High Platelet Counts Associated With Osteopenia and Osteoporosis

Platelet levels within the upper regions of the normal range suggest that a patient may have chronic inflammation-related diseases, such as osteoporosis, and warrant investigation, say the authors of what is believed to be the first study to look at link between platelet levels and osteoporosis in an elderly population.

They say their findings suggest that platelet count may affect bone metabolism and remodelling.

“In this study, we found that higher platelet counts within the normal range (150–450 × 103μL) are significantly associated with osteopenia and osteoporosis in middle-aged and elderly people. This result implies that higher but normal range platelet count reflecting subclinical chronic inflammation is associated with osteoporosis,” says Dr Yu-Jin Kwon, clinical assistant professor at the department of family medicine, Yongin Severance Hospital Yonsei University College of Medicine, Gyeonggi-do, Republic of Korea.

While it is too early to say that platelet count could be used to predict osteoporosis, based on the results of this single study, he adds, “Doctors could consider that people with high platelet levels but normal range might have chronic inflammation-related diseases, including osteoporosis.”

The Korean research team looked at data from two independent population studies in which almost 8,500 middle aged and elderly people who had their bone mineral density measured and their platelet levels assessed. Dual-energy X-ray absorptiometry was used to measure bone mineral density in 5,181 postmenopausal women and men over 50 years of age in the 2008-11 Korea National Health and Nutrition Examination Survey (KNHANES), while the Korean Genome and Epidemiology Study (KoGES) used quantitative ultrasound to assess it in 3312 adults over 50. The relationship between platelet levels and bone mineral density was then explored using statistical analysis.

See next page:  Chronic Inflammation and High Platelet Levels

CHRONIC INFLAMMATION AND HIGH PLATELET LEVELS

The results published in journal Archives of Osteoporosis indicate that high platelet counts were significantly associated with osteopenia and osteoporosis.

The KNHANES data showed that bone mineral density decreased in the femur neck, total femur, and lumbar spine areas as platelet counts increased, even within the normal range, with platelet levels above 217 × 103/μL and 269 × 103/μL associated with osteopenia and osteoporosis respectively. In KoGES, patients were divided into three groups according to their platelet levels, and at 10-year follow up the distal radius T-score was found to be significantly lower in the group that had recorded highest platelet levels.

Dr. Kwon explains that chronic inflammation would be the most likely mechanism to link high platelet levels to osteoporosis. “Inflammatory cytokines modulate bone remodeling through osteoclast activation, leading to bone loss. Increased inflammatory stimuli provoke platelet activation, and activated platelets affect osteoclastogenesis via prostaglandin and receptor activator of nuclear factor-κB ligand signaling,” he says. “In addition, activated platelets release thromboxanes and other mediators that consequently increase inflammation.”

Inflammation is known to have a crucial pathophysiological role in the development of osteoporosis and the involvement of platelets in regulating inflammation and interaction with leukocyte are well studied, he adds. However, the effect of platelets on bone is complex and not fully understood.

“Platelets are known to be involved in both bone formation and resorption. Degranulation of activated platelets leads to the release of several growth factors (e.g. platelet-derived growth factor [PDGF]) contributing to the recruitment of osteogenic cells after the injury,” he explains. “Platelet also contains mediators, which may be involved in the bone remodelling.”

REFERENCE

Kim J, Kim HS, Lee HS, Kwon YJ. "The relationship between platelet count and bone mineral density: results from two independent population-based studies," Archives of Osteoporosis. March 12, 2020. DOI: 10.1007/s11657-020-0700-4