (section modulus; Zp, mm³ and strength strain index; SSIp, mm³) were measured at six cortical sites along the tibia. Mean active peak vertical (pkZ) ground reaction forces (GRFs), assessed from a fatigue run on an instrumented treadmill, were used in conjunction with pQCT measurements to estimate bone strength relative to load (mm²/N∗kg^-1) at all cortical sites.

RESULTS

SSIp and Zp were 9-11% lower in the SFX group at mid-shaft of the tibia, while ToA and vBMD did not differ between groups at any measurement site. The SFX group had 11-17% lower bone strength relative to mean pkZ GRFs (p<0.05).

CONCLUSION

These findings indicate that estimated bone strength at the mid-tibia and mean pkZ GRFs are lower in runners with a history of stress fracture. Bone strength relative to load is also lower in this same region suggesting that strength deficits in the middle 1/3 of the tibia and altered gait biomechanics may predispose an individual to stress fracture.

SCAT3 assessment of non-head injured and head injured athletes competing in a large international youth soccer tournament

To our knowledge, no study has evaluated Sideline Concussion Assessment Tool -3rd Edition (SCAT3) scores during competition in athletes who have not had a head injury. The purpose of our pilot study was to compare SCAT3 scores in non-injured (NI), injured (but not head injured) (I), and head injured (HI) youth soccer players during competition and to establish preliminary baseline data for non-head injured athletes in a competitive setting. The HI group demonstrated significantly more symptoms (M = 9.7, SE = 0.8) than the I and NI (3.3, SE = 1.2, and 3.2, SE = 0.7, respectively) groups. The HI group also demonstrated a significantly higher symptom severity score (25.3, SE = 2.8) than the I and NI groups (7.7, SE = 4.1, and 5.9, SE = 2.5, respectively). There were no statistically significant differences in mean total Standardized Assessment of Concussion (SAC) scores and mean subsection SAC scores between the groups. Clinicians should also be aware that non-injured in-competition athletes may report more symptoms on the SCAT3 than those evaluated in a non-competition setting.

A multistate framework for the analysis of subsequent injury in sport (M-FASIS)

Physical activity is beneficial for many aspects of health but is associated with a risk of injury. Studies that assess causal risk factors of injury and reinjury provide valuable information to help develop and improve injury prevention programs. However, the underlying assumptions of analytical approaches often used to estimate causal factors in injury and subsequent injury research are often violated. This means that ineffective or even harmful interventions could be proposed because the underlying analyses produced unreliable or invalid causal effect estimates. We describe an adapted version of the multistate framework [multistate framework for the analysis of subsequent injury in sport (M-FASIS)] that makes investigator choices more transparent with respect to outcome and healing time. In addition, M-FASIS incorporates all previous sport injury analytical frameworks and accounts for injuries or conditions that heal or do not heal to 100%, acute and overuse injuries, illnesses, and competing event outcomes.