Obesity as a Risk Factor for Autoimmune Diseases: A Systematic Review and Meta-Analysis

Area of Science:

• Immunology
• Epidemiology
• Public Health

Background:

• Obesity is a proinflammatory state linked to adverse health outcomes.
• The relationship between obesity and autoimmune diseases remains incompletely understood.
• Existing research presents conflicting evidence regarding obesity's role in autoimmunity.

Purpose of the Study:

• To systematically evaluate the association between obesity and the prevalence and incidence of autoimmune diseases.
• To synthesize findings from existing studies using meta-analysis to clarify the obesity-autoimmunity link.

Main Methods:

• A comprehensive literature search was conducted in PubMed and Embase.
• Data from 26 studies (8 cross-sectional, 18 longitudinal) were pooled using meta-analysis techniques.
• Adjusted odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) were calculated for obesity (BMI > 30) versus normal weight (BMI < 25).

Main Results:

• Obesity was associated with increased prevalence of rheumatoid arthritis (OR=1.11) and psoriasis (OR=1.35).
• Obesity increased the risk of developing rheumatoid arthritis (HR=1.30), psoriasis (HR=1.18), multiple sclerosis (HR=1.49), and Crohn's/ulcerative colitis (HR=1.35).
• A significant association was found between obesity and the incidence of any autoimmune disease (HR=1.41).

Conclusions:

• The overall evidence strongly supports obesity as a significant risk factor for developing autoimmune diseases.
• While definitive conclusions for individual diseases require further investigation, the aggregate data underscore the public health implications of obesity in autoimmunity.
• Further research is warranted to elucidate the specific mechanisms linking obesity to various autoimmune conditions.