Chronic low-level inflammation, prompted by cholesterol build-up in immune system cells, may have a key role, the findings suggested. Tendons are the tough fibers connecting muscles and bones in the body.
The researchers trawled six medical research databases, looking for studies investigating links between blood fats and tendon abnormalities/pain. Compared with people whose tendon structure was normal, those with abnormal tendon structure had a significantly more unfavorable blood fat (lipid) profile, the results showed.
They had significantly higher total cholesterol, including higher low density ('bad') cholesterol and lower high density ('good') cholesterol, and higher triglyceride levels. Furthermore, people with an unfavorable lipid profile were much more likely to have tendon injuries and higher levels of pain associated with musculoskeletal problems in their arms.
Two of the three studies, which looked at Achilles tendon thickness, found that people with an unfavorable lipid profile had thicker tendons than those with lipid levels in the normal range. "Together, these findings provide significant support for a metabolic hypothesis of tendon injury and implicate lipid parameters as a potential link," the researchers noted.
The study was published online in the British Journal of Sports Medicine