Is there an association between preterm birth or low birthweight and chronic widespread pain? Results from the 1958 Birth Cohort Study

Mental health, pain and tiredness in adults born very preterm or with very low birthweight

AIM

Adults born preterm have increased risk of mental health problems and other neurodevelopmental conditions. We aimed to investigate associations of mental health with pain and tiredness in adults born very preterm (VP; <32 weeks) or very low birthweight (VLBW; <1500 g) and at term, and whether these associations are influenced by physical activity.

METHODS

As part of an EU Horizon 2020 project, individual participant data from six prospective cohort studies were harmonised for 617 VP/VLBW and 1122 term-born participants. Mental health was assessed by the Achenbach System of Empirically Based Assessment Adult Self-Report. Pain and tiredness were harmonised based on specific items from self-reported questionnaires. Associations between mental health and pain or tiredness were explored by linear regression.

RESULTS

An increase in the mental health scales internalising, externalising and total problems was associated with increased pain and tiredness in the preterm and term group alike. Results were maintained when adjusting for physical activity.

CONCLUSION

The findings indicate that associations between mental health, pain and tiredness in adults are independent of gestation or birthweight. Future research should explore other potential mechanisms that may underlie the increased risk of mental health problems in the preterm population.

The epidemiology of regular opioid use and its association with mortality: Prospective cohort study of 466 486 UK biobank participants

BACKGROUND

Opioids have, at most, small benefits for non-cancer pain in the medium and long-term but there is good evidence that they cause harm. The current study describes the characteristics and clinical status of people taking regular opioids in Great Britain and determines whether use is associated with mortality risk.

METHODS

An analysis of participants in UK Biobank, a prospective population-based study. At recruitment (2006-10) participants reported medicines which they regularly used in addition to lifestyle and health-related factors. Information was available on deaths until October 2016.

FINDINGS

There were 466 486 participants (54% women) aged 40-69 years and without a prior history of cancer of whom 5.5% were regularly using opioids. Use increased with age-group, was more common in females (6.3% v. 4.6%) and 87% of persons using them reported chronic pain. The highest rates of use (~1 in 9) were in people with low household income, who left school <16 years and lived in areas with high deprivation. Amongst 15,032 people who could not work because of ill-health, 1 in 3 were regularly taking opioids. Regular users reported insomnia (88.7%), a recent major recent life event (57.3%) and were much more likely than non-users to rate their health as poor (RR 5.5, 99% CI (4.9, 6.1)). Those taking weak (4.2% of participants) or strong (1.4%) opioids were more likely to die during follow-up (6.9% and 9.1% respectively v. 3.3% in non-users) an excess which remained after adjustment for demographic, socio-economic, health and lifestyle factors (MRR 1.18 99% CI (1.06, 1.32) and 1.20 99% CI (1.01, 1.43)) respectively.

INTERPRETATION

Regular use of opioids is common in Great Britain, particularly in groups of low socio-economic status. Most users still report chronic pain, poor health generally and are at increased risk of premature death although it is not established that this relationship is causal.

FUNDING

There were no external sources of funding obtained for the current analyses.

Early Neonatal Pain-A Review of Clinical and Experimental Implications on Painful Conditions Later in Life

Modern health care has brought our society innumerable benefits but has also introduced the experience of pain very early in life. For example, it is now routine care for newborns to receive various injections or have blood drawn within 24 h of life. For infants who are sick or premature, the pain experiences inherent in the required medical care are frequent and often severe, with neonates requiring intensive care admission encountering approximately fourteen painful procedures daily in the hospital. Given that much of the world has seen a steady increase in preterm births for the last several decades, an ever-growing number of babies experience multiple painful events before even leaving the hospital. These noxious events occur during a critical period of neurodevelopment when the nervous system is very vulnerable due to immaturity and neuroplasticity. Here, we provide a narrative review of the literature pertaining to the idea that early life pain has significant long-term effects on neurosensory, cognition, behavior, pain processing, and health outcomes that persist into childhood and even adulthood. We refer to clinical and pre-clinical studies investigating how early life pain impacts acute pain later in life, focusing on animal model correlates that have been used to better understand this relationship. Current knowledge around the proposed underlying mechanisms responsible for the long-lasting consequences of neonatal pain, its neurobiological and behavioral effects, and its influence on later pain states are discussed. We conclude by highlighting that another important consequence of early life pain may be the impact it has on later chronic pain states-an area of research that has received little attention.

Parental Multisite Chronic Pain and the Risk of Adult Offspring Developing Additional Chronic Pain Sites: Family-Linkage Data From the Norwegian HUNT Study

We investigated if parental multisite chronic pain increases the risk of adult offspring developing additional chronic pain sites, and if offspring body mass index (BMI) and leisure time physical activity modify this association. We used longitudinal data on 7,654 offspring linked with their parents who participated in the population-based HUNT Study (Norway) in 1995 to 1997 and 2006 to 2008. Logistic regression was used to estimate odds ratios (ORs) with 95% confidence interval (CI). One-third of offspring (n = 2,573) developed additional chronic pain sites. Having both parents with 1-2 chronic pain sites increased the risk of developing additional pain sites compared to having parents free of chronic pain (OR = 1.33; 95% CI 1.05-1.68), with larger effects observed when both parents had ≥3 chronic pain sites (OR = 1.46; 95% CI 1.17-1.82). These associations were largely driven by maternal pain, that is, there was no association between paternal chronic pain and risk of additional pain sites in offspring. The parent-offspring transfer of additional pain sites (when both parents had ≥3 pain sites) strengthened when offspring were obese (OR = 2.56; 95% CI 1.75-3.75) or physically inactive (OR = 1.73; 95% CI 1.33-2.27). In conclusion, parental multisite chronic pain increases the risk of offspring developing additional chronic pain sites, particularly those with obesity or inactivity. PERSPECTIVE: This longitudinal analysis investigated the parent-offspring transmission of multisite chronic pain, and whether lifestyle behaviors in offspring modify this association. The findings suggest that having parents with multisite chronic pain increases the risk of offspring developing additional chronic pain sites, particularly if offspring are obese or inactive.

Long-term effects of neonatal pain

Pain experienced during neonatal intensive care management can influence neurodevelopmental outcome and the somatosensory and/or emotional components of pain response in later life. Alterations in biological factors (e.g. peripheral and central somatosensory function and modulation, brain structure and connectivity) and psychosocial factors (e.g. gender, coping style, mood, parental response) that influence pain have been identified in children and young adults born very preterm or extremely preterm. Earlier gestational age at birth and cumulative pain exposure from tissue-breaking procedures and/or neonatal surgery influence the degree of change. In neonatal rodents, repeated needle insertion or hindpaw incision identify developmentally-regulated and activity-dependent long term alterations in nociceptive processing, and the efficacy of novel or current analgesic interventions can be compared. As prior neonatal experience and sex may influence current pain experience or the risk of persistent pain, these factors should be considered within the biopsychosocial assessment and formulation of pain in later life.

Chronic Widespread Pain and Fibromyalgia Syndrome: Life-Course Risk Markers in Young People

Although the life-course concept of risk markers as potential etiological influences is well established in epidemiology, it has not featured in academic publications or clinical practice in the context of chronic widespread pain (CWP) and fibromyalgia syndrome (FMS). Studies of risk markers are required considerations for evaluation of patients and for research because there is no single cause, pathological feature, laboratory finding, or biomarker for CWP or FMS. The early-life risk markers identified by extensive literature review with best evidence for potential causal influence on the development and progression of CWP and FMS include genetic factors, premature birth, female sex, early childhood adversity, cognitive and psychosocial influences, impaired sleep, primary pain disorders, multiregional pain, physical trauma, infectious illness, obesity and inactivity, hypermobility of joints, iron deficiency, and small-fiber polyneuropathy. The case history illustrates the potential etiological influence of multiple risk markers offset by personal resilience.

Are perinatal factors associated with musculoskeletal pain across the lifespan? A systematic review with meta-analysis

BACKGROUND

Musculoskeletal conditions are common health issues with great impact on individuals. Although many factors have been associated with the development of musculoskeletal pain, such as perinatal factors, its aetiology is still poorly understood.

OBJECTIVE

To systematically investigate whether perinatal factors can increase the risk of having musculoskeletal pain across the lifespan.

METHODS

MEDLINE, CINAHL, Scopus, Web of Science and EMBASE databases were searched from their inception to December 2017. Descriptors used in our search strategy were related to "perinatal factors" and "musculoskeletal pain". There were no language, age, sex or date restrictions. Meta-analysis was used to pool the estimates of association between perinatal factors and musculoskeletal pain.

RESULTS

Among the six articles included in this systematic review, three were extracted for the meta-analysis. The pooled of three and two studies showed no association between chronic musculoskeletal pain and low birth weight (OR 1.8, 95% CI 0.9-3.8, I² = 0; n = 157) or pre-term birth (OR 0.5, 95% CI 0.0-4.5; I² = 78%; n = 374) in adults, respectively. Overall, the quality of evidence after applying the GRADE approach was very low across all the studies.

CONCLUSION

In adults, our meta-analysis showed no association between birth weight or pre-term birth and musculoskeletal pain, and the quality of the evidence was very low. Thus, the very low quality of evidence and limited number of studies do not suggest a direct clear association. Further high-quality longitudinal studies accounting for more relevant confounders are needed to better understand the complex mechanism that may operate between perinatal factors and musculoskeletal pain.

Contributions of birthweight, annualised weight gain and BMI to back pain in adults: a population-based co-twin control study of 2754 Australian twins

PURPOSE

To investigate associations between anthropometric measures (birthweight, weight gain and current BMI) and back pain; and to determine whether these associations differ between those born with low or full birthweight.

METHODS

The cross-sectional associations between the lifetime prevalence of back pain and anthropometric measures (birthweight, weight gain and current BMI) among 2754 adult twins were investigated in three stages: total sample; within-pair case-control for monozygotic and dizygotic twins together; and within-pair case-control analysis separated by dizygotic and monozygotic. Results were expressed as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Birthweight was not associated with back pain (OR 0.99; 95% CI 0.99-1.00), but a weak association was found between weight gain (OR 1.01; CI 1.00-1.01) or current BMI (OR 1.02; 95% CI 1.00-1.05) and back pain in the total sample analysis. These associations did not remain significant after adjusting for genetics. The associations did not differ between those whose were born with low or full birthweight.

CONCLUSION

Birthweight was not associated with prevalence of back pain in adulthood. Weight gain and current BMI were weakly associated with back pain prevalence in the total sample analysis but did not differ between those born with low or full birthweight. However, the small-magnitude association only just achieved significance and appeared to be confounded by genetics and the early shared environment. Our results suggest that a direct link between these predictors and back pain in adults is unlikely. These slides can be retrieved under Electronic Supplementary Material.

Somatosensory function and pain in extremely preterm young adults from the UK EPICure cohort: sex-dependent differences and impact of neonatal surgery

BACKGROUND

Surgery or multiple procedural interventions in extremely preterm neonates influence neurodevelopmental outcome and may be associated with long-term changes in somatosensory function or pain response.

METHODS

This observational study recruited extremely preterm (EP, <26 weeks' gestation; n=102, 60% female) and term-born controls (TC; n=48) aged 18-20 yr from the UK EPICure cohort. Thirty EP but no TC participants had neonatal surgery. Evaluation included: quantitative sensory testing (thenar eminence, chest wall); clinical pain history; questionnaires (intelligence quotient; pain catastrophising; anxiety); and structural brain imaging.

RESULTS

Reduced thermal threshold sensitivity in EP vs TC participants persisted at age 18-20 yr. Sex-dependent effects varied with stimulus intensity and were enhanced by neonatal surgery, with reduced threshold sensitivity in EP surgery males but increased sensitivity to prolonged noxious cold in EP surgery females (P<0.01). Sex-dependent differences in thermal sensitivity correlated with smaller amygdala volume (P<0.05) but not current intelligence quotient. While generalised decreased sensitivity encompassed mechanical and thermal modalities in EP surgery males, a mixed pattern of sensory loss and sensory gain persisted adjacent to neonatal scars in males and females. More EP participants reported moderate-severe recurrent pain (22/101 vs 4/48; χ2=0.04) and increased pain intensity correlated with higher anxiety and pain catastrophising.

CONCLUSIONS

After preterm birth and neonatal surgery, different patterns of generalised and local scar-related alterations in somatosensory function persist into early adulthood. Sex-dependent changes in generalised sensitivity may reflect central modulation by affective circuits. Early life experience and sex/gender should be considered when evaluating somatosensory function, pain experience, or future chronic pain risk.

Microglia in health and pain: impact of noxious early life events

NEW FINDINGS

What is the topic of this review? This review discusses the origins and development of microglia, and how stress, pain or inflammation in early life disturbs microglial function during critical developmental periods, leading to altered pain sensitivity and/or increased risk of chronic pain in later life. What advances does it highlight? We highlight recent advances in understanding how disrupted microglial function impacts the developing nervous system and the consequences for pain processing and susceptibility for development of chronic pain in later life. The discovery of microglia is accredited to Pío del Río-Hortega, who recognized this 'third element' of CNS cells as being morphologically distinct from neurons and astrocytes. For decades after this finding, microglia were altogether ignored or relegated as simply being support cells. Emerging from virtual obscurity, microglia have now gained notoriety as immune cells that assume a leading role in the development, maintenance and protection of a healthy CNS. Pioneering studies have recently shed light on the origins of microglia, their role in the developing nervous system and the complex roles they play beyond the immune response. These studies reveal that altered microglial function can have a profoundly negative impact on the developing brain and may be a determinant in a range of neurodevelopmental disorders and neurodegenerative diseases. The realization that aberrant microglial function also critically underlies chronic pain, a debilitating disorder that afflicts over 1.5 billion people worldwide, was a major conceptual leap forward in the pain field. Adding to this advance is emerging evidence that early life noxious experiences can have a long-lasting impact on central pain processing and adult pain sensitivity. With microglia now coming of age, in this review we examine the association between adverse early life events, such as stress, injury or inflammation, and the influence of sex differences, on the role of microglia in pain physiology in adulthood.

Self-reported Chronic Pain in Young Adults With a Low Birth Weight

OBJECTIVE

To investigate self-reported pain in young adults with a low birth weight.

MATERIALS AND METHODS

This study was a part of a long-term follow-up study of preterm very low birth weight (VLBW; birth weight ≤1500 g), term small for gestational age (SGA; birth weight <10th percentile adjusted for sex and parity), and control young adults born during 1986 to 1988. Of the 300 individuals invited, 216 (62 VLBW, 67 term SGA, and 87 controls) completed a pain questionnaire. Of these, 151 (70%) had answered a pain severity question at 19 years. Chronic pain was defined as pain lasting for >6 months and being moderate, severe, or very severe during the past 4 weeks.

RESULTS

The prevalence of chronic pain at 26 years was 16% in the VLBW group, 21% in the term SGA group, and 7% in the control group. The VLBW and the term SGA groups had higher odds ratios for chronic pain (crude OR, 2.6; 95% CI, 0.9-7.6 for the VLBW group and crude OR, 3.6; 95% CI, 1.3-9.9 for the term SGA group vs. controls). The main results remained after adjusting for potential confounding factors. Some attenuation was observed when adjusting for anxiety and depressive problems. Moderate to very severe pain increased from 16% to 41% in the term SGA group from 19 to 26 years, whereas less changes were seen in the VLBW and the control groups.

DISCUSSION

Results of our study imply that pain should be in focus when conducting long-term follow-up programs of individuals with a low birth weight.

Does Motor Development in Infancy Predict Spinal Pain in Later Childhood? A Cohort Study

Study Design Longitudinal cohort study. Background Spinal pain is responsible for a huge personal and societal burden, but its etiology remains unclear. Deficits in motor control have been associated with spinal pain in adults, and delayed motor development is associated with a range of health problems and risks in children. Objective To assess whether there is an independent relationship between the age at which infants first sit and walk without support and spinal pain at 11 years of age. Methods Data from the Danish National Birth Cohort were analyzed, using the age at which children first sat and first walked without support as predictors. Parents reported the predictors when the children were 6 months and 18 months of age, and also provided information in response to a comprehensive list of covariates, including child sex, birth weight, and cognitive development; socioeconomic indicators; and parental health variables. Outcomes were measured at 11 years of age using the Young Spine Questionnaire, which assesses the presence and intensity of spinal pain. Data were analyzed using multivariable logistic regression models to estimate determinants of neck, thoracic, lumbar, and multisite pain. Results The analyses included data from approximately 23 000 children and their parents. There were no consistent independent associations between the age at first sitting or walking and spinal pain at the age of 11. Odds ratios were between 0.95 and 1.00 for the various pain sites. Conclusion The age at which a child first sits or walks without support does not influence the likelihood that he or she will experience spinal pain in later childhood. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2017;47(10):763-768. doi:10.2519/jospt.2017.7484.

Applying a Lifespan Developmental Perspective to Chronic Pain: Pediatrics to Geriatrics

An ideal taxonomy of chronic pain would be applicable to people of all ages. Developmental sciences focus on lifespan developmental approaches, and view the trajectory of processes in the life course from birth to death. In this article we provide a review of lifespan developmental models, describe normal developmental processes that affect pain processing, and identify deviations from those processes that lead to stable individual differences of clinical interest, specifically the development of chronic pain syndromes. The goals of this review were 1) to unify what are currently separate purviews of "pediatric pain," "adult pain," and "geriatric pain," and 2) to generate models so that specific elements of the chronic pain taxonomy might include important developmental considerations.

PERSPECTIVE

A lifespan developmental model is applied to the forthcoming Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society Pain Taxonomy to ascertain the degree to which general "adult" descriptions apply to pediatric and geriatric populations, or if age- or development-related considerations need to be invoked.

Low back pain across the life course

Back pain episodes are traditionally regarded as individual events, but this model is currently being challenged in favour of treating back pain as a long-term or lifelong condition. Back pain can be present throughout life, from childhood to older age, and evidence is mounting that pain experience is maintained over long periods: for example, people with pain continue to have it on and off for years, and people without pain do not suddenly develop long-term pain. A number of factors predict back pain presence in epidemiological studies, and these are often present, and predictive, at different life stages. There are also factors present at particular life stages, such as childhood or adolescence, which predict back pain in adulthood. However, there are little published data on long-term pain patterns or predictors over the life course. Such studies could improve our understanding of the development and fluctuations in back pain, and therefore influence treatment approaches.

Biological and neurodevelopmental implications of neonatal pain

Nociceptive pathways are functional following birth. In addition to physiological and behavioral responses, neurophysiological measures and neuroimaging evaluate nociceptive pathway function and quantify responses to noxious stimuli in preterm and term neonates. Intensive care and surgery can expose neonates to painful stimuli when the developing nervous system is sensitive to changing input, resulting in persistent impacts into later childhood. Early pain experience has been correlated with increased sensitivity to subsequent painful stimuli, impaired neurodevelopmental outcomes, and structural changes in brain development. Parallel preclinical studies have elucidated underlying mechanisms and evaluate preventive strategies to inform future clinical trials.

Neonatal pain in very preterm infants: long-term effects on brain, neurodevelopment and pain reactivity

Effects of early life psychosocial adversity have received a great deal of attention, such as maternal separation in experimental animal models and abuse/neglect in young humans. More recently, long-term effects of the physical stress of repetitive procedural pain have begun to be addressed in infants hospitalized in neonatal intensive care. Preterm infants are more sensitive to pain and stress, which cannot be distinguished in neonates. The focus of this review is clinical studies of long-term effects of repeated procedural pain-related stress in the neonatal intensive care unit (NICU) in relation to brain development, neurodevelopment, programming of stress systems, and later pain sensitivity in infants born very preterm (24-32 weeks' gestational age). Neonatal pain exposure has been quantified as the number of invasive and/or skin-breaking procedures during hospitalization in the NICU. Emerging studies provide convincing clinical evidence for an adverse impact of neonatal pain/stress in infants at a time of physiological immaturity, rapidly developing brain microstructure and networks, as well as programming of the hypothalamic-pituitary-adrenal axis. Currently it appears that early pain/stress may influence the developing brain and thereby neurodevelopment and stress-sensitive behaviors, particularly in the most immature neonates. However, there is no evidence for greater prevalence of pain syndromes compared to children and adults born healthy at full term. In addressing associations between pain/stress and outcomes, careful consideration of confounding clinical factors related to prematurity is essential. The need for pain management for humanitarian care is widely advocated. Non-pharmacological interventions to help parents reduce their infant's stress may be brain-protective.