Association between Sjögren syndrome and osteoporosis: A bidirectional Mendelian randomization study

Area of Science:

• Rheumatology
• Genetics
• Epidemiology

Background:

• Sjögren syndrome (SS) is a chronic autoimmune disease.
• Osteoporosis (OP) is a skeletal disorder characterized by reduced bone mass.
• The relationship between SS and OP requires further investigation.

Purpose of the Study:

• To investigate the potential causal relationship between Sjögren syndrome and osteoporosis using a Mendelian randomization approach.
• To determine if SS is a risk factor for OP, or if OP predisposes individuals to SS.

Main Methods:

• Utilized a two-sample Mendelian randomization (MR) study design.
• Employed genetic variants associated with Sjögren syndrome as instrumental variables.
• Applied various statistical methods including inverse variance weighting and weighted median, alongside sensitivity analyses.

Main Results:

• A significant positive association was found between genetic predisposition to Sjögren syndrome and the presence of osteoporosis (OR: 1.191, P < .005).
• No significant evidence supported a causal effect of osteoporosis on Sjögren syndrome.
• Sensitivity analyses confirmed the robustness of the primary findings.

Conclusions:

• Genetic evidence supports Sjögren syndrome as a risk factor for developing osteoporosis.
• The study indicates no reverse causality, suggesting osteoporosis does not increase the risk of Sjögren syndrome.