Pain site persistence and changes from childhood to adolescence: a prospective cohort study.

BACKGROUND: Pain is a complex experience that interferes with the well-being of youth who experience it. We aimed to assess whether recurrent pain sites in childhood can predict later recurrent pain sites prospectively. METHODS: Pain was assessed using the Luebeck Pain Screening Questionnaire at ages 7, 10, and 13 from the Generation XXI cohort. We used multinomial regression to assess the association of recurrent pain sites at ages 7 and 10 with those at age 13. RESULTS: We included 3833 participants. Boys with recurrent abdominal/pelvic pain at age 7 were more likely to report headaches (OR 2.81; 95%CI 1.48-5.34), abdominal/pelvic (OR 2.92; 95%CI 1.46-5.84), and musculoskeletal pain (OR 1.55; 95%CI 1.02-2.34) at age 13. Girls with recurrent abdominal/pelvic pain at age 7 were more likely to report both musculoskeletal (OR 1.62; 95%CI 1.10-2.40) and abdominal/pelvic pain (OR 1.74; 95%CI 1.15-2.65). At age 10, all pain sites were associated with pain in the same site at age 13. CONCLUSION: Recurrent abdominal/pelvic pain at age 7 may be related to the development of various pains in adolescence. Pain at a given site at age 10 can be associated with pain at that same site at age 13. IMPACT: Recurrent abdominal or pelvic pain during childhood was distinctively associated with an increased risk of recurrent pain in other sites during adolescence. Recurrent pain during childhood was associated with pain in the same sites at age 13, and this persistence seemed to emerge between the ages of 7 and 10 for both boys and girls. Studying early pain sites may add to the understanding of the etiology of chronic pain.

Evaluation of four gamma-based methods for calculating confidence intervals for age-adjusted mortality rates when data are sparse.

BACKGROUND: Equal-tailed confidence intervals that maintain nominal coverage (0.95 or greater probability that a 95% confidence interval covers the true value) are useful in interval-based statistical reliability standards, because they remain conservative. For age-adjusted death rates, while the Fay-Feuer gamma method remains the gold standard, modifications have been proposed to streamline implementation and/or obtain more efficient intervals (shorter intervals that retain nominal coverage). METHODS: This paper evaluates three such modifications for use in interval-based statistical reliability standards, the Anderson-Rosenberg, Tiwari, and Fay-Kim intervals, when data are sparse and sample size-based standards alone are overly coarse. Initial simulations were anchored around small populations (P = 2400 or 1200), the median crude all-cause US mortality rate in 2010-2019 (833.8 per 100,000), and the corresponding age-specific probabilities of death. To allow for greater variation in the age-adjustment weights and age-specific probabilities, a second set of simulations draws those at random, while holding the mean number of deaths at 20 or 10. Finally, county-level mortality data by race/ethnicity from four causes are selected to capture even greater variation: all causes, external causes, congenital malformations, and Alzheimer disease. RESULTS: The three modifications had comparable performance when the number of deaths was large relative to the denominator and the age distribution was as in the standard population. However, for sparse county-level data by race/ethnicity for rarer causes of death, and for which the age distribution differed sharply from the standard population, coverage probability in all but the Fay-Feuer method sometimes fell below 0.95. More efficient intervals than the Fay-Feuer interval were identified under specific circumstances. When the coefficient of variation of the age-adjustment weights was below 0.5, the Anderson-Rosenberg and Tiwari intervals appeared to be more efficient, whereas when it was above 0.5, the Fay-Kim interval appeared to be more efficient. CONCLUSIONS: As national and international agencies reassess prevailing data presentation standards to release age-adjusted estimates for smaller areas or population subgroups than previously presented, the Fay-Feuer interval can be used to develop interval-based statistical reliability standards with appropriate thresholds that are generally applicable. For data that meet certain statistical conditions, more efficient intervals could be considered.

Mother-reported pain experience between ages 7 and 10: A prospective study in a population-based birth cohort.

BACKGROUND: Trajectory studies suggest considerable stability of persistent or recurrent pain in adolescence. This points to the first decade of life as an important aetiologic window for shaping future pain, where the potential for prevention may be optimised. OBJECTIVES: We aimed to quantify changes in mother-reported pain experience in children between ages 7 and 10 and describe clusters of different pain experiences defined by complementary pain features. METHODS: We conducted a prospective study using data from 4036 Generation XXI birth cohort participants recruited in 2005-06. Pain history was reported by mothers at ages 7 and 10 using the Luebeck pain screening questionnaire. We tracked changes in six pain features over time using relative risks (RRs) and their 95% confidence intervals (95% CIs). Clusters were obtained using the k-medoids algorithm. RESULTS: The risk of severe pain at age 10 increased with increasing severity at age 7, with RRs ranging from 2.18 (95% CI 1.90, 2.50) for multisite to 4.43 (95% CI 3.19, 6.15) for high frequency pain at age 7. A majority of children (59.4%) had transient or no pain but two clusters included children with stable recurrent pain (n = 404, 10.2% of the sample). One of those (n = 177) was characterised by higher probabilities of multisite pain (74.6% and 66.7% at ages 7 and 10, respectively), with psychosocial triggers/contexts (59.3% and 61.0%) and daily-living restrictions (72.2% and 84.6%). Most children in that cluster (58.3%) also self-reported recent pain at age 10 and had more frequent family history of chronic pain (60.5%). CONCLUSIONS: All pain features assessed tracked with a positive gradient between ages 7 and 10, arguing for the significance of the first decade of life in the escalation of the pain experience. Multisite pain and psychosocial attributions appeared to be early markers of more adverse pain experiences.

Measuring the Magnitude of Health Inequality Between 2 Population Subgroup Proportions.

In this paper, we evaluate 11 measures of inequality, d(p1, p2), between 2 proportions p1 and p2, some of which are new to the health disparities literature. These measures are selected because they are continuous, nonnegative, equal to 0 if and only if |p1 - p2| = 0, and maximal when |p1 - p2| = 1. They are also symmetrical [d(p1, p2) = d(p2, p1)] and complement-invariant [d(p1, p2) = d(1 - p2, 1 - p1)]. To study intermeasure agreement, 5 of the 11 measures, including the absolute difference, are retained, because they remain finite and are maximal if and only if |p1 - p2| = 1. Even when the 2 proportions are assumed to be drawn at random from a shared distribution-interpreted as the absence of an avoidable difference-the expected value of d(p1, p2) depends on the shape of the distribution (and the choice of d) and can be quite large. To allow for direct comparisons among measures, we propose a standard measurement unit akin to a z score. For skewed underlying beta distributions, 4 of the 5 retained measures, once standardized, offer more conservative assessments of the magnitude of inequality than the absolute difference. We conclude that, even for measures that share the highlighted mathematical properties, magnitude comparisons are most usefully assessed relative to an elicited or estimated underlying distribution for the 2 proportions.

Issues in Developing Multidimensional Indices of State-level Health Inequalities: National Health Interview Survey, 2013-2015.

To describe methodological issues that arise in the construction and design-based estimation of multidimensional indices that aggregate state-specific inequalities in core health measures, using data from the National Health Interview Survey (NHIS).

National Center for Health Statistics Data Presentation Standards for Proportions.

The National Center for Health Statistics (NCHS) disseminates information on a broad range of health topics through diverse publications. These publications must rely on clear and transparent presentation standards that can be broadly and efficiently applied. Standards are particularly important for large, cross-cutting reports where estimates cannot be individually evaluated and indicators of precision cannot be included alongside the estimates. This report describes the NCHS Data Presentation Standards for Proportions. The multistep NCHS Data Presentation Standards for Proportions are based on a minimum denominator sample size and on the absolute and relative widths of a confidence interval calculated using the Clopper-Pearson method. Proportions (usually multiplied by 100 and expressed as percentages) are the most commonly reported estimates in NCHS reports.

Measurement of Health Disparities, Health Inequities, and Social Determinants of Health to Support the Advancement of Health Equity.

Reduction of health disparities and advancement of health equity in the United States require high-quality data indicative of where the nation stands vis-à-vis health equity, as well as proper analytic tools to facilitate accurate interpretation of these data. This article opens with an overview of health equity and social determinants of health. It then proposes a set of recommended practices in measurement of health disparities, health inequities, and social determinants of health at the national level to support the advancement of health equity, highlighting that (1) differences in health and its determinants that are associated with social position are important to assess; (2) social and structural determinants of health should be assessed and multiple levels of measurement should be considered; (3) the rationale for methodological choices made and measures chosen should be made explicit; (4) groups to be compared should be simultaneously classified by multiple social statuses; and (5) stakeholders and their communication needs can often be considered in the selection of analytic methods. Although much is understood about the role of social determinants of health in shaping the health of populations, researchers should continue to advance understanding of the pathways through which they operate on particular health outcomes. There is still much to learn and implement about how to measure health disparities, health inequities, and social determinants of health at the national level, and the challenges of health equity persist. We anticipate that the present discussion will contribute to the laying of a foundation for standard practice in the monitoring of national progress toward achievement of health equity.

Bullying Involvement and Physical Pain Between Ages 10 and 13 Years: Reported History and Quantitative Sensory Testing in a Population-Based Cohort.

We aimed to quantify the prospective association between bullying and physical pain in a population-based cohort of adolescents. We assessed 4,049 participants of the 10 and 13 years waves of the Generation XXI birth cohort study in Portugal. Pain history was collected using the Luebeck pain screening questionnaire. A subsample of 1,727 adolescents underwent computerized cuff pressure algometry to estimate pain detection/tolerance thresholds, temporal pain summation and conditioned pain modulation. Participants completed the Bully Scale Survey and were classified as "victim only", "both victim and aggressor", "aggressor only", or "not involved". Associations were quantified using Poisson or linear regression, adjusted for sex and adverse childhood experiences. When compared to adolescents "not involved", participants classified as "victim only" or "both victim and aggressor" at age 10 had higher risk of pain with psychosocial triggers, pain that led to skipping leisure activities, multisite pain, pain of higher intensity, and pain of longer duration, with relative risks between 1.21 (95% confidence interval: .99, 1.49) and 2.17 (1.57, 3.01). "Victims only" at age 10 had lower average pain detection and tolerance thresholds at 13 years (linear regression coefficients: -1.81 [-3.29, -.33] and -2.73 [-5.17, -.29] kPa, respectively), as well as higher pain intensity ratings (.37 [.07, .68] and .39 [.06, .72] mm), when compared with adolescents not involved. No differences were seen for the remaining bullying profiles or sensory measures. Our findings suggest that bullying may have long-term influence on the risk of chronic musculoskeletal pain and may interfere with responses to painful stimuli. PERSPECTIVE: We found prospective evidence that bullying victimization in youth: 1) is more likely to lead to negative reported pain experiences than the reverse, 2) may have long-term influence on adverse pain experiences, and 3) may contribute to pain phenotypes partly by interfering with somatosensory responses to painful stimuli.

Association between adverse childhood experiences and bodily pain in early adolescence.

We aimed to examine the relationship between lifetime exposure to adverse childhood experiences (ACEs) during the first decade of life and recent pain features reported in early adolescence. We conducted a prospective study using data from 4564 adolescent Generation XXI birth cohort participants recruited in 2005-2006. Adverse childhood experiences were reported by children at ages 10 and 13 years using a 15-item questionnaire. Recent pain features (e.g., any pain, pain sites, recurrent pain intensity, and recurrent pain duration) were measured using structured questionnaires, including the Luebeck pain screening questionnaire at age 13. Using hierarchical binary and multinomial logistic regression analyses with progressive adjustments for confounders, we estimated the associations [adjused odds ratios (aOR) with their 95% confidence intervals (95% CI)] between exposure to ACEs at 10 and pain features at 13 years. The study revealed a statistically significant association between exposure to ACEs reported at age 10 and any pain experienced at age 13 (OR = 1.09; 95% CI [1.07, 1.12]). Even after accounting for the newly reported ACEs at age 13, the association with ACEs at age 10, remained significant (aOR = 1.11 [95% CI, 1.08-1.14]). Consistent patterns were observed when the number of pain sites, recurrent pain intensity, or recurrent pain duration were used as outcome variables instead of any pain at age 13. Adverse childhood experiences occurring during the first decade of life predict the onset of pain features during early adolescence. Consequently, childhood exposure to adversity should be considered a pivotal initial exposure in a pathway leading to chronic pain later in life.

Prevalence, characteristics, and impact of spinal and lower limb recurrent pain at age 13.

OBJECTIVES: To compare spinal and lower limb pain in adolescents regarding prevalence, characteristics, causes, and impact. METHODS: A descriptive cross-sectional study was conducted in 13-year-old adolescents (female n=2210; male n=2353) from the Portuguese Generation XXI birth cohort. Data were collected between 2018 and 2020 through personal interviews by applying the Luebeck Pain Questionnaire. The pain features examined in each anatomical location (back and lower limb) were recurrence, duration, frequency, intensity, perceived causes, and impact on school and leisure activities. Frequencies and the Chi-square test were used. RESULTS: Questionnaires from 4563 adolescents were analysed, 57.9% had pain in the last three months (main pain in the spine: 11.6%; main pain in the lower limb: 29.0%). Of those, 69.4% and 62.4% reported recurrent pain in the spine and lower limb, respectively. Recurrent pain was more frequent in girls than in boys (spine: 80.0%; 57.0%; lower limb: 70.4%; 58.1% respectively). Pain lasted more than three months in most adolescents (spine: about 60%; lower limb: above 50%); frequency was similarly high in both regions and both sexes (girls: 47.0%; boys: 45.7% in the spine; girls: 45.7%; boys: 40.3% in the lower limb); intensity was rated as high by girls (spine: 45.5%; lower limb: 47.3%) and moderate by boys (spine: 42.0%; lower limb: 41.0%). The leading causes of pain were daily living activities, both for the spine (girls: 65.9%; boys: 76.5%) and the lower limb (girls: 62.2%; boys: 72.1%). Psychosocial causes were the second most common cause of spinal pain (girls: 25.0%; boys: 21.0%). Other causes of lower limb pain were traumatic (girls: 25.5%; boys: 16.6%) and physical factors (girls: 20.7%; boys: 23.8%). Absences from school (girls: 11.7%; boys: 4.8%) and restrictions of leisure activities (girls: 20.7%; boys: 25.2%) were more related to pain in the lower limb. CONCLUSION: More than half of the adolescents reported spinal or lower limb recurrent pain, which presents a higher frequency, higher intensity, and longer duration in the spine. However, lower limb pain led to more concurrent limitations.

Pain history and experimental pressure pain responses in adolescents: Results from a population-based birth cohort.

BACKGROUND: Sensitized pain mechanisms are often reported in musculoskeletal pain conditions, but population-based paediatric studies are lacking. We assessed whether adolescents with musculoskeletal pain history had evidence of increased responsiveness to experimental pressure stimuli. METHODS: Data were from 1496 adolescents of the Generation XXI birth cohort. Pain history was collected using the Luebeck Pain Questionnaire (self-reported at 13, parent-reported at 7 and 10 years). Two case definitions for musculoskeletal pain were considered: (1) cross-sectional-musculoskeletal pain lasting more than 3 months at age 13 and (2) longitudinal-musculoskeletal pain at age 13 with musculoskeletal pain reports at ages 7 and/or 10. Lower limb cuff pressure algometry was used to assess pain detection and tolerance thresholds, conditioned pain modulation effects (CPM, changes in thresholds in the presence on painful conditioning) and temporal summation of pain effects (TSP, changes in pain intensity to 10 phasic painful cuff stimulations). RESULTS: Adolescents with musculoskeletal pain at age 13 plus a history of pain in previous evaluations (longitudinal definition) had lower pain tolerance thresholds compared to the remaining sample (40.2 v. 49.0 kPa, p = 0.02), but showed no differences in pain detection threshold, CPM effect and TSP effect. Pain sensitivity, CPM effects and TSP effects were not significantly different when the current pain only case definition (cross-sectional) was used. CONCLUSIONS: Adolescents with current musculoskeletal pain who had a history of pain since childhood had lower tolerance to cuff stimulation. This may suggest long-standing musculoskeletal pain since childhood may contribute to sensitisation, rather than the presence of current pain only. SIGNIFICANCE: Repeated musculoskeletal pain up to age 13 years may contribute to higher pain sensitivity (particularly lowered pressure pain tolerance) in the general adolescent population. This does not seem to be the case when reported pain experiences are recent or when the outcomes are temporal pain summation or CPM. In this community-based paediatric sample, the vast majority showed no sign of altered pain processing, but a small fraction may reveal some pain sensitization at 13 years of age.

Invited commentary: Can changes in the distributions of and associations between education and income bias estimates of temporal trends in health disparities?

Chen et al. (Am J Epidemiol. 2013;177(9):870-881) develop a simulation study for comparing various measures of socioeconomic health disparities when bias can arise from temporal changes in the bivariate distribution of education and income. In this commentary, I argue that, in relation to health, the "meaning" of education cannot be reduced to its socioeconomic value; improved health literacy, for instance, can result in important health benefits. Further, I suggest that unless there is a substantial prior understanding of the data-generating mechanism, directed acyclic graph models should be avoided because causal relationships cannot be inferred from regression. An alternative is to resort to conditional independence graphs, which use only undirected edges. Finally, although the slope index of inequality can, in some specific cases, be seen to reduce bias in temporal comparisons of socioeconomic health disparities, it was not designed for causal inference. The slope index of inequality simply describes the average change in the proportion in poor health when the population is ordered by socioeconomic status.

Evaluation of the National Center for Health Statistics Data Presentation Standards for Rates From Vital Statistics and Sample Surveys.

For the CIs used in the Standards for rates from vital statistics and complex health surveys, this report evaluates coverage probability, relative width, and the resulting percentage of rates flagged as statistically unreliable when compared with previously used standards. Additionally, the report assesses the impact of design effects and the denominator's sampling variability, when applicable.

Refining the prediction of multisite pain in 13-year-old boys and girls by using parent-reported pain experiences in the first decade of life.

BACKGROUND: We evaluated different pain profiles as prospective predictors of multisite pain in 13-year-old adolescents (1300 girls and 1457 boys) enrolled in Generation XXI, a birth cohort study in Portugal. METHODS: Pain history was queried using the Luebeck Pain Questionnaire through parent proxy- (ages 7 and 10) and adolescent (age 13) self-reports. We estimated the risk of multisite pain (2 or more pain sites) at age 13, according to previous pain experiences, including accumulation and timing. We defined five profiles that combined adverse features at ages 7 and 10 (recurrence, multisite, frequency, duration, intensity, triggers, activity restrictions, passive coping, and family history) and estimated their relative risks (RR) and likelihood ratios (LR) for adolescent multisite pain. RESULTS: At age 13, 39.2% of girls and 27.2% of boys reported multisite pain in the previous three months. The risk was higher among girls with multisite and recurrent pain at ages 7 and 10 than in girls without those adverse features, especially if psychosocial triggers were also present (RR 1.87; 95% confidence interval 1.36, 2.36 and LR 3.49; 1.53, 7.96). Boys with recurrent pain of higher frequency and causing activity restrictions at ages 7 and 10 had a higher risk of multisite pain at 13 (RR 2.05; 1.03, 3.05 and LR 3.06; 1.12, 8.39). Earlier adverse experiences were more predictive of future pain in girls than in boys. CONCLUSIONS: Different profiles were useful to rule in future multisite pain in boys and girls. This provides clues for early stratification of chronic pain risk. SIGNIFICANCE: We identified sex-specific pain features that can be collected by practitioners in the first decade of life to improve the stratification of children in terms of their future risk of a maladaptive pain experience in adolescence. Using a prospective population-based cohort design, we show that early multisite pain and psychosocial triggers are relevant predictors of future multisite pain in girls, whereas repeated reports of high-frequency pain leading to activity restrictions are predictive of adolescent multisite pain in boys.

Adverse childhood experiences and bodily pain at 10 years of age: Findings from the Generation XXI cohort.

BACKGROUND: Youth and young adults with pain conditions report having a history of adverse childhood experiences (ACEs) more frequently than their healthy peers. The relationship between ACEs and pain before adolescence in population-based settings is not extensively researched. OBJECTIVE: To examine the association between the history of ACEs and bodily pain at 10 years of age. PARTICIPANTS AND SETTING: Cross-sectional analysis of 4738 participants of Generation XXI population-based birth cohort, recruited in 2005-06 in Porto, Portugal. METHODS: Study includes self-reported data on ACEs exposures and bodily pain (pain presence, sites, and intensity a week prior to the interview). Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were obtained from binary and multinomial logistic regression analyses to estimate the likelihood of various pain features according to the extent of exposure to ACEs (i.e., 0 ACEs, 1-3 ACEs, 4-5 ACEs, and ≥ 6 ACEs). RESULTS: Prevalence of pain, multisite, and high-intensity pain a week prior to the interview increased with increasing exposure to ACEs. After controlling for sociodemographic characteristics, children who had experienced ≥6 ACEs were more likely to report pain [AOR 3.18 (95% CI 2.19, 4.74)], multisite pain [AOR 2.45 (95% CI 1.37, 4.40)], and high-intensity pain [AOR 4.27 (95% CI 2.56, 7.12)] compared with children with no ACEs. CONCLUSIONS: A dose-response association was observed between the cumulative number of ACEs and reports of pain in 10-year-old children, suggesting that embodiment of ACEs starts as early as childhood and that pain related to ACEs begins earlier than previously reported.

A multidimensional perspective of the relation between social isolation and depression among Portuguese older adults.

We aimed to explore how different social isolation components were associated with depression among older adults in Portugal. We analysed data collected through structured questionnaires in 2017 from 643 Portuguese adults aged 60 and over. Depression was assessed using the Geriatric Depression Scale (Short-Form). Social isolation was operationalised using objective indicators - living alone, marital status, leisure activities - and subjective indicator - perceived social support. Because social isolation is a multidimensional construct that is likely to be more than the sum of its components, cluster analysis was conducted to group individuals into social isolation profiles. Associations were estimated using adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Five profiles were identified: Cluster 1 (partnered; high social support; high variety of leisure activities); Cluster 2 (partnered; high social support; few leisure activities); Cluster 3 (not partnered; low social support; few leisure activities); Cluster 4 (living alone; high social support; high variety of leisure activities); Cluster 5 (partnered; high social support; limited variety of leisure activities). Compared with Cluster 1, participants in Cluster 2 were three times more likely to have depression, independent of age, gender, education, comorbidities and self-rated health (OR = 3.04; 95% CI: 1.38-6.71). Participants in Cluster 3 presented the highest probability of depression that was not explained by any of the confounders (OR = 4.74; 95% CI: 2.15-10.44). Older adults living alone are not necessarily more prone to depression, with social support and leisure activities playing an important role. To disentangle how social isolation affects health, objective and subjective isolation measures should be considered.

Examining Progress Toward Elimination of Racial and Ethnic Health Disparities for Healthy People 2020 Objectives Using Three Measures of Overall Disparity.

This report examines changes in health disparities over time by race and ethnicity for HP2020 objectives using three measures of disparity.

A symmetrized Theil index measure of health disparities: An example using dental caries in U.S. children and adolescents.

While the health status of Americans has generally improved over time, health disparities among groups of the population have been pervasive. Designing a measure that tracks the resulting disparities remains a challenge. In this paper, we propose a new measure of health disparities the Symmetrized Theil Index (STI), and derive its design-based sampling variance in grouped survey data. Because STI is symmetric, it circumvents the drawback of the Theil Index in how groups are weighted: indeed, the latter is mostly influenced by groups with high disease frequencies. Moreover, STI is related to Pearson's chi-square test of independence for binary data, and to the F-test in one-way analysis-of-variance for continuous data. We illustrate our approach using data on dental caries for children and adolescents from the third National Health and Nutrition Examination Surveys (NHANES III; 1988-1994) and NHANES 1999-2004. Tooth decay remains the most common chronic disease in U.S. children and adolescents. Although their oral health has generally improved, we find no change in the prevalence or severity of untreated tooth decay in U.S. children and adolescents between surveys. These findings are consistently observed for both the overall STI and its between-group component across gender, race/ethnicity, country of birth, survey respondent's education, income and poverty-income ratio.

HPV vaccine status and sexual behavior among young sexually-active women in the US: evidence from the National Health and Nutrition Examination Survey, 2007-2014.

Concern has been expressed that human papillomavirus (HPV) vaccination programs might promote risky sexual behavior through mechanisms such as risk compensation, behavioral disinhibition, or perceived endorsement of sexual activity. This study assesses whether HPV vaccination status is associated with any differences in selected sexual behaviors among young sexually-active women in the US. Our dataset includes young, adult female respondents from questionnaire data collected in the National Center for Health Statistics' National Health and Nutrition Examination Survey from 2007 to 2014. The empirical approach implements a doubly robust estimation procedure, based on inverse probability of treatment weighting. For robustness, we implement several specifications for the propensity model and the outcomes model. We find no consistent association between HPV vaccination and condom usage or frequency of sex. Specifically, we find no evidence that HPV vaccination is associated with condom usage or with whether a person had sex more than 52 or more than 104 times per year. We find inconsistent evidence that HPV vaccination is associated with a person having sex more than 12 times per year. As in previous research, HPV vaccination does not appear to have a substantive effect on sexual behavior among young sexually-active women in the US.