(Press-News.org) Many older adults may be taking "excessive" doses of drugs for thyroid problems which can lead to an increased risk of fractures, finds a study published on bmj.com today.
The study raises concern that treatment targets may need to be modified in the elderly and that regular dose monitoring remains essential even into older age.
Levothyroxine is a synthetic form of thyroxine (thyroid hormone) and is widely used to treat an underactive thyroid gland (hypothyroidism).
Most hypothyroid patients are diagnosed in early or middle adulthood but, as people age, their thyroxine requirements fall. Although regular monitoring of patients on levothyroxine is recommended, doses often remain unchanged into old age.
This can lead to excess thyroid hormone levels (hyperthyroidism) which can increase the risk of fractures, particularly in older women.
Previous studies of the association between levothyroxine and fractures have had mixed results, so a team of researchers in Toronto, Canada set out to measure the effect of levothyroxine dose on the risk of fractures in older adults.
Using population-based data from Ontario, Canada, the study included 213,511 people aged 70 years or older with at least one levothyroxine prescription dispensed between April 1, 2002 and March 31, 2007. Hospital records were used to identify fractures and each case was matched with up to five controls from within the group who had not yet fractured.
Cases and controls were defined as current users, recent past users (discontinued 15-180 days prior to study) or remote users (discontinued more than 180 days prior to study) of levothyroxine.
A total of 22,236 (10.4%) individuals experienced at least one fracture during the study period.
Compared with remote use, current and recent past levothyroxine use was associated with a significantly higher fracture risk. Among current users, high and medium doses of levothyroxine were associated with a significantly higher risk of fractures compared with low dose levothyroxine.
Even after taking account of other fracture risk factors, a dose-related association was seen in both men and women, for hip fractures as well as for any fracture.
The authors conclude: "Our findings provide evidence that levothyroxine treatment may increase the risk of fragility fractures in older people even at conventional dosages, suggesting that closer monitoring and modification of treatment targets may be warranted in this vulnerable population."
This view is supported in an accompanying editorial by Professor Graham Leese at Ninewells Hospital in Dundee, who warns that ideal thyroxine doses may vary with age and be unexpectedly low in elderly people.
It is 120 years since the effect of excess thyroid hormone on bone was first described, he writes, yet research in this area still lacks funding. "With the prevalence of treated hypothyroidism increasing, and the annual economic burden of fractures in the United Kingdom currently estimated at €5.8bn (£5.1bn; $8.4bn), such research warrants a higher priority."
INFORMATION: END
Biologists at UC San Diego have discovered that electrical oscillations in the brain, long thought to play a role in organizing cognitive functions such as memory, are critically important for the brain to store the information that allows us to navigate through our physical environment.
The scientists report in the April 29 issue of the journal Science that neurons called "grid cells" that create maps of the external environment in one portion of our brain require precisely timed electrical oscillations in order to function properly from another part of the brain that ...
What Medicare would pay for and where a radiation oncologist practiced were two factors that strongly influenced the choice of intensity-modulated radiation therapy (IMRT) for treating breast cancer, according to an article published April 29 online in the Journal of the National Cancer Institute. The use of IMRT and the cost of radiation therapy increased sharply over the period of the study.
IMRT is a radiation delivery technique that modulates the radiation beams to conform to the shape of the tumor or tumor bed in an attempt to maximize the dose of radiation to the ...
Researchers from Woods Hole Oceanographic Institution (WHOI) and their colleagues have discovered that massive, swirling ocean eddies—known to be up to 500 kilometers across at the surface—can reach all the way to the ocean bottom at mid-ocean ridges, some 2,500 meters deep, transporting tiny sea creatures, chemicals, and heat from hydrothermal vents over large distances.
The previously unknown deep-sea phenomenon, reported in the April 28 issue of the journal Science, helps explain how some larvae travel huge distances from one vent area to another, said Diane K. Adams, ...
FINDINGS: Whitehead Institute scientists report that two proteins once thought to have only supporting roles, are the true "stars" of the kinetochore assembly process in human cells.
RELEVANCE: The kinetochore is vital to proper DNA distribution during cell division. This finding suggests that scientists may be able to stimulate kinetochore assembly in a process that could lead to new genetic research tools, such as efficient creation of artificial human chromosomes. Widespread use of artificial human chromosomes has been thwarted by scientists' current inability to ...
Call it a mystery with a stubby tail: an odd-looking mouse discovered through a U.S. government breeding program in the 1940s that had a short, kinky tail and an extra set of ribs in its neck – and nobody knew why.
A team of scientists led by researchers at the University of California, San Francisco has now spilled the genetic secrets of this mutant rodent. In doing so, they may have uncovered a new wrinkle in the genetic code – an entirely unrecognized way our bodies regulate how genes are expressed in different tissues throughout life.
This discovery has broad implications ...
An international team of astronomers today revealed details of a "super-exotic" exoplanet that would make the planet Pandora in the movie Avatar pale in comparison.
The planet, named 55 Cancri e, is 60 per cent larger in diameter than Earth but eight times as massive. Twice as dense as Earth – almost as dense as lead – it is the densest solid planet known, according to a team led by astronomers from the Massachusetts Institute of Technology (MIT), the University of British Columbia (UBC), the Harvard‑Smithsonian Center for Astrophysics and the University of California ...
One of the ocean currents which particularly interests oceanographers and climatologists is the Gulf Stream. This current, originating in the Gulf of Mexico, transports enormous amounts of warm tropical waters to the North Atlantic and is the cause of Europe's habitable climate. Climate predictions point to the fact that this will change in the future and affect especially the climate in countries of the Mediterranean region, with more dry spells. As global warming progresses, the North Atlantic will receive more precipitation and a greater amount of water from the melting ...
Fish and marine species are among the most threatened wildlife on earth, due partly to over exploitation by fishing fleets. Yet there are differences in assessing trends in worldwide fishing stocks which, researchers writing in Conservation Biology argue, stem from inappropriate use of time trends in catches.
"Estimates of fishery status based on catches suggest that around 30% of fisheries are collapsed and 70% are overexploited or collapsed," said lead author Dr Trevor Branch from the University of Washington in Seattle. "Our assessment shows that the data are seriously ...
People with rare diseases have the same right to high-quality health care in line with current medical knowledge as other patients do. However, relevant and reliable clinical studies on rare diseases are often lacking. Among other things, this makes the development of corresponding guidelines more difficult, but precisely such guidelines could help improve treatment quality.
The German Federal Ministry of Health therefore commissioned the Institute for Quality and Efficiency in Health Care (IQWiG) to answer the following question: What methodological approaches are used ...
Neural tube defects in neonates are common in Germany compared with the rest of Europe. Extensive folic acid fortification of foods in Germany might prevent these in 85-100% of cases, Wolfgang Herrmann and Rima Obeid argue in this issue of Deutsches Ärzteblatt International (Dtsch Arztebl Int 2011; 108[15]; 249-54).
A woman's folic acid intake before and during early pregnancy ensures that the fetus does not develop the neural tube defect commonly known as spina bifida. Every year, 800 pregnancies in Germany are diagnosed with a neural tube defect. Most of those pregnancies ...
