31 research outputs found

    Monoclonal gammopathy of undetermined significance and risk of lymphoid and myeloid malignancies: 728 cases followed up to 30 years in Sweden.

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    To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.In 728 Swedish cases of monoclonal gammopathy of undetermined significance (MGUS), followed up to 30 years (median, 10 years), we estimated the cumulative risk of hematologic disorders originating from lymphoid and myeloid lineages. Using Cox regression models, we examined associations of demographic and laboratory factors with progression and determined the discriminatory power of 3 prediction models for progression. Eighty-four MGUS cases developed a lymphoid disorder, representing a cumulative risk of 15.4%. Multiple myeloma (MM) occurred in 53 patients, and the 30-year cumulative risk was 10.6%; an ∼0.5% annual risk. Three factors were significantly associated with progression: abnormal free light-chain (FLC) ratio (1.65), M-protein concentration (≥1.5 g/dL), and reduction of 1 or 2 noninvolved immunoglobulin isotype levels (immunoparesis). A prediction model with separate effects for these 3 factors and the M-protein isotype had higher discriminatory power than other models, although the differences were not statistically significant. The 30-year cumulative risk for myeloid malignancies was 1.5 g/dL, factors previously considered by Mayo Clinic researchers, are predictors for MM progression and suggests that separate consideration of immunoparesis and the Mayo Clinic risk factors could improve identification of MGUS patients at high risk for progression

    'In search of lost time': Identifying the causative role of cumulative competition load and competition time-loss in professional tennis using a structural nested mean model.

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    Injury prevention is critical to the achievement of peak performance in elite sport. For professional tennis players, the topic of injury prevention has gained even greater importance in recent years as multiple of the best male players have been sidelined owing to injury. Identifying potential causative factors of injury is essential for the development of effective prevention strategies, yet such research is hampered by incomplete data, the complexity of injury etiology, and observational study biases. The present study attempts to address these challenges by focusing on competition load and time-loss to competition-a completely observable risk factor and outcome-and using a structural nested mean model (SNMM) to identify the potential causal role of cumulative competition load on the risk of time-loss. Using inverse probability of treatment weights to balance exposure histories with respect to player ability, past injury, and consecutive competition weeks at each time point; the SNMM analysis of 389 professional male players and 55,773 weeks of competition found that total load significantly increases the risk of time-loss (HR = 1.05 per 1,000 games of additional load 95% CI 1.01-1.10) and this effect becomes magnified with age. Standard regression showed a protective effect of load, highlighting the value of more robust causal methods in the study of dynamic exposures and injury in sport and the need for further applications of these methods for understanding how time-loss and injuries of elite athletes might be prevented in the future

    Comparing Matchplay Characteristics and Physical Demands of Junior and Professional Tennis Athletes in the Era of Big Data

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    Differences in the competitive performance characteristics of junior and professional tennis players are not well understood. The present study provides a comprehensive comparative analysis of junior and professional matchplay. The study utilized multiple large-scale datasets covering match, point, and shot outcomes over multiple years of competition. Regression analysis was used to identify differences between junior and professional matchplay. Top professional men and women were found to play significantly more matches, sets, and games compared to junior players of an equivalent ranking. Professional players had a greater serve advantage, men winning 4 and women winning 2 additional percentage points on serve compared to juniors. Clutch ability in break point conversion was 6 to 8 percentage points greater for junior players. In general, shots were more powerful and more accurate at the professional level with the largest differences observed for male players on serve. Serving to the center of the court was more than two times more common for junior players on first serve. While male professionals performed 50% more total work in a Grand Slam match than juniors, junior girls performed 50% more work than professional women. Understanding how competitiveness, play demands, and the physical characteristics of shots differ between junior and professional tennis players can help set realistic expectations and developmentally appropriate training for transitioning players

    Book Review: Applied Meta-Analysis With R

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    The influence of age-policy changes on the relative age effect across the Australian Rules football talent pathway

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    Objectives: To identify the influence of age-policy changes on the relative age effect (RAE) across the Australian Football League (AFL) talent pathway. Design: Retrospective cross-sectional analysis of junior AFL players attending the National Draft (National), State, and State Under 16s (U16) combines between 1999–2016. Methods: Birth-date data was obtained for players attending the AFL State U16 (n = 663, age: 15.9 ± 0.4 years), State (n = 803, age: 19.1 ± 1.7 years), National (n = 1111, age: 18.3 ± 0.8 years) combines. Corresponding aged-matched Australian general population birth rate data was also collected. Results: A chi-squared analysis comparing birth month distributions found all combine groups differed significantly from the general population (Under 16s: χ2 = 62.61, State: χ2 = 38.83, National: χ2 = 129.13, p < 0.001). Specifically, Under 16s had greater birth frequencies for months January to March (≥2%, p < 0.05), with more State players born in January (4.9%, p < 0.05). Age-policy changes at the National level reduced birth distribution bias for some months, however the RAE remained for March, June and July (3.9%, 6.1%, 4.3%, p < 0.05). State U16s and National players had 2–9% lower birth frequencies for November–December births compared general population. Conclusions: Selection bias exists towards older players is present at the AFL’s State U16, and is maintained at State and National level combines. Age-policy changes are only partially successful at addressing the RAE at the National level, with alternative strategies also recommended in order to address the RAE across the AFL talent pathways.No Full Tex

    Factors associated with younger adolescents' exposure to online alcohol advertising

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    Little is known about the extent and nature of youth exposure to online alcohol advertising, or factors that may be associated with exposure. The current study recruited middle school students who completed a paper survey and then logged each alcohol advertisement that they encountered over a two-week period using cell phones as part of an ecological momentary assessment (EMA) design. We examined the percentage of youth who reported exposure to online alcohol advertising in the past two weeks, average weekly rate of exposure, types of online alcohol advertisements youth reported seeing, and factors that increased youths’ risk of exposure to online alcohol advertising. Analyses are based on 485 participants (47% female; 25% Hispanic, 25% white, 27% black; 6% Asian, 16% other). Youth logged exposures to a total of 3,966 (16,018 weighted for under-reporting) alcohol advertisements across the monitoring period; 154 (568 weighted) or 3.6% were online ads. Seventeen percent of youth reported seeing any online alcohol ad; the majority of online ads seen were video commercials (44.8%) and banner/side ads (26.6%). Factors associated with greater ad exposure were being older, rebellious, and Black race; greater parental monitoring and more hours spent on social media were associated with less exposure. Findings provide important information about adolescents’ exposure to online alcohol advertising and what might contribute to a greater likelihood of exposure. Given that online ad exposure is linked to drinking behavior, prevention programming for younger adolescents should continue to address this issue to help youth make healthy choices regarding alcohol use

    Functioning, Forgetting, or Failing Health: Which Factors Are Associated With a Community-Based Move Among Older Adults?

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    OBJECTIVE: To examine whether the health and functioning of middle-aged and older adults are associated with an increased likelihood of community-based moves. METHOD: Biennial data from adults aged 51 and older in the Health and Retirement Study (HRS) and discrete-time survival models were used to assess the likelihood of community-based moves from 2000 to 2010 as a function of 11 measures of health and functioning. RESULTS: Respondents diagnosed with heart disease, stroke, hypertension, lung disease, and psychiatric problems were more likely to move during the study period than those with no such diagnosis. Changes in activities of daily living and instrumental activities of daily living functioning, cognitive impairment, and falls were also related to a greater likelihood of moving during the study period. Cancer and diabetes were not related to overall moves, although diabetes was associated with an increased likelihood of local moves. For the most part, it was longstanding not recent diagnoses that were significantly related to the likelihood of moving. DISCUSSION: Although some health conditions precipitate moves among middle-aged and older adults, others do not. This work has important implications for understanding the role of different aspects of health and functioning in the likelihood of migration among older adults
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