Can Your Cholesterol Levels Influence Your Risk of Developing IBD?

Cholesterol is often associated with heart health, but its impact on digestive health, namely inflammatory bowel disease (IBD), is increasingly being studied. Previous studies on lipid levels and disease activity are inconsistent, and a causal relationship between lipid levels and IBD remains dubious.

Some reports show lower cholesterol levels and high triglyceride levels in people with IBD compared to healthy individuals. However, other studies do not find significant differences. The inconsistencies highlight the challenges of traditional observational studies, which can be affected by factors that distort results and reverse causation.

IBD is a chronic intestinal inflammatory disease affecting different parts of the digestive tract. It includes ulcerative colitis (UC) and Crohn’s disease (CD). Symptoms typically include abdominal pain, diarrhea, blood in stool, and weight loss. IBD requires a long course of therapy and lasts a lifetime. It is a growing global health concern, most prevalent in developed Western countries. However, over the last decade, Asia and Eastern Europe have experienced an ever-increasing incidence rate of IBD.

In a study recently published in BMJ Open eGastroenterology, researchers led by Xiaoli Ping from the Department of Pediatric Gastroenterology, Children’s Medical Center in China, used bidirectional Mendelian randomization (MR) analysis to investigate the causal association between the serum lipid profile and inflammatory bowel disease (IBD).

The purpose of MR analysis is to investigate causal relationships between an exposure (such as a risk factor or biomarker) and an outcome (such as a disease or health outcome). ​It provides more reliable evidence for causal relationships. MR analysis is particularly valuable when studying modifiable risk factors or biomarkers, as it can provide insights into potential targets for interventions or treatments.

The researchers utilized a two-sample MR analysis to explore the relationship between total cholesterol, total triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A, apolipoprotein B and lipoprotein (a), and IBD. Results from various MR methods indicated null causal effects between serum lipid profiles and IBD, Crohn's disease, and ulcerative colitis.

The authors noted potential factors contributing to the coexistence of dyslipidemia and IBD, including changes in dietary habits, dysregulated immune response, the effects of therapeutic drugs, malnutrition, intestinal dysfunction, or malabsorption. ​They cautioned that these underlying mechanisms must be studied further to establish a stronger connection.

The study contributes to the existing knowledge by providing evidence that no lipid indices are potential risk factors for the onset of IBD. While the researchers found no causal relationship between serum lipids and IBD, the findings still suggest the importance of monitoring lipid indices in patients with IBD. Clinicians should focus on other factors rather than solely targeting lipid levels when managing patients with dyslipidemia and IBD. ​

Understanding the complex interactions between serum lipids and IBD can aid disease prevention and early intervention strategies. The study adds to the existing knowledge by providing evidence that serum lipid profiles may not be a risk factor for the onset of IBD. However, further research is needed to explore potential non-linear causal relationships between serum lipids and IBD.