The relationship between genetics, type 2 diabetes, and physical activity with musculoskeletal pain

Abstract

Musculoskeletal pain, such as low back pain, neck/shoulder pain, knee pain and hip pain have high prevalence rates. Many factors are believed to impact these complex conditions. However, it is not well-understood how these musculoskeletal pain conditions are affected by factors such as genetics, physical activity or type 2 diabetes. This thesis aimed to investigate how these factors impact on the prevalence, risk of musculoskeletal pain, particularly low back pain (LBP). Five studies were conducted to achieve these aims. Genetics influences LBP outcomes, but such influence is similar among many different outcomes of LBP, with the exception of the intensity of pain associated with the worst episode. Given the importance of genetics on LBP, researchers will benefit from a data resource that allows for adjustment of genetic factors. As a consequence, The AUstralian Twin BACK pain and physical activity study with one-year follow-up was established to provide great opportunities for future investigations on the relationship between types and dosages of physical activity and LBP by collecting LBP and physical activity status on a weekly and monthly basis, respectively. Regarding type 2 diabetes and its association with musculoskeletal pain, the cross-sectional analyses conducted in this thesis revealed positive and significant associations, mainly with neck/shoulder, hip and knee pain, whereas longitudinal analyses showed that type 2 diabetes only increased the risk of neck/shoulder pain. Of interest, when examining the relationship between the use of metformin and musculoskeletal pain, back pain prevalence was lower amongst those who were taking metformin in people with type 2 diabetes. Finally, amongst those with type 2 diabetes, specific phenotypes of participants with obesity, engaged in low levels of physical activity, or those aged over 60 years old, who were taking metformin were less likely to report chronic low back pain than those who were not taking the drug.