Pain Tolerance and Pain Perception in Adolescents Born Extremely Preterm

Does birth weight or preterm birth predict worse pain prognosis in adulthood? A Northern Finland Birth Cohort study followed up to 46 years of age

Although pain is a highly common symptom, only a subset of individuals develops chronic and disabling conditions. Delving into the predictors for poor musculoskeletal pain (MSK) outcomes in adulthood may help identify those needing early prevention and intervention. This study aimed to evaluate whether birth weight or preterm birth predicts worse prognosis of MSK pain in adulthood. Participants in the Northern Finland Birth Cohort 1966 were followed from birth to 46 years of age. Associations of birth weight (measured using corrections to gestational age) and preterm birth (<37 completed weeks) with high-risk classification for worse pain using three prognostic tools: the Örebro Musculoskeletal Pain Screening Questionnaire-Short Form (ÖMPSQ-SF), STartT Back Tool (SBT), and Risk of Pain Spreading (ROPS) assessed at 46 years among people reporting MSK pain (n=3200-4525). Log-binomial regression models for dummy outcomes (ÖMPSQ-SF and SBT) and generalized linear regression models for continuous outcomes (ROPS) were employed. Birth weight did not predict high-risk classification by any tool. Compared to full-term participants, those born preterm had higher risk of being classified into the high-risk group only according to ÖMPSQ-SF (relative risk 1.61, 95% confidence interval 1.00-2.59) and SBT (1.61, 1.14-2.28). Adjustments did not change these results. Preterm birth appeared to predict allocation to the group with poorer prognosis of MSK outcomes as measured by ÖMPSQ-SF and SBT, but not by ROPS. This highlights the need for further research into the role of preterm birth in the development or accumulation of adverse pain-related thoughts and experiences in mid-life. PERSPECTIVE: Preterm birth tended to predict allocation to the high-risk group for worse pain prognosis in adulthood. Similar was not observed concerning birth weight. Further research is warranted to validate the results and delve into explanatory pathways.

Cardiovascular responses to heat and cold exposure are altered by preterm birth in guinea pigs

Adversity early in life can modify the trajectory for disease risk extending decades beyond the event. Preterm birth produces persistent cardiovascular alterations that may appear maladaptive in adulthood. We have previously hypothesized that those born preterm may exhibit cardiovascular vulnerability in the climate change context. Further, this vulnerability may be present as early as childhood. We aimed to identify the early signs of cardiovascular dysfunction at childhood-equivalent age using our animal model of preterm birth. Using a whole-body thermal stress test, guinea pigs aged 35-d and 38-d (equivalent to 8-10-year-old children) and born at term or preterm gestations were exposed to progressive hyper- (TC = 41.5°C) and hypo-thermia (TC = 34°C; normothermia TC = 39°C). Comprehensive cardiovascular monitoring included ECG, blood pressure, microvascular perfusion, blood gas, and catecholamine profile, as well as skin and core body temperature. Preterm-born animals exhibited attenuated vascular responses to hyperthermic stress, and a significant elevation in systolic blood pressure in response to hypothermic stress. Such responses are similar to those observed in elderly populations and indicate the presence of cardiovascular dysfunction. This is the first study to demonstrate the impact of preterm birth on the cardiovascular response to both heat and cold stress. Further, this dysfunction has been observed at an earlier age than that achievable using traditional stress testing techniques. The present findings warrant further investigation.

Early pain experiences in dairy calves on pain sensitivity later in life

In humans, early painful experiences can increase pain sensitivity later in life, but little is known regarding this phenomenon in cattle. This study assessed if a painful event early in life affects later pain sensitivity in 40-d-old calves. Holstein calves (n = 26) were randomly assigned to control or treatment conditions, blocked within sex and birth weight. At 9.5 ± 1.8 d old, treatment calves had 1 horn bud disbudded using caustic paste, whereas control calves had 1 horn sham disbudded; in both cases, multimodal pain control was provided. All calves had the contralateral horn bud disbudded using a hot iron 4 wk later, again with multimodal pain control. Mechanical nociceptive responses were assessed weekly using an algometer applied adjacent to both horn buds and on the rump, beginning 3 d before the first disbudding and ending 30 d after the second disbudding. Following the second disbudding, both groups of calves showed evidence of increased sensitivity (i.e., algometer pressure declined 3.69 ± 0.60 √N to 2.13 ± 0.70 √N) on the contralateral bud, but there was no difference between the control group and the treatment groups. An interaction between treatment and time, likely driven by treatment differences, was found on the rump when tested 5 h after the second disbudding event. These responses are not consistent with the hypothesis that an early pain experience results in increased sensitivity to later painful experiences.

The relation between preterm birth and self-reported spinal pain in pre-adolescence-a study of 47,063 subjects from the Danish National Birth Cohort

Repeated exposure to pain and stress in early life may cause alterations in pain sensitivity later in life. Children born preterm are often exposed to painful invasive procedures. This study aimed to explore the relationship between being born preterm and self-report of spinal pain in pre-adolescence. This prospective study was based on the Danish National Birth Cohort and consisted of 47,063 11-14-year-olds. Data from the Danish National Birth Cohort were linked with national registers through Statistics Denmark. Analyses were performed as multiple logistic regression models estimating odds ratios and 95% confidence intervals. Spinal pain (neck, mid back, and/or low back pain) was assessed using a subdivision of the Young Spine Questionnaire. Severe spinal pain was defined as having pain often or once in a while with an intensity of four to six on the Revised Faces Pain Scale. Inverse probability weighting was used to account for potential selection bias. Girls born very preterm (< 34 full weeks of gestation) were less likely to report spinal pain (OR: 0.60; 95% CI: 0.40-0.93) compared with those term-born. The associations were weaker when examining moderate to severe spinal pain and when examining the three spinal regions separately. None of these was statistically significant.

CONCLUSION

We found no associations for boys. In conclusion, this study indicates that girls born very preterm are seemingly less likely to have severe spinal pain in pre-adolescence than girls born at term.

WHAT IS KNOWN

• Spinal pain is one of the largest disease burdens globally, and the evidence regarding the etiology of spinal pain in children and adolescents is limited. • Repeated exposure to pain and stress in early life (i.e., being preterm) may cause alterations in pain sensitivity later in life.

WHAT IS NEW

• Girls born very preterm (< 34 full weeks of gestation) seem less likely to report severe spinal pain in pre-adolescence compared with girls born at full term. • There is no association between gestational age and later experience of spinal pain in pre-adolescent boys.

Neonatal stress exposure and DNA methylation of stress-related and neurodevelopmentally relevant genes: An exploratory study

BACKGROUND

Stress exposure during Neonatal Intensive Care Unit (NICU) stay may have long-lasting effects on neurodevelopmental outcomes in extremely preterm infants. Altered DNA methylation of stress-related and neurodevelopmentally relevant genes may be an underlying mechanism.

AIMS

This exploratory study aimed to investigate the association between neonatal stress exposure and DNA methylation in these genes at two different time points: early during the NICU stay (7-14 days after birth) and later, at discharge from the NICU.

SUBJECTS

We included 45 extremely preterm infants in this prospective cohort study, gestational age 24-30 weeks.

OUTCOME MEASURES

We collected fecal samples at days 7-14 (n = 44) and discharge (n = 28) and determined DNA methylation status in predefined regions of NR3C1, SLC6A4, HSD11B2, OPRM1, SLC7A5, SLC1A2, IGF2, NNAT, BDNF and GABRA6 using pyrosequencing. Because of low DNA concentrations in some fecal samples, we could do so in 25-50 % of collected samples. We prospectively quantified daily neonatal stress exposure using the Neonatal Infant Stressor Scale (NISS) and explored associations between cumulative NISS scores and average DNA methylation status.

RESULTS

Rates of methylation of most genes were not statistically different between day 7-14 and discharge, except for OPRM1. We found moderately high and mostly negative correlation coefficients upon discharge with the cumulative NISS for the NR3C1, SLC6A4, SLC1A2, IGF2, BDNF and OPRM1 genes, albeit not statistically significant.

CONCLUSIONS

Findings suggest that expression of stress-related and neurodevelopmentally relevant genes may be differently regulated following higher neonatal stress exposure. Larger studies should challenge the findings of this study and ideally test the effects on gene expression.

The impact of gender medicine on neonatology: the disadvantage of being male: a narrative review

This narrative non-systematic review addresses the sex-specific differences observed both in prenatal period and, subsequently, in early childhood. Indeed, gender influences the type of birth and related complications. The risk of preterm birth, perinatal diseases, and differences on efficacy for pharmacological and non-pharmacological therapies, as well as prevention programs, will be evaluated. Although male newborns get more disadvantages, the physiological changes during growth and factors like social, demographic, and behavioural reverse this prevalence for some diseases. Therefore, given the primary role of genetics in gender differences, further studies specifically targeted neonatal sex-differences will be needed to streamline medical care and improve prevention programs.

Current pain management practices for preterm infants with necrotizing enterocolitis: a European survey

BACKGROUND

Necrotizing enterocolitis (NEC) is a highly painful intestinal complication in preterm infants that requires adequate pain management to prevent short- and long-term effects of neonatal pain. There is a lack of international guidelines for pain management in NEC patients. Therefore, this study aims to describe current pain management for NEC patients in European neonatal intensive care units (NICUs).

METHODS

An online survey was designed and conducted to assess current practices in pain management for NEC patients in European NICUs. The survey was distributed via neonatal societies, digital platforms, and professional contacts.

RESULTS

Out of the 259 responding unique European NICUs from 36 countries, 61% had a standard protocol for analgesic therapy, 73% assessed pain during NEC, and 92% treated NEC patients with intravenous analgosedatives. There was strong heterogeneity in the used pain scales and initial analgesic therapy, which mainly included acetaminophen (70%), fentanyl (56%), and/or morphine (49%). A third of NICU representatives considered their pain assessment adequate, and half considered their analgesic therapy adequate for NEC patients.

CONCLUSIONS

Various pain scales and analgesics are used to treat NEC patients in European NICUs. Our results provide the first step towards an international guideline to improve pain management for NEC patients.

IMPACT

This study provides an overview of current pain management practices for infants with necrotizing enterocolitis (NEC) in European neonatal intensive care units. Choice of pain assessment tools, analgosedatives, and dosages vary considerably among NICUs and countries. A third of NICU representatives were satisfied with their current pain assessment practices and half of NICU representatives with their analgesic therapy practices in NEC patients in their NICU. The results of this survey may provide a first step towards developing a European pain management consensus guideline for patients with NEC.

Self‐reported sensitivity to pain in early and moderately‐late preterm‐born adolescents: A community‐based cohort study

We aimed to compare ratings of self‐reported and parent‐reported pain sensitivity between early preterm (EP), moderately‐late preterm (MLP), and full‐term (FT) adolescents. For EP adolescents, we aimed to determine whether pain sensitivity was associated with early‐life events. EP (n = 68, response rate 47.4%), MLP (n = 128, response rate 33.0%), and FT (n = 78, response rate 31.1%) adolescents and their parents (n = 277) answered an author‐generated question on pain sensitivity at 14‐15 years of age within a community‐based cohort study. Differences between groups were determined using the chi‐square test for trends. For EP adolescents, we assessed associations of treatment modalities (inotrope treatment, mechanical ventilation, and C‐section) and neonatal morbidities (sepsis/necrotizing enterocolitis, small‐for‐gestational age status, asphyxia, and cerebral pathologies) with adolescent pain sensitivity using logistic regression analyses. Increased pain sensitivity was reported by 18% of EP adolescents, compared with 12% of MLP adolescents, and 7% of FT adolescents (P = 0.033). Parent‐reported pain sensitivity did not differ by gestational age group. For EP adolescents, inotrope treatment was associated with increased pain sensitivity (odds ratio, 5.00, 95% confidence interval, 1.23‐20.4, P = 0.025). No other neonatal treatment modalities or morbidities were associated with pain sensitivity in adolescence. In conclusion, we observed higher proportions of increased pain sensitivity for EP and MLP adolescents. Physicians treating preterm adolescents should be aware of altered pain sensitivity.

The burden of early life stress on the nociceptive system development and pain responses

For a long time, the capacity of the newborn infant to feel pain was denied. Today it is clear that the nociceptive system, even if still immature, is functional enough in the newborn infant to elicit pain responses. Unfortunately, pain is often present in the neonatal period, in particular in the case of premature infants which are subjected to a high number of painful procedures during care. These are accompanied by a variety of environmental stressors, which could impact the maturation of the nociceptive system. Therefore, the question of the long-term consequences of early life stress is a critical question. Early stressful experience, both painful and non-painful, can imprint the nociceptive system and induce long-term alteration in brain function and nociceptive behavior, often leading to an increase sensitivity and higher susceptibility to chronic pain. Different animal models have been developed to understand the mechanisms underlying the long-term effects of different early life stressful procedures, including pain and maternal separation. This review will focus on the clinical and preclinical data about early life stress and its consequence on the nociceptive system.

Cultural adaptation and harmonization of four Nordic translations of the revised Premature Infant Pain Profile (PIPP-R)

Background

Preterm infants are especially vulnerable to pain. The intensive treatment often necessary for their survival unfortunately includes many painful interventions and procedures. Untreated pain can lead to both short- and long-term negative effects. The challenge of accurately detecting pain has been cited as a major reason for lack of pain management in these non-verbal patients. The Premature Infant Pain Profile (PIPP) is one of the most extensively validated measures for assessing procedural pain in premature infants. A revised version, PIPP-R, was recently published and is reported to be more user-friendly and precise than the original version. The aims of the study were to develop translated versions of the PIPP-R in Finnish, Icelandic, Norwegian, and Swedish languages, and to establish their content validity through a cultural adaptation process using cognitive interviews.

Methods

PIPP-R was translated using the recommendations from the International Society for Pharmacoeconomics and Outcomes Research and enhanced with cognitive interviews. The respondent nurse was given a copy of the translated, national version of the measure and used this together with a text describing the infant in the film to assess the pain of an infant in a short film. During the assessment the nurse was asked to verbalize her thought process (thinking aloud) and upon completion the interviewer administered probing questions (verbal probing) from a structured interview guide. The interviews were recorded, transcribed, and analyzed using a structured matrix approach.

Results

The systematic approach resulted in translated and culturally adapted versions of PIPP-R in the Finnish, Icelandic, Norwegian and Swedish languages. During the cultural adaptation process several problems were discovered regarding how the respondent understood and utilized the measure. The problems were either measure problems or other problems. Measure problems were solved by a change in the translated versions of the measure, while for other problems different solutions such as education or training were suggested.

Conclusions

This study have resulted in translations of the PIPP-R that have content validity, high degree of clinical utility and displayed beginning equivalence with each other and the original version of the measure.

Safety and effectiveness of parent/nurse controlled analgesia on patient outcomes in the neonatal intensive care unit: a systematic review protocol

REVIEW QUESTION

The review question is: How safe is parent/nurse controlled analgesia and what is its effectiveness on patient outcomes in the neonatal intensive care unit?

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.

Conditioned pain modulation identifies altered sensitivity in extremely preterm young adult males and females

BACKGROUND

Conditioned pain modulation is a potential biomarker for risk of persistent pain. As early-life experience can alter subsequent somatosensory processing and pain response, we evaluated conditioned pain modulation after extremely preterm birth.

METHODS

This observational study recruited extremely preterm (<26 weeks gestation; n=98) and term-born control (n=48) young adults (19-20 yr) from the longitudinal EPICure cohort. Pressure pain threshold (PPT; variable test stimulus lower leg) was measured before, during, and after a conditioning stimulus (contralateral hand immersion; 5°C water; 30 s). Questionnaires assessed current pain, medication use, anxiety, and pain catastrophising.

RESULTS

For participants tolerating conditioning, there were significant main effects of extremely preterm status, sex, and time on PPT during and after hand immersion. Inhibitory modulation was evoked in 64/98 extremely preterm (3, no change) and 38/48 term-born control (3, facilitation) subjects. The conditioned pain modulation effect (percentage change in PPT) did not differ between the extremely preterm and term-born control groups {53% [95% confidence interval (CI): 41-65] vs 57% [95% CI: 42-71]}. Reduced cold tolerance (<20 s) hampered conditioned pain modulation quantification in a higher proportion of extremely preterm participants [extremely preterm vs term-born control: 31/98 (32%) vs 7/48 (15%); P=0.03]. One-third of extremely preterm females withdrew the hand before parallel PPT (<15 s), and had lower baseline PPT than term-born control females [4.9 (95% CI: 4.8-5.1) vs 5.3 (95% CI: 5.1-5.5) ln kPa; P=0.02]. Higher anxiety, pain catastrophising, and medication use correlated with pain intensity, but not conditioned pain modulation effect.

CONCLUSIONS

Cold conditioning evoked inhibitory modulation in the majority of young adults and identified a subgroup of extremely preterm females with increased baseline sensitivity. Early-life experience and sex/gender should be considered when evaluating persistent pain risk with conditioned pain modulation.

Efficacy of facilitated tucking combined with non-nutritive sucking on very preterm infants' pain during the heel-stick procedure: A randomized controlled trial

BACKGROUND

Reducing acute pain in premature infants during neonatal care improves their neurophysiological development. The use of pharmacological and non-pharmacological analgesia, such as sucrose, is limited per day, particularly for very preterm infants. Thus, the usual practice of non-nutritive sucking is often used alone. Facilitated tucking could be an additional strategy to non-nutritive sucking for reducing pain. To the best of our knowledge, no randomized trial has compared the combination of facilitated tucking and non-nutritive sucking to non-nutritive sucking alone.

OBJECTIVES

To compare the efficacy of facilitated tucking in combination with non-nutritive sucking (intervention group) to non-nutritive sucking alone (control group) in reducing pain during the heel-stick procedure in very preterm infants.

DESIGN

Prospective, randomized controlled trial.

SETTINGS

Level III and II neonatal care units, including the neurosensory care management program.

METHODS

Very preterm infants (gestational age between 28 and 32 weeks) were randomly assigned by a computer programme to the intervention or control group during a heel-stick procedure within the first 48 h of life. In both groups, infants were placed in an asymmetric position on a cushion; noise and light were limited following routine care. A heel-stick was performed first in the care sequence. In the intervention group, facilitated tucking was performed by a nurse or nursing assistant. The procedure was video recorded from 15 s (T-15 s) before the procedure until three minutes (T + 3 min) after the end of the procedure. Pain was blindly assessed by two independent specialist nurses. The primary outcome was the pain score evaluated 15 s before the procedure and 30 s immediately after by the premature infant pain profile (PIPP) scale. The secondary outcome was the pain score evaluated between T-15 s and T + 3 min by the DAN scale (a French acronym for the acute pain of a newborn).

RESULTS

Sixty infants were included (30 in each group). The PIPP pain scores did not differ between the intervention group (median: 8.0; interquartile range (IQR): 6.0-12.0) and the control group (median: 9.5; IQR: 7.0-13.0, p = 0.32). Pain assessed by the DAN scale at T + 3 min was lower in the intervention group than in the control group (median: 0.3; IQR: 0.0-1.0 and 2.0; IQR: 0.5-3.0, respectively, p = 0.001).

CONCLUSIONS

The combined use of facilitated tucking and non-nutritive sucking did not significantly alleviate pain during the heel-stick procedure. However, the addition of facilitated tucking facilitated faster pain recovery following the heel-stick procedure.

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.

Neonatal Invasive Procedures Predict Pain Intensity at School Age in Children Born Very Preterm

INTRODUCTION

Children born very preterm display altered pain thresholds. Little is known about the neonatal clinical and psychosocial factors associated with their later pain perception.

OBJECTIVE

We aimed to examine whether the number of neonatal invasive procedures, adjusted for other clinical and psychosocial factors, was associated with self-ratings of pain during a blood collection procedure at school age in children born very preterm.

MATERIALS AND METHODS

56 children born very preterm (24 to 32 weeks gestational age), followed longitudinally from birth, and free of major neurodevelopmental impairments underwent a blood collection by venipuncture at age 7.5 years. The children's pain was self-reported using the Coloured Analog Scale and the Facial Affective Scale. Parents completed the Child Behavior Checklist and the State-Trait Anxiety Inventory. Pain exposure (the number of invasive procedures) and clinical factors from birth to term-equivalent age were obtained prospectively. Multiple linear regression was used to predict children's pain self-ratings from neonatal pain exposure after adjusting for neonatal clinical and concurrent psychosocial factors.

RESULTS

A greater number of neonatal invasive procedures and higher parent trait-anxiety were associated with higher pain intensity ratings during venipuncture at age 7.5 years. Fewer surgeries and lower concurrent child externalizing behaviors were associated with a higher pain intensity.

CONCLUSIONS

In very preterm children, exposure to neonatal pain was related to altered pain self-ratings at school age, independent of other neonatal factors. Neonatal surgeries and concurrent psychosocial factors were also associated with pain ratings.

Pain threshold, tolerance and intensity in adolescents born very preterm or with low birth weight

BACKGROUND

Data on long-term consequences of neonatal pain is limited.

AIM

To assess whether perinatal factors, later pain experience and pain coping strategies are associated with altered pain threshold, pain tolerance and pain intensity in adolescents born preterm.

STUDY DESIGN

Observational, longitudinal study (Project on Preterm and SGA-infants, POPS-19).

SUBJECTS

We analyzed data of 412 adolescents at the age of 19years, who were born at a gestational age<32weeks or with a birth weight<1500g.

OUTCOME MEASURES

Participants performed a standardized cold pressor test to assess pain threshold, tolerance and intensity. Furthermore, they completed a pain coping questionnaire (PCQ).

RESULTS

In univariate analysis, female gender and necrotizing enterocolitis (NEC) were associated with lower pain tolerance, indicated by reaching the ceiling time of 180s in ice water (females 19% vs males 29%, NEC 7% vs no NEC 25%). Female gender was associated with higher pain intensity (mean difference 0.58; 95%CI 0.21; 0.95) and lower pain threshold (log rank test p 0.007). In a multivariate Cox regression analyses, emotion focused avoidance pain coping style was significantly associated with lower pain threshold (hazard ratio HR 1.38; 95%CI 1.02; 1.87) and pain tolerance (HR 1.72; 95%CI 1.21; 2.42). NEC was significantly associated with lower pain threshold (HR 1.47; 95%CI 1.01; 2.14) and pain tolerance (HR 1.63; 95%CI 1.09; 2.41).

CONCLUSION

In adolescence, maladaptive pain coping strategy was associated with lower pain threshold, pain tolerance and higher pain intensity. NEC was associated with altered pain response in adolescents born preterm.

Exposure to Early Life Pain: Long Term Consequences and Contributing Mechanisms

From an evolutionary perspective, adaptations of an organism to its early environment are essential for survival. The occurrence of early life perturbation, coincident with increased developmental plasticity, provides a unique opportunity for such adaptations to become programmed and persist throughout life. However, adaptations that are beneficial to maintaining homeostasis in one's early environment may result in extreme response strategies that confer vulnerability or dysfunction later in life. This review summarizes recent findings in human and animal studies demonstrating that early life pain results in a hypo-/hyper-sensitive phenotype in response to acute and persistent pain and stress later in life. Changes in cognition and immune function in response to early life pain have also been observed. Recent data on the neural mechanisms underlying these long-term changes are discussed, as well as potential strategies to minimize the impact of early life pain.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Long-Term Persistency of Abnormal Heart Rate Variability following Long NICU Stay and Surgery at Birth

Preterm birth is associated with painful procedures during the neonatal intensive care unit (NICU) stay. Full-term newborns can also experience pain, following surgery. These procedures can have long-lasting consequences. It has been shown that children born preterm show pain responses and cardiac alterations. This study aimed to explore the heart rate reactivity to pain in 107 subjects born either preterm or full-term who were between 7 and 25 years old at testing. We also evaluated the effect of pain experienced at birth, as represented by a longer NICU stay, time under ventilation, and surgery at birth. Participants were asked to immerse their right forearm in 10°C water for 2 minutes. Electrocardiograms were recorded at baseline and during the immersion procedure. Full-term subjects showed a stable increase in heart rate throughout the procedure, whereas preterm ones showed a strong increase at the beginning, which decreased over time. Also, preterm and full-term subjects who experienced pain at birth showed higher resting heart rate, stronger sympathetic activity, and lower cardiac vagal activity. Our study demonstrated a long-term impact of a long NICU stay and surgery at birth on cardiac autonomic activity. This could lead to impaired reactions to pain or stress in later life.

Early life events predispose the onset of childhood functional gastrointestinal disorders

BACKGROUND

Functional gastrointestinal disorders (FGIDs) are common digestive conditions characterized by chronic or recurrent symptoms in the absence of a clearly recognized gastrointestinal etiology. The biopsychosocial model, the most accepted concept explaining chronic pain conditions, proposes that the interplay of multiple factors such as genetic susceptibility, early life experiences, sociocultural issues, and coping mechanisms affect children at different stages of their lives leading to the development of different pain phenotypes and pain behaviors. Early life events including gastrointestinal inflammation, trauma, and stress may result in maladaptive responses that could lead to the development of chronic pain conditions such as FGIDs.

AIMS

In this review, we discuss novel findings from studies regarding the long-term effect of early life events and their relationship with childhood chronic abdominal pain and FGIDs.

METHODS

A bibliographic search of the PubMed database was conducted for articles published over the last 20 years using the keywords: "Functional gastrointestinal disorders", "chronic abdominal pain", "chronic pain", "gastrointestinal inflammation", and "early life events". Forty-three articles were chosen for review.

RESULTS

Based on the current evidence, events that take place early in life predispose children to the development of chronic abdominal pain and FGIDs. Conditions that have been studied include cow's milk protein hypersensitivity, pyloric stenosis, gastrointestinal infections, and Henoch-Schonlein purpura, among others.

CONCLUSIONS

Early events may play an important role in the complex pathogenesis of functional gastrointestinal conditions. Timely intervention may have a critical impact on the prevention of this group of chronic incapacitating conditions.