Beta-blocker use, bone mineral density, and fracture risk in older women: results from the Epidemiologie de l'Osteoporose prospective study

Beta-blockers increase bone mineral density

Authors of animal studies suggest that beta-blockers stimulate bone formation and inhibit bone resorption. On the other hand, data in humans are limited and conflicting results exist in literature. We conducted a prospective case-control study in order to investigate the effects of beta-blockers on bone mineral density in the elderly population. None of the patients were receiving anti-resorptive medicine. Bone mineral density of 50 beta-blocker users was significantly greater at all measured skeletal sites compared with 100 nonusers. Bone mineral density for total hip and spine (beta-blocker users and nonusers) were, 0.85 +/- 0.13, 0.80 +/- 0.11 and 0.90 +/- 0.15, 0.83 +/- 0.12, respectively. Our results suggest that use of beta-blockers is associated with an increase in bone mineral density.

LEVEL OF EVIDENCE

Therapeutic study, LEVEL III (case control study). See the Guidelines for Authors for a complete description of the levels of evidence.

Neural regulation of bone and the skeletal effects of serotonin (5-hydroxytryptamine)

There is increasing evidence for a contribution of the neural system to the regulation of bone metabolism. The skeleton is richly innervated by both sympathetic and sensory neurons. While these nerves serve sensory and vascular functions, they are also being found to influence bone cell activities. The most convincing evidence for this has been provided by studies into the skeletal effects of the hormone leptin, which has been shown to centrally regulate bone mass, and through studies into the skeletal effects of hypothalamic neuropeptide Y2 and Y4 receptors. This paper discusses recent evidence for the neural regulation of bone metabolism and, in particular, the potential role of the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Recent studies have demonstrated the presence of functional pathways in bone for both responding to and regulating the uptake of 5-HT. This is of high clinical relevance given the role of the serotonergic system in affective disorders, and the wide use of pharmacological agents that target the 5-HT system to manage these disorders. Initial data suggest that exposure to these agents at different stages during the lifespan may have significant effects on the skeleton.

Effects of a beta-blocker on bone turnover in normal postmenopausal women: a randomized controlled trial

INTRODUCTION

The central nervous system has been demonstrated to regulate bone mass in mice, possibly via the beta2-adrenoreceptors on osteoblasts. beta-blockers increase bone mass in mice, and some observational studies have suggested a beneficial effect of these drugs on bone in humans

EXPERIMENTAL SUBJECTS

We studied 41 normal postmenopausal women.

MATERIALS AND METHODS

We conducted a randomized, placebo- controlled trial, comparing the effects on bone markers of propranolol 160 mg/d and placebo over 3 months.

RESULTS

Serum osteocalcin declined by almost 20% in the first 2 wk of propranolol treatment, and this effect increased over time (P < 0.0001). Other osteoblast markers, procollagen type-I N-terminal propeptide and total alkaline phosphatase activity, were not significantly changed by propranolol. Urine free deoxypyridinoline declined by approximately 10% between 0 and 6 wk (P = 0.019) in the beta-blocker group and was stable thereafter. Serum C-terminal telopeptide of type I collagen also showed a small decrease, but this was not significantly different between groups. Serum albumin concentrations decreased by more than 2 g/liter in the first 2 wk of propranolol treatment, remaining stable subsequently (P = 0.007). Serum creatinine tended to increase in the propranolol group (P = 0.06), as did weight. Bone densities in the lumbar spine and total proximal femur did not change significantly in either group.

CONCLUSIONS

The present study provides no evidence that beta-blocker drugs stimulate bone formation; if anything, propranolol reduces osteoblast activity. It also influences renal function and fluid balance, effects that might indirectly affect bone metabolism. Current evidence does not justify the use of beta-blockers for treatment of osteoporosis.