Classification of blood pressure during sleep impacts designation of nocturnal nondipping.

The identification of nocturnal nondipping blood pressure (< 10% drop in mean systolic blood pressure from awake to sleep periods), as captured by ambulatory blood pressure monitoring, is a valuable element of risk prediction for cardiovascular disease, independent of daytime or clinic blood pressure measurements. However, capturing measurements, including determination of wake/sleep periods, is challenging. Accordingly, we sought to evaluate the impact of different definitions and algorithms for defining sleep onset on the classification of nocturnal nondipping. Using approaches based upon participant self-reports, applied definition of a common sleep period (12 am -6 am), manual actigraphy, and automated actigraphy we identified changes to the classification of nocturnal nondipping, and conducted a secondary analysis on the potential impact of an ambulatory blood pressure monitor on sleep. Among 61 participants in the Eastern Caribbean Health Outcomes Research Network hypertension study with complete ambulatory blood pressure monitor and sleep data, the concordance for nocturnal nondipping across methods was 0.54 by Fleiss' Kappa (depending on the method, 36 to 51 participants classified as having nocturnal nondipping). Sleep quality for participants with dipping versus nondipping was significantly different for total sleep length when wearing the ambulatory blood pressure monitor (shorter sleep duration) versus not (longer sleep duration), although there were no differences in sleep efficiency or disturbances. These findings indicate that consideration of sleep time measurements is critical for interpreting ambulatory blood pressure. As technology advances to detect blood pressure and sleep patterns, further investigation is needed to determine which method should be used for diagnosis, treatment, and future cardiovascular risk.

Breast cancer screening during the COVID-19 pandemic: moving from disparities to health equity.

The COVID-19 pandemic created unprecedented disruptions to routine health care in the United States. Screening mammography, a cornerstone of breast cancer control and prevention, was completely halted in the spring of 2020, and screening programs have continued to face challenges with subsequent COVID-19 waves. Although screening mammography rates decreased for all women during the pandemic, a number of studies have now clearly documented that reductions in screening have been greater for some populations than others. Specifically, minoritized women have been screened at lower rates than White women across studies, although the specific patterns of disparity vary depending on the populations and communities studied. We posit that these disparities are likely due to a variety of structural and contextual factors, including the differential impact of COVID-19 on communities. We also outline key considerations for closing gaps in screening mammography. First, practices, health systems, and communities must measure screening mammography use to identify whether gaps exist and which populations are most affected. Second, we propose that strategies to close disparities in breast cancer screening must be multifaceted, targeting the health system or practice, but also structural factors at the policy level. Health disparities arise from a complex set of conditions, and multimodal solutions that address the complex, multifactorial conditions that lead to disparities may be more likely to succeed and are necessary for promoting health equity.

The Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study: Design, Methods, and Baseline Characteristics.

Noncommunicable diseases (NCDs) account for a higher proportion of mortality and morbidity in the Caribbean and US territories-majority-minority communities-than in the United States or Canada. Strategies to address this disparity include enhancing data collection efforts among racial/ethnic communities. The ECHORN Cohort Study (ECS), a regional adult cohort study, estimates prevalence and assesses risk factors for NCDs in two United States territories and two Caribbean islands. Here, we describe the cohort study approach, sampling methods, data components, and demographic makeup for wave one participants. We enrolled ECS participants from each participating island using random and probability sampling frames. Data components include a clinical examination, laboratory tests, a brief clinical questionnaire, and a self-administered health survey. A subset of ECS participants provided a blood sample to biobank for future studies. Approximately 2961 participants were enrolled in wave one of the ECS. On average, participants are 57 years of age, and the majority self-identify as female. Data from the ECS allow for comparisons of NCD outcomes among racial/ethnic populations in the US territories and the US and evaluations of the impact of COVID-19 on NCD management and will help highlight opportunities for new research.

Development of the Anthropometric Grouping Index for the Eastern Caribbean Population Using the Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study Data.

Improving public health initiative requires an accurate anthropometric index that is better suited to a specific community. In this study, the anthropometric grouping index is proposed as a more efficient and discriminatory alternative to the popular BMI for the Eastern Caribbean population. A completely distribution-free cluster analysis was performed to obtain the 11 categories, leading to AGI-11. Further, we studied these groups using novel non-parametric clustering summaries. Finally, two generalized linear mixed models were fitted to assess the association between elevated blood sugar, AGI-11 and BMI. Our results showed that AGI-11 tends to be more sensitive in predicting levels of elevated blood sugar compared to BMI. For instance, individuals identified as obese III according to BMI are (POR: 2.57; 95% CI: (1.68, 3.74)) more likely to have elevated blood sugar levels, while, according to AGI, individuals with similar characteristics are (POR: 3.73; 95% CI: (2.02, 6.86)) more likely to have elevated blood sugar levels. In conclusion, the findings of the current study suggest that AGI-11 could be used as a predictor of high blood sugar levels in this population group. Overall, higher values of anthropometric measures correlated with a higher likelihood of high blood sugar levels after adjusting by sex, age, and family history of diabetes.

Patient preferences for facility-based management of hypertension and diabetes in rural Uganda: a discrete choice experiment.

OBJECTIVE: To explore how respondents with common chronic conditions-hypertension (HTN) and diabetes mellitus (DM)-make healthcare-seeking decisions. SETTING: Three health facilities in Nakaseke District, Uganda. DESIGN: Discrete choice experiment (DCE). PARTICIPANTS: 496 adults with HTN and/or DM. MAIN OUTCOME MEASURES: Willingness to pay for changes in DCE attributes: getting to the facility, interactions with healthcare providers, availability of medicines for condition, patient peer-support groups; and education at the facility. RESULTS: Respondents were willing to pay more to attend facilities that offer peer-support groups, friendly healthcare providers with low staff turnover and greater availabilities of medicines. Specifically, we found the average respondent was willing to pay an additional 77 121 Ugandan shillings (UGX) for facilities with peer-support groups over facilities with none; and 49 282 UGX for 1 month of medicine over none, all other things being equal. However, respondents would have to compensated to accept facilities that were further away or offered health education. Specifically, the average respondent would have to be paid 3929 UGX to be willing to accept each additional kilometre they would have to travel to the facilities, all other things being equal. Similarly, the average respondent would have to be paid 60 402 UGX to accept facilities with some health education, all other things being equal. CONCLUSIONS: Our findings revealed significant preferences for health facilities based on the availability of medicines, costs of treatment and interactions with healthcare providers. Understanding patient preferences can inform intervention design to optimise healthcare service delivery for patients with HTN and DM in rural Uganda and other low-resource settings.

Towards Reducing Health Information Inequities in the Caribbean: The Eastern Caribbean Health Outcomes Research Network Data Sharing Platform Usability Study.

There is a dearth of health research among Caribbean populations. Underrepresented individuals are affected by structural and data inequities that limit the usefulness, availability, and accessibility to health information systems and research-generated data. To overcome this limitation, a data sharing platform was created for the Eastern Caribbean Health Outcomes Research Network Cohort Study. This study aimed to evaluate the usability of the platform. Usability testing was conducted remotely, via video conferencing, using a cognitive walkthrough and think-aloud protocol. Participants completed a self-administered web-based survey which included an adapted version of the System Usability Scale (SUS). The results showed (N=16) overall average SUS score was 73.1 (SD±21.0), translating to a 'good' usability rating. Most recommendations for improvement focused on navigation and error prevention. Participatory data sharing platforms have the potential to reduce health information inequities in the Caribbean, however, usability testing should be conducted to improve user satisfaction and increase engagement.

Phenotypes of Hypertensive Ambulatory Blood Pressure Patterns: Design and Rationale of the ECHORN Hypertension Study.

Objective: To describe the rationale and design of a prospective study of ambulatory blood pressure measurement (ABPM) combined with measurement of contextual factors to identify hypertensive phenotypes in a Caribbean population with high rates of HTN and cardiovascular disease. Design: Prospective, multi-center sub-study. Setting: Eastern Caribbean Health Outcomes Research Network Cohort (ECHORN) Study, with study sites in Puerto Rico, the US Virgin Islands, Trinidad and Tobago, and Barbados. Participants: Community-residing adults without a diagnosis of HTN and not taking antihypertensive medication. Intervention: Ambulatory BP patterns are assessed using 24-hour ABPM. Contextual factors are assessed with: ecological momentary assessment (7-item survey of experiences, exposures and responses associated with daytime BP measurements); actigraphy (capturing physical activity and sleep quality); and self-report surveys (assessing physical and social health, environmental and social stressors and supports). Main Outcome Measures: Phenotypes of contextual factors associated with hypertensive BP patterns (sustained HTN, masked HTN, and nocturnal non-dipping). Methods and Results: This study will enroll 500 participants; assessments of blood pressure and contextual factors will be conducted during Waves 2 and 3 of the ECHORN parent study, occurring 2 years apart. In Wave 2, we will assess the association between contextual factors and ABPM patterns. Using advanced analytic clustering methods, we will identify phenotypes of contextual factors associated with hypertensive ABPM patterns. We will then test the stability of these phenotypes and their ability to predict change in ABPM patterns between Waves 2 and 3. Conclusions: Assessment of ABPM, and the contextual factors influencing ABPM, can identify unique phenotypes of HTN, which can then be used to develop more precision-based approaches to the prevention, detection and treatment of HTN in high-risk populations.

Risk of Injury by Unionization: Survival Analysis of a Large Industrial Cohort.

OBJECTIVE: To investigate the effect of union status on injury risk among a large industrial cohort. METHODS: The cohort included hourly employees at 19 US plants between 2000 and 2007. Plants were classified by union status, and injuries were classified by severity. Cox-proportional hazard shared frailty model was used to determine time to first reportable injury. RESULTS: A total of 26,462 workers were included: 18,955 (72%) unionized and 7507 (28%) non-unionized. Union workers incurred 3194 injuries (16.9%) compared with 618 injuries for non-union workers (8.2%). After adjusting for multiple covariates, union workers had a 51% higher risk of reportable injury. CONCLUSIONS: Our results provide evidence for higher risk of reportable injuries in union workers; explanations for this increased risk remain unclear.

Occupational noise exposure and risk of hypertension in an industrial workforce.

BACKGROUND: Community noise exposure has been shown to increase the risk of hypertension; however, the relationship between occupational noise exposure and hypertension is less clear. METHODS: Using an inception cohort of workers in a specialty metals manufacturing company, we retrospectively assessed occupational noise exposure, hearing acuity, and incident hypertension diagnoses using administrative datasets. Time-weighted average noise exposure levels were assigned to employees based on their job histories. Cox proportional hazards models were performed to determine the association of noise exposure with risk of incident hypertension. RESULTS: The adjusted hazard ratio (HR) of incident hypertension did not significantly differ between groups by cumulative continuous or categorized noise exposure metric. CONCLUSION: We found no increased risk of incident hypertension with exposure to occupational noise among workers. Further assessment examining workers' use of hearing protection devices is warranted.

Expert ratings of job demand and job control as predictors of injury and musculoskeletal disorder risk in a manufacturing cohort.

OBJECTIVE: To examine associations between workplace injury and musculoskeletal disorder (MSD) risk and expert ratings of job-level psychosocial demand and job control, adjusting for job-level physical demand. METHODS: Among a cohort of 9260 aluminium manufacturing workers in jobs for which expert ratings of job-level physical and psychological demand and control were obtained during the 2 years following rating obtainment, multivariate mixed effects models were used to estimate relative risk (RR) of minor injury and minor MSD, serious injury and MSD, minor MSD only and serious MSD only by tertile of demand and control, adjusting for physical demand as well as other recognised risk factors. RESULTS: Compared with workers in jobs rated as having low psychological demand, workers in jobs with high psychological demand had 49% greater risk of serious injury and serious MSD requiring medical treatment, work restrictions or lost work time (RR=1.49; 95% CI 1.10 to 2.01). Workers in jobs rated as having low control displayed increased risk for minor injury and minor MSD (RR=1.45; 95% CI 1.12 to 1.87) compared with those in jobs rated as having high control. CONCLUSIONS: Using expert ratings of job-level exposures, this study provides evidence that psychological job demand and job control contribute independently to injury and MSD risk in a blue-collar manufacturing cohort, and emphasises the importance of monitoring psychosocial workplace exposures in addition to physical workplace exposures to promote worker health and safety.

Bladder cancer screening in aluminum smelter workers.

OBJECTIVE: To present results of a bladder cancer screening program conducted in 18 aluminum smelters in the United States from January 2000 to December 2010. METHODS: Data were collected on a cohort of workers with a history of working in coal tar pitch volatile exposed areas including urine analysis for conventional cytology and ImmunoCyt/uCyt+ assay. RESULTS: ImmunoCyt/uCyt+ and cytology in combination showed a sensitivity of 62.30%, a specificity of 92.60%, a negative predictive value of 99.90%, and a positive predictive value of 2.96%. Fourteen cases of bladder cancer were detected, and the standardized incidence ratio of bladder cancer was 1.18 (95% confidence interval, 0.65 to 1.99). Individuals who tested positive on either test who were later determined to be cancer free had undergone expensive and invasive tests. CONCLUSIONS: Evidence to support continued surveillance of this cohort has not been demonstrated.

Does tinnitus, hearing asymmetry, or hearing loss predispose to occupational injury risk?

OBJECTIVE: To determine the relative contributions of tinnitus, asymmetrical hearing loss, low frequency hearing loss (pure tone average of 0.5, 1, 2, 3 kHz; PTA.5123), or high frequency hearing loss (pure tone average of 4, 6 kHz; PTA46), to acute injury risk among a cohort of production and maintenance workers at six aluminum manufacturing plants, adjusting for ambient noise exposure and other recognized predictors of injury risk. DESIGN: Retrospective analysis. STUDY SAMPLE: The study considered 9920 workers employed during 2003 to 2008. The cohort consisted of 8818 workers (89%) whose complete records were available. RESULTS: Adjusting for noise exposure and other recognized injury predictors, a 25% increased acute injury risk was observed among workers with a history of tinnitus in conjunction with high-frequency hearing loss (PTA46). Low frequency hearing loss may be associated with minor, yet less serious, injury risk. We did not find evidence that asymmetry contributes to injury risk. CONCLUSION: These results provide evidence that tinnitus, combined with high-frequency hearing loss, may pose an important safety threat to workers, especially those who work in high-noise exposed environments. These at risk workers may require careful examination of their communication and hearing protection needs.

Quality of Life in Patients with Noninfectious Uveitis Treated with or without Systemic Anti-inflammatory Therapy.

PURPOSE: To compare vision-related (VR-QOL) and health-related quality of life (HR-QOL) in patients with noninfectious uveitis treated with systemic anti-inflammatory therapy versus nonsystemic therapy. METHODS: A prospective, cross-sectional study design was employed. VR-QOL and HR-QOL were assessed by the 25-Item Visual Function Questionnaire (VFQ-25) and the Short Form 12-Item Health Survey (SF-12), respectively. Multivariate regression analysis was performed to assess the VR-QOL and HR-QOL based on treatment. RESULTS: Among the 80 patients, the median age was 51 years with 28 males (35%). The adjusted effect of treatment modality on VR-QOL or HR-QOL showed no statistically significant difference in all subscores of VFQ-25 or physical component score (PCS) and mental component score (MCS) of SF-12. Systemic therapy did not compromise VR-QOL or HR-QOL compared to nonsystemic therapy. CONCLUSIONS: Systemic therapy can be effectively used to control serious cases of noninfectious uveitis without significant relative adverse impact on quality of life.

Acoustic neuroma: potential risk factors and audiometric surveillance in the aluminium industry.

OBJECTIVES: To look for an association between acoustic neuroma (AN) and participation in a hearing conservation programme (HCP) and also for an association between AN and possible occupational risk factors in the aluminium industry. METHODS: We conducted a case-control analysis of a population of US aluminium production workers in 8 smelters and 43 other plants. Using insurance claims data, 97 cases of AN were identified between 1996 and 2009. Each was matched with four controls. Covariates included participation in a HCP, working in an aluminium smelter, working in an electrical job and hearing loss. RESULTS: In the bivariate analyses, covariates associated with AN were participation in the HCP (OR=1.72; 95% CI 1.09 to 2.69) and smelter work (OR=1.88; 95% CI 1.06 to 3.36). Electrical work was not significant (OR=1.60; 95% CI 0.65 to 3.94). Owing to high participation in the HCP in smelters, multivariate subanalyses were required. In the multivariate analyses, participation in the HCP was the only statistically significant risk factor for AN. In the multivariate analysis restricted to employees not working in a smelter, the OR was 1.81 (95% CI 1.04 to 3.17). Hearing loss, an indirect measure of in-ear noise dose, was not predictive of AN. CONCLUSIONS: Our results suggest the incidental detection of previously undiagnosed tumours in workers who participated in the company-sponsored HCP. The increased medical surveillance among this population of workers most likely introduced detection bias, leading to the identification of AN cases that would have otherwise remained undetected.

Occupational injury risk by sex in a manufacturing cohort.

OBJECTIVES: This study expands previous research comparing injury risk for women and men in a cohort of 24,000 US aluminium manufacturing workers in 15 facilities from 2001 to 2010. METHODS: We compared injury rates (all injury, first aid, medical treatment, restricted work and lost work time) by sex and by job and sex. Using a mixed effect modelling approach, we calculated ORs and 95% CIs adjusting for age, job tenure, ethnicity and year as fixed effects and person, job and plant as random effects. Additionally, we modelled the data stratified by plant type to examine potential differences in injury risk between smelter (generally recognised as more hazardous) and fabrication production environments. RESULTS: Risk of injury was higher for women in four out of the five injury outcomes: all injuries combined (OR: 1.58, CI 1.48 to 1.67), injuries requiring first aid (OR: 1.61, CI 1.54 to 1.70), injuries requiring medical treatment (OR: 1.18, CI 1.03 to 1.36) and injuries requiring restricted work (OR: 1.65, CI 1.46 to 1.87). No difference in the risk of lost time injury by sex was found in this cohort. Analyses stratified by plant type showed similarly elevated injury risk for women, although the risk estimates were higher in smelters than fabrication plants. CONCLUSIONS: To our knowledge, this is the largest single-firm study examining injury risk by sex with sufficient data to appropriately adjust for job. We show a consistently higher injury risk for women compared with men in the smelting and fabrication environments.

Effect of systematic ergonomic hazard identification and control implementation on musculoskeletal disorder and injury risk.

OBJECTIVES: This study aimed to examine the effect of an ergonomic hazard control (HC) initiative, undertaken as part of a company ergonomics standard, on worker injury risk. METHODS: Using the company's ergonomic hazards database to identify jobs with and without ergonomic HC implementation and linking to individual job and injury histories, injury risk among person-jobs with HC implementation (the HC group) was compared to those without HC (NoHC group) using random coefficient models. Further analysis of the HC group was conducted to determine the effect of additional ergonomic hazards controlled on injury risk. RESULTS: Among 123 jobs at 17 plant locations, 347 ergonomic hazards were quantitatively identified during the study period. HC were implemented for 204 quantified ergonomic hazards in 84 jobs, impacting 10 385 persons (12 967 person-jobs). No HC were implemented for quantified ergonomic hazards in the remaining 39 jobs affecting 4155 persons (5046 person-jobs). Adjusting for age, sex, plant origin, and year to control for any temporal trend in injury risk, the relative risk (RR) for musculoskeletal disorder (MSD) was 0.85 and the RR for any injury or MSD was 0.92 in the HC compared to NoHC group. Among the HC group, each ergonomic hazard controlled was associated with risk reduction for MSD and acute injury outcomes (RR 0.93). CONCLUSION: Systematic ergonomic HC through participatory ergonomics, as part of a mandatory company ergonomics standard, is associated with MSD and injury risk reduction among workers in jobs with HC implemented.

Contribution of health status and prevalent chronic disease to individual risk for workplace injury in the manufacturing environment.

OBJECTIVES: An 'information gap' has been identified regarding the effects of chronic disease on occupational injury risk. We investigated the association of ischaemic heart disease, hypertension, diabetes, depression and asthma with acute occupational injury in a cohort of manufacturing workers from 1 January 1997 through 31 December 2007. METHODS: We used administrative data on real-time injury, medical claims, workplace characteristics and demographics to examine this association. We employed a piecewise exponential model within an Andersen-Gill framework with a frailty term at the employee level to account for inclusion of multiple injuries for each employee, random effects at the employee level due to correlation among jobs held by an employee, and experience on the job as a covariate. RESULTS: One-third of employees had at least one of the diseases during the study period. After adjusting for potential confounders, presence of these diseases was associated with increased hazard of injury: heart disease (HR 1.23, 95% CI 1.11 to 1.36), diabetes (HR 1.17, 95% CI 1.08 to 1.27), depression (HR 1.25, 95% CI 1.12 to 1.38) and asthma (HR 1.14, 95% CI 1.02 to 1.287). Hypertension was not significantly associated with hazard of injury. Associations of chronic disease with injury risk were less evident for more serious reportable injuries; only depression and a summary health metric derived from claims remained significantly positive in this subset. CONCLUSIONS: Our results suggest that chronic heart disease, diabetes and depression confer an increased risk for acute occupational injury.

Development of a job-exposure matrix for exposure to total and fine particulate matter in the aluminum industry.

Increasing evidence indicates that exposure to particulate matter (PM) at environmental concentrations increases the risk of cardiovascular disease, particularly PM with an aerodynamic diameter of less than 2.5 µm (PM(2.5)). Despite this, the health impacts of higher occupational exposures to PM(2.5) have rarely been evaluated. In part, this research gap derives from the absence of information on PM(2.5) exposures in the workplace. To address this gap, we have developed a job-exposure matrix (JEM) to estimate exposure to two size fractions of PM in the aluminum industry. Measurements of total PM (TPM) and PM(2.5) were used to develop exposure metrics for an epidemiologic study. TPM exposures for distinct exposure groups (DEGs) in the JEM were calculated using 8385 personal TPM samples collected at 11 facilities (1980-2011). For eight of these facilities, simultaneous PM(2.5) and TPM personal monitoring was conducted from 2010 to 2011 to determine the percent of TPM that is composed of PM(2.5) (%PM(2.5)) in each DEG. The mean TPM from the JEM was then multiplied by %PM(2.5) to calculate PM(2.5) exposure concentrations in each DEG. Exposures in the smelters were substantially higher than in fabrication units; mean TPM concentrations in smelters and fabrication facilities were 3.86 and 0.76 mg/m(3), and the corresponding mean PM(2.5) concentrations were 2.03 and 0.40 mg/m(3). Observed occupational exposures in this study generally exceeded environmental PM(2.5) concentrations by an order of magnitude.

Incident ischemic heart disease and recent occupational exposure to particulate matter in an aluminum cohort.

Fine particulate matter (PM(2.5)) in air pollution, primarily from combustion sources, is recognized as an important risk factor for cardiovascular events but studies of workplace PM(2.5) exposure are rare. We conducted a prospective study of exposure to PM(2.5) and incidence of ischemic heart disease (IHD) in a cohort of 11,966 US aluminum workers. Incident IHD was identified from medical claims data from 1998 to 2008. Quantitative metrics were developed for recent exposure (within the last year) and cumulative exposure; however, we emphasize recent exposure in the absence of interpretable work histories before follow-up. IHD was modestly associated with recent PM(2.5) overall. In analysis restricted to recent exposures estimated with the highest confidence, the hazard ratio (HR) increased to 1.78 (95% CI: 1.02, 3.11) in the second quartile and remained elevated. When the analysis was stratified by work process, the HR rose monotonically to 1.5 in both smelter and fabrication facilities, though exposure was almost an order of magnitude higher in smelters. The differential exposure-response may be due to differences in exposure composition or healthy worker survivor effect. These results are consistent with the air pollution and cigarette smoke literature; recent exposure to PM(2.5) in the workplace appears to increase the risk of IHD incidence.

Piecewise exponential models to assess the influence of job-specific experience on the hazard of acute injury for hourly factory workers.

BACKGROUND: An inverse relationship between experience and risk of injury has been observed in many occupations. Due to statistical challenges, however, it has been difficult to characterize the role of experience on the hazard of injury. In particular, because the time observed up to injury is equivalent to the amount of experience accumulated, the baseline hazard of injury becomes the main parameter of interest, excluding Cox proportional hazards models as applicable methods for consideration. METHODS: Using a data set of 81,301 hourly production workers of a global aluminum company at 207 US facilities, we compared competing parametric models for the baseline hazard to assess whether experience affected the hazard of injury at hire and after later job changes. Specific models considered included the exponential, Weibull, and two (a hypothesis-driven and a data-driven) two-piece exponential models to formally test the null hypothesis that experience does not impact the hazard of injury. RESULTS: We highlighted the advantages of our comparative approach and the interpretability of our selected model: a two-piece exponential model that allowed the baseline hazard of injury to change with experience. Our findings suggested a 30% increase in the hazard in the first year after job initiation and/or change. CONCLUSIONS: Piecewise exponential models may be particularly useful in modeling risk of injury as a function of experience and have the additional benefit of interpretability over other similarly flexible models.