Obese individuals experience higher levels of pain than those of normal weight – researchers explained at the EFIC Congress in Hamburg, Germany. They added that obese patients may require stonger pain killers than those who are not overweight.
(EFIC stands for European Federation of IASP® Chapters. A multidisciplinary professional organization in the field of pain research and medicine.)
Several studies presented at the Congress have revealed that obesity is a contributory factor to greater levels of chronic pain.
Dr. Sharron Dolan, from Glasgow Caledonian University, Glasgow, Scotland, and team wondered why obese rats had a higher incidence of chronic painful conditions, such as migraine, osteoarthritis, musculoskeletal conditions, and alterations in pain sensitivity? They set out to discover the mechanism behind the unanswered questions. Numerous testing procedures were performed on rats that were fattened, as well as normal weight rats – first without any inflammation, then in response to inflammatory stimulation.
Dr. Dolan explained to the Congress:
“Following administration of an inflammatory agent to the paw, obese rats were significantly more sensitive to mechanical and thermal stimulation of the inflamed paw, and displayed great paw oedema compared to lean rats (stressing that these results were a huge step forward).
The increased hyperalgesia and peripheral inflammation observed in obese rats fits well with the hypothesis that obesity is a chronic low-grade inflammatory disorder, producing a state where responses to subsequent inflammatory challenge are potentiated.
These alterations may underlie the increased susceptibility of obese individuals to develop chronic inflammatory pain conditions. It might signal the need for more aggressive analgesic treatment regimes in these individuals.”
Karine Ferreira, from the State Cancer Institute of the Medical School of the University of São Paulo, explained:
“Obesity is clearly associated with chronic pain in humans. Well-fed individuals, whose body mass index (BMI) lies between 35 and 39.9, are more likely to report pain.”
Ferreira reported on key discoveries of a recent investigation in which her team analyzed the relationship between pain and obesity in over 2,400 adults. Almost a third of the participants – 29.2% – had reported pain during the previous three months. The mean BMI was 25.3.
Those with normal weight were more likely to report head and neck pain (48.9%) and headache (54.1%) than other BMI categories. Those who were in obese class I (30.5%) and class III (28.6%) were more likely to suffer from pain in their legs and feet. Participants in obese class II were more likely to report pain in multiple places. It was seen that respondents with obese class III reported higher pain levels that interfered with walking ability than those with normal weight.
Weight classifications and frequency of pain according to category According to the BMI category, the frequency of pain was:
- Underweight – BMI under 18.5 kg/m2 – 21.8% of patients reported pain within 3 months
- Normal weight – BMI 18.5 to 24.9 kg/m2 – 26.5%
- Overweight – BMI 25 to 29.9 kg/m2 – 30.7%
- Obese class I – BMI 30 to 34.9 kg/m2 – 36.3%
- Obese class II – BMI 35 to 39.9 kg/m2 – 49.1%
- Obese class III – BMI 40 and more kg/m2 – 28.7%
Written by Grace Rattue