Osteoporosis, a condition defined by low bone mineral density (BMD) (typically < -2.5 SD), cause a higher fracture risk and lead to significant economic, social, and clinical impacts. Genome-wide studies mainly in Caucasians have found many genetic links to osteoporosis, fractures, and BMD, with limited research in East Asians. We investigated the genetic aspects of BMD in 86,716 individuals from the Taiwan Biobank and their causal links to health conditions within East Asians. A genome-wide association study (GWAS) was conducted, followed by observational studies, polygenic risk score assessments, and genetic correlation analyses to identify associated health conditions linked to BMD. GWAS and gene-based GWAS studies identified 78 significant SNPs and 75 genes related to BMD, highlighting pathways like Hedgehog, WNT-mediated, and TGF-β. Our cross-trait linkage disequilibrium score regression analyses for BMD and osteoporosis consistently validated their genetic correlations with body mass index (BMI) and type 2 diabetes (T2D) in East Asians. Higher BMD was linked to lower osteoporosis risk but increased BMI and T2D, whereas osteoporosis linked to lower BMI, waist circumference, HbA1c, and reduced T2D risk. Bidirectional Mendelian randomization (MR) analyses revealed that a higher BMI causally increases BMD in East Asians. However, no direct causal relationships were found between BMD and T2D, or between osteoporosis and either BMI or T2D. This study identified key genetic factors for bone health in Taiwan, and revealed significant health conditions in East Asians, particularly highlighting the genetic interplay between bone health and metabolic traits like T2D and BMI.
Keywords: Bone mineral density; genome-wide association studies; health conditions; osteoporosis; polygenic risk score.
We investigated how genetics affect bone health and related conditions like diabetes and obesity in 86,716 East Asians. Previously, most studies focused on Caucasian populations, but our work helps to understand these issues in East Asians. Our findings show that stronger bones are linked to a lower chance of osteoporosis but a higher risk of obesity and type 2 diabetes. On the other hand, those with osteoporosis tend to have lower body weight and a decreased risk of diabetes, illustrating a complex relationship between bone health and body metabolism. Future research will focus on deeper genetic interactions and developing targeted interventions for bone health and related metabolic disorders in East Asians.
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