Heart failure predicts an increased bone fracture rate. Is vitamin D deficiency the reason for the correlation?

A recent and interesting medical paper says that researchers have “discovered” that persons diagnosed with heart failure in hospital emergency departments have a dramatically increased risk of bone fractures. [1] The researchers stated that after one year, those diagnosed with heart failure (HF) had four times the risk of any fracture and more than six times the risk of hip fracture when compared to those who came to emergency departments for non-HF reasons.

One of the authors stated that it is not known how heart failure promotes bone fractures. My answer, of course, is that heart failure does not promote fractures; the risk of each of these terrible diseases is profoundly increased by vitamin D deficiency. We know, for instance, that lack of vitamin D in the blood can cause rickets, osteoporosis and osteomalacia. The earliest known value of vitamin D was in the prevention of rickets, the horrible, deforming bone disease of D-deficient children. Osteoporosis (brittle bones that are susceptible to fractures) also develops if there is insufficient vitamin D in the blood.

One of the most compelling studies on fracture risk was done by Dr. Sato and his colleagues in Japan.[2] They studied the effects of sunlight—or the lack thereof—on the bone mass of elderly women who were either exposed to sunlight or were kept inside a care facility. Over twelve months, 129 women were exposed to sunlight every day, and another 129 received no sunlight exposure. The results were startling: in these sedentary women, the sunlight group increased bone mass by an average 3.1%; in the non-sunlight-exposed group, it decreased by 3.3%, a difference of 6.4%. This is important, because high bone mass prevents fractures. The risk of fracture increases two to three times for every 10 percent drop in bone density.[3] In Sato’s study, however, the women who stayed indoors out of the sunlight had six times as many fractures as those who sunbathed outdoors. Also interesting to note is that vitamin D levels in the sunlight-exposed group increased by 400%.

An investigation in Spain concluded that women who actively participated in sun exposure had one-eleventh the chance of a hip fracture as those who did not![4] Another in Switzerland found that only 4% of hip fracture patients had vitamin D blood levels of 30 ng/ml.[5] In other words, 96% were vitamin D-deficient.

So what does this have to do with heart failure (HF)? Much more than you might imagine! Vitamin D deficiency appears to dramatically increase the risk of HF, just as it increases the risk of osteoporosis and fractures. Inflammation is common with HF, and is often caused by proteins called cytokines that are either pro-inflammatory or anti-inflammatory elements of the immune system. Vitamin D has an amazing ability to inhibit pro-inflammatory cytokine production[6],[7]while stimulating the production of anti-inflammatory cytokines[7]and is particularly useful in improving the cytokine profiles in patients with congestive heart failure.[7]

In France, deaths from HF are 20% higher than average in January and 15% lower in August—a swing of 355 [8] Similarly, in Spain HF hospital admissions are 25% higher than average in January and 33% lower in August.[9] That is a 58% seasonal swing! We know that vitamin D levels are much higher in summer than winter, so it is highly likely that the higher HF rate in January is due to lower vitamin D levels.

Further corroborating the idea that vitamin D deficiency leads to or exacerbates heart failure is the fact that the incidence of heart failure in black Americans, compared to white Americans, is 40% higher in men and 100% higher in women.[10] Remember that dark-skinned people living at high latitudes have lower vitamin D levels—an easily-remedied situation. Not surprisingly, heart failure is related to low vitamin D in all races, and most sufferers have serum levels below 20 ng/ml, which is quite deficient. Adults with this condition also show a history of sedentary, indoor living.[11]

Tragically, newborns also suffer heart failure, and until lately studies had not considered vitamin D deficiency as a possible cause. However, in a study conducted in southeast England, sixteen infants were identified that had suffered HF between 2000 and 2006.[12] Six were of Indian and ten of African ethnicity. Six of them suffered cardiac arrest, three died, eight were placed on lung machines, and two were referred for heart transplants. The average serum vitamin D level of these children was only 7.4 ng/ml, and some of the infants had undetectable levels. Obviously, a few dollars worth of vitamin D could have prevented this catastrophe.

So there you have the answer. Both heart failure and fractures have a common underlying cause, and although there may be other factors that lead to heart failure and fractures, vitamin D deficiency is the certainly the most easily remedied. When will the world wake up to the crying need to optimize vitamin D levels?

References:

[1] van Diepen, S et al. Heart failure is a risk factor for orthopedic fracture. A population-based analysis of 16 294 patients. Circulation 2008; Available at: http://circ.ahajournals.org.
[2] Sato, Y. et al. Amelioration of osteoporosis and hypovitaminosis D by sunlight exposure in stroke patients. Neurology 2003;61:338-42.
[3] Nguyen, T. et al. Prediction of osteoporotic fractures by postural instability and bone density. BMJ 1993;307:1111-15.
[4] Larrosa, M. Vitamin D deficiency and related factors in patients with osteoporotic hip fracture. Med Clin (BARC) 2008;130:6-9.
[5] Bischoff-Ferrari, H. et al. Severe vitamin D deficiency in Swiss hip-fracture patients. Bone 2007 Nov 28 [Epub ahead of print]
[6] Muller, K. et al. 1,25-Dihydroxyvitamin D3 inhibits cytokine production by human blood monocytes at the post-transcriptional level. Cytokine 1992;4:506-12.
[7] Schleithoff, S. et al. Vitamin d supplementation improves cytokine profiles in patients with congestive heart failure: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr 2006;83:731-2.
[8] Boulay, F. et al. Seasonal variation in chronic heart failure hospitalizations and mortality in France. Circulation. 1999;100:280-86.
[9] Martinez-Selles, M. et al. Annual rates of admission and seasonal variations in hospitalizations for heart failure. Eur J Heart Fail 2002;:779-86.
[10] American Heart Association. Heart and stroke statistics – 2004 update.
[11] Zitterman, A. et al. Vitamin D insufficiency in congestive heart failure: Why and what to do about it? Heart Fail Rev 2006;11:25-33.
[12] Maiya, S. et al. Hypocalcaemia and vitamin D deficiency: an important, but preventable cause of life-threatening heart failure. Heart 2008;94:581-84