The relationship between platelet count and bone mineral density: results from two independent population-based studies.

In two population-based study of middle-aged and older people, we investigated if platelet count was associated with bone mineral density and determined whether the association remained over time. Highest platelet counts within the normal range are significantly associated with osteopenia and osteoporosis in middle-aged and elderly people. PURPOSE: Recently, platelets were found to play a role in bone remodeling. However, data on the association between platelet count and osteoporosis are lacking. Our study aimed to investigate the association between platelet counts, osteopenia, and osteoporosis in middle-aged and elderly Koreans. METHODS: We analyzed cross-sectional data from 5181 adults (postmenopausal women and men over 50 years of age) in the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES) and longitudinal prospective data from 3312 adults over 50 years of age in the Korean Genome and Epidemiology Study (KoGES). Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry in the KNHANES and quantitative ultrasound in the KoGES. The platelet counts were categorized into quintiles within normal ranges (150-450 × 103 µL). The associations between platelet counts, osteopenia, and osteoporosis were estimated using a multinomial logistic model. RESULTS: BMD of the femur neck, total femur, and lumbar spine all decreased with increasing platelet counts. The cut-off points of the platelet counts to differentiate normal BMD from osteopenia and osteopenia from osteoporosis were 217 × 103/µL and 269 × 103/µL, respectively. The odds ratios (95% confidence intervals) in the highest platelet quartile were 1.39 (1.03-1.88) for osteopenia and 1.60 (1.07-2.37) for osteoporosis after adjusting for confounding factors. The distal radius T-score was significantly decreased in the highest platelet tertile group at a follow-up of 10 years. CONCLUSION: Highest platelet counts within the normal range are significantly associated with osteopenia and osteoporosis in middle-aged and elderly people.