Atherosclerosis and Low Back Pain

Atherosclerosis is well-known for its role in the development of coronary heart disease and stroke. The vascular occlusion that it causes leads to the infarction of heart and brain tissue. But coronary and cerebral blood vessels are by no means the only vessels that become clogged by atheromatous plaques. In 1993, Kauppila et al., from the department of forensic medicine at Helsinki University, postulated that insufficient arterial blood flow may play a role in low back pain. Their post-mortem angiographic study found that, compared to controls, significantly more people with a history of low back pain had anomalies in the arteries that supplied the lumbar spine – the arteries were narrowed by atheromatous lesions and some were completely missing.

Since that landmark study, several cadaver and clinical studies have corroborated the link between stenosis (and occlusion) of the lumbar arteries and the presence of low back pain. In fact, many studies have found an association between the aforementioned lumbar vascular insufficiency and degeneration of the corresponding lumbar discs. This shouldn’t be a surprise because, as Kauppila states, “the disc is located at the end of the nutrient chain, making it one of the first structures to suffer during insufficient nutrient supply.”

In epidemiological studies, associations between cardiovascular risk factors and low back pain (or disc degeneration) are weaker and conflicting. Nevertheless, several studies have linked high blood cholesterol and smoking with low back pain and disc degeneration. It’s important to remember that correlation is different from causation and more research is needed to determine a cause and effect relationship. So, a healthy diet and abstinence from smoking may play a role in the prevention and treatment of low back pain. Further still, and this is pure conjecture on my part, they may have a role to play in maintaining the health of all poorly vascularised tissues (spinal discs, tendons, articular cartilage of joints, etc.).

 

High Cholesterol Can Cause Tendon Pathology

A recent literature review by Yang et al. suggests that high blood cholesterol is a risk factor in the development and progression of tendon pathology. They found that cholesterol levels were directly correlated with the severity of tendon problems. There is evidence that elevated cholesterol levels lead to inflammatory, structural and mechanical changes in tendons which predispose patients with high cholesterol levels to an increased risk of developing tendinopathies.

Higher Fibre Intake Improves Health

Last month Reynolds et al. published an article in The Lancet that looked into the relationship between carbohydrate quality and health. They carried out a series of systematic reviews and meta-analyses that evaluated around 135 million person-years of data from 185 prospective studies as well as 58 clinical trials with 4635 adults. They found that those with higher intakes of fibre had lower body weight, lower systolic blood pressure and lower total cholesterol. Those with higher fibre intakes also had a decreased incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer, which may explain the 15-30% decrease in all-cause mortality between the groups with high and low fibre intake. Daily intake of fibre between 25g-30g seemed to confer the greatest risk reduction, although they note that “higher intakes of dietary fibre could confer even greater benefit“.

Pain and Sleep

A few days ago, Krause et al. from the University of California (Berkeley), published the results of their research on the relationship between pain and sleep. They found that poor sleep quality was linked to increases in pain experience, whereas better sleep quality decreased pain. Krause notes that “the results clearly show that even very subtle changes in nightly sleep – reductions that many of us think little of in terms of consequences – have a clear impact on your next-day pain burden”. In the laboratory, they were able to identify that sleep deprivation amplifies the reactivity in parts of the brain (somatosensory cortex) responsible for the perception of pain. Whilst deactivating the responses from some pain relieving centres (insula and nucleus accumbens).

The irony is that pain often disrupts sleep, and thus the pain experience gets magnified and a vicious cycle is created.

Bad Moods Can Increase Inflammation

Jennifer Graham-Engeland et al. from Pennsylvania State University have recently found a link between negative moods and inflammation. The main author stated that, “Because affect is modifiable, we are excited about these findings and hope that they will spur additional research to understand the connection between affect and inflammation, which in turn may promote novel psychosocial interventions that promote health broadly and help break a cycle that can lead to chronic inflammation, disability, and disease.”

Decreasing Social Media Use Improves Mental Health

Hunt et al., from the University of Pennsylvania, have recently published their findings on the effects of social media use on well-being. After baseline monitoring, 143 undergraduates were randomly split into 2 groups. The first group (control group) continued to use Facebook, Instagram and Snapchat as usual whereas the second group was restricted to 10 min per platform per day i.e. 30 min/day in total. The authors found that “the limited use group showed significant reductions in loneliness and depression over three weeks compared to the control group. Both groups showed significant decreases in anxiety and fear of missing out over baseline, suggesting a benefit of increased self-monitoring. Our findings strongly suggest that limiting social media use to approximately 30 minutes per day may lead to significant improvement in well-being.

It would be interesting to know whether limiting use even further could yield better results. Also, could some social media platforms be worse for mental health than others?

Stress Affects Brain Function and Structure

Echouffo-Tcheugui et al., from Harvard Medical School, recently published a paper studying the effects of stress on brain function and structure in over 2000 middle-aged participants from the Framingham Heart Study. They measured early morning serum cortisol as an indicator of stress levels. They found that “higher cortisol was associated with worse memory and visual perception, as well as lower total cerebral brain and occipital and frontal lobar gray matter volumes. The association of cortisol with total cerebral brain volume varied by sex (p for interaction = 0.048); higher cortisol was inversely associated with cerebral brain volume in women (p = 0.001) but not in men (p = 0.717)“.

The authors commented on the importance of finding ways to manage stress, “such as getting enough sleep, engaging in moderate exercise and incorporating relaxation techniques into their daily lives“.

“The dream of my life

Is to lie down by a slow river

And stare at the light in the trees –

To learn something by being nothing

A little while

but the rich

Lens of attention.”

Mary Oliver

How Does Cannabis Relieve Pain?

The use of cannabis to relieve pain is controversial, not just for legal reasons but also because of the conflicting research findings with regards to its efficacy. A recent study by Martin De Vita et al., from Syracuse University in New York, looked into the effects of cannabis on pain. They selected, reviewed and analysed studies that had researched the effect of cannabis on experimentally induced pain. De Vita et al. conclude that “although the cannabinoids examined in this review may prevent the onset of laboratory-induced pain by increasing pain thresholds, they do not appear to reduce the intensity of experimental pain that is already being experienced. Instead, these substances make experimental pain feel less unpleasant and more tolerable, suggesting a notable influence on affective processes. The cumulative research synthesized in this review has helped characterize how cannabis and cannabinoids affect different dimensions of pain reactivity.

There are 2 components to pain: the purely sensory component and the affective (emotional) component. It’s been known for a while that opioids and our endogenous opioid pathways play an important role in sensory pain perception. It now appears that cannabis and our endogenous cannabinoid pathways play a part in the emotional dimension of pain. Interestingly, mindfulness meditation, which has proven effects on pain relief, doesn’t use opioid pathways. In fact, the mechanisms underlying mindfulness meditation’s pain-relieving effects are as yet unknown. Could it be possible that they employ cannabinoid receptors and pathways?

Low Carbohydrate Diets Are Bad For Health

Yesterday professor Banach, from the Medical University of Lodz in Poland, released the findings of his research at the European Society of Cardiology. The prospective study looked at the relationship between low carbohydrate diets, all-cause mortality and deaths specifically from coronary heart disease, stroke and cancer. The study group consisted of almost 25,000 adults from the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010. Over an average 6.4-year follow-up, compared to the group with the highest consumption of carbohydrates, the group with the lowest consumption had an increased risk of all-cause mortality (32%) and an increased risk of death from coronary heart disease (51%), stroke (50%) and cancer (35%). These results were backed up by the findings of a meta-analysis of several studies involving close to 450,000 people.

Professor Banach said: “Low carbohydrate diets might be useful in the short term to lose weight, lower blood pressure, and improve blood glucose control, but our study suggests that in the long-term they are linked with an increased risk of death from any cause, and deaths due to cardiovascular disease, cerebrovascular disease, and cancerThe reduced intake of fibre and fruits and increased intake of animal protein, cholesterol, and saturated fat with these diets may play a role. Differences in minerals, vitamins and phytochemicals might also be involved. Our study highlights an unfavourable association between low carbohydrate diets and total and cause-specific death, based on individual data and pooled results of previous studies. The findings suggest that low carbohydrate diets are unsafe and should not be recommended.