ShortCuts-This Week in the Journals

November 5, 2007

brookbridge.jpgCommentary by Henry Tran, MD 

Hip fractures in the elderly are associated with a very high morbidity and mortality. Often a fracture can be the prelude to an accelerated decline in the health and functionality of a patient. Most hip fractures are related to osteoporosis and the standard of care has been the use of calcium supplementation and bisphosphonates, though long term trial data to support this practice is lacking. This week in the NEJM, Lyles et al. published a trial examining the use of zoledronic acid in secondary prevention of fracture and reduction of mortality. As the accompanying editorial points out, this is the first controlled trial of a medication to show reduction of recurrent fracture after an initial hip fracture. Yearly infusions of zoledronic acid (median 1.9 years), reduced new clinical fractures by 35% (NNT = 18.8) and reduced all cause mortality by 28% (NNT = 27) as compared to placebo. The results are impressive and should embolden clinicians to be more assertive with the use of bisphosphonates in patients at high risk for fracture.

From the world of bench research: an intriguing study was published in the Proceedings of the National Academy of Sciences and is causing quite a stir in the lay press. We know that exercise increases muscle and reduces fat, but what are the metabolic and physical factors behind this? A study by Rubin et al. examined the effect of low magnitude mechanical signals (LMMS) on adipogenesis in mice models. Basically, the investigators created a vibrating plate at such a low magnitude as to be barely perceptible by human touch. They placed mice on the vibrating plates for 15 minutes a day for 9 weeks. As compared to mice exposed to “sham” treatment, the LMMS mice had 27% less adipogenesis as determined by in vivo CT scans. It should be noted that while both LMMS and control mice experienced similar increases of average body mass weight, bone volume and total lean volume increased more in LMMS mice than control mice. The authors theorize that the vibrations inhibited differentiation of mesenchymal stem cells into adipocytes and promoted bone formation instead. Obviously this has enormous implications in the treatment of obesity and diabetes. For many years I’ve heard and dismissed anecdotes that Russian and other east European training programs use vibrating plates as part of their Olympic training regiments. Maybe there is actually something to this after all.

“Doc, I have a cold, give me some antibiotics please!” This is a common request that creates a dilemma for primary care practitioners as they balance the risk of antibiotic overuse and the benefit of treating early infections. Harnessing the power of a nationalized health care system, British researchers published a retrospective study, including 3.6 million cases of respiratory infections from a general practice database, in order to evaluate the overall effectiveness of antibiotics. They found that the overall risk of a serious complication (pneumonia, peritonsillar abscess, mastoiditis) within one month of an upper respiratory tract infection, otitis media, or sore throat was quite low. Antibiotics did reduce this risk, however the number needed to treat (NNT) > 4000! This probably represents more patients than one practitioner will see in a year. However the incidence of pneumonia was much higher after chest infections (bronchitis, early pneumonia), particularly in patients over age 65. In this subgroup, antibiotic use was much more effective, NNT = 39. The researchers conclude that practitioners can safely withhold antibiotics in most common infections, but should focus their use on older patients with symptoms of lower respiratory infections. Wouldn’t it be great if the US also had a nationalized health care system? Well that’s for another Shortcuts article…

The World Cancer Research Fund and the American Institute for Cancer Research published their 500-page report detailing the reduction of cancer risk through diet, weight management, and exercise. Most of the 10 major recommendations made common sense, but it’s nice to have evidence  to back you up too. The most notable recommendations are:
1) 60 minutes of moderate exercise a day
2) No more than two drinks per day for men, one drink per day for women
3) New mothers should aim to breastfeed exclusively for six months
4) Dietary supplements are not recommended to reduce cancer risk
5) Achieve and maintain a normal body weight after age 21

The old adage “an ounce of prevention is worth a pound of cure” probably holds true. Perhaps these recommendations may be more powerful than the collective of our current cancer therapeutics.

Image courtesy of Wikimedia Commons