Does the association of habitual physical activity with the metabolic syndrome differ by level of cardiorespiratory fitness?

OBJECTIVE: Cardiovascular fitness (VO(2max)) and physical activity are both related to risk of metabolic disease. It is unclear, however, whether the metabolic effects of sedentary living are the same in fit and unfit individuals. The purpose of this study was, therefore, to describe the association between physical activity and the metabolic syndrome and to test whether fitness level modifies this relationship. RESEARCH DESIGN AND METHODS: Physical activity was measured objectively using individually calibrated heart rate against energy expenditure. VO(2max) was predicted from a submaximal exercise stress test. Fat mass and fat-free mass (FFM) were calculated using impedance biometry. A metabolic syndrome score was computed by summing the standardized values for obesity, hypertension, hyperglycemia, insulin resistance, hypertriglyceridemia, and the inverse level of HDL cholesterol and was expressed as a continuously distributed outcome. To correct for exposure measurement error, a random subsample (22% of cohort) re-attended for three repeat measurements in the year following the first assessment. RESULTS: The relationship of VO(2max) (ml O2.kg(FFM)(-1).min(-1)) and the metabolic syndrome score was of borderline significance after adjusting for age, sex, physical activity, and measurement error (beta = -0.58, P = 0.06). The magnitude of the association between physical activity (kJ.d(-1).kg(FFM)(-1)) and the metabolic syndrome was more than three times greater than for VO(2max) (standardized beta = -1.83, P = 0.0042). VO(2max), however, modified the relationship between physical activity energy expenditure and metabolic syndrome (P = 0.036). CONCLUSIONS: This study demonstrates a strong inverse association between physical activity and metabolic syndrome, an association that is much steeper in unfit individuals. Thus, prevention of metabolic disease may be most effective in the subset of unfit inactive people.     

Clinical outcomes and rates of aortic growth and reoperation after 1-stage repair of extensive chronic thoracic aortic dissection

Objective

The study objective was to analyze clinical outcomes, distal segmental aortic growth, and aortic reoperation rates after 1-stage open repair of extensive chronic thoracic aortic dissection via bilateral anterior thoracotomy.

Flash autoclave settings may influence eradication but not presence of well‐established biofilms on orthopaedic implant material

Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic‐relevant materials following flash autoclave. In this study, monomicrobial and polymicrobial biofilms were grown on the surface of clinically relevant titanium materials and exposed to flash autoclave settings that included varying times and temperatures. Data indicated that when the sterilization and control temperatures of an autoclave were the same, biofilms were able to survive flash autoclaving that was performed for a short duration. Higher temperature and increased duration rendered biofilms non‐viable, but none of the autoclave settings had the ability to remove or disperse the presence of biofilms from the titanium surfaces. These findings may be beneficial for facilities, clinics, or hospitals to consider if biofilms are suspected to be present on materials or devices, in particular implants that have had associated infection and are considered for re‐implantation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1543–1550, 2018.

     

Controversies and evidence for cardiovascular disease in the diverse Hispanic population

Objective

Hispanics account for approximately 17% of the U.S. population. They are one of the fastest growing racial/ethnic groups, second only to Asians. This heterogeneous population has diverse socioeconomic conditions, making the prevention, diagnosis, and management of vascular disease difficult. This paper discusses the cultural, racial, and social aspects of the Hispanic community in the United States and assesses how they affect vascular disease within this population. Furthermore, it explores risk factors, medical and surgical treatments, and outcomes of vascular disease in the Hispanic population; generational evolution of these conditions; and the phenomenon called the Hispanic paradox.

Nonstandard Lumbar Region in Predicting Fracture Risk

Femoral neck (FN) bone mineral density (BMD) is the most commonly used skeletal site to estimate fracture risk. The role of lumbar spine (LS) BMD in fracture risk prediction is less clear due to osteophytes that spuriously increase LS BMD, particularly at lower levels. The aim of this study was to compare fracture predictive ability of upper L1–L2 BMD with standard L2–L4 BMD and assess whether the addition of either LS site could improve fracture prediction over FN BMD. This study comprised a prospective cohort of 3016 women and men over 60?yr from the Dubbo Osteoporosis Epidemiology Study followed up for occurrence of minimal trauma fractures from 1989 to 2014. Dual-energy X-ray absorptiometry was used to measure BMD at L1–L2, L2–L4, and FN at baseline. Fracture risks were estimated using Cox proportional hazards models separately for each site. Predictive performances were compared using receiver operating characteristic curve analyses. There were 565 women and 179 men with a minimal trauma fracture during a mean of 11?±?7?yr. L1–L2 BMD T-score was significantly lower than L2–L4 T-score in both genders (p?<?0.0001). L1–L2 and L2–L4 BMD models had a similar fracture predictive ability. LS BMD was better than FN BMD in predicting vertebral fracture risk in women [area under the curve 0.73 (95% confidence interval, 0.68–0.79) vs 0.68 (95% confidence interval, 0.62–0.74), but FN was superior for hip fractures prediction in both women and men. The addition of L1–L2 or L2–L4 to FN BMD in women increased overall and vertebral predictive power compared with FN BMD alone by 1% and 4%, respectively (p?<?0.05). In an elderly population, L1–L2 is as good as but not better than L2–L4 site in predicting fracture risk. The addition of LS BMD to FN BMD provided a modest additional benefit in overall fracture risk. Further studies in individuals with spinal degenerative disease are needed.