In this chapter we will discuss the role of various factors associated with particular lifestyle choices in the management of chronic pain. Lifestyle choices will be grouped into the following four general categories: (1) weight, exercise, and nutrition; (2) common substances of daily living, specifically caffeine, tobacco, and alcohol; (3) sleep, and; (4) other lifestyle factors with variable degrees of choice, including social isolation/social support, employment-related factors, and religiosity/spirituality.

WEIGHT

There is a solid body of research evidence that confirms a positive correlation between weight and chronic pain. Several studies have found that individuals with high body mass index (BMI) levels report higher levels of pain associated with various chronic pain conditions, including chronic widespread pain,¹ chronic low back pain (CLBP),^1–4 arthritic pain,^5,6 abdominal pain, headaches—both tension and migraines—and fibromyalgia (FMS),¹ among others. Moreover, the relationship appears to be incremental; that is, increasingly higher levels of weight lead to incrementally higher levels of pain. Using four target overweight categories, a large-scale study that gathered survey data through telephone interviews with over 1 million subjects found that “overweight” subjects (BMI >25) reported 20% higher rates of pain than subjects in the “low-normal weight group” (BMI = 18.5-24.9); 68% higher for subjects in the “Obese I” group (BMI = 30-34.9), 136% higher for the “Obese II” group (BMI = 35-39.9), and 254% higher for the “Obese III” group (BMI >40)⁷. Other studies have confirmed the incremental nature of this relationship.

In addition to higher levels of pain intensity, higher levels of BMI are also correlated with a higher prevalence of a number of chronic pain conditions. Moreover, there is evidence that the relationship between excess weight and chronic pain can be bidirectional. Although a chronic pain condition may lead to higher levels of inactivity that may result in weight gain, there is also evidence that excessive weight may lead to the onset and maintenance of chronic pain conditions. A prospective study by Heuch and colleagues⁴ found that high levels of BMI were associated with subsequent prevalence of low back pain in individuals with no previous history of low back pain at baseline. Moreover, in this study the presence of a history of low back pain at baseline did not predict subsequent higher levels of BMI.

High BMI levels among chronic pain sufferers have also been associated with a negative quality of life, poor physical functioning, greater disability, and greater accident liability.^8,9 Psychological factors, mainly anxiety and depression, can also play a significant role in modulating the relationship between weight and pain. This relationship can also be bidirectional; whereas anxiety and depression may lead to significant weight gain, being overweight may reinforce feelings of anxiety and depression. However, regardless of the particular direction of causality, it in turn may exacerbate pain intensity.

Traditional theories to explain the relationship between excess weight and higher levels of pain intensity typically implicated the effect associated with extra strain placed on the body, primarily on the joints, by the extra weight. Recent research has explored other possible explanatory mechanisms, such as the role of inflammation. There is evidence that carrying extra weight in the body, a state often referred to as adiposopathy or “sick fat syndrome” is associated with a chronic systemic inflammatory state, which in turn can enhance pain intensity.¹⁰ Other proposed mechanisms have looked at the role of associated factors like exercise and nutrition. Clearly, the relationship between excess weight and chronic pain is a complex and multifactorial one, and further research is needed to elucidate the specific nature.

There is some evidence that weight loss interventions may be effective in the management of chronic pain conditions. One study with knee osteoarthritis (OA) patients found that a weight reduction of at least 2 kg (4.4 lbs) in the previous 10 years was associated with a greater than 50% reduced likelihood of symptomatic OA.¹¹ The authors estimated that if overweight and obese OA sufferers lost an average of 5 kg (11 lbs) or reached a normal BMI, approximately 24% of surgery for knee OA might be avoided. Several other studies have confirmed these findings, showing that weight reduction, in particular through the combination of diet and exercise, may lead to a significant decrease in pain severity.¹² Another study showed that after having attained even modest weight loss during an 18-month period, knee OA sufferers undergoing a combination of diet plus exercise reported a significant improvement in pain and physical function.¹³ The diet plus exercise group had a significantly better outcome than diet only, exercise only, and healthy lifestyle groups.

Similar positive outcomes of weight loss have been reported with CLBP and other chronic pain conditions. A study with FMS sufferers found that after completing a 20-week behavioral weight loss treatment and losing an average 9.2 lbs (4.4% weight reduction), participants reported a significant reduction of FMS symptoms, pain interference, higher quality of life, and greater body satisfaction.¹⁴

Clearly, being overweight plays a significant precipitating and maintaining role in the onset and course of chronic pain conditions. The ideal target goal for overweight and obese individuals should be to engage in a weight loss program to reach a BMI within the normal range (18.5–24.9). However, because most overweight and obese individuals struggle with a number of unsuccessful attempts to lose weight, it is important to highlight that even more realistic modest reductions in weight, short of reaching the ideal BMI, can have a significant positive impact on their chronic pain conditions. It is also clear that weight loss approaches that rely on a combination of diet and exercise yield far better outcomes for chronic pain sufferers than those that rely on diet alone. Moreover, because of the involvement of psychological and social factors in both weight and chronic pain problems, integrative behavioral weight management programs that address the interplay of biological, psychological, and social factors will probably yield the best results. For example, rather than focusing on a specific diet and exercise regimen only, it is essential to highlight the role of social contextual factors (e.g., socioeconomic and sociocultural factors, such as accessibility and affordability of healthy foods) and psychological factors (e.g., emotional eating, distorted cognitions about food) that reinforce maladaptive eating patterns. Table 100-1 summarizes the basic recommendations for chronic pain patients with regard to weight.

EXERCISE

There’s a substantial body of research that confirms the inversely proportional relationship between levels of physical activity, or exercise, and chronic pain conditions. That is, higher levels of physical activity are associated with lower levels of pain and related dysfunction. One can reasonably argue that this relationship is to be naturally expected as individuals with greater pain intensity will tend to restrict physical activity to prevent reinjury and pain exacerbation. However, much of the research has focused on the subsequent effect of physical activity on disease course and severity among individuals suffering from preexisting chronic pain conditions. Thus, chronic pain sufferers who engage in higher levels of physical activity endorse subsequent lower levels of pain ratings and related disability. Although the estimated effect size of this relationship appears to be small to moderate based on various systematic reviews of the literature,¹⁵ the observed positive effect of exercise is remarkably consistent.

Not surprisingly, most of the research that has explored the effects of exercise on chronic pain conditions has targeted musculoskeletal pain conditions. Among these, CLBP has received the most attention, followed by OA, most commonly knee and hip. Some studies have also looked at the effect of exercise on other pain conditions, such as FMS. In general, findings with musculoskeletal conditions have yielded pretty consistent results. Several studies, including various meta-analyses and systematic reviews of the literature, have confirmed the significant beneficial effect of exercise, primarily general aerobic and strengthening exercises.^15–17 Both aerobic and strengthening exercises have been associated with significant reductions in pain intensity ratings and associated disability. Although land-based programs have been studied substantially more than water-based ones, both types of exercise programs are found to be effective.

With regard to comparing the relative effectiveness of different exercise modalities, while some studies have found aerobic exercises to be more effective than localized conditioning exercises,¹⁸ others have found them to be equally effective.^19,20 Studies with exercise combinations, typically general aerobic and strengthening exercises with more localized exercises that target the sufferers’ particular pain conditions (e.g., trunk muscle conditioning and joint range of motion exercises, eye fixation and other balance exercises, etc.), have found these combinations to be effective.^15,17,21 In addition, the importance of including stretching/flexibility exercises in an exercise program has been noted, primarily to reduce the risk of reinjury. While more research is needed to solidly establish the relative contributions of various types of exercise, it seems reasonable to assume that a combination of stretching/flexibility, aerobic, and strengthening exercises (both general and localized as relevant) will probably yield optimal results. In addition to more conventional aerobic and strengthening exercises, there is evidence that supports the effectiveness of other less conventional physical activities, such as yoga and Tai Chi, in the treatment of musculoskeletal disorders.^17,22

Both provider-supervised and nonsupervised (“home-based”) exercise programs are found to be effective. However, it appears that provider supervision, at least during the initial stages of establishing an exercise routine, may lead to a greater adherence.²⁰ One particular recommendation is to include provider supervision for the first 12 workout sessions, with scheduled follow-up “booster” sessions to review progress and readjust goals.²² It is also important to keep in mind the individual factors that are specific to each chronic pain sufferer’s particular condition. Therefore, individual tailoring of an exercise program to the particular type of injury or condition is essential to minimize risk of new injury or reinjury from exercise. Overactivity (i.e., engagement in excessive amounts of activity or exercise) can also significantly exacerbate pain conditions and related disability.²³ And comparisons of individual versus group exercise programs have shown both modalities to be effective, with some evidence that group settings may reinforce adherence.^21,22 Moreover, groups have the added benefit of providing social support, which can have a significant impact on promoting mental health and social functioning, thus reducing functional disability.

Despite findings about the relative contributions of various exercise modalities, it is essential to keep in mind that the effectiveness of any exercise program will depend primarily on adherence to that program. The proven effectiveness of a wide range of exercise modalities allows the practitioner to tailor an exercise program to an individual’s particular circumstances and preferences. This will significantly increase the likelihood that an individual will adhere to any exercise routine. There is also evidence that the positive effects of exercise on chronic pain are quickly lost once an exercise routine is discontinued, which further supports the need to promote ongoing adherence and maintenance.

As mentioned earlier, most of the research that has explored the relationship between levels of physical activity or exercise and chronic pain has focused on pain severity and related functional disability as the two most relevant outcome measures. However, positive outcomes of exercise have been observed in other variables that are relevant to pain, such as psychological status (i.e., depression, anxiety, stress, anger), cardiovascular health (heart rate, cholesterol), and work status, among others. The notions of fear avoidance and pacing have also been studied with regard to their role in the pain-exercise relationship. Fear avoidance, in the pain literature, refers to the commonly observed reduction in physical and other daily activities as a means to minimize pain escalation. It has been highlighted as a key variable moderating the observed relationship between significant reductions in physical activity and higher levels of pain severity and disability. Pacing is defined as a strategy to divide one’s daily activities into smaller, more manageable portions, with planned and calculated increases in activity.²³ Pacing is regarded as an important strategy in striking an optimal compromise between minimizing the risk of injury with gradual progressions of increased physical activity while preventing fear avoidance and the resulting detrimental reduction in physical activity. There appears to be inconsistency in the literature regarding the effectiveness of pacing in the management of chronic pain. These discrepancies may stem from methodological issues that limit comparisons among various studies. Despite the inconsistent findings, most providers emphasize pacing as an important strategy in the management of chronic pain conditions.

Various theories have been proposed to explain the beneficial effects of exercise on chronic pain conditions. Clearly, improved muscle conditioning through exercise can have a significant impact on pain reduction and improved functioning. Exercise also encourages the release of endorphins, which are well known to have an analgesic effect. In addition, given the relationship between excess weight and chronic pain reviewed in the previous section, the potential role of exercise on weight loss can be of significant benefit in pain management. In addition to improved physical conditioning, enhancing physical fitness may promote a sense of confidence to engage in daily activities, thus reducing fear avoidance. This may also lead to improved social functioning, which in turn may help increase social support and reduce anxiety and depression. As discussed in previous chapters, anxiety, depression, and in particular anger and hostility have been implicated in reinforcing chronic pain conditions.

Based on findings from the literature reviewed, Table 100-2 lists recommendations to develop an exercise program to assist in the management of chronic pain conditions.

NUTRITION

The role of nutrition in chronic pain conditions has received significant attention in recent years. However, given the myriad of popularly held misconceptions associated with nutrition as our society tends to look to foods and supplements as the magic cure for all health problems, this is an area where one needs to be very cautious to discern fad from science. This section reviews some of the nutrients, some ingested as foods or supplements or both, that have been studied scientifically and that show some evidence to support their potential influence, either detrimental or beneficial, on chronic pain conditions. After some general considerations of the potential role of certain nutrients with various chronic pain conditions, we will discuss some specific considerations relevant to migraine headaches.

Vitamin D

One nutrient that has received significant attention in the pain literature is vitamin D. Although we can obtain vitamin D from some foods (e.g., oily fish such as salmon, mackerel, sardines, cod liver oil), our primary source comes from the sun’s ultraviolet rays (UVB). It is estimated that a very large number of individuals worldwide suffer from vitamin D deficiency, which has been referred to as a largely unrecognized world epidemic. Obviously, individuals with least amount of sun exposure are at higher risk of vitamin D deficiency, but other risk groups include individuals with darker skin (high skin melanin levels interfere with absorption of UVB), obese individuals, and the elderly among others.

Vitamin D deficiency has been linked to a variety of diseases. Most specifically with relevance to chronic pain conditions, low level of vitamin D (typically <20 ng/mL) have been shown to be associated with the development of osteoporosis and rheumatoid arthritis (RA),²⁴ muscle weakness and other muscular-skeletal problems,^24–27 fractures resulting from falls among the elderly,²⁶ and chronic widespread pain,²⁸ among others.

Although randomized clinical trials of the effects of vitamin D therapy are more limited than studies documenting the adverse effects of its deficiency, results from some studies appear promising. A study with FMS patients with mild to moderate vitamin D deficiency (10–25 ng/mL) who underwent vitamin D₃ supplementation (50,000U/wk) for 8 weeks showed a significant improvement in FMS symptoms, especially symptoms of fatigue.^26,29 Improvements in pain intensity and analgesic use were also found in studies with RA patients taking large doses of vitamin D for 1 year²⁶ and in postmenopausal women with osteoporotic fractures who took vitamin D in conjunction with calcium and fluoride.³⁰

The effects of vitamin D deficiency with particular relevance to pain appear to be related to its central role in the absorption of calcium. Vitamin D deficiency is associated with the marked suppression in intestinal calcium and the resulting disruption of calcium balance, which leads to low bone mineral and density. This in turn results in poor bone health and an increased risk of fractures, especially among the elderly. Given the close interplay with calcium, vitamin D supplementation based on results from blood serum levels needs to be determined in coordination with calcium levels. The IOM recommendations³¹ for vitamin D supplementation are 600 IU daily for children and adults up to 70 years old and 800 IU for adults 71 years or older. However, it has been suggested that, without adequate sun exposure, children and adults may require higher doses between 800 and 1,000 IU per day.²⁴

Polyunsaturated Fatty Acids

Polyunsaturated fatty acids (PUFAs) have received a great deal of attention in recent years with regard to their role in a variety of health conditions, including pain. An important distinction is the contrast between the omega-3 (n-3 series) and omega-6 (n-6 series) PUFAs, given the observed anti-inflammatory effect of the former and the proinflammatory effect of the latter. A comprehensive review of the literature identified 17 randomized controlled studies (RCTs) that looked at omega-3 supplementation with individuals suffering from RA and joint pain secondary to inflammatory bowel disease (IBD).³² The general picture from the findings is consistent, showing that omega-3 supplementation is associated with reduction in lower pain intensity, minutes of morning stiffness, number of painful joints, and use of nonsteroidal anti-inflammatory drugs (NSAIDs). In addition to RA and IBD, positive findings have also been reported with pain associated with dysmenorrhea and neuropathy.³³ The consistent results from these studies suggest that omega-3 PUFAs seem to play a central role in the modulation of pain, in particular conditions associated with inflammation. In addition to their anti-inflammatory action, they are antioxidants and are believed to promote intestinal calcium absorption.

In contrast to the clear picture that has emerged with omega-3 PUFAs, findings are less consistent with the omega-6 PUFAs. Some omega-6 PUFAs have a proinflammatory effect that can exacerbate pain, in particular when taken at a high ratio to omega-3 PUFAs. But, it appears some omega-6 PUFAs may also have an anti-inflammatory effect via the conversion of linoleic acid (LA) to gamma-linoleic acid (GLA). GLA can be found in rare oils such as black currant, borage, and hemp oil. Thus, the particular effect of omega-6 PUFAs on pain depends on the specific types and ratios of PUFAs consumed. Given the potential detrimental effect on pain by promoting inflammation and affecting bone health, one must exercise caution consuming omega 6-PUFAs with chronic pain conditions. The estimated current ratio of omega-6 to omega-3 PUFAs in most Western diets is 10 to 15:1, while the recommended ideal ratio is 1:1.²⁵ The daily recommended intake of omega-3 is 500 mg, which is much higher than the intake level in the typical diet of most industrialized countries. Given that most Western diets provide a much higher ratio of omega-6 to omega-3 PUFAs than the recommended daily intake, it seems reasonable to supplement omega-3 and limit omega-6 consumption. Foods that are rich sources of omega-3 PUFAs include walnuts, flaxseed, fish (especially high-fat fish like salmon, sardines, and tuna), vegetable oils (olive, canola), and beans, among others. Omega-6 PUFAs are commonly obtained from vegetable oils derived from corn, sunflower, safflower, soy, and cottonseed, among others.

Glucosamine and Chondroitin Sulfate

Glucosamine is the most commonly used supplement by individuals suffering from OA. It is frequently taken alone and often in combination with chondroitin. However, studies with both supplements have yielded inconsistent results. Some comprehensive reviews concluded that glucosamine was effective in significantly reducing pain and improving joint space narrowing in OA sufferers.³⁴ However, other reviews have failed to confirm these findings. It has been suggested that some of the inconsistent findings can be explained by the lack of consistency with the type of glucosamine tested, as well as the particular assessment tools used in different research methodologies. There is suggestion that results may be more positive with glucosamine sulfate than with glucosamine hydrochloride.³⁵ Similarly, findings with chondroitin are mixed, and many studies have investigated its effect in combination with glucosamine, which makes it difficult to compare the effectiveness of chondroitin alone. Both glucosamine and chondroitin have been found to be relatively safe, with reported concerns appearing to be anecdotal at this time, and no significant negative side effects have been confirmed in well-designed research studies. Despite their apparent safety, it is important for a person deciding to take these supplements to consult with a physician in case of possible contraindications or reactions with medications. Greater consistency in future research methodologies may clarify the question of the effectiveness of these popular supplements.

Probiotics

There has been a great deal of attention on the potential beneficial role of probiotics in the treatment of irritable bowel syndrome (IBS) and IBD. There is evidence that alterations of natural gastrointestinal microbiota may be involved in the pathophysiology of both IBS and IBD. Probiotics are live microbiologic organisms that live in foods with live active culture, such as yogurt and some fermented foods. There is some evidence that probiotics can reregulate microbiotic alterations that may be involved in IBS and IBD, in particular decreasing some of the elevations in proinflammatory bacteria. Some studies with IBS patients taking probiotics supplements have shown significant reductions in pain associated with IBS.^36–38 Results with IBD have been mixed, with suggestion that the effects of probiotics may be more effective in ulcerative colitis and pouchitis than in Crohn’s disease.³⁷ An important caution with probiotics is that it appears that some types of probiotics may have specific effects on particular subtypes of IBS and IBD. For example, probiotics with the greatest efficacy data currently for treating IBS are Bifidobacterium infantis 35624 and Escherichia coli DSM 17252.³⁶ Moreover, B. infantis has been shown to be most effective in reducing pain in patients with diarrhea-predominant IBS. Although further research will help determine with greater specificity what types of probiotics may be most beneficial for what subtypes of gastrointestinal conditions given their apparent safety, there seems to be little risk in taking these supplements.

Other Supplements with Potential Value in the Treatment of Chronic Pain Conditions

A variety of herbal products, spices, and other supplements have received attention given claims of their apparent effectiveness reducing pain and inflammation. Among these is “devil’s claw” (Harpagophytum procumbens), an African plant that appears to have anti-inflammatory property. Some studies have reported positive findings decreasing pain in OA35 and CLBP.³⁹ Although more research is needed before its effectiveness can be established, this supplement appears to hold potential value in the treatment of a number of chronic pain conditions.

Another supplement that has received attention for its anti-inflammatory property is turmeric, a spice derived from the plant Curcuma longa. Turmeric is commonly used in Indian cooking as a spice and coloring agent in curry powders and other foods. Curcumin is the substance that gives it its yellow color, and it is believed by some to be the major active therapeutic ingredient in turmeric. Both turmeric and curcumin have been used for years in Ayurvedic medicine to treat various health conditions. Research reveals that both appear to have antioxidant and anti-inflammatory properties. Preliminary clinical research has shown potential value in the treatment of RA.^27,40 However, more research is needed to determine its effectiveness in the treatment of OA and other chronic pain conditions.

A variety of other herbs and supplements have received attention given their potential value in the treatment of a variety of chronic pain conditions. What most of the supplements seem to have in common for the treatment of pain are their anti-inflammatory properties. A partial list of these includes flavonoids, magnesium, capsaicin, vitamin B₁₂, folate, SAMe, methylsulfonylmethane (MSM), ginger, red clover, carotenoids, white willow bark, cayenne, alpha-lipoic acid, acetyl-L-carnitine, and selenium, among others. Again, more research is needed in order to establish whether any of these can be indeed effective in the treatment of chronic pain.

Nutrition and Migraines

Perhaps one of the chronic pain conditions most commonly associated with food triggers (besides IBS and IBD given their obvious gut involvement) is migraines. Popular lore has promoted a long list of foods that have been reported to act as significant triggers for migraine episodes, including sweeteners containing aspartame, aged cheese, chocolate, monosodium glutamate (MSG), tyramine-containing foods (e.g., processed meats, soy sauce), and others. Bernstein,⁴¹ a migraine scientist and specialist, warned that the sensitivity of migraines to particular foods has likely been overemphasized, highlighting the marked individual differences in responses to particular food triggers. Moreover, the author proposed that abrupt episodes of hypoglycemia (typically following intake of foods with a high glycemic index) may account for many of the claimed food sensitivities by migraine sufferers. The following dietary recommendations followed this proposition to ensure effective management of migraines: (1) eating breakfast regularly, including protein-based foods, (2) having a meal that includes proteins every 4–6 hours, (3) ensuring an adequate amount of complex carbohydrates in the diet, (4) having healthy snacks with protein, (5) staying adequately hydrated, (6) keeping a food diary to carefully monitor and record particular individual sensitivities (not necessarily allergies) to foods, and (7) avoiding foods with a high glycemic index.

Conclusion

Although there seems to be strong evidence that several foods and supplements have potential value in the treatment of chronic pain conditions, we are far from having attained a clear picture of what particular supplements are most effective for what conditions. The evidence appears strong to support the value of vitamin D and omega-3 PUFAs, in particular for treating neuromuscular conditions that can be significantly exacerbated by inflammatory mechanisms, and skeletal problems, such as those involved in RA and OA. There is also strong evidence to support the consumption of probiotics in the treatment of IBS, and possibly IBD. In addition, avoiding foods with a high glycemic index to prevent hypoglycemic episodes appears to be a sound preventive measure in the management of migraine headache. With regard to some of the other supplements discussed, although promising, further research is needed before their therapeutic value can be firmly established. In the meantime, personal decisions to include any of these supplements in a dietary regimen should be done after consultation with a physician to rule out any possible counter indications associated with existent medical conditions or interactions with medications. Perhaps the nutrition-related lifestyle change that bears greatest potential value in the management of chronic pain, as well as in many other health conditions, is to adopt a balanced diet following the recommendations made by the USDA (www.ChooseMyPlate.gov).⁴² In other words, a low-fat, high-fiber, high-protein diet with adequate servings of fruits and vegetables, which are generally lacking in the typical diet of many highly industrialized and Western countries, will yield invaluable health benefits. Nutritional recommendations are summarized in Table 100-3.