Objective
Greater quadriceps strength has been found to reduce risk for symptomatic knee osteoarthritis (SxKOA) and knee joint space narrowing (JSN). However, this finding could relate to muscle mass or activation pattern. The purpose of this study was to assess whether greater thigh muscle mass protects against (1) incident radiographic (RKOA), (2) incident SxKOA or (3) worsening of knee JSN by 30-month follow-up.
Design
Multicenter Knee Osteoarthritis (MOST) study participants, who underwent dual energy x-ray absorptiometry (DXA) at the Iowa site were included. Thigh muscle mass was calculated from DXA image sub-regions. Sex-stratified, knee-based analyses controlled for incomplete independence between limbs within subjects. The effect of thigh lean mass and specific strength as predictors of ipsilateral RKOA, SxKOA and worsening of JSN were assessed, while controlling for age, BMI, and history of knee surgery.
Results
A total of 519 men (948 knees) and 784 women (1453 knees) were included. Mean age and BMI were 62 years and 30 kg/m2. Thigh muscle mass was not associated with risk for RKOA, SxKOA or knee JSN. However, in comparison with the lowest tertile, those in the highest and middle tertiles of knee extensor specific strength had a lower risk for SxKOA and JSN (OR 0.29–0.68).
Conclusions
Thigh muscle mass does not appear to confer protection against incident or worsening knee OA. These findings suggest that future studies of risk for knee OA should focus on the roles of knee extensor neuromuscular activation and muscle physiology, rather than the muscle mass.
Aim: The appropriate selection of hospitalized patients for venous thromboembolism (VTE) prophylaxis is an important unresolved issue. We sought to validate the Caprini model, a famous individual VTE risk assessment model (RAM), in hospitalized Chinese patients. Methods: We performed a retrospective case-control study among unselected hospitalized patients admitted to a comprehensive hospital in China. A total of 347 patients were confirmed to have VTE during hospitalization, and 651 controls were randomly selected to match the patients according to medical service. Both the patients and controls were retrospectively assessed for the risk of VTE using the Caprini RAM. Results: The average Caprini cumulative risk score in the patients was significantly higher than that observed in the controls (4.69±2.58 vs 3.16±1.82, p<0.0001). Compared with that observed in the low-risk group, a classification of high-risk according to the Caprini model was associated with a 1.65-fold increased risk of VTE (95%CI 1.05-2.61), while that of highest-risk was associated with a 4.84-fold increased risk of VTE (95%CI 3.06-7.64). After further stratifying the highest risk level with a cumulative risk score of ≥ 5 into scores of 5-6, 7-8 and ≥ 9, the patients with a score of 5-6 were found to exhibit a 3.33-fold increased risk of VTE (95%CI 2.06-5.40), those with a score 7-8 exhibited a 9.41-fold increased risk of VTE (95%CI 4.90-18.08) and those with a score of ≥ 9 exhibited a 24.69-fold (95%CI 7.98-76.40) increased risk of VTE compared with their low-risk counterparts. Conclusions: Our study suggests that the Caprini RAM can be used to effectively stratify hospitalized Chinese patients into VTE risk categories based on individual risk factors. The classification of the highest risk level with a cumulative risk score of ≥ 5 provided significantly more clinical information, and further stratification of this group of patients is needed. J Atheroscler Thromb, 2014; 21:261-272.
A convenient water-based sol-gel technique was used to prepare a highly efficient lithium orthosilicate-based sorbent (Li 4 SiO 4 -G) for CO 2 capture at high temperature. The Li 4 SiO 4 -G sorbent was systematically studied and compared with the Li 4 SiO 4 -S sorbent prepared by solid-state reaction. Both sorbents were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetry. The CO 2 sorption stability was investigated in a dual fixed-bed reactor. Li 4 SiO 4 -G exhibited a special Li 4 SiO 4 structure with smaller crystalline nanoparticles, larger surface area, and higher CO 2 adsorption properties as compared with Li 4 SiO 4 -S. The Li 4 SiO 4 -G sorbent also maintained higher capacities during multiple cycles.
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