Radon Potential, Geologic Formations, and Lung Cancer Risk

OBJECTIVE: Exposure to radon is associated with approximately 10% of U.S. lung cancer cases. Geologic rock units have varying concentrations of uranium, producing fluctuating amounts of radon. This exploratory study examined the spatial and statistical associations between radon values and geological formations to illustrate potential population-level lung cancer risk from radon exposure. METHOD: This was a secondary data analysis of observed radon values collected in 1987 from homes (N = 309) in Kentucky and geologic rock formation data from the Kentucky Geological Survey. Radon value locations were plotted on digital geologic maps using ArcGIS and linked to specific geologic map units. Each map unit represented a package of different types of rock (e.g., limestone and/or shale). Log-transformed radon values and geologic formation categories were compared using one-way analysis of variance. RESULTS: Observed radon levels varied significantly by geologic formation category. Of the 14 geologic formation categories in north central Kentucky, four were associated with median radon levels, ranging from 8.10 to 2.75 pCi/L. CONCLUSION: Radon potential maps that account for geologic factors and observed radon values may be superior to using observed radon values only. Knowing radon-prone areas could help target population-based lung cancer prevention interventions given the inequities that exist related to radon

PLS and dimension reduction for classification

Linear discriminant analysis, Ridge regression, Shrinkage estimation, Misclassification rates, Principal components,

Hip Abductor Function and Lower Extremity Landing Kinematics: Sex Differences

Context: Rapid deceleration during sporting activities, such as landing from a jump, has been identified as a common mechanism of acute knee injury. Research into the role of potential sex differences in hip abductor function with lower extremity kinematics when landing from a jump is limited

Hip Abductor Function and Lower Extremity Landing Kinematics: Sex Differences

CONTEXT: Rapid deceleration during sporting activities, such as landing from a jump, has been identified as a common mechanism of acute knee injury. Research into the role of potential sex differences in hip abductor function with lower extremity kinematics when landing from a jump is limited. OBJECTIVE: To evaluate sex differences in hip abductor function in relation to lower extremity landing kinematics. DESIGN: 2 x 2 mixed-model factorial design using a between-subjects factor (sex) and a repeated factor (test). SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: A sample of convenience consisting of 30 healthy adults (15 women, 15 men) with no history of lower extremity surgery and no lower extremity injuries within 6 months of testing. INTERVENTION(S): Landing kinematics were assessed as subjects performed 3 pre-exercise landing trials that required them to hop from 2 legs and land on a single leg. Isometric peak torque (PT) of the hip abductors was measured, followed by an endurance test during which subjects maintained 50% of their PT to the limits of endurance. After a 15-minute rest period, subjects completed a 30-second bout of isometric hip abduction, from which we calculated the percentage of endurance capacity (%E). Immediately after exercise, subjects completed 3 postexercise landing trials. MAIN OUTCOME MEASURE(S): PT, %E, and peak joint displacement (PJD) of the hip and knee in all 3 planes of motion. RESULTS: Women demonstrated lower PT values (5.8 +/- 1.2% normalized to body weight and height) than did their male counterparts (7.2 +/- 1.5% normalized to body weight and height, P = .009). However, no sex differences were seen in %E. Women also demonstrated larger knee valgus PJD (7.26 degrees +/- 6.61 degrees) than did men (3.29 degrees +/- 3.54 degrees, P = .04). Women\u27s PT was moderately correlated with hip flexion, adduction, and knee valgus PJD; however, PT did not significantly correlate with men\u27s landing kinematics. Regardless of sex, hip flexion (P = .002) and hip adduction (P = .001) were significantly increased following the 30-second bout of exercise. CONCLUSIONS: Women demonstrated lower hip abductor PT and increased knee valgus PJD when landing from a jump, potentially increasing the risk of acute knee injury. Furthermore, correlations between hip abductor strength and landing kinematics were generally larger for women than for men, suggesting that hip abductor strength may play a more important role in neuromuscular control of the knee for women

Influence function analysis applied to partial least squares

Partial least squares, Influence function analysis, Outliers,