Belly fat linked to widespread chronic pain, especially in women

Excess abdominal fat is linked to widespread chronic pain, especially in women, according to the first study of its kind published in the open access journal Regional anesthesia and pain medicine.

Reducing excess fat deposits in the abdomen may help reduce chronic musculoskeletal pain, especially if it is experienced in multiple body locations, the researchers suggest.

Previously published research has shown that obesity is associated with musculoskeletal pain, but it is not known whether excess adipose tissue is associated with chronic pain in the musculoskeletal system and in multiple body locations, the researchers say.

To find out, they used data from 32,409 participants in the UK Biobank study who completed questionnaires and underwent health assessments. About half (51%) were women and their average age was 55 years.

They underwent MRI scans of their abdomens to measure the amount of fat around the abdominal organs (visceral adipose tissue or VAT) and the amount of fat just under the skin that can be pinched off (subcutaneous adipose tissue or SAT).

During the scan, participants were asked whether they had experienced pain in their neck/shoulder, back, hip, knee or ‘all over the body’ for more than 3 months.

The MRI scan and pain assessments were repeated approximately 2 years later for 638 participants.

Extensive analyzes showed a dose-response association between the number of chronic pain sites and VAT, SAT, the ratio of the two, and weight (BMI).

The association was stronger in women in whom the odds ratio of having a greater number of chronic pain sites was twice as high for VAT, and 60% greater for both SAT and the VAT:SAT ratio. In men, these odds ratios were 34%, 39% and 13% higher, respectively.

Higher levels of adipose tissue were also associated with a greater likelihood of reporting chronic pain, and again the link was more pronounced in women.

All of these associations persisted even after adjusting for age, height, ethnicity, household income, education level, alcohol consumption, smoking status, physical activity, coexisting conditions, sleep duration, psychological distress, and duration of follow-up.

This is an observational study and as such cannot establish cause and effect, and the authors also acknowledge several limitations.

These include the relatively small size of the repeat imaging sample and the lack of severity assessment in the pain questionnaire. More follow-up visits would also have made it possible to collect more information about patterns and fluctuations in the number of chronic pain sites, they add.

But they conclude: “Abdominal adipose tissue was associated with chronic musculoskeletal pain, suggesting that excessive and ectopic fat deposits may be involved in the pathogenesis of multisite and widespread chronic musculoskeletal pain.”

They add, “Therefore, reducing abdominal adipose tissue may be considered a target for chronic pain management, especially in those with multisite and widespread pain.”

And they suggest that the stronger associations seen in women may be a result of sex differences in fat distribution and hormones.