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Lage bloedwaarden natrium geven meer kans op botbreuken bij ouderen*
Uit een Nederlandse studie onder ruim vijfduizend vijfenvijftigplussers die gemiddeld 7 jaar gevolgd werden blijkt dat lage bloedwaarden natrium de kans op botbreuken wel met 40-60% doet verhogen. Zij hadden ook ruim 20% meer kans om dood te gaan in de onderzochte periode. Lage bloedwaarden natrium kunnen ontstaan als gevolg van o.a. teveel te drinken, diaree en diuretica waardoor je het risico loopt dat je natrium gehalte onder een bepaalde waarde zakt en dat er daardoor water in je lichaamscellen vloeit. Met noemt dit Hyponatremia (EAH). Je merkt dit doordat de volgende verschijnselen zich voor kunnen gaan doen: Gezwollen vingers of een te nauw zittend horloge, misselijkheid, braken, toenemende hoofdpijn en een gevoel van je niet goed voelen. Serieuzere problemen zijn een toenemende zwelling van de hersenen, wat leidt tot verwarring, geïrriteerdheid en geagiteerdheid. Uit de studie bleek dat hyponatremia niet het gevolg was van geringere botdichtheid, want in verschillende groepen werden vergelijkbare waarden botdichtheid gemeten. Waarom bij hyponatremia dan wel meer botbreuken optreden zal nog verder onderzocht moeten worden.
Low Sodium May Be Responsible For Fractures And Falls In Elderly
Older adults with even mildly decreased levels of sodium in the blood (hyponatremia) experience increased rates of fractures and falls, according to a study presented at the American Society of Nephrology's 43rd Annual Meeting and Scientific Exposition. Falls are a serious health problem for the elderly and account for about 50 percent of deaths due to injury in the elderly. 
"Screening for a low sodium concentration in the blood, and treating it when present, may be a new strategy to prevent fractures," comments Ewout J. Hoorn, MD, PhD (Erasmus Medical Center, Rotterdam, the Netherlands). However, hyponatremia does not appear to affect the risk of osteoporosis, as defined by low bone mineral testing, so more research is needed to understand the link between sodium levels and fracture risk. 
The study included more than 5,200 Dutch adults over age 55, all with initial information on sodium levels and six-year follow-up data on fractures and falls. "A number of recent studies suggested a relationship between hyponatremia, falls, osteoporosis, and fractures," Hoorn explains. The authors' goal was to confirm these possible associations using prospective, long-term follow-up data. 
About eight percent of the study participants, all community dwelling adults, had hyponatremia. This group of older participants had a higher rate of diabetes and was more likely to use diuretics (water pills) than those with normal sodium levels. Subjects with hyponatremia had a higher rate of falls during follow-up: 24 versus 16 percent. However, there was no difference in bone mineral density between groups, so hyponatremia was not related to underlying osteoporosis. 
Nevertheless, the group with low sodium levels had a higher rate of fractures. With adjustment for other risk factors, the risk of vertebral / vertebral compression fractures was 61 percent higher in the older adults with hyponatremia. The risk of non-spinal fractures, such as hip fractures, was also significantly increased: a 39 percent difference. 
The relationship between hyponatremia and fracture risk was independent of the increased rate of falls in the low-sodium group. Subjects with hyponatremia also had a 21 percent increase in the risk of death during follow-up. 
Hyponatremia is the most common electrolyte disorder, usually developing because the kidneys retain too much water. "Although the complications of hyponatremia are well-recognized in hospitalized patients, this is one of the first studies to show that mild hyponatremia also has important complications in the general population," says Hoorn. 
Further study will be needed to clarify the mechanism by which low sodium levels increase fracture risk. In the meantime, "Screening older adults for and treatment of hyponatremia in older adults may be an important new strategy to prevent fractures," adds Hoorn. 
Notes: 
Study co-authors are Fernando Rivadeneira, MD, PhD, Joyce B.J. van Meurs, PhD, Gijsbertus Ziere, MD, PhD, Bruno H. Ch. Stricker, MB, PhD, Albert Hofman MD, PhD, Huibert A.P. Pols MD, PhD, Robert Zietse MD, PhD, André G. Uitterlinden PhD, M. Carola Zillikens MD, PhD (Erasmus Medical Center). 
The authors reported no financial disclosures. 
The study abstract, "Mild Hyponatremia as a Risk Factor for Fractures: The Rotterdam Study," [F-FC232] was presented as an oral presentation at the Colorado Convention Center in Denver, CO. 
Source: 
Shari Leventhal
American Society of Nephrology 
[F-FC232] Mild Hyponatremia as a Risk Factor for Fractures: The Rotterdam Study
Ewout J. Hoorn, Robert Zietse, M. Carola Zillikens. Internal Medicine, Erasmus Medical Center, Rotterdam, Netherlands
INTRODUCTION: Recent studies suggest that mild hyponatremia is associated with fractures, but prospective studies are lacking. Our aim was to study whether hyponatremia is associated with fractures and, if so, whether this is mediated through falls and/or bone mineral density (BMD).
METHODS: 5208 elderly (> 55 years) with available serum sodium at baseline were included from the prospective, population-based Rotterdam Study. The following data were analyzed: BMD, vertebral fractures (mean follow-up 6.4 years), non-vertebral fractures (mean follow-up 7.4 years), recent falling, co-morbidity, medication, and mortality.
RESULTS: Hyponatremia (serum sodium < 136 mmol/L) was detected in 399 community subjects (7.7%, 133.4 ± 2.0 mmol/L). Subjects with hyponatremia were older (73.5 ± 10.3 vs. 70.0 ± 9.0 years, P<0.001), had more recent falls (23.8% vs. 16.4%, P<0.01), higher type 2 diabetes mellitus prevalence (22.2 vs. 10.3%, P<0.001), and more often used diuretics (36.9% vs. 21.3%, P<0.001). Hyponatremia was not related to BMD, but was associated with increased risk of incident non-vertebral fractures (HR=1.39, 95% CI 1.11-1.73, P=0.004) after adjustment for age, sex and body mass index. Further adjustments for disability index, use of diuretics or psycholeptics, recent falls and prevalent diabetes did not modify results. Subjects with hyponatremia also had increased risk of vertebral fractures after adjustment for all covariates (OR=1.61, 95% CI 1.00-2.59, P=0.049). Finally, all-cause mortality was higher in subjects with hyponatremia (HR=1.21, 95% CI 1.03-1.43, P=0.022).
CONCLUSION: Mild hyponatremia in the elderly is associated with increased risk of vertebral fractures and incident non-vertebral fractures but not with BMD. Increased fracture risk in hyponatremia was also independent of recent falls, pointing towards a possible effect on bone quality. This study adds to the growing body of evidence that chronic hyponatremia is not a benign condition, and suggests the need for monitoring and treatment.
(Maart 2011) 

 

 

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