Bone structure and geometry in young men: the influence of smoking, alcohol intake and physical activity.

BACKGROUND: The development of osteoporosis is influenced by peak bone mass attained in youth - the influence of lifestyle factors upon which is poorly described, especially amongst males. We sought to address this issue in a large scale study. METHODS: Hip bone mineral density (dual X-ray absorptiometry, DXA), bone microarchitecture (calcaneal quantitative ultrasound, QUS) and femoral geometry (magnetic resonance imaging, MRI) were characterised in 723 healthy male military recruits (mean ± S.E. age 19.92 ± 0.09 years [range 16-18 years], height 177.67 ± 0.24 cm, weight 73.17 ± 0.37 kg) on entry to UK Army training. Association was sought with prior physical activity, smoking status and alcohol intake. RESULTS: DXA measures were made in 651, MRI measures in 650, and QUS measures in 572 recruits. Increasing levels of weight-bearing physical activity enhanced periostial bone apposition, increases in both total hip and femoral neck bone mineral density (BMD; p ≤ 0.0001 in both cases), and cortical [p<0.0001] and periostial bone volumes [p=0.016]. Smoking habit was associated with preserved bone geometry, but worse BMD [p=0.0001] and QUS characteristics [p ≤ 0.0005]. Moderate alcohol consumption was associated with greater BMD [p ≤ 0.015]. CONCLUSIONS: Whilst exercise (and perhaps moderate alcohol intake) is beneficial to bone morphometry, smoking is detrimental to bone mineral density in young males notable for the likely short duration of smoking to influence skeletal properties. However, differences in socio-economic status, lifestyle and related environmental factors may to some extent confound our results.

A comparative analysis of glove permeation resistance to paint stripping formulations.

Although there is a wide variety of work gloves available to users of commercial paint stripping products, there are no published studies examining which type of gloves provide the best protection. To address this need, a multiphase study was undertaken to evaluate how several types of gloves resist multichemical-based paint stripping formulations. Due to the wide range of commercial paint stripping formulations available, seven categories of surrogate paint stripper formulations were created to evaluate glove performance initially. Twenty different glove types were identified for initial evaluation. Degradation resistance screening was carried out for each glove style and paint stripping formulation. Screening results were used to identify those glove styles least affected by the surrogate paint strippers. Those gloves were then evaluated for their resistance to permeation using continuous contact testing based on ASTM Test Method F 739. Glove styles showing extensive permeation with early breakthrough were then evaluated to see how they performed with only intermittent contact with the surrogate paint strippers using a modified form of ASTM Test Method F 1383. These results were used to select glove styles to be tested using commercially available paint stripping products. Gloves made of plastic laminate and butyl rubber were the most effective against the majority of paint strippers. More glove styles resisted permeation by N-methylpyrrolidone and dibasic ester-based paint strippers than conventional solvent products such as methylene chloride, methanol, isopropanol, acetone, and toluene. The study also found that decreased contact time caused relatively little change in permeation resistance and that the surrogate paint stripper data did not always accurately predict resistance to the commercial paint stripper formulations.