Does pain tolerance mediate the effect of physical activity on chronic pain in the general population? The Tromsø Study.

ABSTRACT: Knowledge is needed regarding mechanisms acting between physical activity (PA) and chronic pain. We investigated whether cold pain tolerance mediates an effect of leisure-time physical activity on the risk of chronic pain 7 to 8 years later using consecutive surveys of the population-based Tromsø Study. We included participants with information on baseline leisure-time PA (LTPA) and the level of cold pressor-assessed cold pain tolerance, who reported chronic pain status at follow-up as any of the following: chronic pain for ≥3 months, widespread chronic pain, moderate-to-severe chronic pain, or widespread moderate-to-severe chronic pain. We included 6834 participants (52% women; mean age, 55 years) in counterfactual mediation analyses. Prevalence decreased with severity, for example, 60% for chronic pain vs 5% for widespread moderate-to-severe chronic pain. People with one level higher LTPA rating (light to moderate or moderate to vigorous) at baseline had lower relative risk (RR) of 4 chronic pain states 7 to 8 years later. Total RR effect of a 1-level LTPA increase was 0.95 (0.91-1.00), that is, -5% decreased risk. Total effect RR for widespread chronic pain was 0.84 (0.73-0.97). Indirect effect for moderate-to-severe chronic pain was statistically significant at RR 0.993 (0.988-0.999); total effect RR was 0.91 (0.83-0.98). Statistically significantly mediated RR for widespread moderate-to-severe chronic pain was 0.988 (0.977-0.999); total effect RR was 0.77 (0.64-0.94). This shows small mediation of the effect of LTPA through pain tolerance on 2 moderate-to-severe chronic pain types. This suggests pain tolerance to be one possible mechanism through which PA modifies the risk of moderate-to-severe chronic pain types with and without widespread pain.

Longitudinal relationships between habitual physical activity and pain tolerance in the general population.

Physical activity (PA) might influence the risk or progression of chronic pain through pain tolerance. Hence, we aimed to assess whether habitual leisure-time PA level and PA change affects pain tolerance longitudinally in the population. Our sample (n = 10,732; 51% women) was gathered from the sixth (Tromsø6, 2007-08) and seventh (Tromsø7, 2015-16) waves of the prospective population-based Tromsø Study, Norway. Level of leisure-time PA (sedentary, light, moderate, or vigorous) was derived from questionnaires; experimental pain tolerance was measured by the cold-pressor test (CPT). We used ordinary, and multiple-adjusted mixed, Tobit regression to assess 1) the effect of longitudinal PA change on CPT tolerance at follow-up, and 2) whether a change in pain tolerance over time varied with level of LTPA. We found that participants with high consistent PA levels over the two surveys (Tromsø6 and Tromsø7) had significantly higher tolerance than those staying sedentary (20.4 s. (95% CI: 13.7, 27.1)). Repeated measurements show that light (6.7 s. (CI 3.4, 10.0)), moderate (CI 14.1 s. (9.9, 18.3)), and vigorous (16.3 s. (CI 6.0, 26.5)) PA groups had higher pain tolerance than sedentary, with non-significant interaction showed slightly falling effects of PA over time. In conclusion, being physically active at either of two time points measured 7-8 years apart was associated with higher pain tolerance compared to being sedentary at both time-points. Pain tolerance increased with higher total activity levels, and more for those who increased their activity level during follow-up. This indicates that not only total PA amount matters but also the direction of change. PA did not significantly moderate pain tolerance change over time, though estimates suggested a slightly falling effect possibly due to ageing. These results support increased PA levels as a possible non-pharmacological pathway towards reducing or preventing chronic pain.

Physical activity and cold pain tolerance in the general population.

BACKGROUND: The relationship between habitual physical activity (PA) and experimental pain tolerance has been investigated in small samples of young, healthy and/or single-sex volunteers. We used a large, population-based sample to assess this relationship in men and women with and without chronic pain. METHODS: We used data from the sixth and seventh Tromsø Study surveys (2007-2008; 2015-2016), with assessed pain tolerance of participants with the cold pressor test (CPT: dominant hand in circulating cold water at 3°C, maximum test time 106 s), and self-reported total amount of habitual PA in leisure time (n = 19,087), exercise frequency (n = 19,388), exercise intensity (n = 18,393) and exercise duration (n = 18,343). A sub-sample had PA measured by accelerometers (n = 4,922). We used Cox regression to compare CPT tolerance times between self-reported PA levels. For accelerometer-measured PA, we estimated hazard ratios for average daily activity counts, and for average daily minutes of moderate-to-vigorous PA done in bouts lasting 10 min or more. Models were tested for PA-sex, and PA-chronic pain and PA-moderate-to-severe chronic pain interactions. RESULTS: Leisure-time PA, exercise intensity and exercise duration were positively associated with CPT tolerance (p < .001; p = .011; p < .001). More PA was associated with higher CPT tolerance. At high levels of leisure-time PA and exercise intensity, men had a significantly higher CPT tolerance than women. Accelerometer-measured PA was not associated with CPT tolerance. CONCLUSIONS: This study is one of the first to show that higher self-reported habitual PA was connected to higher experimental pain tolerance in a population-based sample, especially for men. This was not found for accelerometer-measured PA. SIGNIFICANCE: This study finds that higher level of self-reported leisure-time physical activity is associated with increased cold pressor pain tolerance in a large population-based sample. Though present in both sexes, the association is strongest among men. Despite the robust dose-response relationship between pain tolerance and self-reported activity level, no such relationship was found for accelerometer-measured activity, reflecting a possible discrepancy in the aspect of physical activity measured. Though the study design does not permit causal conclusions, the findings suggest that increasing physical activity may increase pain tolerance in the general population.

Opioid consumption in two surgical hospital wards. / Forbruk av opioider ved to kirurgiske sykehusavdelinger.

BACKGROUND: The purpose of the study was to document the consumption of opioids in two surgical departments at the University Hospital of North Norway, Tromsø, in the period 2010-17. MATERIAL AND METHOD: The consumption of opioids in the department of gastrointestinal surgery and the department of cardiovascular and thoracic surgery was obtained from Nord hospital pharmacy. All opioids were converted to oral morphine equivalents. RESULTS: The consumption of morphine in the department of gastrointestinal surgery was reduced from 223 835 oral morphine equivalents per year in the period 2010-13, to 147 641 in the period 2014-17. In the department of cardiovascular and thoracic surgery, the yearly consumption of morphine was reduced from 28 652 oral morphine equivalents in the period 2010-13, to 22 945 in the period 2014-17. The consumption of oxycodone in the department of gastrointestinal surgery increased from 210 643 oral morphine equivalents per year in the period 2010-13, to 376 322 in the period 2014-17. In the department of cardiovascular and thoracic surgery, the consumption of oxycodone increased from 28 922 oral morphine equivalents per year in the period 2010-13, to 123 875 in the period 2014-17. In the department of gastrointestinal surgery, the increase was most evident for oxycodone administered intravenously or subcutaneously. In the department of cardiovascular and thoracic surgery, the largest increase was for oxycodone administered orally. INTERPRETATION: The consumption of opioids increased in both departments studied, and oxycodone constituted the largest part of the increase.

Publisher Correction: Room-level occupant counts and environmental quality from heterogeneous sensing modalities in a smart building.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Room-level occupant counts and environmental quality from heterogeneous sensing modalities in a smart building.

The research areas of occupant sensing and occupant behavior modeling are lacking comprehensive public datasets for providing baseline results and fostering data-driven approaches. This data descriptor covers a dataset collected via sensors on room-level occupant counts together with related data on indoor environmental quality. The dataset comprises 44 full days, collated in the period March 2018 to April 2019, and was collected in a public building in Northern Europe. Sensor readings cover three rooms, including one lecture room and two study zones. The data release contains two versions of the dataset, one which has the raw readings and one which has been upsampled to a one-minute resolution. The dataset can be used for developing and evaluating data-driven applications, occupant sensing, and building analytics. This dataset can be an impetus for the researchers and designers to conduct experiments and pilot studies, hence used for benchmarking.

Rights assessment and quality of referrals - rate of agreement between four pain management centres. / Rettighetsvurdering og kvalitet på henvisninger ­ grad av samsvar mellom fire smertesentre.

BACKGROUND: Chronic pain is a widespread health problem. The four regional interdisciplinary pain management centres in Norway receive approximately 5 000 referrals from GPs and the specialist health service annually. Equality in service provision requires referrals to be identically assessed. The objective of the study was to evaluate the degree of correspondence between the admission teams in the pain management centres in their assessment of the quality of the referrals received and in their assessment of the patients' right to necessary health care. MATERIAL AND METHOD: Each admission team assessed 40 referrals. They undertook a 'primary assessment' of 10 referrals received in the regular manner and a 'secondary assessment' of 30 referrals sent in the regular manner to the other centres. Each referral was assessed for quality and rights in each centre. The proportion of agreement and the intra-class correlation coefficient (ICC) were used to assess correspondence between the admission teams. RESULTS: The quality of the referrals was deemed 'not good' in 45 % of the primary assessments and 43 % of the secondary assessments. The degree of correspondence varied from low (ICC = 0.19) to moderate (ICC = 0.74). The primary and secondary assessments both granted 63 % of the patients 'the legal right to health care'. The overall degree of correspondence was 69 %, i.e. lower than what is considered 'acceptable agreement' (75 %). INTERPRETATION: The study shows that there is a need for structured referrals, and for the admission teams to harmonise their assessments to a greater degree in order to ensure equality in service provision across the health regions.

Persistent post-surgical pain and experimental pain sensitivity in the Tromsø study: comorbid pain matters.

In a large survey incorporating medical examination (N=12,981), information on chronic pain and surgery was collected, and sensitivity to different pain modalities was tested. Tolerance to the cold pressor test was analysed with survival statistics for 10,486 individuals, perceived cold pressor pain intensity was calculated for 10,367 individuals, heat pain threshold was assessed for 4,054 individuals, and pressure pain sensitivity for 4,689 individuals. Persistent post-surgical pain, defined by self-report, was associated with lower cold pressor tolerance (sex-adjusted hazard ratio=1.34, 95% confidence interval=1.08-1.66), but not when adjusting for other chronic pain. Other experimental pain modalities did not differentiate between individuals with or without post-surgical pain. Of the individuals with chronic pain (N=3352), 6.2% indicated surgery as a cause, although only 0.5% indicated surgery as the only cause. The associations found between persistent post-surgical pain and cold pressor tolerance is largely explained by the co-existence of chronic pain from other causes. We conclude that most cases of persistent post-surgical pain are coexistent with other chronic pain, and that, in an unselected post-surgical population, persistent post-surgical pain is not significantly associated with pain sensitivity when controlling for comorbid pain from other causes. A low prevalence of self-reported persistent pain from surgery attenuates statistically significant associations. We hypothesize that general chronic pain is associated with central changes in pain processing as expressed by reduced tolerance for the cold pressor test.

Persistent postsurgical pain in a general population: prevalence and predictors in the Tromsø study.

Population-based data on the prevalence of persistent postsurgical pain are scarce. This study aimed to assess the prevalence of persistent postsurgical pain in a general population and to describe associated physical, social, and psychological factors, including symptoms of nerve injury and sensitization. A cross-sectional survey was performed in northern Norway with questionnaire items covering surgery, pain, and sensory abnormalities in the area of surgery. Of the 12,982 participants, 24.0% (3111) had undergone one or more surgical procedures during the 3 years preceding the survey. Of these, 2043 had the surgery performed more than 3 months before the investigation. Persistent pain in the area of surgery was reported by 40.4% of the patients (826 of 2043), moderate or severe pain by 18.3% (373 of 2043). Hypoesthesia, hyperesthesia, or both was reported by 24.5% (501 of 2043). There were strong associations between sensory abnormalities and persistent pain, increasingly with higher pain intensities; odds ratios were 2.68 for hypoesthesia and 6.27 for hyperesthesia. Of the 826 individuals reporting persistent pain in the anatomical area of surgery, 51.0% reported chronic pain when questioned without specific reference to the surgery. The present study supports evidence from clinical studies of persistent postsurgical pain, indicating a high prevalence, but reveals large discrepancies in report of pain, depending on the questions asked and the context in which the questions are presented. Strong associations between sensory abnormalities and pain indicate neuropathic mechanisms in a major proportion of cases.

Anxiety and depression symptoms in arterial hypertension: the influence of antihypertensive treatment. the HUNT study, Norway.

Antihypertensive drugs have been suggested to modulate symptoms of depression and anxiety. It is disputed whether this is due to the hypertension per se, its treatment, or both. The aim of this study was to investigate these associations in a large population sample. 55,472 participants in the Nord-Trøndelag Health Study (HUNT 2, 1995-1997), Norway, who completed the Hospital Anxiety and Depression rating Scale, were divided into 3 groups according to their diastolic blood pressure and antihypertensive treatment status. A cut-off of ≥90 mmHg diastolic blood pressure was used to identify hypertensive status. Differences in anxiety and depression symptom levels in untreated and treated hypertensives (all treatments) versus the normotensive reference group were explained by differences in age and gender distribution in the three groups in this study. However, the receipt of two or more antihypertensive drugs was associated with depressive symptoms alone (OR = 1.40, 95% CI = 1.03-1.90), but not with symptoms of anxiety (OR = 1.14, 95% CI = 0.83-1.57) or mixed anxiety and depression (OR = 1.19, 95% CI = 0.82-1.72) in the fully adjusted model, compared to untreated hypertension. Antihypertensive monotherapy (all agents) nor any single antihypertensive drug class were associated with symptoms of depression, anxiety, or mixed anxiety and depression. There may be a positive association between multi antihypertensive drug use and symptoms of depression, whereas this was not found in persons with symptoms of anxiety or mixed anxiety and depression. This might reflect poor antihypertensive treatment adherence leading to polypharmacy, or other unfavorable health behaviors in people with symptoms of pure depression.