Leptin – a factor well-known for its role in controlling appetite – might be a driver of bodily pain, according to a new report. Investigating levels of the molecule in both women with fibromyalgia and healthy women has provided scientists with clues of the underlying processes of pain signaling and might lead to better future pain treatments.

Last week, Fibromyalgia News Today reported on the scientific progress of a research team from the University of Alabama at Birmingham, investigating brain-immune interactions in fibromyalgia patients. The study described the team’s efforts to understand leptin’s role in pain signaling.

Earlier research has shown that the appetite-controlling molecule is also regulated by sleep and infection, and has been linked to inflammatory diseases such as rheumatoid arthritis, lupus, and multiple sclerosis.

The report, titled “Association of Leptin with Body Pain in Women,“ is actually composed of two studies. The first small pilot study followed three women over 25 days who were affected by fibromyalgia, analyzing both leptin and pain on a daily basis.

The findings, published in the Journal of Women’s Health, show that leptin levels fluctuated along with reported pain, with higher levels on days when women experienced more pain.

The second study explored previously collected data from the Women’s Health Initiative (WHI) Observational Study. The study, performed between 1993 and 1998, offered the research team blood samples and data on bodily pain, as well as participants’ BMI levels. The group consisted of 5,676 postmenopausal women, representative of the general population.

Analyzing this large group of women, the researchers found that both leptin and BMI were associated with bodily pain, independent of each other.

The evidence of a link between leptin and pain in the second study was rather weak. This could have been a consequence of blood samples and pain ratings not taken on the same occasion, since the first study indicated that leptin levels could fluctuate several times over consecutive days, making the prospect of finding a link small. Most women in the large sample also were not likely to suffer from a pain condition.

However, the researchers believe a potential link between leptin and pain might be more evident in pain conditions, as was the case in the three fibromyalgia women. They also caution that, given the daily fluctuations, levels need to be measured on consecutive occasions to provide a more clear picture of the factor’s role in pain signaling.

While none of the studies presents evidence that leptin causes pain, the results point researchers in a direction worth exploring for pain conditions such as fibromyalgia.