Race Effects on Conditioned Pain Modulation in Youth.

Race and ethnicity shape the experience of pain in adults. African Americans typically exhibit greater pain intensity and evoked pain responsiveness than non-Hispanic whites. However, it remains unclear whether there are racial differences in conditioned pain modulation (CPM) and if these are present in youth. CPM refers to a reduction in perceived pain intensity for a test stimulus during application of a conditioning stimulus and may be especially relevant in determining risk for chronic pain. The present study assessed CPM to evoked thermal pain in 78 healthy youth (ages 10-17 years), 51% of whom were African American and 49% of whom were non-Hispanic white. African American youth reported lower mean conditioning pain ratings than non-Hispanic white youth, controlling for mean preconditioning pain ratings, which is consistent with stronger CPM. Multilevel models demonstrated stronger CPM effects in African American than non-Hispanic white youth, as evident in more rapid within-person decreases in pain ratings during the conditioning phase. These findings suggest that diminished CPM likely does not account for the enhanced responsiveness to evoked thermal pain observed in African American youth. These results may have implications for understanding racial differences in chronic pain experienced in adulthood. Perspective: This study evaluated conditioned pain modulation to evoked thermal pain in African American and non-Hispanic white youth. Findings could have implications for the development of personalized chronic pain treatment strategies that are informed by race and ethnicity.

Heightened Temporal Summation of Pain in Patients with Functional Gastrointestinal Disorders and History of Trauma.

BACKGROUND: Individuals with functional gastrointestinal disorders (FGIDs) report experiencing trauma more often than healthy controls, but little is known regarding psychophysical correlates. PURPOSE: The purpose of this study was to test the hypothesis that adolescents and young adults with FGIDs since childhood and a trauma history (n = 38) would exhibit heightened temporal summation to thermal pain stimuli, an index of central sensitization, and greater clinical symptoms compared to patients with FGIDs and no trauma history (n = 95) and healthy controls (n = 135). METHODS: Participants completed self-report measures, an experimental pain protocol, and psychiatric diagnostic interview as part of a larger longitudinal study. RESULTS: FGID + Trauma patients exhibited greater temporal summation than FGID + No Trauma patients and healthy controls. Additionally, FGID + Trauma patients exhibited greater gastrointestinal and non-gastrointestinal symptom severity, number of chronic pain sites, and disability. CONCLUSIONS: Assessing for trauma history in patients with FGIDs could identify a subset at risk for greater central sensitization and pain-related symptoms.

Race effects on temporal summation to heat pain in youth.

Racial differences in pain responsiveness have been demonstrated in adults. However, it is unclear whether racial differences are also present in youth and whether they extend to experimental pain indices assessing temporal summation of second pain (TSSP). Temporal summation of second pain provides an index of pain sensitivity and may be especially relevant in determining risk for chronic pain. This study assessed pain tolerance and TSSP to evoked thermal pain in 78 healthy youth (age range, 10-17), 51% of whom were African American and 49% were non-Hispanic white. Multilevel models revealed within-individual increases in pain ratings during the temporal summation task in non-Hispanic white youth that were consistent with TSSP. Pain ratings did not change significantly during the temporal summation task in African-American youth. Baseline evoked pain ratings were significantly higher in African-American compared with non-Hispanic white youth. These findings suggest that enhanced responsiveness to evoked thermal pain in African Americans is present in adolescence but is unlikely to be related to elevated TSSP. These results may have implications for understanding racial differences in chronic pain experience in adulthood.

Lactose-Free Milk or Soy-Based Formulas Do Not Improve Caregivers' Distress or Perceptions of Difficult Infant Behavior.

OBJECTIVES: The aim of the study was to test the hypothesis that caregiver-reported difficulties in infant behavior and caregivers' distress will significantly improve on lactose-free (LF) milk-based or LF soy-based formulas compared with a milk-based, lactose-containing formula. METHODS: In this double-blind randomized controlled trial, infants (mean age: 4.97 weeks) with caregiver-reported feeding problems on a milk-based lactose-containing formula were randomized to receive either LF milk-based (n = 96), LF soy-based (n = 97), or milk-based, lactose-containing (n = 103) formula. Study formula was infants' sole item of diet for 14 days. Infants' caregivers completed measures of infant behavior and caregivers' distress for the week preceding baseline and again for the week preceding the 14-day follow-up. RESULTS: Infants who received LF milk or LF soy-based formulas did not significantly differ from those who received milk-based, lactose-containing formula on follow-up caregiver-reported measures of infant difficultness from the Infant Characteristics Questionnaire, F(2, 277) = 0.83, nor on measures of caregivers' distress, assessed with measures of caregivers' mental health and parenting efficacy, F(2, 285) = 0.73-1.07. Across the 3 formula groups, scores on outcome measures significantly improved from baseline to follow-up (P < 0.001). CONCLUSIONS: Our study does not support LF milk or LF soy-based formulas to alleviate common infant behaviors such as fussiness, crying, or need for attention. Moreover, the data suggest that some difficulties in infant behaviors, as well as caregivers' distress and perceived efficacy in parenting difficult infants, may improve within a couple weeks of reporting difficulties to the pediatrician.

Validation of the Abdominal Pain Index using a revised scoring method.

OBJECTIVE: Evaluate the psychometric properties of child- and parent-report versions of the four-item Abdominal Pain Index (API) in children with functional abdominal pain (FAP) and healthy controls, using a revised scoring method that facilitates comparisons of scores across samples and time. METHODS: Pediatric patients aged 8-18 years with FAP and controls completed the API at baseline (N = 1,967); a subset of their parents (N = 290) completed the API regarding the child's pain. Subsets of patients completed follow-up assessments at 2 weeks (N = 231), 3 months (N = 330), and 6 months (N = 107). Subsets of both patients (N = 389) and healthy controls (N = 172) completed a long-term follow-up assessment (mean age at follow-up = 20.21 years, SD = 3.75). RESULTS: The API demonstrated good concurrent, discriminant, and construct validity, as well as good internal consistency. CONCLUSION: We conclude that the API, using the revised scoring method, is a useful, reliable, and valid measure of abdominal pain severity.

A developmental analysis of the factorial validity of the parent-report version of the Adult Responses to Children's Symptoms in children versus adolescents with chronic pain or pain-related chronic illness.

UNLABELLED: The widely used Adult Responses to Children's Symptoms measures parental responses to child symptom complaints among youth aged 7 to 18 years with recurrent/chronic pain. Given developmental differences between children and adolescents and the impact of developmental stage on parenting, the factorial validity of the parent-report version of the Adult Responses to Children's Symptoms with a pain-specific stem was examined separately in 743 parents of 281 children (7-11 years) and 462 adolescents (12-18 years) with chronic pain or pain-related chronic illness. Factor structures of the Adult Responses to Children's Symptoms beyond the original 3-factor model were also examined. Exploratory factor analysis with oblique rotation was conducted on a randomly chosen half of the sample of children and adolescents as well as the 2 groups combined to assess underlying factor structure. Confirmatory factor analysis was conducted on the other randomly chosen half of the sample to cross-validate factor structure revealed by exploratory factor analyses and compare it to other model variants. Poor loading and high cross-loading items were removed. A 4-factor model (Protect, Minimize, Monitor, and Distract) for children and the combined (child and adolescent) sample and a 5-factor model (Protect, Minimize, Monitor, Distract, and Solicitousness) for adolescents was superior to the 3-factor model proposed in previous literature. Future research should examine the validity of derived subscales and developmental differences in their relationships with parent and child functioning. PERSPECTIVE: This article examined developmental differences in the structure of a widely used measure of caregiver responses to chronic pain or pain-related chronic illness in youth. Results suggest that revised structures that differ across developmental groups can be used with youth with a range of clinical pain-related conditions.

Functional abdominal pain in childhood and long-term vulnerability to anxiety disorders.

BACKGROUND: Cross-sectional studies link functional abdominal pain (FAP) to anxiety and depression in childhood, but no prospective study has evaluated psychiatric status in adulthood or its relation to pain persistence. METHODS: Pediatric patients with FAP (n = 332) and control subjects (n = 147) were tracked prospectively and evaluated for psychiatric disorders and functional gastrointestinal disorders (FGIDs) at follow-up in adolescence and young adulthood (mean age = 20.01 years). Participants were classified according to presence (FGID-POS) or absence (FGID-NEG) of FGIDs at follow-up. RESULTS: Lifetime and current risk of anxiety disorders was higher in FAP than controls (lifetime: 51% vs 20%; current: 30% vs 12%). Controlling for gender and age, the odds ratio was 4.9 (confidence interval = 2.83-7.43) for lifetime anxiety disorder and 3.57 (confidence interval = 2.00-6.36) for current anxiety disorder at follow-up for FAP versus controls. Lifetime risk of depressive disorder was significantly higher in FAP versus controls (40% vs. 16%); current risk did not differ. In most cases, initial onset of anxiety disorders was before pediatric FAP evaluation; onset of depressive disorders was subsequent to FAP evaluation. Within the FAP group, risk of current anxiety disorders at follow-up was significantly higher for FGID-POS versus FGID-NEG (40% vs 24%), and both were higher than controls (12%); current depressive disorders did not differ across FGID-POS, FGID-NEG, and controls. CONCLUSIONS: Patients with FAP carry long-term vulnerability to anxiety that begins in childhood and persists into late adolescence and early adulthood, even if abdominal pain resolves.

Individual and additive effects of mothers' and fathers' chronic pain on health outcomes in young adults with a childhood history of functional abdominal pain.

OBJECTIVE: To evaluate effects of mothers' and fathers' chronic pain on health outcomes in adult sons and daughters with a childhood history of functional abdominal pain (FAP). METHOD: Adults (n = 319; Mean age = 22.09 years) with a childhood history of FAP reported parental history of chronic pain and their own current health (chronic pain, somatic symptoms, disability, use of medication and health care, illness-related job loss). RESULTS: Positive histories of maternal and paternal chronic pain were each associated with poorer health in sons and daughters, regardless of child or parent gender. Having 2 parents with chronic pain was associated with significantly poorer health than having 1 or neither parent with chronic pain. CONCLUSIONS: Chronic pain in both mothers and fathers is associated with poor health and elevated health service use in young adults with a childhood history of FAP. Having both parents with chronic pain increases risk for adverse outcomes.

Functional abdominal pain patient subtypes in childhood predict functional gastrointestinal disorders with chronic pain and psychiatric comorbidities in adolescence and adulthood.

Although pediatric functional abdominal pain (FAP) has been linked to abdominal pain later in life, childhood predictors of long-term outcomes have not been identified. This study evaluated whether distinct FAP profiles based on patterns of pain and adaptation in childhood could be identified and whether these profiles predicted differences in clinical outcomes and central sensitization (wind-up) on average 9years later. In 843 pediatric FAP patients, cluster analysis was used to identify subgroups at initial FAP evaluation based on profiles of pain severity, gastrointestinal (GI) and non-GI symptoms, pain threat appraisal, pain coping efficacy, catastrophizing, negative affect, and activity impairment. Three profiles were identified: high pain dysfunctional, high pain adaptive, and low pain adaptive. Logistic regression analyses controlling for age and sex showed that, compared with pediatric patients with the low pain adaptive profile, those with the high pain dysfunctional profile were significantly more likely at long-term follow-up to meet criteria for pain-related functional gastrointestinal disorder (FGID) (odds ratio: 3.45, confidence interval: 1.95 to 6.11), FGID with comorbid nonabdominal chronic pain (odds ratio: 2.6, confidence interval: 1.45 to 4.66), and FGID with comorbid anxiety or depressive psychiatric disorder (odds ratio: 2.84, confidence interval: 1.35 to 6.00). Pediatric patients with the high pain adaptive profile had baseline pain severity comparable to that of the high pain dysfunctional profile, but had outcomes as favorable as the low pain adaptive profile. In laboratory pain testing at follow-up, high pain dysfunctional patients showed significantly greater thermal wind-up than low pain adaptive patients, suggesting that a subgroup of FAP patients has outcomes consistent with widespread effects of heightened central sensitization.